diff --git a/Documentation/js_licenses.txt b/Documentation/js_licenses.txt
index e14df57..9ac438a 100644
--- a/Documentation/js_licenses.txt
+++ b/Documentation/js_licenses.txt
@@ -1464,219 +1464,6 @@
 ----
 
 
-[[shadow-selection-polyfill]]
-shadow-selection-polyfill
-
-* shadow-selection-polyfill
-
-[[shadow-selection-polyfill_license]]
-----
-
-                                 Apache License
-                           Version 2.0, January 2004
-                        http://www.apache.org/licenses/
-
-   TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION
-
-   1. Definitions.
-
-      "License" shall mean the terms and conditions for use, reproduction,
-      and distribution as defined by Sections 1 through 9 of this document.
-
-      "Licensor" shall mean the copyright owner or entity authorized by
-      the copyright owner that is granting the License.
-
-      "Legal Entity" shall mean the union of the acting entity and all
-      other entities that control, are controlled by, or are under common
-      control with that entity. For the purposes of this definition,
-      "control" means (i) the power, direct or indirect, to cause the
-      direction or management of such entity, whether by contract or
-      otherwise, or (ii) ownership of fifty percent (50%) or more of the
-      outstanding shares, or (iii) beneficial ownership of such entity.
-
-      "You" (or "Your") shall mean an individual or Legal Entity
-      exercising permissions granted by this License.
-
-      "Source" form shall mean the preferred form for making modifications,
-      including but not limited to software source code, documentation
-      source, and configuration files.
-
-      "Object" form shall mean any form resulting from mechanical
-      transformation or translation of a Source form, including but
-      not limited to compiled object code, generated documentation,
-      and conversions to other media types.
-
-      "Work" shall mean the work of authorship, whether in Source or
-      Object form, made available under the License, as indicated by a
-      copyright notice that is included in or attached to the work
-      (an example is provided in the Appendix below).
-
-      "Derivative Works" shall mean any work, whether in Source or Object
-      form, that is based on (or derived from) the Work and for which the
-      editorial revisions, annotations, elaborations, or other modifications
-      represent, as a whole, an original work of authorship. For the purposes
-      of this License, Derivative Works shall not include works that remain
-      separable from, or merely link (or bind by name) to the interfaces of,
-      the Work and Derivative Works thereof.
-
-      "Contribution" shall mean any work of authorship, including
-      the original version of the Work and any modifications or additions
-      to that Work or Derivative Works thereof, that is intentionally
-      submitted to Licensor for inclusion in the Work by the copyright owner
-      or by an individual or Legal Entity authorized to submit on behalf of
-      the copyright owner. For the purposes of this definition, "submitted"
-      means any form of electronic, verbal, or written communication sent
-      to the Licensor or its representatives, including but not limited to
-      communication on electronic mailing lists, source code control systems,
-      and issue tracking systems that are managed by, or on behalf of, the
-      Licensor for the purpose of discussing and improving the Work, but
-      excluding communication that is conspicuously marked or otherwise
-      designated in writing by the copyright owner as "Not a Contribution."
-
-      "Contributor" shall mean Licensor and any individual or Legal Entity
-      on behalf of whom a Contribution has been received by Licensor and
-      subsequently incorporated within the Work.
-
-   2. Grant of Copyright License. Subject to the terms and conditions of
-      this License, each Contributor hereby grants to You a perpetual,
-      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
-      copyright license to reproduce, prepare Derivative Works of,
-      publicly display, publicly perform, sublicense, and distribute the
-      Work and such Derivative Works in Source or Object form.
-
-   3. Grant of Patent License. Subject to the terms and conditions of
-      this License, each Contributor hereby grants to You a perpetual,
-      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
-      (except as stated in this section) patent license to make, have made,
-      use, offer to sell, sell, import, and otherwise transfer the Work,
-      where such license applies only to those patent claims licensable
-      by such Contributor that are necessarily infringed by their
-      Contribution(s) alone or by combination of their Contribution(s)
-      with the Work to which such Contribution(s) was submitted. If You
-      institute patent litigation against any entity (including a
-      cross-claim or counterclaim in a lawsuit) alleging that the Work
-      or a Contribution incorporated within the Work constitutes direct
-      or contributory patent infringement, then any patent licenses
-      granted to You under this License for that Work shall terminate
-      as of the date such litigation is filed.
-
-   4. Redistribution. You may reproduce and distribute copies of the
-      Work or Derivative Works thereof in any medium, with or without
-      modifications, and in Source or Object form, provided that You
-      meet the following conditions:
-
-      (a) You must give any other recipients of the Work or
-          Derivative Works a copy of this License; and
-
-      (b) You must cause any modified files to carry prominent notices
-          stating that You changed the files; and
-
-      (c) You must retain, in the Source form of any Derivative Works
-          that You distribute, all copyright, patent, trademark, and
-          attribution notices from the Source form of the Work,
-          excluding those notices that do not pertain to any part of
-          the Derivative Works; and
-
-      (d) If the Work includes a "NOTICE" text file as part of its
-          distribution, then any Derivative Works that You distribute must
-          include a readable copy of the attribution notices contained
-          within such NOTICE file, excluding those notices that do not
-          pertain to any part of the Derivative Works, in at least one
-          of the following places: within a NOTICE text file distributed
-          as part of the Derivative Works; within the Source form or
-          documentation, if provided along with the Derivative Works; or,
-          within a display generated by the Derivative Works, if and
-          wherever such third-party notices normally appear. The contents
-          of the NOTICE file are for informational purposes only and
-          do not modify the License. You may add Your own attribution
-          notices within Derivative Works that You distribute, alongside
-          or as an addendum to the NOTICE text from the Work, provided
-          that such additional attribution notices cannot be construed
-          as modifying the License.
-
-      You may add Your own copyright statement to Your modifications and
-      may provide additional or different license terms and conditions
-      for use, reproduction, or distribution of Your modifications, or
-      for any such Derivative Works as a whole, provided Your use,
-      reproduction, and distribution of the Work otherwise complies with
-      the conditions stated in this License.
-
-   5. Submission of Contributions. Unless You explicitly state otherwise,
-      any Contribution intentionally submitted for inclusion in the Work
-      by You to the Licensor shall be under the terms and conditions of
-      this License, without any additional terms or conditions.
-      Notwithstanding the above, nothing herein shall supersede or modify
-      the terms of any separate license agreement you may have executed
-      with Licensor regarding such Contributions.
-
-   6. Trademarks. This License does not grant permission to use the trade
-      names, trademarks, service marks, or product names of the Licensor,
-      except as required for reasonable and customary use in describing the
-      origin of the Work and reproducing the content of the NOTICE file.
-
-   7. Disclaimer of Warranty. Unless required by applicable law or
-      agreed to in writing, Licensor provides the Work (and each
-      Contributor provides its Contributions) on an "AS IS" BASIS,
-      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
-      implied, including, without limitation, any warranties or conditions
-      of TITLE, NON-INFRINGEMENT, MERCHANTABILITY, or FITNESS FOR A
-      PARTICULAR PURPOSE. You are solely responsible for determining the
-      appropriateness of using or redistributing the Work and assume any
-      risks associated with Your exercise of permissions under this License.
-
-   8. Limitation of Liability. In no event and under no legal theory,
-      whether in tort (including negligence), contract, or otherwise,
-      unless required by applicable law (such as deliberate and grossly
-      negligent acts) or agreed to in writing, shall any Contributor be
-      liable to You for damages, including any direct, indirect, special,
-      incidental, or consequential damages of any character arising as a
-      result of this License or out of the use or inability to use the
-      Work (including but not limited to damages for loss of goodwill,
-      work stoppage, computer failure or malfunction, or any and all
-      other commercial damages or losses), even if such Contributor
-      has been advised of the possibility of such damages.
-
-   9. Accepting Warranty or Additional Liability. While redistributing
-      the Work or Derivative Works thereof, You may choose to offer,
-      and charge a fee for, acceptance of support, warranty, indemnity,
-      or other liability obligations and/or rights consistent with this
-      License. However, in accepting such obligations, You may act only
-      on Your own behalf and on Your sole responsibility, not on behalf
-      of any other Contributor, and only if You agree to indemnify,
-      defend, and hold each Contributor harmless for any liability
-      incurred by, or claims asserted against, such Contributor by reason
-      of your accepting any such warranty or additional liability.
-
-   END OF TERMS AND CONDITIONS
-
-   APPENDIX: How to apply the Apache License to your work.
-
-      To apply the Apache License to your work, attach the following
-      boilerplate notice, with the fields enclosed by brackets "[]"
-      replaced with your own identifying information. (Don't include
-      the brackets!)  The text should be enclosed in the appropriate
-      comment syntax for the file format. We also recommend that a
-      file or class name and description of purpose be included on the
-      same "printed page" as the copyright notice for easier
-      identification within third-party archives.
-
-   Copyright [yyyy] [name of copyright owner]
-
-   Licensed under the Apache License, Version 2.0 (the "License");
-   you may not use this file except in compliance with the License.
-   You may obtain a copy of the License at
-
-       http://www.apache.org/licenses/LICENSE-2.0
-
-   Unless required by applicable law or agreed to in writing, software
-   distributed under the License is distributed on an "AS IS" BASIS,
-   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-   See the License for the specific language governing permissions and
-   limitations under the License.
-
-----
-
-
 [[tslib]]
 tslib
 
diff --git a/Documentation/licenses.txt b/Documentation/licenses.txt
index 1d96189..1bff25c 100644
--- a/Documentation/licenses.txt
+++ b/Documentation/licenses.txt
@@ -4423,219 +4423,6 @@
 ----
 
 
-[[shadow-selection-polyfill]]
-shadow-selection-polyfill
-
-* shadow-selection-polyfill
-
-[[shadow-selection-polyfill_license]]
-----
-
-                                 Apache License
-                           Version 2.0, January 2004
-                        http://www.apache.org/licenses/
-
-   TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION
-
-   1. Definitions.
-
-      "License" shall mean the terms and conditions for use, reproduction,
-      and distribution as defined by Sections 1 through 9 of this document.
-
-      "Licensor" shall mean the copyright owner or entity authorized by
-      the copyright owner that is granting the License.
-
-      "Legal Entity" shall mean the union of the acting entity and all
-      other entities that control, are controlled by, or are under common
-      control with that entity. For the purposes of this definition,
-      "control" means (i) the power, direct or indirect, to cause the
-      direction or management of such entity, whether by contract or
-      otherwise, or (ii) ownership of fifty percent (50%) or more of the
-      outstanding shares, or (iii) beneficial ownership of such entity.
-
-      "You" (or "Your") shall mean an individual or Legal Entity
-      exercising permissions granted by this License.
-
-      "Source" form shall mean the preferred form for making modifications,
-      including but not limited to software source code, documentation
-      source, and configuration files.
-
-      "Object" form shall mean any form resulting from mechanical
-      transformation or translation of a Source form, including but
-      not limited to compiled object code, generated documentation,
-      and conversions to other media types.
-
-      "Work" shall mean the work of authorship, whether in Source or
-      Object form, made available under the License, as indicated by a
-      copyright notice that is included in or attached to the work
-      (an example is provided in the Appendix below).
-
-      "Derivative Works" shall mean any work, whether in Source or Object
-      form, that is based on (or derived from) the Work and for which the
-      editorial revisions, annotations, elaborations, or other modifications
-      represent, as a whole, an original work of authorship. For the purposes
-      of this License, Derivative Works shall not include works that remain
-      separable from, or merely link (or bind by name) to the interfaces of,
-      the Work and Derivative Works thereof.
-
-      "Contribution" shall mean any work of authorship, including
-      the original version of the Work and any modifications or additions
-      to that Work or Derivative Works thereof, that is intentionally
-      submitted to Licensor for inclusion in the Work by the copyright owner
-      or by an individual or Legal Entity authorized to submit on behalf of
-      the copyright owner. For the purposes of this definition, "submitted"
-      means any form of electronic, verbal, or written communication sent
-      to the Licensor or its representatives, including but not limited to
-      communication on electronic mailing lists, source code control systems,
-      and issue tracking systems that are managed by, or on behalf of, the
-      Licensor for the purpose of discussing and improving the Work, but
-      excluding communication that is conspicuously marked or otherwise
-      designated in writing by the copyright owner as "Not a Contribution."
-
-      "Contributor" shall mean Licensor and any individual or Legal Entity
-      on behalf of whom a Contribution has been received by Licensor and
-      subsequently incorporated within the Work.
-
-   2. Grant of Copyright License. Subject to the terms and conditions of
-      this License, each Contributor hereby grants to You a perpetual,
-      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
-      copyright license to reproduce, prepare Derivative Works of,
-      publicly display, publicly perform, sublicense, and distribute the
-      Work and such Derivative Works in Source or Object form.
-
-   3. Grant of Patent License. Subject to the terms and conditions of
-      this License, each Contributor hereby grants to You a perpetual,
-      worldwide, non-exclusive, no-charge, royalty-free, irrevocable
-      (except as stated in this section) patent license to make, have made,
-      use, offer to sell, sell, import, and otherwise transfer the Work,
-      where such license applies only to those patent claims licensable
-      by such Contributor that are necessarily infringed by their
-      Contribution(s) alone or by combination of their Contribution(s)
-      with the Work to which such Contribution(s) was submitted. If You
-      institute patent litigation against any entity (including a
-      cross-claim or counterclaim in a lawsuit) alleging that the Work
-      or a Contribution incorporated within the Work constitutes direct
-      or contributory patent infringement, then any patent licenses
-      granted to You under this License for that Work shall terminate
-      as of the date such litigation is filed.
-
-   4. Redistribution. You may reproduce and distribute copies of the
-      Work or Derivative Works thereof in any medium, with or without
-      modifications, and in Source or Object form, provided that You
-      meet the following conditions:
-
-      (a) You must give any other recipients of the Work or
-          Derivative Works a copy of this License; and
-
-      (b) You must cause any modified files to carry prominent notices
-          stating that You changed the files; and
-
-      (c) You must retain, in the Source form of any Derivative Works
-          that You distribute, all copyright, patent, trademark, and
-          attribution notices from the Source form of the Work,
-          excluding those notices that do not pertain to any part of
-          the Derivative Works; and
-
-      (d) If the Work includes a "NOTICE" text file as part of its
-          distribution, then any Derivative Works that You distribute must
-          include a readable copy of the attribution notices contained
-          within such NOTICE file, excluding those notices that do not
-          pertain to any part of the Derivative Works, in at least one
-          of the following places: within a NOTICE text file distributed
-          as part of the Derivative Works; within the Source form or
-          documentation, if provided along with the Derivative Works; or,
-          within a display generated by the Derivative Works, if and
-          wherever such third-party notices normally appear. The contents
-          of the NOTICE file are for informational purposes only and
-          do not modify the License. You may add Your own attribution
-          notices within Derivative Works that You distribute, alongside
-          or as an addendum to the NOTICE text from the Work, provided
-          that such additional attribution notices cannot be construed
-          as modifying the License.
-
-      You may add Your own copyright statement to Your modifications and
-      may provide additional or different license terms and conditions
-      for use, reproduction, or distribution of Your modifications, or
-      for any such Derivative Works as a whole, provided Your use,
-      reproduction, and distribution of the Work otherwise complies with
-      the conditions stated in this License.
-
-   5. Submission of Contributions. Unless You explicitly state otherwise,
-      any Contribution intentionally submitted for inclusion in the Work
-      by You to the Licensor shall be under the terms and conditions of
-      this License, without any additional terms or conditions.
-      Notwithstanding the above, nothing herein shall supersede or modify
-      the terms of any separate license agreement you may have executed
-      with Licensor regarding such Contributions.
-
-   6. Trademarks. This License does not grant permission to use the trade
-      names, trademarks, service marks, or product names of the Licensor,
-      except as required for reasonable and customary use in describing the
-      origin of the Work and reproducing the content of the NOTICE file.
-
-   7. Disclaimer of Warranty. Unless required by applicable law or
-      agreed to in writing, Licensor provides the Work (and each
-      Contributor provides its Contributions) on an "AS IS" BASIS,
-      WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
-      implied, including, without limitation, any warranties or conditions
-      of TITLE, NON-INFRINGEMENT, MERCHANTABILITY, or FITNESS FOR A
-      PARTICULAR PURPOSE. You are solely responsible for determining the
-      appropriateness of using or redistributing the Work and assume any
-      risks associated with Your exercise of permissions under this License.
-
-   8. Limitation of Liability. In no event and under no legal theory,
-      whether in tort (including negligence), contract, or otherwise,
-      unless required by applicable law (such as deliberate and grossly
-      negligent acts) or agreed to in writing, shall any Contributor be
-      liable to You for damages, including any direct, indirect, special,
-      incidental, or consequential damages of any character arising as a
-      result of this License or out of the use or inability to use the
-      Work (including but not limited to damages for loss of goodwill,
-      work stoppage, computer failure or malfunction, or any and all
-      other commercial damages or losses), even if such Contributor
-      has been advised of the possibility of such damages.
-
-   9. Accepting Warranty or Additional Liability. While redistributing
-      the Work or Derivative Works thereof, You may choose to offer,
-      and charge a fee for, acceptance of support, warranty, indemnity,
-      or other liability obligations and/or rights consistent with this
-      License. However, in accepting such obligations, You may act only
-      on Your own behalf and on Your sole responsibility, not on behalf
-      of any other Contributor, and only if You agree to indemnify,
-      defend, and hold each Contributor harmless for any liability
-      incurred by, or claims asserted against, such Contributor by reason
-      of your accepting any such warranty or additional liability.
-
-   END OF TERMS AND CONDITIONS
-
-   APPENDIX: How to apply the Apache License to your work.
-
-      To apply the Apache License to your work, attach the following
-      boilerplate notice, with the fields enclosed by brackets "[]"
-      replaced with your own identifying information. (Don't include
-      the brackets!)  The text should be enclosed in the appropriate
-      comment syntax for the file format. We also recommend that a
-      file or class name and description of purpose be included on the
-      same "printed page" as the copyright notice for easier
-      identification within third-party archives.
-
-   Copyright [yyyy] [name of copyright owner]
-
-   Licensed under the Apache License, Version 2.0 (the "License");
-   you may not use this file except in compliance with the License.
-   You may obtain a copy of the License at
-
-       http://www.apache.org/licenses/LICENSE-2.0
-
-   Unless required by applicable law or agreed to in writing, software
-   distributed under the License is distributed on an "AS IS" BASIS,
-   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-   See the License for the specific language governing permissions and
-   limitations under the License.
-
-----
-
-
 [[tslib]]
 tslib
 
diff --git a/java/com/google/gerrit/elasticsearch/AbstractElasticIndex.java b/java/com/google/gerrit/elasticsearch/AbstractElasticIndex.java
index 44a377a..562464d 100644
--- a/java/com/google/gerrit/elasticsearch/AbstractElasticIndex.java
+++ b/java/com/google/gerrit/elasticsearch/AbstractElasticIndex.java
@@ -90,7 +90,7 @@
   protected static final String SEARCH = "_search";
   protected static final String SETTINGS = "settings";
 
-  protected static byte[] decodeBase64(String base64String) {
+  static byte[] decodeBase64(String base64String) {
     return BaseEncoding.base64().decode(base64String);
   }
 
diff --git a/java/com/google/gerrit/elasticsearch/ElasticChangeIndex.java b/java/com/google/gerrit/elasticsearch/ElasticChangeIndex.java
index 162654d..7d4e0c7 100644
--- a/java/com/google/gerrit/elasticsearch/ElasticChangeIndex.java
+++ b/java/com/google/gerrit/elasticsearch/ElasticChangeIndex.java
@@ -14,55 +14,35 @@
 
 package com.google.gerrit.elasticsearch;
 
-import static java.nio.charset.StandardCharsets.UTF_8;
 import static java.util.Objects.requireNonNull;
 
-import com.google.common.collect.FluentIterable;
-import com.google.common.collect.ImmutableListMultimap;
 import com.google.common.collect.ImmutableSet;
-import com.google.common.collect.Iterables;
-import com.google.common.collect.ListMultimap;
-import com.google.common.collect.MultimapBuilder;
-import com.google.common.collect.Sets;
 import com.google.gerrit.elasticsearch.ElasticMapping.MappingProperties;
 import com.google.gerrit.elasticsearch.bulk.BulkRequest;
 import com.google.gerrit.elasticsearch.bulk.IndexRequest;
 import com.google.gerrit.elasticsearch.bulk.UpdateRequest;
-import com.google.gerrit.entities.Account;
 import com.google.gerrit.entities.Change;
 import com.google.gerrit.entities.Project;
 import com.google.gerrit.entities.converter.ChangeProtoConverter;
-import com.google.gerrit.entities.converter.PatchSetApprovalProtoConverter;
-import com.google.gerrit.entities.converter.PatchSetProtoConverter;
 import com.google.gerrit.exceptions.StorageException;
 import com.google.gerrit.index.FieldDef;
 import com.google.gerrit.index.QueryOptions;
-import com.google.gerrit.index.RefState;
 import com.google.gerrit.index.Schema;
 import com.google.gerrit.index.query.DataSource;
 import com.google.gerrit.index.query.Predicate;
 import com.google.gerrit.index.query.QueryParseException;
-import com.google.gerrit.server.ReviewerByEmailSet;
-import com.google.gerrit.server.ReviewerSet;
-import com.google.gerrit.server.StarredChangesUtil;
 import com.google.gerrit.server.change.MergeabilityComputationBehavior;
 import com.google.gerrit.server.config.GerritServerConfig;
 import com.google.gerrit.server.config.SitePaths;
 import com.google.gerrit.server.index.IndexUtils;
 import com.google.gerrit.server.index.change.ChangeField;
 import com.google.gerrit.server.index.change.ChangeIndex;
-import com.google.gerrit.server.project.SubmitRuleOptions;
 import com.google.gerrit.server.query.change.ChangeData;
 import com.google.gson.JsonArray;
 import com.google.gson.JsonElement;
 import com.google.gson.JsonObject;
 import com.google.inject.Inject;
 import com.google.inject.assistedinject.Assisted;
-import java.sql.Timestamp;
-import java.time.Instant;
-import java.time.format.DateTimeFormatter;
-import java.util.Collections;
-import java.util.Optional;
 import java.util.Set;
 import org.apache.http.HttpStatus;
 import org.eclipse.jgit.lib.Config;
@@ -190,242 +170,12 @@
         changeDataFactory.create(
             parseProtoFrom(decodeBase64(c.getAsString()), ChangeProtoConverter.INSTANCE));
 
-    // Any decoding that is done here must also be done in {@link LuceneChangeIndex}.
-
-    // Patch sets.
-    cd.setPatchSets(
-        decodeProtos(source, ChangeField.PATCH_SET.getName(), PatchSetProtoConverter.INSTANCE));
-
-    // Approvals.
-    if (source.get(ChangeField.APPROVAL.getName()) != null) {
-      cd.setCurrentApprovals(
-          decodeProtos(
-              source, ChangeField.APPROVAL.getName(), PatchSetApprovalProtoConverter.INSTANCE));
-    } else if (fields.contains(ChangeField.APPROVAL.getName())) {
-      cd.setCurrentApprovals(Collections.emptyList());
-    }
-
-    // Added & Deleted.
-    JsonElement addedElement = source.get(ChangeField.ADDED.getName());
-    JsonElement deletedElement = source.get(ChangeField.DELETED.getName());
-    if (addedElement != null && deletedElement != null) {
-      // Changed lines.
-      int added = addedElement.getAsInt();
-      int deleted = deletedElement.getAsInt();
-      cd.setChangedLines(added, deleted);
-    }
-
-    // Star.
-    JsonElement starredElement = source.get(ChangeField.STAR.getName());
-    if (starredElement != null) {
-      ListMultimap<Account.Id, String> stars = MultimapBuilder.hashKeys().arrayListValues().build();
-      JsonArray starBy = starredElement.getAsJsonArray();
-      if (starBy.size() > 0) {
-        for (int i = 0; i < starBy.size(); i++) {
-          String[] indexableFields = starBy.get(i).getAsString().split(":");
-          Optional<Account.Id> id = Account.Id.tryParse(indexableFields[0]);
-          if (id.isPresent()) {
-            stars.put(id.get(), indexableFields[1]);
-          }
-        }
+    for (FieldDef<ChangeData, ?> field : getSchema().getFields().values()) {
+      if (fields.contains(field.getName()) && source.get(field.getName()) != null) {
+        field.setIfPossible(cd, new ElasticStoredValue(source.get(field.getName())));
       }
-      cd.setStars(stars);
-    }
-
-    // Mergeable.
-    JsonElement mergeableElement = source.get(ChangeField.MERGEABLE.getName());
-    if (mergeableElement != null && !skipFields.contains(ChangeField.MERGEABLE.getName())) {
-      String mergeable = mergeableElement.getAsString();
-      if ("1".equals(mergeable)) {
-        cd.setMergeable(true);
-      } else if ("0".equals(mergeable)) {
-        cd.setMergeable(false);
-      }
-    }
-
-    // Reviewed-by.
-    if (source.get(ChangeField.REVIEWEDBY.getName()) != null) {
-      JsonArray reviewedBy = source.get(ChangeField.REVIEWEDBY.getName()).getAsJsonArray();
-      if (reviewedBy.size() > 0) {
-        Set<Account.Id> accounts = Sets.newHashSetWithExpectedSize(reviewedBy.size());
-        for (int i = 0; i < reviewedBy.size(); i++) {
-          int aId = reviewedBy.get(i).getAsInt();
-          if (reviewedBy.size() == 1 && aId == ChangeField.NOT_REVIEWED) {
-            break;
-          }
-          accounts.add(Account.id(aId));
-        }
-        cd.setReviewedBy(accounts);
-      }
-    } else if (fields.contains(ChangeField.REVIEWEDBY.getName())) {
-      cd.setReviewedBy(Collections.emptySet());
-    }
-
-    // Hashtag.
-    if (source.get(ChangeField.HASHTAG.getName()) != null) {
-      JsonArray hashtagArray = source.get(ChangeField.HASHTAG.getName()).getAsJsonArray();
-      if (hashtagArray.size() > 0) {
-        Set<String> hashtags = Sets.newHashSetWithExpectedSize(hashtagArray.size());
-        for (int i = 0; i < hashtagArray.size(); i++) {
-          hashtags.add(hashtagArray.get(i).getAsString());
-        }
-        cd.setHashtags(hashtags);
-      }
-    } else if (fields.contains(ChangeField.HASHTAG.getName())) {
-      cd.setHashtags(Collections.emptySet());
-    }
-
-    // Star.
-    if (source.get(ChangeField.STAR.getName()) != null) {
-      JsonArray starArray = source.get(ChangeField.STAR.getName()).getAsJsonArray();
-      if (starArray.size() > 0) {
-        ListMultimap<Account.Id, String> stars =
-            MultimapBuilder.hashKeys().arrayListValues().build();
-        for (int i = 0; i < starArray.size(); i++) {
-          StarredChangesUtil.StarField starField =
-              StarredChangesUtil.StarField.parse(starArray.get(i).getAsString());
-          stars.put(starField.accountId(), starField.label());
-        }
-        cd.setStars(stars);
-      }
-    } else if (fields.contains(ChangeField.STAR.getName())) {
-      cd.setStars(ImmutableListMultimap.of());
-    }
-
-    // Reviewer.
-    if (source.get(ChangeField.REVIEWER.getName()) != null) {
-      cd.setReviewers(
-          ChangeField.parseReviewerFieldValues(
-              cd.getId(),
-              FluentIterable.from(source.get(ChangeField.REVIEWER.getName()).getAsJsonArray())
-                  .transform(JsonElement::getAsString)));
-    } else if (fields.contains(ChangeField.REVIEWER.getName())) {
-      cd.setReviewers(ReviewerSet.empty());
-    }
-
-    // Reviewer-by-email.
-    if (source.get(ChangeField.REVIEWER_BY_EMAIL.getName()) != null) {
-      cd.setReviewersByEmail(
-          ChangeField.parseReviewerByEmailFieldValues(
-              cd.getId(),
-              FluentIterable.from(
-                      source.get(ChangeField.REVIEWER_BY_EMAIL.getName()).getAsJsonArray())
-                  .transform(JsonElement::getAsString)));
-    } else if (fields.contains(ChangeField.REVIEWER_BY_EMAIL.getName())) {
-      cd.setReviewersByEmail(ReviewerByEmailSet.empty());
-    }
-
-    // Pending-reviewer.
-    if (source.get(ChangeField.PENDING_REVIEWER.getName()) != null) {
-      cd.setPendingReviewers(
-          ChangeField.parseReviewerFieldValues(
-              cd.getId(),
-              FluentIterable.from(
-                      source.get(ChangeField.PENDING_REVIEWER.getName()).getAsJsonArray())
-                  .transform(JsonElement::getAsString)));
-    } else if (fields.contains(ChangeField.PENDING_REVIEWER.getName())) {
-      cd.setPendingReviewers(ReviewerSet.empty());
-    }
-
-    // Pending-reviewer-by-email.
-    if (source.get(ChangeField.PENDING_REVIEWER_BY_EMAIL.getName()) != null) {
-      cd.setPendingReviewersByEmail(
-          ChangeField.parseReviewerByEmailFieldValues(
-              cd.getId(),
-              FluentIterable.from(
-                      source.get(ChangeField.PENDING_REVIEWER_BY_EMAIL.getName()).getAsJsonArray())
-                  .transform(JsonElement::getAsString)));
-    } else if (fields.contains(ChangeField.PENDING_REVIEWER_BY_EMAIL.getName())) {
-      cd.setPendingReviewersByEmail(ReviewerByEmailSet.empty());
-    }
-
-    // Stored-submit-record-strict.
-    decodeSubmitRecords(
-        source,
-        ChangeField.STORED_SUBMIT_RECORD_STRICT.getName(),
-        ChangeField.SUBMIT_RULE_OPTIONS_STRICT,
-        cd);
-
-    // Stored-submit-record-lenient.
-    decodeSubmitRecords(
-        source,
-        ChangeField.STORED_SUBMIT_RECORD_LENIENT.getName(),
-        ChangeField.SUBMIT_RULE_OPTIONS_LENIENT,
-        cd);
-
-    // Ref-state.
-    if (fields.contains(ChangeField.REF_STATE.getName())) {
-      cd.setRefStates(RefState.parseStates(getByteArray(source, ChangeField.REF_STATE.getName())));
-    }
-
-    // Ref-state-pattern.
-    if (fields.contains(ChangeField.REF_STATE_PATTERN.getName())) {
-      cd.setRefStatePatterns(getByteArray(source, ChangeField.REF_STATE_PATTERN.getName()));
-    }
-
-    // Unresolved-comment-count.
-    decodeUnresolvedCommentCount(source, ChangeField.UNRESOLVED_COMMENT_COUNT.getName(), cd);
-
-    // Attention set.
-    if (fields.contains(ChangeField.ATTENTION_SET_FULL.getName())) {
-      ChangeField.parseAttentionSet(
-          FluentIterable.from(source.getAsJsonArray(ChangeField.ATTENTION_SET_FULL.getName()))
-              .transform(ElasticChangeIndex::decodeBase64JsonElement)
-              .toSet(),
-          cd);
-    }
-
-    if (fields.contains(ChangeField.MERGED_ON.getName())) {
-      decodeMergedOn(source, cd);
     }
 
     return cd;
   }
-
-  private Iterable<byte[]> getByteArray(JsonObject source, String name) {
-    JsonElement element = source.get(name);
-    return element != null
-        ? Iterables.transform(element.getAsJsonArray(), e -> decodeBase64(e.getAsString()))
-        : Collections.emptyList();
-  }
-
-  private void decodeSubmitRecords(
-      JsonObject doc, String fieldName, SubmitRuleOptions opts, ChangeData out) {
-    JsonArray records = doc.getAsJsonArray(fieldName);
-    if (records == null) {
-      return;
-    }
-    ChangeField.parseSubmitRecords(
-        FluentIterable.from(records)
-            .transform(ElasticChangeIndex::decodeBase64JsonElement)
-            .toList(),
-        opts,
-        out);
-  }
-
-  private static String decodeBase64JsonElement(JsonElement input) {
-    return new String(decodeBase64(input.getAsString()), UTF_8);
-  }
-
-  private void decodeUnresolvedCommentCount(JsonObject doc, String fieldName, ChangeData out) {
-    JsonElement count = doc.get(fieldName);
-    if (count == null) {
-      return;
-    }
-    out.setUnresolvedCommentCount(count.getAsInt());
-  }
-
-  private void decodeMergedOn(JsonObject doc, ChangeData out) {
-    JsonElement mergedOnField = doc.get(ChangeField.MERGED_ON.getName());
-
-    Timestamp mergedOn = null;
-    if (mergedOnField != null) {
-      // Parse from ElasticMapping.TIMESTAMP_FIELD_FORMAT.
-      // We currently use built-in ISO-based dateOptionalTime.
-      // https://www.elastic.co/guide/en/elasticsearch/reference/current/mapping-date-format.html#built-in-date-formats
-      DateTimeFormatter isoFormatter = DateTimeFormatter.ISO_INSTANT;
-      mergedOn = Timestamp.from(Instant.from(isoFormatter.parse(mergedOnField.getAsString())));
-    }
-    out.setMergedOn(mergedOn);
-  }
 }
diff --git a/java/com/google/gerrit/elasticsearch/ElasticStoredValue.java b/java/com/google/gerrit/elasticsearch/ElasticStoredValue.java
new file mode 100644
index 0000000..a02a715
--- /dev/null
+++ b/java/com/google/gerrit/elasticsearch/ElasticStoredValue.java
@@ -0,0 +1,86 @@
+// Copyright (C) 2021 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package com.google.gerrit.elasticsearch;
+
+import static com.google.common.collect.ImmutableList.toImmutableList;
+
+import com.google.gerrit.index.StoredValue;
+import com.google.gson.JsonElement;
+import java.sql.Timestamp;
+import java.time.Instant;
+import java.time.format.DateTimeFormatter;
+import java.util.stream.StreamSupport;
+
+/** Bridge to recover fields from the elastic index. */
+public class ElasticStoredValue implements StoredValue {
+  private final JsonElement field;
+
+  ElasticStoredValue(JsonElement field) {
+    this.field = field;
+  }
+
+  @Override
+  public String asString() {
+    return field.getAsString();
+  }
+
+  @Override
+  public Iterable<String> asStrings() {
+    return StreamSupport.stream(field.getAsJsonArray().spliterator(), false)
+        .map(f -> f.getAsString())
+        .collect(toImmutableList());
+  }
+
+  @Override
+  public Integer asInteger() {
+    return field.getAsInt();
+  }
+
+  @Override
+  public Iterable<Integer> asIntegers() {
+    return StreamSupport.stream(field.getAsJsonArray().spliterator(), false)
+        .map(f -> f.getAsInt())
+        .collect(toImmutableList());
+  }
+
+  @Override
+  public Long asLong() {
+    return field.getAsLong();
+  }
+
+  @Override
+  public Iterable<Long> asLongs() {
+    return StreamSupport.stream(field.getAsJsonArray().spliterator(), false)
+        .map(f -> f.getAsLong())
+        .collect(toImmutableList());
+  }
+
+  @Override
+  public Timestamp asTimestamp() {
+    return Timestamp.from(Instant.from(DateTimeFormatter.ISO_INSTANT.parse(field.getAsString())));
+  }
+
+  @Override
+  public byte[] asByteArray() {
+    return AbstractElasticIndex.decodeBase64(field.getAsString());
+  }
+
+  @Override
+  public Iterable<byte[]> asByteArrays() {
+    return StreamSupport.stream(field.getAsJsonArray().spliterator(), false)
+        .map(f -> AbstractElasticIndex.decodeBase64(f.getAsString()))
+        .collect(toImmutableList());
+  }
+}
diff --git a/java/com/google/gerrit/elasticsearch/ElasticVersion.java b/java/com/google/gerrit/elasticsearch/ElasticVersion.java
index 5e72780..6ca51fa 100644
--- a/java/com/google/gerrit/elasticsearch/ElasticVersion.java
+++ b/java/com/google/gerrit/elasticsearch/ElasticVersion.java
@@ -18,7 +18,6 @@
 import java.util.regex.Pattern;
 
 public enum ElasticVersion {
-  V7_4("7.4.*"),
   V7_5("7.5.*"),
   V7_6("7.6.*"),
   V7_7("7.7.*"),
diff --git a/java/com/google/gerrit/entities/PatchSet.java b/java/com/google/gerrit/entities/PatchSet.java
index 5c8f7eb..b26e5c3 100644
--- a/java/com/google/gerrit/entities/PatchSet.java
+++ b/java/com/google/gerrit/entities/PatchSet.java
@@ -93,6 +93,12 @@
       return PatchSet.id(Change.id(changeId), patchSetId);
     }
 
+    /** Parse a PatchSet.Id from an edit ref. */
+    public static PatchSet.Id fromEditRef(String ref) {
+      Change.Id changeId = Change.Id.fromEditRefPart(ref);
+      return PatchSet.id(changeId, Ints.tryParse(ref.substring(ref.lastIndexOf('/') + 1)));
+    }
+
     static int fromRef(String ref, int changeIdEnd) {
       // Patch set ID.
       int ps = changeIdEnd + 1;
diff --git a/java/com/google/gerrit/index/FieldDef.java b/java/com/google/gerrit/index/FieldDef.java
index 63f6887..eb64c1d 100644
--- a/java/com/google/gerrit/index/FieldDef.java
+++ b/java/com/google/gerrit/index/FieldDef.java
@@ -15,6 +15,7 @@
 package com.google.gerrit.index;
 
 import static com.google.common.base.Preconditions.checkArgument;
+import static com.google.common.base.Preconditions.checkState;
 import static java.util.Objects.requireNonNull;
 
 import com.google.common.base.CharMatcher;
@@ -22,6 +23,7 @@
 import com.google.gerrit.exceptions.StorageException;
 import java.io.IOException;
 import java.sql.Timestamp;
+import java.util.Optional;
 
 /**
  * Definition of a field stored in the secondary index.
@@ -65,6 +67,11 @@
     T get(I input) throws IOException;
   }
 
+  @FunctionalInterface
+  public interface Setter<I, T> {
+    void set(I object, T value);
+  }
+
   public static class Builder<T> {
     private final FieldType<T> type;
     private final String name;
@@ -81,11 +88,20 @@
     }
 
     public <I> FieldDef<I, T> build(Getter<I, T> getter) {
-      return new FieldDef<>(name, type, stored, false, getter);
+      return new FieldDef<>(name, type, stored, false, getter, null);
+    }
+
+    public <I> FieldDef<I, T> build(Getter<I, T> getter, Setter<I, T> setter) {
+      return new FieldDef<>(name, type, stored, false, getter, setter);
     }
 
     public <I> FieldDef<I, Iterable<T>> buildRepeatable(Getter<I, Iterable<T>> getter) {
-      return new FieldDef<>(name, type, stored, true, getter);
+      return new FieldDef<>(name, type, stored, true, getter, null);
+    }
+
+    public <I> FieldDef<I, Iterable<T>> buildRepeatable(
+        Getter<I, Iterable<T>> getter, Setter<I, Iterable<T>> setter) {
+      return new FieldDef<>(name, type, stored, true, getter, setter);
     }
   }
 
@@ -96,9 +112,15 @@
 
   private final boolean repeatable;
   private final Getter<I, T> getter;
+  private final Optional<Setter<I, T>> setter;
 
   private FieldDef(
-      String name, FieldType<?> type, boolean stored, boolean repeatable, Getter<I, T> getter) {
+      String name,
+      FieldType<?> type,
+      boolean stored,
+      boolean repeatable,
+      Getter<I, T> getter,
+      @Nullable Setter<I, T> setter) {
     checkArgument(
         !(repeatable && type == FieldType.INTEGER_RANGE),
         "Range queries against repeated fields are unsupported");
@@ -107,6 +129,7 @@
     this.stored = stored;
     this.repeatable = repeatable;
     this.getter = requireNonNull(getter);
+    this.setter = Optional.ofNullable(setter);
   }
 
   private static String checkName(String name) {
@@ -145,6 +168,41 @@
     }
   }
 
+  /**
+   * Set the field contents back to an object. Used to reconstruct fields from indexed values. No-op
+   * if the field can't be reconstructed.
+   *
+   * @param object input object.
+   * @param doc indexed document
+   * @return {@code true} if the field was set, {@code false} otherwise
+   */
+  @SuppressWarnings("unchecked")
+  public boolean setIfPossible(I object, StoredValue doc) {
+    if (!setter.isPresent()) {
+      return false;
+    }
+
+    if (FieldType.STRING_TYPES.stream().anyMatch(t -> t.getName().equals(getType().getName()))) {
+      setter.get().set(object, (T) (isRepeatable() ? doc.asStrings() : doc.asString()));
+      return true;
+    } else if (FieldType.INTEGER_TYPES.stream()
+        .anyMatch(t -> t.getName().equals(getType().getName()))) {
+      setter.get().set(object, (T) (isRepeatable() ? doc.asIntegers() : doc.asInteger()));
+      return true;
+    } else if (FieldType.LONG.getName().equals(getType().getName())) {
+      setter.get().set(object, (T) (isRepeatable() ? doc.asLongs() : doc.asLong()));
+      return true;
+    } else if (FieldType.STORED_ONLY.getName().equals(getType().getName())) {
+      setter.get().set(object, (T) (isRepeatable() ? doc.asByteArrays() : doc.asByteArray()));
+      return true;
+    } else if (FieldType.TIMESTAMP.getName().equals(getType().getName())) {
+      checkState(!isRepeatable(), "can't repeat timestamp values");
+      setter.get().set(object, (T) doc.asTimestamp());
+      return true;
+    }
+    return false;
+  }
+
   /** @return whether the field is repeatable. */
   public boolean isRepeatable() {
     return repeatable;
diff --git a/java/com/google/gerrit/index/FieldType.java b/java/com/google/gerrit/index/FieldType.java
index 0db0284..c4c55f23 100644
--- a/java/com/google/gerrit/index/FieldType.java
+++ b/java/com/google/gerrit/index/FieldType.java
@@ -14,6 +14,7 @@
 
 package com.google.gerrit.index;
 
+import com.google.common.collect.ImmutableList;
 import java.sql.Timestamp;
 
 /** Document field types supported by the secondary index system. */
@@ -42,6 +43,14 @@
   /** A field that is only stored as raw bytes and cannot be queried. */
   public static final FieldType<byte[]> STORED_ONLY = new FieldType<>("STORED_ONLY");
 
+  /** List of all types that are stored as {@link String} in the index. */
+  public static final ImmutableList<FieldType<String>> STRING_TYPES =
+      ImmutableList.of(EXACT, PREFIX, FULL_TEXT);
+
+  /** List of all types that are stored as {@link Integer} in the index. */
+  public static final ImmutableList<FieldType<Integer>> INTEGER_TYPES =
+      ImmutableList.of(INTEGER_RANGE, INTEGER);
+
   private final String name;
 
   private FieldType(String name) {
diff --git a/java/com/google/gerrit/index/IndexType.java b/java/com/google/gerrit/index/IndexType.java
index ee44deb..cade439 100644
--- a/java/com/google/gerrit/index/IndexType.java
+++ b/java/com/google/gerrit/index/IndexType.java
@@ -20,7 +20,8 @@
 /**
  * Index types supported by the secondary index.
  *
- * <p>The explicitly known index types are Lucene (the default) and Elasticsearch.
+ * <p>The explicitly known index types are Lucene (the default), Elasticsearch and a fake index used
+ * in tests.
  *
  * <p>The third supported index type is any other type String value, deemed as custom. This is for
  * configuring index types that are internal or not to be disclosed. Supporting custom index types
@@ -29,6 +30,7 @@
 public class IndexType {
   private static final String LUCENE = "lucene";
   private static final String ELASTICSEARCH = "elasticsearch";
+  private static final String FAKE = "fake";
 
   private final String type;
 
@@ -41,7 +43,7 @@
   }
 
   public static ImmutableSet<String> getKnownTypes() {
-    return ImmutableSet.of(LUCENE, ELASTICSEARCH);
+    return ImmutableSet.of(LUCENE, ELASTICSEARCH, FAKE);
   }
 
   public boolean isLucene() {
@@ -52,6 +54,10 @@
     return type.equals(ELASTICSEARCH);
   }
 
+  public boolean isFake() {
+    return type.equals(FAKE);
+  }
+
   @Override
   public String toString() {
     return type;
diff --git a/java/com/google/gerrit/index/StoredValue.java b/java/com/google/gerrit/index/StoredValue.java
new file mode 100644
index 0000000..fe790c5
--- /dev/null
+++ b/java/com/google/gerrit/index/StoredValue.java
@@ -0,0 +1,50 @@
+// Copyright (C) 2021 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package com.google.gerrit.index;
+
+import java.sql.Timestamp;
+
+/**
+ * Representation of a field stored on the index. Used to load field values from different index
+ * backends.
+ */
+public interface StoredValue {
+  /** Returns the {@link String} value of the field. */
+  String asString();
+
+  /** Returns the {@link String} values of the field. */
+  Iterable<String> asStrings();
+
+  /** Returns the {@link Integer} value of the field. */
+  Integer asInteger();
+
+  /** Returns the {@link Integer} values of the field. */
+  Iterable<Integer> asIntegers();
+
+  /** Returns the {@link Long} value of the field. */
+  Long asLong();
+
+  /** Returns the {@link Long} values of the field. */
+  Iterable<Long> asLongs();
+
+  /** Returns the {@link Timestamp} value of the field. */
+  Timestamp asTimestamp();
+
+  /** Returns the {@code byte[]} value of the field. */
+  byte[] asByteArray();
+
+  /** Returns the {@code byte[]} values of the field. */
+  Iterable<byte[]> asByteArrays();
+}
diff --git a/java/com/google/gerrit/index/testing/AbstractFakeIndex.java b/java/com/google/gerrit/index/testing/AbstractFakeIndex.java
new file mode 100644
index 0000000..5cc8e3c
--- /dev/null
+++ b/java/com/google/gerrit/index/testing/AbstractFakeIndex.java
@@ -0,0 +1,319 @@
+// Copyright (C) 2021 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package com.google.gerrit.index.testing;
+
+import static com.google.common.collect.ImmutableList.toImmutableList;
+
+import com.google.common.collect.ImmutableList;
+import com.google.common.collect.ImmutableListMultimap;
+import com.google.common.collect.ImmutableMap;
+import com.google.gerrit.entities.Account;
+import com.google.gerrit.entities.AccountGroup;
+import com.google.gerrit.entities.Change;
+import com.google.gerrit.entities.InternalGroup;
+import com.google.gerrit.entities.Project;
+import com.google.gerrit.index.FieldDef;
+import com.google.gerrit.index.Index;
+import com.google.gerrit.index.QueryOptions;
+import com.google.gerrit.index.Schema;
+import com.google.gerrit.index.project.ProjectData;
+import com.google.gerrit.index.project.ProjectIndex;
+import com.google.gerrit.index.query.DataSource;
+import com.google.gerrit.index.query.FieldBundle;
+import com.google.gerrit.index.query.ListResultSet;
+import com.google.gerrit.index.query.Predicate;
+import com.google.gerrit.index.query.ResultSet;
+import com.google.gerrit.server.account.AccountState;
+import com.google.gerrit.server.config.SitePaths;
+import com.google.gerrit.server.index.IndexUtils;
+import com.google.gerrit.server.index.account.AccountIndex;
+import com.google.gerrit.server.index.change.ChangeField;
+import com.google.gerrit.server.index.change.ChangeIndex;
+import com.google.gerrit.server.index.group.GroupIndex;
+import com.google.gerrit.server.query.change.ChangeData;
+import com.google.inject.Inject;
+import com.google.inject.assistedinject.Assisted;
+import java.sql.Timestamp;
+import java.util.Comparator;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+
+/**
+ * Fake secondary index implementation for usage in tests. All values are kept in-memory.
+ *
+ * <p>This class is thread-safe.
+ */
+public abstract class AbstractFakeIndex<K, V, D> implements Index<K, V> {
+  private final Schema<V> schema;
+  /**
+   * SitePaths (config files) are used to signal that an index is ready. This implementation is
+   * consistent with other index backends.
+   */
+  private final SitePaths sitePaths;
+
+  private final String indexName;
+  private final Map<K, D> indexedDocuments;
+
+  AbstractFakeIndex(Schema<V> schema, SitePaths sitePaths, String indexName) {
+    this.schema = schema;
+    this.sitePaths = sitePaths;
+    this.indexName = indexName;
+    this.indexedDocuments = new HashMap<>();
+  }
+
+  @Override
+  public Schema<V> getSchema() {
+    return schema;
+  }
+
+  @Override
+  public void close() {
+    // No-op
+  }
+
+  @Override
+  public void replace(V doc) {
+    synchronized (indexedDocuments) {
+      indexedDocuments.put(keyFor(doc), docFor(doc));
+    }
+  }
+
+  @Override
+  public void delete(K key) {
+    synchronized (indexedDocuments) {
+      indexedDocuments.remove(key);
+    }
+  }
+
+  @Override
+  public void deleteAll() {
+    synchronized (indexedDocuments) {
+      indexedDocuments.clear();
+    }
+  }
+
+  @Override
+  public DataSource<V> getSource(Predicate<V> p, QueryOptions opts) {
+    List<V> results;
+    synchronized (indexedDocuments) {
+      results =
+          indexedDocuments.values().stream()
+              .map(doc -> valueFor(doc))
+              .filter(doc -> p.asMatchable().match(doc))
+              .sorted(sortingComparator())
+              .skip(opts.start())
+              .limit(opts.limit())
+              .collect(toImmutableList());
+    }
+    return new DataSource<V>() {
+      @Override
+      public int getCardinality() {
+        return results.size();
+      }
+
+      @Override
+      public ResultSet<V> read() {
+        return new ListResultSet<>(results);
+      }
+
+      @Override
+      public ResultSet<FieldBundle> readRaw() {
+        ImmutableList.Builder<FieldBundle> fieldBundles = ImmutableList.builder();
+        for (V result : results) {
+          ImmutableListMultimap.Builder<String, Object> fields = ImmutableListMultimap.builder();
+          for (FieldDef<V, ?> field : getSchema().getFields().values()) {
+            if (field.get(result) == null) {
+              continue;
+            }
+            if (field.isRepeatable()) {
+              fields.putAll(field.getName(), (Iterable<?>) field.get(result));
+            } else {
+              fields.put(field.getName(), field.get(result));
+            }
+          }
+          fieldBundles.add(new FieldBundle(fields.build()));
+        }
+        return new ListResultSet<>(fieldBundles.build());
+      }
+    };
+  }
+
+  @Override
+  public void markReady(boolean ready) {
+    IndexUtils.setReady(sitePaths, indexName, schema.getVersion(), ready);
+  }
+
+  /** Method to get a key from a document. */
+  protected abstract K keyFor(V doc);
+
+  /** Method to get a document the index should hold on to from a Gerrit Java data type. */
+  protected abstract D docFor(V value);
+
+  /** Method to a Gerrit Java data type from a document that the index was holding on to. */
+  protected abstract V valueFor(D doc);
+
+  /** Comparator representing the default search order. */
+  protected abstract Comparator<V> sortingComparator();
+
+  /**
+   * Fake implementation of {@link ChangeIndex} where all filtering happens in-memory.
+   *
+   * <p>This index is special in that ChangeData is a mutable object. Therefore we can't just hold
+   * onto the object that the caller wanted us to index. We also can't just create a new ChangeData
+   * from scratch because there are tests that assert that certain computations (e.g. diffs) are
+   * only done once. So we do what the prod indices do: We read and write fields using FieldDef.
+   */
+  public static class FakeChangeIndex
+      extends AbstractFakeIndex<Change.Id, ChangeData, Map<String, Object>> implements ChangeIndex {
+    private final ChangeData.Factory changeDataFactory;
+
+    @Inject
+    FakeChangeIndex(
+        SitePaths sitePaths,
+        ChangeData.Factory changeDataFactory,
+        @Assisted Schema<ChangeData> schema) {
+      super(schema, sitePaths, "changes");
+      this.changeDataFactory = changeDataFactory;
+    }
+
+    @Override
+    protected Change.Id keyFor(ChangeData value) {
+      return value.getId();
+    }
+
+    @Override
+    protected Comparator<ChangeData> sortingComparator() {
+      Comparator<ChangeData> lastUpdated =
+          Comparator.comparing(cd -> cd.change().getLastUpdatedOn());
+      Comparator<ChangeData> merged =
+          Comparator.comparing(cd -> cd.getMergedOn().orElse(new Timestamp(0)));
+      Comparator<ChangeData> id = Comparator.comparing(cd -> cd.getId().get());
+      return lastUpdated.thenComparing(merged).thenComparing(id).reversed();
+    }
+
+    @Override
+    protected Map<String, Object> docFor(ChangeData value) {
+      ImmutableMap.Builder<String, Object> doc = ImmutableMap.builder();
+      for (FieldDef<ChangeData, ?> field : getSchema().getFields().values()) {
+        Object docifiedValue = field.get(value);
+        if (docifiedValue != null) {
+          doc.put(field.getName(), field.get(value));
+        }
+      }
+      return doc.build();
+    }
+
+    @Override
+    protected ChangeData valueFor(Map<String, Object> doc) {
+      ChangeData cd =
+          changeDataFactory.create(
+              Project.nameKey((String) doc.get(ChangeField.PROJECT.getName())),
+              Change.id(Integer.valueOf((String) doc.get(ChangeField.LEGACY_ID_STR.getName()))));
+      for (FieldDef<ChangeData, ?> field : getSchema().getFields().values()) {
+        field.setIfPossible(cd, new FakeStoredValue(doc.get(field.getName())));
+      }
+      return cd;
+    }
+  }
+
+  /** Fake implementation of {@link AccountIndex} where all filtering happens in-memory. */
+  public static class FakeAccountIndex
+      extends AbstractFakeIndex<Account.Id, AccountState, AccountState> implements AccountIndex {
+    @Inject
+    FakeAccountIndex(SitePaths sitePaths, @Assisted Schema<AccountState> schema) {
+      super(schema, sitePaths, "accounts");
+    }
+
+    @Override
+    protected Account.Id keyFor(AccountState value) {
+      return value.account().id();
+    }
+
+    @Override
+    protected AccountState docFor(AccountState value) {
+      return value;
+    }
+
+    @Override
+    protected AccountState valueFor(AccountState doc) {
+      return doc;
+    }
+
+    @Override
+    protected Comparator<AccountState> sortingComparator() {
+      return Comparator.comparing(a -> a.account().id().get());
+    }
+  }
+
+  /** Fake implementation of {@link GroupIndex} where all filtering happens in-memory. */
+  public static class FakeGroupIndex
+      extends AbstractFakeIndex<AccountGroup.UUID, InternalGroup, InternalGroup>
+      implements GroupIndex {
+    @Inject
+    FakeGroupIndex(SitePaths sitePaths, @Assisted Schema<InternalGroup> schema) {
+      super(schema, sitePaths, "groups");
+    }
+
+    @Override
+    protected AccountGroup.UUID keyFor(InternalGroup value) {
+      return value.getGroupUUID();
+    }
+
+    @Override
+    protected InternalGroup docFor(InternalGroup value) {
+      return value;
+    }
+
+    @Override
+    protected InternalGroup valueFor(InternalGroup doc) {
+      return doc;
+    }
+
+    @Override
+    protected Comparator<InternalGroup> sortingComparator() {
+      return Comparator.comparing(g -> g.getId().get());
+    }
+  }
+
+  /** Fake implementation of {@link ProjectIndex} where all filtering happens in-memory. */
+  public static class FakeProjectIndex
+      extends AbstractFakeIndex<Project.NameKey, ProjectData, ProjectData> implements ProjectIndex {
+    @Inject
+    FakeProjectIndex(SitePaths sitePaths, @Assisted Schema<ProjectData> schema) {
+      super(schema, sitePaths, "projects");
+    }
+
+    @Override
+    protected Project.NameKey keyFor(ProjectData value) {
+      return value.getProject().getNameKey();
+    }
+
+    @Override
+    protected ProjectData docFor(ProjectData value) {
+      return value;
+    }
+
+    @Override
+    protected ProjectData valueFor(ProjectData doc) {
+      return doc;
+    }
+
+    @Override
+    protected Comparator<ProjectData> sortingComparator() {
+      return Comparator.comparing(p -> p.getProject().getName());
+    }
+  }
+}
diff --git a/java/com/google/gerrit/index/testing/BUILD b/java/com/google/gerrit/index/testing/BUILD
new file mode 100644
index 0000000..a30eaca
--- /dev/null
+++ b/java/com/google/gerrit/index/testing/BUILD
@@ -0,0 +1,27 @@
+load("@rules_java//java:defs.bzl", "java_library")
+
+java_library(
+    name = "testing",
+    testonly = True,
+    srcs = glob(
+        ["**/*.java"],
+    ),
+    visibility = ["//visibility:public"],
+    deps = [
+        "//java/com/google/gerrit/common:annotations",
+        "//java/com/google/gerrit/entities",
+        "//java/com/google/gerrit/exceptions",
+        "//java/com/google/gerrit/index",
+        "//java/com/google/gerrit/index:query_exception",
+        "//java/com/google/gerrit/index/project",
+        "//java/com/google/gerrit/proto",
+        "//java/com/google/gerrit/server",
+        "//java/com/google/gerrit/server/logging",
+        "//lib:guava",
+        "//lib:jgit",
+        "//lib:protobuf",
+        "//lib/flogger:api",
+        "//lib/guice",
+        "//lib/guice:guice-assistedinject",
+    ],
+)
diff --git a/java/com/google/gerrit/index/testing/FakeIndexModule.java b/java/com/google/gerrit/index/testing/FakeIndexModule.java
new file mode 100644
index 0000000..126ff10
--- /dev/null
+++ b/java/com/google/gerrit/index/testing/FakeIndexModule.java
@@ -0,0 +1,69 @@
+// Copyright (C) 2021 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package com.google.gerrit.index.testing;
+
+import com.google.common.collect.ImmutableMap;
+import com.google.gerrit.index.project.ProjectIndex;
+import com.google.gerrit.server.index.AbstractIndexModule;
+import com.google.gerrit.server.index.VersionManager;
+import com.google.gerrit.server.index.account.AccountIndex;
+import com.google.gerrit.server.index.change.ChangeIndex;
+import com.google.gerrit.server.index.group.GroupIndex;
+import java.util.Map;
+
+/** Module to bind {@link FakeIndexModule}. */
+public class FakeIndexModule extends AbstractIndexModule {
+  public static FakeIndexModule singleVersionAllLatest(int threads, boolean secondary) {
+    return new FakeIndexModule(ImmutableMap.of(), threads, secondary);
+  }
+
+  public static FakeIndexModule singleVersionWithExplicitVersions(
+      Map<String, Integer> versions, int threads, boolean secondary) {
+    return new FakeIndexModule(versions, threads, secondary);
+  }
+
+  public static FakeIndexModule latestVersion(boolean secondary) {
+    return new FakeIndexModule(null, -1 /* direct executor */, secondary);
+  }
+
+  private FakeIndexModule(Map<String, Integer> singleVersions, int threads, boolean secondary) {
+    super(singleVersions, threads, secondary);
+  }
+
+  @Override
+  protected Class<? extends AccountIndex> getAccountIndex() {
+    return AbstractFakeIndex.FakeAccountIndex.class;
+  }
+
+  @Override
+  protected Class<? extends ChangeIndex> getChangeIndex() {
+    return AbstractFakeIndex.FakeChangeIndex.class;
+  }
+
+  @Override
+  protected Class<? extends GroupIndex> getGroupIndex() {
+    return AbstractFakeIndex.FakeGroupIndex.class;
+  }
+
+  @Override
+  protected Class<? extends ProjectIndex> getProjectIndex() {
+    return AbstractFakeIndex.FakeProjectIndex.class;
+  }
+
+  @Override
+  protected Class<? extends VersionManager> getVersionManager() {
+    return FakeIndexVersionManager.class;
+  }
+}
diff --git a/java/com/google/gerrit/index/testing/FakeIndexVersionManager.java b/java/com/google/gerrit/index/testing/FakeIndexVersionManager.java
new file mode 100644
index 0000000..5044e38
--- /dev/null
+++ b/java/com/google/gerrit/index/testing/FakeIndexVersionManager.java
@@ -0,0 +1,75 @@
+// Copyright (C) 2021 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package com.google.gerrit.index.testing;
+
+import com.google.common.collect.Iterables;
+import com.google.gerrit.index.Index;
+import com.google.gerrit.index.IndexDefinition;
+import com.google.gerrit.index.Schema;
+import com.google.gerrit.server.config.GerritServerConfig;
+import com.google.gerrit.server.config.SitePaths;
+import com.google.gerrit.server.index.GerritIndexStatus;
+import com.google.gerrit.server.index.OnlineUpgradeListener;
+import com.google.gerrit.server.index.VersionManager;
+import com.google.gerrit.server.plugincontext.PluginSetContext;
+import com.google.inject.Inject;
+import com.google.inject.Singleton;
+import java.util.Collection;
+import java.util.TreeMap;
+import org.eclipse.jgit.lib.Config;
+
+/** Fake version manager for {@link AbstractFakeIndex}. */
+@Singleton
+public class FakeIndexVersionManager extends VersionManager {
+
+  @Inject
+  FakeIndexVersionManager(
+      @GerritServerConfig Config cfg,
+      SitePaths sitePaths,
+      PluginSetContext<OnlineUpgradeListener> listeners,
+      Collection<IndexDefinition<?, ?, ?>> defs) {
+    super(sitePaths, listeners, defs, VersionManager.getOnlineUpgrade(cfg));
+  }
+
+  @Override
+  protected <K, V, I extends Index<K, V>> TreeMap<Integer, Version<V>> scanVersions(
+      IndexDefinition<K, V, I> def, GerritIndexStatus cfg) {
+    TreeMap<Integer, Version<V>> versions = new TreeMap<>();
+    for (Schema<V> schema : def.getSchemas().values()) {
+      int v = schema.getVersion();
+      boolean exists = versions.containsKey(v);
+      versions.put(v, new Version<>(schema, v, exists, cfg.getReady(def.getName(), v)));
+    }
+    return versions;
+  }
+
+  @Override
+  protected <K, V, I extends Index<K, V>> void initIndex(
+      IndexDefinition<K, V, I> def, GerritIndexStatus cfg) {
+    // Set latest versions ready.
+    if (def.getSchemas().isEmpty()) {
+      super.initIndex(def, cfg);
+      return;
+    }
+    Schema<V> schema = Iterables.getLast(def.getSchemas().values());
+    try {
+      cfg.setReady(def.getName(), schema.getVersion(), true);
+      cfg.save();
+    } catch (Exception e) {
+      throw new IllegalStateException(e);
+    }
+    super.initIndex(def, cfg);
+  }
+}
diff --git a/java/com/google/gerrit/index/testing/FakeStoredValue.java b/java/com/google/gerrit/index/testing/FakeStoredValue.java
new file mode 100644
index 0000000..ca46ed1
--- /dev/null
+++ b/java/com/google/gerrit/index/testing/FakeStoredValue.java
@@ -0,0 +1,76 @@
+// Copyright (C) 2021 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package com.google.gerrit.index.testing;
+
+import com.google.gerrit.index.StoredValue;
+import java.sql.Timestamp;
+
+/** Bridge to recover fields from the fake index. */
+public class FakeStoredValue implements StoredValue {
+  private final Object field;
+
+  FakeStoredValue(Object field) {
+    this.field = field;
+  }
+
+  @Override
+  public String asString() {
+    return (String) field;
+  }
+
+  @Override
+  @SuppressWarnings("unchecked")
+  public Iterable<String> asStrings() {
+    return (Iterable<String>) field;
+  }
+
+  @Override
+  public Integer asInteger() {
+    return (Integer) field;
+  }
+
+  @Override
+  @SuppressWarnings("unchecked")
+  public Iterable<Integer> asIntegers() {
+    return (Iterable<Integer>) field;
+  }
+
+  @Override
+  public Long asLong() {
+    return (Long) field;
+  }
+
+  @Override
+  @SuppressWarnings("unchecked")
+  public Iterable<Long> asLongs() {
+    return (Iterable<Long>) field;
+  }
+
+  @Override
+  public Timestamp asTimestamp() {
+    return (Timestamp) field;
+  }
+
+  @Override
+  public byte[] asByteArray() {
+    return (byte[]) field;
+  }
+
+  @Override
+  @SuppressWarnings("unchecked")
+  public Iterable<byte[]> asByteArrays() {
+    return (Iterable<byte[]>) field;
+  }
+}
diff --git a/java/com/google/gerrit/lucene/LuceneChangeIndex.java b/java/com/google/gerrit/lucene/LuceneChangeIndex.java
index c3d4440..ac616ca 100644
--- a/java/com/google/gerrit/lucene/LuceneChangeIndex.java
+++ b/java/com/google/gerrit/lucene/LuceneChangeIndex.java
@@ -15,7 +15,6 @@
 package com.google.gerrit.lucene;
 
 import static com.google.common.collect.ImmutableList.toImmutableList;
-import static com.google.common.collect.ImmutableSet.toImmutableSet;
 import static com.google.gerrit.lucene.AbstractLuceneIndex.sortFieldName;
 import static com.google.gerrit.server.git.QueueProvider.QueueType.INTERACTIVE;
 import static com.google.gerrit.server.index.change.ChangeField.LEGACY_ID;
@@ -24,11 +23,8 @@
 import static com.google.gerrit.server.index.change.ChangeIndexRewriter.CLOSED_STATUSES;
 import static com.google.gerrit.server.index.change.ChangeIndexRewriter.OPEN_STATUSES;
 import static java.util.Objects.requireNonNull;
-import static java.util.stream.Collectors.toList;
 
 import com.google.common.base.Throwables;
-import com.google.common.collect.Collections2;
-import com.google.common.collect.FluentIterable;
 import com.google.common.collect.ImmutableList;
 import com.google.common.collect.ImmutableSet;
 import com.google.common.collect.Iterables;
@@ -38,25 +34,19 @@
 import com.google.common.flogger.FluentLogger;
 import com.google.common.util.concurrent.Futures;
 import com.google.common.util.concurrent.ListeningExecutorService;
-import com.google.gerrit.entities.Account;
 import com.google.gerrit.entities.Change;
-import com.google.gerrit.entities.PatchSet;
 import com.google.gerrit.entities.Project;
 import com.google.gerrit.entities.converter.ChangeProtoConverter;
-import com.google.gerrit.entities.converter.PatchSetApprovalProtoConverter;
-import com.google.gerrit.entities.converter.PatchSetProtoConverter;
 import com.google.gerrit.entities.converter.ProtoConverter;
 import com.google.gerrit.exceptions.StorageException;
 import com.google.gerrit.index.FieldDef;
 import com.google.gerrit.index.QueryOptions;
-import com.google.gerrit.index.RefState;
 import com.google.gerrit.index.Schema;
 import com.google.gerrit.index.query.FieldBundle;
 import com.google.gerrit.index.query.Predicate;
 import com.google.gerrit.index.query.QueryParseException;
 import com.google.gerrit.index.query.ResultSet;
 import com.google.gerrit.proto.Protos;
-import com.google.gerrit.server.StarredChangesUtil;
 import com.google.gerrit.server.change.MergeabilityComputationBehavior;
 import com.google.gerrit.server.config.GerritServerConfig;
 import com.google.gerrit.server.config.SitePaths;
@@ -65,7 +55,6 @@
 import com.google.gerrit.server.index.change.ChangeField;
 import com.google.gerrit.server.index.change.ChangeIndex;
 import com.google.gerrit.server.index.change.ChangeIndexRewriter;
-import com.google.gerrit.server.project.SubmitRuleOptions;
 import com.google.gerrit.server.query.change.ChangeData;
 import com.google.gerrit.server.query.change.ChangeDataSource;
 import com.google.inject.Inject;
@@ -73,16 +62,13 @@
 import com.google.protobuf.MessageLite;
 import java.io.IOException;
 import java.nio.file.Path;
-import java.sql.Timestamp;
 import java.util.ArrayList;
-import java.util.Collection;
 import java.util.Iterator;
 import java.util.List;
 import java.util.Set;
 import java.util.concurrent.Callable;
 import java.util.concurrent.ExecutionException;
 import java.util.concurrent.Future;
-import java.util.function.Consumer;
 import java.util.function.Function;
 import org.apache.lucene.document.Document;
 import org.apache.lucene.index.IndexWriter;
@@ -119,34 +105,10 @@
   private static final String CHANGES = "changes";
   private static final String CHANGES_OPEN = "open";
   private static final String CHANGES_CLOSED = "closed";
-  private static final String ADDED_FIELD = ChangeField.ADDED.getName();
-  private static final String APPROVAL_FIELD = ChangeField.APPROVAL.getName();
   private static final String CHANGE_FIELD = ChangeField.CHANGE.getName();
-  private static final String DELETED_FIELD = ChangeField.DELETED.getName();
-  private static final String MERGEABLE_FIELD = ChangeField.MERGEABLE.getName();
-  private static final String PATCH_SET_FIELD = ChangeField.PATCH_SET.getName();
-  private static final String PENDING_REVIEWER_FIELD = ChangeField.PENDING_REVIEWER.getName();
-  private static final String PENDING_REVIEWER_BY_EMAIL_FIELD =
-      ChangeField.PENDING_REVIEWER_BY_EMAIL.getName();
-  private static final String REF_STATE_FIELD = ChangeField.REF_STATE.getName();
-  private static final String REF_STATE_PATTERN_FIELD = ChangeField.REF_STATE_PATTERN.getName();
-  private static final String REVIEWEDBY_FIELD = ChangeField.REVIEWEDBY.getName();
-  private static final String REVIEWER_FIELD = ChangeField.REVIEWER.getName();
-  private static final String REVIEWER_BY_EMAIL_FIELD = ChangeField.REVIEWER_BY_EMAIL.getName();
-  private static final String HASHTAG_FIELD = ChangeField.HASHTAG_CASE_AWARE.getName();
-  private static final String STAR_FIELD = ChangeField.STAR.getName();
-  private static final String SUBMIT_RECORD_LENIENT_FIELD =
-      ChangeField.STORED_SUBMIT_RECORD_LENIENT.getName();
-  private static final String SUBMIT_RECORD_STRICT_FIELD =
-      ChangeField.STORED_SUBMIT_RECORD_STRICT.getName();
-  private static final String TOTAL_COMMENT_COUNT_FIELD = ChangeField.TOTAL_COMMENT_COUNT.getName();
-  private static final String UNRESOLVED_COMMENT_COUNT_FIELD =
-      ChangeField.UNRESOLVED_COMMENT_COUNT.getName();
-  private static final String ATTENTION_SET_FULL_FIELD = ChangeField.ATTENTION_SET_FULL.getName();
-  private static final String MERGED_ON_FIELD = ChangeField.MERGED_ON.getName();
 
   @FunctionalInterface
-  static interface IdTerm {
+  interface IdTerm {
     Term get(String name, int id);
   }
 
@@ -159,7 +121,7 @@
   }
 
   @FunctionalInterface
-  static interface ChangeIdExtractor {
+  interface ChangeIdExtractor {
     Change.Id extract(IndexableField f);
   }
 
@@ -520,231 +482,14 @@
       cd = changeDataFactory.create(Project.nameKey(project.stringValue()), extractor.extract(f));
     }
 
-    // Any decoding that is done here must also be done in {@link ElasticChangeIndex}.
-
-    if (fields.contains(PATCH_SET_FIELD)) {
-      decodePatchSets(doc, cd);
+    for (FieldDef<ChangeData, ?> field : getSchema().getFields().values()) {
+      if (fields.contains(field.getName()) && doc.get(field.getName()) != null) {
+        field.setIfPossible(cd, new LuceneStoredValue(doc.get(field.getName())));
+      }
     }
-    if (fields.contains(APPROVAL_FIELD)) {
-      decodeApprovals(doc, cd);
-    }
-    if (fields.contains(ADDED_FIELD) && fields.contains(DELETED_FIELD)) {
-      decodeChangedLines(doc, cd);
-    }
-    if (fields.contains(MERGEABLE_FIELD)) {
-      decodeMergeable(doc, cd);
-    }
-    if (fields.contains(REVIEWEDBY_FIELD)) {
-      decodeReviewedBy(doc, cd);
-    }
-    if (fields.contains(HASHTAG_FIELD)) {
-      decodeHashtags(doc, cd);
-    }
-    if (fields.contains(STAR_FIELD)) {
-      decodeStar(doc, cd);
-    }
-    if (fields.contains(REVIEWER_FIELD)) {
-      decodeReviewers(doc, cd);
-    }
-    if (fields.contains(REVIEWER_BY_EMAIL_FIELD)) {
-      decodeReviewersByEmail(doc, cd);
-    }
-    if (fields.contains(PENDING_REVIEWER_FIELD)) {
-      decodePendingReviewers(doc, cd);
-    }
-    if (fields.contains(PENDING_REVIEWER_BY_EMAIL_FIELD)) {
-      decodePendingReviewersByEmail(doc, cd);
-    }
-    if (fields.contains(ATTENTION_SET_FULL_FIELD)) {
-      decodeAttentionSet(doc, cd);
-    }
-    decodeSubmitRecords(
-        doc, SUBMIT_RECORD_STRICT_FIELD, ChangeField.SUBMIT_RULE_OPTIONS_STRICT, cd);
-    decodeSubmitRecords(
-        doc, SUBMIT_RECORD_LENIENT_FIELD, ChangeField.SUBMIT_RULE_OPTIONS_LENIENT, cd);
-    if (fields.contains(REF_STATE_FIELD)) {
-      decodeRefStates(doc, cd);
-    }
-    if (fields.contains(REF_STATE_PATTERN_FIELD)) {
-      decodeRefStatePatterns(doc, cd);
-    }
-    if (fields.contains(MERGED_ON_FIELD)) {
-      decodeMergedOn(doc, cd);
-    }
-
-    decodeUnresolvedCommentCount(doc, cd);
-    decodeTotalCommentCount(doc, cd);
     return cd;
   }
 
-  private void decodePatchSets(ListMultimap<String, IndexableField> doc, ChangeData cd) {
-    List<PatchSet> patchSets = decodeProtos(doc, PATCH_SET_FIELD, PatchSetProtoConverter.INSTANCE);
-    if (!patchSets.isEmpty()) {
-      // Will be an empty list for schemas prior to when this field was stored;
-      // this cannot be valid since a change needs at least one patch set.
-      cd.setPatchSets(patchSets);
-    }
-  }
-
-  private void decodeApprovals(ListMultimap<String, IndexableField> doc, ChangeData cd) {
-    cd.setCurrentApprovals(
-        decodeProtos(doc, APPROVAL_FIELD, PatchSetApprovalProtoConverter.INSTANCE));
-  }
-
-  private void decodeChangedLines(ListMultimap<String, IndexableField> doc, ChangeData cd) {
-    IndexableField added = Iterables.getFirst(doc.get(ADDED_FIELD), null);
-    IndexableField deleted = Iterables.getFirst(doc.get(DELETED_FIELD), null);
-    if (added != null && deleted != null) {
-      cd.setChangedLines(added.numericValue().intValue(), deleted.numericValue().intValue());
-    } else {
-      // No ChangedLines stored, likely due to failure during reindexing, for
-      // example due to LargeObjectException. But we know the field was
-      // requested, so update ChangeData to prevent callers from trying to
-      // lazily load it, as that would probably also fail.
-      cd.setNoChangedLines();
-    }
-  }
-
-  private void decodeMergeable(ListMultimap<String, IndexableField> doc, ChangeData cd) {
-    IndexableField f = Iterables.getFirst(doc.get(MERGEABLE_FIELD), null);
-    if (f != null && !skipFields.contains(MERGEABLE_FIELD)) {
-      String mergeable = f.stringValue();
-      if ("1".equals(mergeable)) {
-        cd.setMergeable(true);
-      } else if ("0".equals(mergeable)) {
-        cd.setMergeable(false);
-      }
-    }
-  }
-
-  private void decodeReviewedBy(ListMultimap<String, IndexableField> doc, ChangeData cd) {
-    Collection<IndexableField> reviewedBy = doc.get(REVIEWEDBY_FIELD);
-    if (!reviewedBy.isEmpty()) {
-      Set<Account.Id> accounts = Sets.newHashSetWithExpectedSize(reviewedBy.size());
-      for (IndexableField r : reviewedBy) {
-        int id = r.numericValue().intValue();
-        if (reviewedBy.size() == 1 && id == ChangeField.NOT_REVIEWED) {
-          break;
-        }
-        accounts.add(Account.id(id));
-      }
-      cd.setReviewedBy(accounts);
-    }
-  }
-
-  private void decodeHashtags(ListMultimap<String, IndexableField> doc, ChangeData cd) {
-    Collection<IndexableField> hashtag = doc.get(HASHTAG_FIELD);
-    Set<String> hashtags = Sets.newHashSetWithExpectedSize(hashtag.size());
-    for (IndexableField r : hashtag) {
-      hashtags.add(r.binaryValue().utf8ToString());
-    }
-    cd.setHashtags(hashtags);
-  }
-
-  private void decodeStar(ListMultimap<String, IndexableField> doc, ChangeData cd) {
-    Collection<IndexableField> star = doc.get(STAR_FIELD);
-    ListMultimap<Account.Id, String> stars = MultimapBuilder.hashKeys().arrayListValues().build();
-    for (IndexableField r : star) {
-      StarredChangesUtil.StarField starField = StarredChangesUtil.StarField.parse(r.stringValue());
-      if (starField != null) {
-        stars.put(starField.accountId(), starField.label());
-      }
-    }
-    cd.setStars(stars);
-  }
-
-  private void decodeReviewers(ListMultimap<String, IndexableField> doc, ChangeData cd) {
-    cd.setReviewers(
-        ChangeField.parseReviewerFieldValues(
-            cd.getId(),
-            FluentIterable.from(doc.get(REVIEWER_FIELD)).transform(IndexableField::stringValue)));
-  }
-
-  private void decodeReviewersByEmail(ListMultimap<String, IndexableField> doc, ChangeData cd) {
-    cd.setReviewersByEmail(
-        ChangeField.parseReviewerByEmailFieldValues(
-            cd.getId(),
-            FluentIterable.from(doc.get(REVIEWER_BY_EMAIL_FIELD))
-                .transform(IndexableField::stringValue)));
-  }
-
-  private void decodePendingReviewers(ListMultimap<String, IndexableField> doc, ChangeData cd) {
-    cd.setPendingReviewers(
-        ChangeField.parseReviewerFieldValues(
-            cd.getId(),
-            FluentIterable.from(doc.get(PENDING_REVIEWER_FIELD))
-                .transform(IndexableField::stringValue)));
-  }
-
-  private void decodePendingReviewersByEmail(
-      ListMultimap<String, IndexableField> doc, ChangeData cd) {
-    cd.setPendingReviewersByEmail(
-        ChangeField.parseReviewerByEmailFieldValues(
-            cd.getId(),
-            FluentIterable.from(doc.get(PENDING_REVIEWER_BY_EMAIL_FIELD))
-                .transform(IndexableField::stringValue)));
-  }
-
-  private void decodeAttentionSet(ListMultimap<String, IndexableField> doc, ChangeData cd) {
-    ChangeField.parseAttentionSet(
-        doc.get(ATTENTION_SET_FULL_FIELD).stream()
-            .map(field -> field.binaryValue().utf8ToString())
-            .collect(toImmutableSet()),
-        cd);
-  }
-
-  private void decodeSubmitRecords(
-      ListMultimap<String, IndexableField> doc,
-      String field,
-      SubmitRuleOptions opts,
-      ChangeData cd) {
-    ChangeField.parseSubmitRecords(
-        Collections2.transform(doc.get(field), f -> f.binaryValue().utf8ToString()), opts, cd);
-  }
-
-  private void decodeRefStates(ListMultimap<String, IndexableField> doc, ChangeData cd) {
-    cd.setRefStates(RefState.parseStates(copyAsBytes(doc.get(REF_STATE_FIELD))));
-  }
-
-  private void decodeRefStatePatterns(ListMultimap<String, IndexableField> doc, ChangeData cd) {
-    cd.setRefStatePatterns(copyAsBytes(doc.get(REF_STATE_PATTERN_FIELD)));
-  }
-
-  private void decodeUnresolvedCommentCount(
-      ListMultimap<String, IndexableField> doc, ChangeData cd) {
-    decodeIntField(doc, UNRESOLVED_COMMENT_COUNT_FIELD, cd::setUnresolvedCommentCount);
-  }
-
-  private void decodeTotalCommentCount(ListMultimap<String, IndexableField> doc, ChangeData cd) {
-    decodeIntField(doc, TOTAL_COMMENT_COUNT_FIELD, cd::setTotalCommentCount);
-  }
-
-  private static void decodeIntField(
-      ListMultimap<String, IndexableField> doc, String fieldName, Consumer<Integer> consumer) {
-    IndexableField f = Iterables.getFirst(doc.get(fieldName), null);
-    if (f != null && f.numericValue() != null) {
-      consumer.accept(f.numericValue().intValue());
-    }
-  }
-
-  private void decodeMergedOn(ListMultimap<String, IndexableField> doc, ChangeData cd) {
-    IndexableField mergedOnField =
-        Iterables.getFirst(doc.get(MERGED_ON_FIELD), /* defaultValue= */ null);
-    Timestamp mergedOn = null;
-    if (mergedOnField != null && mergedOnField.numericValue() != null) {
-      mergedOn = new Timestamp(mergedOnField.numericValue().longValue());
-    }
-    cd.setMergedOn(mergedOn);
-  }
-
-  private static <T> List<T> decodeProtos(
-      ListMultimap<String, IndexableField> doc, String fieldName, ProtoConverter<?, T> converter) {
-    return doc.get(fieldName).stream()
-        .map(IndexableField::binaryValue)
-        .map(bytesRef -> parseProtoFrom(bytesRef, converter))
-        .collect(toImmutableList());
-  }
-
   private static <P extends MessageLite, T> T parseProtoFrom(
       BytesRef bytesRef, ProtoConverter<P, T> converter) {
     P message =
@@ -752,16 +497,4 @@
             converter.getParser(), bytesRef.bytes, bytesRef.offset, bytesRef.length);
     return converter.fromProto(message);
   }
-
-  private static List<byte[]> copyAsBytes(Collection<IndexableField> fields) {
-    return fields.stream()
-        .map(
-            f -> {
-              BytesRef ref = f.binaryValue();
-              byte[] b = new byte[ref.length];
-              System.arraycopy(ref.bytes, ref.offset, b, 0, ref.length);
-              return b;
-            })
-        .collect(toList());
-  }
 }
diff --git a/java/com/google/gerrit/lucene/LuceneStoredValue.java b/java/com/google/gerrit/lucene/LuceneStoredValue.java
new file mode 100644
index 0000000..efe489b
--- /dev/null
+++ b/java/com/google/gerrit/lucene/LuceneStoredValue.java
@@ -0,0 +1,95 @@
+// Copyright (C) 2021 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package com.google.gerrit.lucene;
+
+import static com.google.common.collect.ImmutableList.toImmutableList;
+import static java.util.stream.Collectors.toList;
+
+import com.google.common.collect.Iterables;
+import com.google.gerrit.index.StoredValue;
+import java.sql.Timestamp;
+import java.util.List;
+import org.apache.lucene.index.IndexableField;
+import org.apache.lucene.util.BytesRef;
+
+/** Bridge to recover fields from the lucene index. */
+public class LuceneStoredValue implements StoredValue {
+  /**
+   * Lucene represents repeated fields as a list of {@link IndexableField}, so we hold onto a list
+   * here to cover both repeated and non-repeated fields.
+   */
+  private final List<IndexableField> field;
+
+  LuceneStoredValue(List<IndexableField> field) {
+    this.field = field;
+  }
+
+  @Override
+  public String asString() {
+    return Iterables.getFirst(asStrings(), null);
+  }
+
+  @Override
+  public Iterable<String> asStrings() {
+    return field.stream().map(f -> f.stringValue()).collect(toImmutableList());
+  }
+
+  @Override
+  public Integer asInteger() {
+    return Iterables.getFirst(asIntegers(), null);
+  }
+
+  @Override
+  public Iterable<Integer> asIntegers() {
+    return field.stream().map(f -> f.numericValue().intValue()).collect(toImmutableList());
+  }
+
+  @Override
+  public Long asLong() {
+    return Iterables.getFirst(asLongs(), null);
+  }
+
+  @Override
+  public Iterable<Long> asLongs() {
+    return field.stream().map(f -> f.numericValue().longValue()).collect(toImmutableList());
+  }
+
+  @Override
+  public Timestamp asTimestamp() {
+    return asLong() == null ? null : new Timestamp(asLong());
+  }
+
+  @Override
+  public byte[] asByteArray() {
+    return Iterables.getFirst(asByteArrays(), null);
+  }
+
+  @Override
+  public Iterable<byte[]> asByteArrays() {
+    return copyAsBytes(field);
+  }
+
+  private static List<byte[]> copyAsBytes(List<IndexableField> fields) {
+    return fields.stream()
+        .map(
+            f -> {
+              BytesRef ref = f.binaryValue();
+              byte[] b = new byte[ref.length];
+              System.arraycopy(ref.bytes, ref.offset, b, 0, ref.length);
+              return b;
+            })
+        .collect(toList());
+  }
+}
diff --git a/java/com/google/gerrit/server/git/receive/ReceiveCommitsAdvertiseRefsHook.java b/java/com/google/gerrit/server/git/receive/ReceiveCommitsAdvertiseRefsHook.java
index 6c1f097..5e951d3 100644
--- a/java/com/google/gerrit/server/git/receive/ReceiveCommitsAdvertiseRefsHook.java
+++ b/java/com/google/gerrit/server/git/receive/ReceiveCommitsAdvertiseRefsHook.java
@@ -27,9 +27,9 @@
 import com.google.gerrit.server.git.HookUtil;
 import com.google.gerrit.server.index.change.ChangeField;
 import com.google.gerrit.server.query.change.ChangeData;
+import com.google.gerrit.server.query.change.ChangePredicates;
 import com.google.gerrit.server.query.change.ChangeStatusPredicate;
 import com.google.gerrit.server.query.change.InternalChangeQuery;
-import com.google.gerrit.server.query.change.OwnerPredicate;
 import com.google.gerrit.server.query.change.ProjectPredicate;
 import com.google.gerrit.server.util.MagicBranch;
 import com.google.inject.Provider;
@@ -118,7 +118,7 @@
                   Predicate.and(
                       new ProjectPredicate(projectName.get()),
                       ChangeStatusPredicate.open(),
-                      new OwnerPredicate(user)))) {
+                      ChangePredicates.owner(user)))) {
         PatchSet ps = cd.currentPatchSet();
         if (ps != null) {
           // Ensure we actually observed a patch set ref pointing to this
diff --git a/java/com/google/gerrit/server/index/change/ChangeField.java b/java/com/google/gerrit/server/index/change/ChangeField.java
index 7e84f1d..7131d44 100644
--- a/java/com/google/gerrit/server/index/change/ChangeField.java
+++ b/java/com/google/gerrit/server/index/change/ChangeField.java
@@ -16,6 +16,7 @@
 
 import static com.google.common.base.MoreObjects.firstNonNull;
 import static com.google.common.collect.ImmutableList.toImmutableList;
+import static com.google.common.collect.ImmutableListMultimap.toImmutableListMultimap;
 import static com.google.common.collect.ImmutableSet.toImmutableSet;
 import static com.google.gerrit.index.FieldDef.exact;
 import static com.google.gerrit.index.FieldDef.fullText;
@@ -57,6 +58,7 @@
 import com.google.gerrit.entities.converter.PatchSetProtoConverter;
 import com.google.gerrit.entities.converter.ProtoConverter;
 import com.google.gerrit.index.FieldDef;
+import com.google.gerrit.index.RefState;
 import com.google.gerrit.index.SchemaUtil;
 import com.google.gerrit.json.OutputFormat;
 import com.google.gerrit.proto.Protos;
@@ -71,6 +73,7 @@
 import com.google.gerrit.server.query.change.ChangeQueryBuilder;
 import com.google.gerrit.server.query.change.ChangeStatusPredicate;
 import com.google.gson.Gson;
+import com.google.protobuf.MessageLite;
 import java.sql.Timestamp;
 import java.time.Instant;
 import java.util.ArrayList;
@@ -84,6 +87,7 @@
 import java.util.Set;
 import java.util.function.Function;
 import java.util.stream.Stream;
+import java.util.stream.StreamSupport;
 import org.eclipse.jgit.lib.PersonIdent;
 
 /**
@@ -153,7 +157,7 @@
   public static final FieldDef<ChangeData, Timestamp> MERGED_ON =
       timestamp(ChangeQueryBuilder.FIELD_MERGED_ON)
           .stored()
-          .build(cd -> cd.getMergedOn().orElse(null));
+          .build(cd -> cd.getMergedOn().orElse(null), (cd, field) -> cd.setMergedOn(field));
 
   /** List of full file paths modified in the current patch set. */
   public static final FieldDef<ChangeData, Iterable<String>> PATH =
@@ -188,7 +192,12 @@
   public static final FieldDef<ChangeData, Iterable<byte[]>> HASHTAG_CASE_AWARE =
       storedOnly("_hashtag")
           .buildRepeatable(
-              cd -> cd.hashtags().stream().map(t -> t.getBytes(UTF_8)).collect(toSet()));
+              cd -> cd.hashtags().stream().map(t -> t.getBytes(UTF_8)).collect(toSet()),
+              (cd, field) ->
+                  cd.setHashtags(
+                      StreamSupport.stream(field.spliterator(), false)
+                          .map(f -> new String(f, UTF_8))
+                          .collect(toImmutableSet())));
 
   /** Components of each file path modified in the current patch set. */
   public static final FieldDef<ChangeData, Iterable<String>> FILE_PART =
@@ -335,7 +344,14 @@
    */
   public static final FieldDef<ChangeData, Iterable<byte[]>> ATTENTION_SET_FULL =
       storedOnly(ChangeQueryBuilder.FIELD_ATTENTION_SET_FULL)
-          .buildRepeatable(ChangeField::storedAttentionSet);
+          .buildRepeatable(
+              ChangeField::storedAttentionSet,
+              (cd, value) ->
+                  parseAttentionSet(
+                      StreamSupport.stream(value.spliterator(), false)
+                          .map(v -> new String(v, UTF_8))
+                          .collect(toImmutableSet()),
+                      cd));
 
   /** The user assigned to the change. */
   public static final FieldDef<ChangeData, Integer> ASSIGNEE =
@@ -344,25 +360,38 @@
 
   /** Reviewer(s) associated with the change. */
   public static final FieldDef<ChangeData, Iterable<String>> REVIEWER =
-      exact("reviewer2").stored().buildRepeatable(cd -> getReviewerFieldValues(cd.reviewers()));
+      exact("reviewer2")
+          .stored()
+          .buildRepeatable(
+              cd -> getReviewerFieldValues(cd.reviewers()),
+              (cd, field) -> cd.setReviewers(parseReviewerFieldValues(cd.getId(), field)));
 
   /** Reviewer(s) associated with the change that do not have a gerrit account. */
   public static final FieldDef<ChangeData, Iterable<String>> REVIEWER_BY_EMAIL =
       exact("reviewer_by_email")
           .stored()
-          .buildRepeatable(cd -> getReviewerByEmailFieldValues(cd.reviewersByEmail()));
+          .buildRepeatable(
+              cd -> getReviewerByEmailFieldValues(cd.reviewersByEmail()),
+              (cd, field) ->
+                  cd.setReviewersByEmail(parseReviewerByEmailFieldValues(cd.getId(), field)));
 
   /** Reviewer(s) modified during change's current WIP phase. */
   public static final FieldDef<ChangeData, Iterable<String>> PENDING_REVIEWER =
       exact(ChangeQueryBuilder.FIELD_PENDING_REVIEWER)
           .stored()
-          .buildRepeatable(cd -> getReviewerFieldValues(cd.pendingReviewers()));
+          .buildRepeatable(
+              cd -> getReviewerFieldValues(cd.pendingReviewers()),
+              (cd, field) -> cd.setPendingReviewers(parseReviewerFieldValues(cd.getId(), field)));
 
   /** Reviewer(s) by email modified during change's current WIP phase. */
   public static final FieldDef<ChangeData, Iterable<String>> PENDING_REVIEWER_BY_EMAIL =
       exact(ChangeQueryBuilder.FIELD_PENDING_REVIEWER_BY_EMAIL)
           .stored()
-          .buildRepeatable(cd -> getReviewerByEmailFieldValues(cd.pendingReviewersByEmail()));
+          .buildRepeatable(
+              cd -> getReviewerByEmailFieldValues(cd.pendingReviewersByEmail()),
+              (cd, field) ->
+                  cd.setPendingReviewersByEmail(
+                      parseReviewerByEmailFieldValues(cd.getId(), field)));
 
   /** References a change that this change reverts. */
   public static final FieldDef<ChangeData, Integer> REVERT_OF =
@@ -642,13 +671,18 @@
   /** Serialized change object, used for pre-populating results. */
   public static final FieldDef<ChangeData, byte[]> CHANGE =
       storedOnly("_change")
-          .build(changeGetter(change -> toProto(ChangeProtoConverter.INSTANCE, change)));
+          .build(
+              changeGetter(change -> toProto(ChangeProtoConverter.INSTANCE, change)),
+              (cd, field) -> cd.setChange(parseProtoFrom(field, ChangeProtoConverter.INSTANCE)));
 
   /** Serialized approvals for the current patch set, used for pre-populating results. */
   public static final FieldDef<ChangeData, Iterable<byte[]>> APPROVAL =
       storedOnly("_approval")
           .buildRepeatable(
-              cd -> toProtos(PatchSetApprovalProtoConverter.INSTANCE, cd.currentApprovals()));
+              cd -> toProtos(PatchSetApprovalProtoConverter.INSTANCE, cd.currentApprovals()),
+              (cd, field) ->
+                  cd.setCurrentApprovals(
+                      decodeProtos(field, PatchSetApprovalProtoConverter.INSTANCE)));
 
   public static String formatLabel(String label, int value) {
     return formatLabel(label, value, null);
@@ -689,11 +723,14 @@
   /** Number of unresolved comment threads of the change, including robot comments. */
   public static final FieldDef<ChangeData, Integer> UNRESOLVED_COMMENT_COUNT =
       intRange(ChangeQueryBuilder.FIELD_UNRESOLVED_COMMENT_COUNT)
-          .build(ChangeData::unresolvedCommentCount);
+          .build(
+              ChangeData::unresolvedCommentCount,
+              (cd, field) -> cd.setUnresolvedCommentCount(field));
 
   /** Total number of published inline comments of the change, including robot comments. */
   public static final FieldDef<ChangeData, Integer> TOTAL_COMMENT_COUNT =
-      intRange("total_comments").build(ChangeData::totalCommentCount);
+      intRange("total_comments")
+          .build(ChangeData::totalCommentCount, (cd, field) -> cd.setTotalCommentCount(field));
 
   /** Whether the change is mergeable. */
   public static final FieldDef<ChangeData, String> MERGEABLE =
@@ -706,7 +743,8 @@
                   return null;
                 }
                 return m ? "1" : "0";
-              });
+              },
+              (cd, field) -> cd.setMergeable(field == null ? false : field.equals("1")));
 
   /** Whether the change is a merge commit. */
   public static final FieldDef<ChangeData, String> MERGE =
@@ -724,12 +762,16 @@
   /** The number of inserted lines in this change. */
   public static final FieldDef<ChangeData, Integer> ADDED =
       intRange(ChangeQueryBuilder.FIELD_ADDED)
-          .build(cd -> cd.changedLines().isPresent() ? cd.changedLines().get().insertions : null);
+          .build(
+              cd -> cd.changedLines().isPresent() ? cd.changedLines().get().insertions : null,
+              (cd, field) -> cd.setLinesInserted(field));
 
   /** The number of deleted lines in this change. */
   public static final FieldDef<ChangeData, Integer> DELETED =
       intRange(ChangeQueryBuilder.FIELD_DELETED)
-          .build(cd -> cd.changedLines().isPresent() ? cd.changedLines().get().deletions : null);
+          .build(
+              cd -> cd.changedLines().isPresent() ? cd.changedLines().get().deletions : null,
+              (cd, field) -> cd.setLinesDeleted(field));
 
   /** The total number of modified lines in this change. */
   public static final FieldDef<ChangeData, Integer> DELTA =
@@ -770,8 +812,12 @@
                   Iterables.transform(
                       cd.stars().entries(),
                       e ->
-                          StarredChangesUtil.StarField.create(e.getKey(), e.getValue())
-                              .toString()));
+                          StarredChangesUtil.StarField.create(e.getKey(), e.getValue()).toString()),
+              (cd, field) ->
+                  cd.setStars(
+                      StreamSupport.stream(field.spliterator(), false)
+                          .map(f -> StarredChangesUtil.StarField.parse(f))
+                          .collect(toImmutableListMultimap(e -> e.accountId(), e -> e.label()))));
 
   /** Users that have starred the change with any label. */
   public static final FieldDef<ChangeData, Iterable<Integer>> STARBY =
@@ -787,7 +833,9 @@
   /** Serialized patch set object, used for pre-populating results. */
   public static final FieldDef<ChangeData, Iterable<byte[]>> PATCH_SET =
       storedOnly("_patch_set")
-          .buildRepeatable(cd -> toProtos(PatchSetProtoConverter.INSTANCE, cd.patchSets()));
+          .buildRepeatable(
+              cd -> toProtos(PatchSetProtoConverter.INSTANCE, cd.patchSets()),
+              (cd, field) -> cd.setPatchSets(decodeProtos(field, PatchSetProtoConverter.INSTANCE)));
 
   /** Users who have edits on this change. */
   public static final FieldDef<ChangeData, Iterable<Integer>> EDITBY =
@@ -821,7 +869,12 @@
                   return ImmutableSet.of(NOT_REVIEWED);
                 }
                 return reviewedBy.stream().map(Account.Id::get).collect(toList());
-              });
+              },
+              (cd, field) ->
+                  cd.setReviewedBy(
+                      StreamSupport.stream(field.spliterator(), false)
+                          .map(Account::id)
+                          .collect(toImmutableSet())));
 
   public static final SubmitRuleOptions SUBMIT_RULE_OPTIONS_LENIENT =
       SubmitRuleOptions.builder().recomputeOnClosedChanges(true).build();
@@ -917,11 +970,27 @@
 
   public static final FieldDef<ChangeData, Iterable<byte[]>> STORED_SUBMIT_RECORD_STRICT =
       storedOnly("full_submit_record_strict")
-          .buildRepeatable(cd -> storedSubmitRecords(cd, SUBMIT_RULE_OPTIONS_STRICT));
+          .buildRepeatable(
+              cd -> storedSubmitRecords(cd, SUBMIT_RULE_OPTIONS_STRICT),
+              (cd, field) ->
+                  parseSubmitRecords(
+                      StreamSupport.stream(field.spliterator(), false)
+                          .map(f -> new String(f, UTF_8))
+                          .collect(toSet()),
+                      SUBMIT_RULE_OPTIONS_STRICT,
+                      cd));
 
   public static final FieldDef<ChangeData, Iterable<byte[]>> STORED_SUBMIT_RECORD_LENIENT =
       storedOnly("full_submit_record_lenient")
-          .buildRepeatable(cd -> storedSubmitRecords(cd, SUBMIT_RULE_OPTIONS_LENIENT));
+          .buildRepeatable(
+              cd -> storedSubmitRecords(cd, SUBMIT_RULE_OPTIONS_LENIENT),
+              (cd, field) ->
+                  parseSubmitRecords(
+                      StreamSupport.stream(field.spliterator(), false)
+                          .map(f -> new String(f, UTF_8))
+                          .collect(toSet()),
+                      SUBMIT_RULE_OPTIONS_LENIENT,
+                      cd));
 
   public static void parseSubmitRecords(
       Collection<String> values, SubmitRuleOptions opts, ChangeData out) {
@@ -987,7 +1056,8 @@
                     .entries()
                     .forEach(e -> result.add(e.getValue().toByteArray(e.getKey())));
                 return result;
-              });
+              },
+              (cd, field) -> cd.setRefStates(RefState.parseStates(field)));
 
   /**
    * All ref wildcard patterns that were used in the course of indexing this document.
@@ -1013,7 +1083,8 @@
                     RefStatePattern.create(RefNames.refsDraftCommentsPrefix(id) + "*")
                         .toByteArray(allUsers(cd)));
                 return result;
-              });
+              },
+              (cd, field) -> cd.setRefStatePatterns(field));
 
   private static String getTopic(ChangeData cd) {
     Change c = cd.change();
@@ -1031,6 +1102,18 @@
     return Protos.toByteArray(converter.toProto(object));
   }
 
+  private static <T> List<T> decodeProtos(Iterable<byte[]> raw, ProtoConverter<?, T> converter) {
+    return StreamSupport.stream(raw.spliterator(), false)
+        .map(bytes -> parseProtoFrom(bytes, converter))
+        .collect(toImmutableList());
+  }
+
+  private static <P extends MessageLite, T> T parseProtoFrom(
+      byte[] bytes, ProtoConverter<P, T> converter) {
+    P message = Protos.parseUnchecked(converter.getParser(), bytes, 0, bytes.length);
+    return converter.fromProto(message);
+  }
+
   private static <T> FieldDef.Getter<ChangeData, T> changeGetter(Function<Change, T> func) {
     return in -> in.change() != null ? func.apply(in.change()) : null;
   }
diff --git a/java/com/google/gerrit/server/index/change/ChangeIndex.java b/java/com/google/gerrit/server/index/change/ChangeIndex.java
index 49d0d4e..b8a5cd9 100644
--- a/java/com/google/gerrit/server/index/change/ChangeIndex.java
+++ b/java/com/google/gerrit/server/index/change/ChangeIndex.java
@@ -19,7 +19,7 @@
 import com.google.gerrit.index.IndexDefinition;
 import com.google.gerrit.index.query.Predicate;
 import com.google.gerrit.server.query.change.ChangeData;
-import com.google.gerrit.server.query.change.LegacyChangeIdPredicate;
+import com.google.gerrit.server.query.change.ChangePredicates;
 import com.google.gerrit.server.query.change.LegacyChangeIdStrPredicate;
 
 /**
@@ -32,7 +32,7 @@
   @Override
   default Predicate<ChangeData> keyPredicate(Change.Id id) {
     return getSchema().useLegacyNumericFields()
-        ? new LegacyChangeIdPredicate(id)
+        ? ChangePredicates.id(id)
         : new LegacyChangeIdStrPredicate(id);
   }
 }
diff --git a/java/com/google/gerrit/server/query/change/AssigneePredicate.java b/java/com/google/gerrit/server/query/change/AssigneePredicate.java
deleted file mode 100644
index 35a91c9..0000000
--- a/java/com/google/gerrit/server/query/change/AssigneePredicate.java
+++ /dev/null
@@ -1,41 +0,0 @@
-// Copyright (C) 2016 The Android Open Source Project
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-// http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-
-package com.google.gerrit.server.query.change;
-
-import com.google.gerrit.entities.Account;
-import com.google.gerrit.server.index.change.ChangeField;
-
-public class AssigneePredicate extends ChangeIndexPredicate {
-  protected final Account.Id id;
-
-  public AssigneePredicate(Account.Id id) {
-    super(ChangeField.ASSIGNEE, id.toString());
-    this.id = id;
-  }
-
-  @Override
-  public boolean match(ChangeData object) {
-    if (id.get() == ChangeField.NO_ASSIGNEE) {
-      Account.Id assignee = object.change().getAssignee();
-      return assignee == null;
-    }
-    return id.equals(object.change().getAssignee());
-  }
-
-  @Override
-  public int getCost() {
-    return 1;
-  }
-}
diff --git a/java/com/google/gerrit/server/query/change/AttentionSetPredicate.java b/java/com/google/gerrit/server/query/change/AttentionSetPredicate.java
deleted file mode 100644
index 2b18767..0000000
--- a/java/com/google/gerrit/server/query/change/AttentionSetPredicate.java
+++ /dev/null
@@ -1,41 +0,0 @@
-// Copyright (C) 2020 The Android Open Source Project
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-// http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-
-package com.google.gerrit.server.query.change;
-
-import static com.google.gerrit.server.util.AttentionSetUtil.additionsOnly;
-
-import com.google.gerrit.entities.Account;
-import com.google.gerrit.server.index.change.ChangeField;
-
-/** Simple predicate for searching by attention set. */
-public class AttentionSetPredicate extends ChangeIndexPredicate {
-  protected final Account.Id id;
-
-  AttentionSetPredicate(Account.Id id) {
-    super(ChangeField.ATTENTION_SET_USERS, id.toString());
-    this.id = id;
-  }
-
-  @Override
-  public boolean match(ChangeData changeData) {
-    return additionsOnly(changeData.attentionSet()).stream()
-        .anyMatch(update -> update.account().equals(id));
-  }
-
-  @Override
-  public int getCost() {
-    return 1;
-  }
-}
diff --git a/java/com/google/gerrit/server/query/change/AuthorPredicate.java b/java/com/google/gerrit/server/query/change/AuthorPredicate.java
index 79914a3..6e362ad 100644
--- a/java/com/google/gerrit/server/query/change/AuthorPredicate.java
+++ b/java/com/google/gerrit/server/query/change/AuthorPredicate.java
@@ -28,9 +28,4 @@
   public boolean match(ChangeData object) {
     return ChangeField.getAuthorParts(object).contains(getValue().toLowerCase());
   }
-
-  @Override
-  public int getCost() {
-    return 1;
-  }
 }
diff --git a/java/com/google/gerrit/server/query/change/BooleanPredicate.java b/java/com/google/gerrit/server/query/change/BooleanPredicate.java
index 68f83e8..6ca3acc 100644
--- a/java/com/google/gerrit/server/query/change/BooleanPredicate.java
+++ b/java/com/google/gerrit/server/query/change/BooleanPredicate.java
@@ -25,9 +25,4 @@
   public boolean match(ChangeData object) {
     return getValue().equals(getField().get(object));
   }
-
-  @Override
-  public int getCost() {
-    return 1;
-  }
 }
diff --git a/java/com/google/gerrit/server/query/change/ChangeData.java b/java/com/google/gerrit/server/query/change/ChangeData.java
index 793e4ec..84c6de0 100644
--- a/java/com/google/gerrit/server/query/change/ChangeData.java
+++ b/java/com/google/gerrit/server/query/change/ChangeData.java
@@ -22,6 +22,7 @@
 import com.google.auto.value.AutoValue;
 import com.google.common.annotations.VisibleForTesting;
 import com.google.common.base.MoreObjects;
+import com.google.common.collect.HashBasedTable;
 import com.google.common.collect.ImmutableList;
 import com.google.common.collect.ImmutableListMultimap;
 import com.google.common.collect.ImmutableMap;
@@ -33,6 +34,7 @@
 import com.google.common.collect.Lists;
 import com.google.common.collect.Maps;
 import com.google.common.collect.SetMultimap;
+import com.google.common.collect.Table;
 import com.google.common.flogger.FluentLogger;
 import com.google.common.primitives.Ints;
 import com.google.gerrit.common.Nullable;
@@ -319,9 +321,15 @@
   private SubmitTypeRecord submitTypeRecord;
   private Boolean mergeable;
   private Set<String> hashtags;
-  private Map<Account.Id, Ref> editsByUser;
+  /** Map from {@link Account.Id} to the tip of the edit ref for this change and a given user. */
+  private Table<Account.Id, PatchSet.Id, ObjectId> editsByUser;
+
   private Set<Account.Id> reviewedBy;
-  private Map<Account.Id, Ref> draftsByUser;
+  /**
+   * Map from {@link Account.Id} to the tip of the draft comments ref for this change and the user.
+   */
+  private Map<Account.Id, ObjectId> draftsByUser;
+
   private ImmutableListMultimap<Account.Id, String> stars;
   private StarsOf starsOf;
   private ImmutableMap<Account.Id, StarRef> starRefs;
@@ -471,6 +479,26 @@
     changedLines = Optional.of(new ChangedLines(insertions, deletions));
   }
 
+  public void setLinesInserted(int insertions) {
+    changedLines =
+        Optional.of(
+            new ChangedLines(
+                insertions,
+                changedLines != null && changedLines.isPresent()
+                    ? changedLines.get().deletions
+                    : -1));
+  }
+
+  public void setLinesDeleted(int deletions) {
+    changedLines =
+        Optional.of(
+            new ChangedLines(
+                changedLines != null && changedLines.isPresent()
+                    ? changedLines.get().insertions
+                    : -1,
+                deletions));
+  }
+
   public void setNoChangedLines() {
     changedLines = Optional.empty();
   }
@@ -994,27 +1022,30 @@
   }
 
   public Set<Account.Id> editsByUser() {
-    return editRefs().keySet();
+    return editRefs().rowKeySet();
   }
 
-  public Map<Account.Id, Ref> editRefs() {
+  public Table<Account.Id, PatchSet.Id, ObjectId> editRefs() {
     if (editsByUser == null) {
       if (!lazyload()) {
-        return Collections.emptyMap();
+        return HashBasedTable.create();
       }
       Change c = change();
       if (c == null) {
-        return Collections.emptyMap();
+        return HashBasedTable.create();
       }
-      editsByUser = new HashMap<>();
+      editsByUser = HashBasedTable.create();
       Change.Id id = requireNonNull(change.getId());
       try (Repository repo = repoManager.openRepository(project())) {
         for (Ref ref : repo.getRefDatabase().getRefsByPrefix(RefNames.REFS_USERS)) {
-          String name = ref.getName().substring(RefNames.REFS_USERS.length());
-          if (id.equals(Change.Id.fromEditRefPart(name))) {
-            Account.Id accountId = Account.Id.fromRefPart(name);
+          if (!RefNames.isRefsEdit(ref.getName())) {
+            continue;
+          }
+          PatchSet.Id ps = PatchSet.Id.fromEditRef(ref.getName());
+          if (id.equals(ps.changeId())) {
+            Account.Id accountId = Account.Id.fromRef(ref.getName());
             if (accountId != null) {
-              editsByUser.put(accountId, ref);
+              editsByUser.put(accountId, ps, ref.getObjectId());
             }
           }
         }
@@ -1029,34 +1060,6 @@
     return draftRefs().keySet();
   }
 
-  public Map<Account.Id, Ref> draftRefs() {
-    if (draftsByUser == null) {
-      if (!lazyload()) {
-        return Collections.emptyMap();
-      }
-      Change c = change();
-      if (c == null) {
-        return Collections.emptyMap();
-      }
-
-      draftsByUser = new HashMap<>();
-      for (Ref ref : commentsUtil.getDraftRefs(notes.getChangeId())) {
-        Account.Id account = Account.Id.fromRefSuffix(ref.getName());
-        if (account != null
-            // Double-check that any drafts exist for this user after
-            // filtering out zombies. If some but not all drafts in the ref
-            // were zombies, the returned Ref still includes those zombies;
-            // this is suboptimal, but is ok for the purposes of
-            // draftsByUser(), and easier than trying to rebuild the change at
-            // this point.
-            && !notes().getDraftComments(account, ref).isEmpty()) {
-          draftsByUser.put(account, ref);
-        }
-      }
-    }
-    return draftsByUser;
-  }
-
   public boolean isReviewedBy(Account.Id accountId) {
     Collection<String> stars = stars(accountId);
 
@@ -1211,7 +1214,14 @@
       }
 
       ImmutableSetMultimap.Builder<NameKey, RefState> result = ImmutableSetMultimap.builder();
-      editRefs().values().forEach(r -> result.put(project, RefState.of(r)));
+      for (Table.Cell<Account.Id, PatchSet.Id, ObjectId> edit : editRefs().cellSet()) {
+        result.put(
+            project,
+            RefState.create(
+                RefNames.refsEdit(
+                    edit.getRowKey(), edit.getColumnKey().changeId(), edit.getColumnKey()),
+                edit.getValue()));
+      }
       starRefs().values().forEach(r -> result.put(allUsersName, RefState.of(r.ref())));
 
       // TODO: instantiating the notes is too much. We don't want to parse NoteDb, we just want the
@@ -1220,7 +1230,14 @@
       notes().getRobotComments(); // Force loading robot comments.
       RobotCommentNotes robotNotes = notes().getRobotCommentNotes();
       result.put(project, RefState.create(robotNotes.getRefName(), robotNotes.getMetaId()));
-      draftRefs().values().forEach(r -> result.put(allUsersName, RefState.of(r)));
+      draftRefs()
+          .entrySet()
+          .forEach(
+              r ->
+                  result.put(
+                      allUsersName,
+                      RefState.create(
+                          RefNames.refsDraftComments(getId(), r.getKey()), r.getValue())));
 
       refStates = result.build();
     }
@@ -1236,6 +1253,33 @@
 
   public void setRefStates(ImmutableSetMultimap<Project.NameKey, RefState> refStates) {
     this.refStates = refStates;
+    if (draftsByUser == null) {
+      // Recover draft refs as well. Draft comments are represented as refs in the repository.
+      // ChangeData exposes #draftsByUser which just provides a Set of Account.Ids of users who
+      // have drafts comments on this change. Recovering this list from RefStates makes it
+      // available even on ChangeData instances retrieved from the index.
+      draftsByUser = new HashMap<>();
+      if (refStates.containsKey(allUsersName)) {
+        refStates.get(allUsersName).stream()
+            .filter(r -> RefNames.isRefsDraftsComments(r.ref()))
+            .forEach(r -> draftsByUser.put(Account.Id.fromRef(r.ref()), r.id()));
+      }
+    }
+    if (editsByUser == null) {
+      // Recover edit refs as well. Edits are represented as refs in the repository.
+      // ChangeData exposes #editsByUser which just provides a Set of Account.Ids of users who
+      // have edits on this change. Recovering this list from RefStates makes it available even
+      // on ChangeData instances retrieved from the index.
+      editsByUser = HashBasedTable.create();
+      if (refStates.containsKey(project())) {
+        refStates.get(project()).stream()
+            .filter(r -> RefNames.isRefsEdit(r.ref()))
+            .forEach(
+                r ->
+                    editsByUser.put(
+                        Account.Id.fromRef(r.ref()), PatchSet.Id.fromEditRef(r.ref()), r.id()));
+      }
+    }
   }
 
   public ImmutableList<byte[]> getRefStatePatterns() {
@@ -1267,4 +1311,32 @@
 
     public abstract ImmutableSortedSet<String> stars();
   }
+
+  private Map<Account.Id, ObjectId> draftRefs() {
+    if (draftsByUser == null) {
+      if (!lazyload()) {
+        return Collections.emptyMap();
+      }
+      Change c = change();
+      if (c == null) {
+        return Collections.emptyMap();
+      }
+
+      draftsByUser = new HashMap<>();
+      for (Ref ref : commentsUtil.getDraftRefs(notes.getChangeId())) {
+        Account.Id account = Account.Id.fromRefSuffix(ref.getName());
+        if (account != null
+            // Double-check that any drafts exist for this user after
+            // filtering out zombies. If some but not all drafts in the ref
+            // were zombies, the returned Ref still includes those zombies;
+            // this is suboptimal, but is ok for the purposes of
+            // draftsByUser(), and easier than trying to rebuild the change at
+            // this point.
+            && !notes().getDraftComments(account, ref).isEmpty()) {
+          draftsByUser.put(account, ref.getObjectId());
+        }
+      }
+    }
+    return draftsByUser;
+  }
 }
diff --git a/java/com/google/gerrit/server/query/change/ChangeIdPredicate.java b/java/com/google/gerrit/server/query/change/ChangeIdPredicate.java
index 05cc6ca..f06d1f2 100644
--- a/java/com/google/gerrit/server/query/change/ChangeIdPredicate.java
+++ b/java/com/google/gerrit/server/query/change/ChangeIdPredicate.java
@@ -36,9 +36,4 @@
     }
     return false;
   }
-
-  @Override
-  public int getCost() {
-    return 1;
-  }
 }
diff --git a/java/com/google/gerrit/server/query/change/ChangeIndexPredicate.java b/java/com/google/gerrit/server/query/change/ChangeIndexPredicate.java
index a176a58..28bfb0b 100644
--- a/java/com/google/gerrit/server/query/change/ChangeIndexPredicate.java
+++ b/java/com/google/gerrit/server/query/change/ChangeIndexPredicate.java
@@ -14,13 +14,16 @@
 
 package com.google.gerrit.server.query.change;
 
+import com.google.common.primitives.Ints;
 import com.google.gerrit.index.FieldDef;
+import com.google.gerrit.index.FieldType;
 import com.google.gerrit.index.query.IndexPredicate;
 import com.google.gerrit.index.query.Matchable;
 import com.google.gerrit.index.query.Predicate;
+import java.util.Objects;
 
 /** Predicate that is mapped to a field in the change index. */
-public abstract class ChangeIndexPredicate extends IndexPredicate<ChangeData>
+public class ChangeIndexPredicate extends IndexPredicate<ChangeData>
     implements Matchable<ChangeData> {
   /**
    * Returns an index predicate that matches no changes in the index.
@@ -41,4 +44,32 @@
   protected ChangeIndexPredicate(FieldDef<ChangeData, ?> def, String name, String value) {
     super(def, name, value);
   }
+
+  @Override
+  public boolean match(ChangeData cd) {
+    if (getField().isRepeatable()) {
+      Iterable<Object> values = (Iterable<Object>) getField().get(cd);
+      for (Object v : values) {
+        if (matchesSingleObject(v)) {
+          return true;
+        }
+      }
+      return false;
+    } else {
+      return matchesSingleObject(getField().get(cd));
+    }
+  }
+
+  @Override
+  public int getCost() {
+    return 1;
+  }
+
+  private boolean matchesSingleObject(Object fieldValueFromObject) {
+    String fieldTypeName = getField().getType().getName();
+    if (fieldTypeName.equals(FieldType.INTEGER.getName())) {
+      return Objects.equals(fieldValueFromObject, Ints.tryParse(value));
+    }
+    throw new UnsupportedOperationException("match function must be provided in subclass");
+  }
 }
diff --git a/java/com/google/gerrit/server/query/change/ChangePredicates.java b/java/com/google/gerrit/server/query/change/ChangePredicates.java
new file mode 100644
index 0000000..568916d
--- /dev/null
+++ b/java/com/google/gerrit/server/query/change/ChangePredicates.java
@@ -0,0 +1,122 @@
+// Copyright (C) 2021 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package com.google.gerrit.server.query.change;
+
+import com.google.gerrit.entities.Account;
+import com.google.gerrit.entities.Change;
+import com.google.gerrit.entities.PatchSet;
+import com.google.gerrit.index.query.Predicate;
+import com.google.gerrit.server.index.change.ChangeField;
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.List;
+
+/** Predicates that match against {@link ChangeData}. */
+public class ChangePredicates {
+  private ChangePredicates() {}
+
+  /**
+   * Returns a predicate that matches changes where the provided {@link Account.Id} is in the
+   * attention set.
+   */
+  public static Predicate<ChangeData> attentionSet(Account.Id id) {
+    return new ChangeIndexPredicate(ChangeField.ATTENTION_SET_USERS, id.toString());
+  }
+
+  /**
+   * Returns a predicate that matches changes that are assigned to the provided {@link Account.Id}.
+   */
+  public static Predicate<ChangeData> assignee(Account.Id id) {
+    return new ChangeIndexPredicate(ChangeField.ASSIGNEE, id.toString());
+  }
+
+  /**
+   * Returns a predicate that matches changes that are a revert of the provided {@link Change.Id}.
+   */
+  public static Predicate<ChangeData> revertOf(Change.Id revertOf) {
+    return new ChangeIndexPredicate(ChangeField.REVERT_OF, revertOf.toString());
+  }
+
+  /**
+   * Returns a predicate that matches changes that have a comment authored by the provided {@link
+   * Account.Id}.
+   */
+  public static Predicate<ChangeData> commentBy(Account.Id id) {
+    return new ChangeIndexPredicate(ChangeField.COMMENTBY, id.toString());
+  }
+
+  /**
+   * Returns a predicate that matches changes where the provided {@link Account.Id} has a pending
+   * change edit.
+   */
+  public static Predicate<ChangeData> editBy(Account.Id id) {
+    return new ChangeIndexPredicate(ChangeField.EDITBY, id.toString());
+  }
+
+  /**
+   * Returns a predicate that matches changes where the provided {@link Account.Id} has a pending
+   * draft comment.
+   */
+  public static Predicate<ChangeData> draftBy(Account.Id id) {
+    return new ChangeIndexPredicate(ChangeField.DRAFTBY, id.toString());
+  }
+
+  /**
+   * Returns a predicate that matches changes that were reviewed by any of the provided {@link
+   * Account.Id}.
+   */
+  public static Predicate<ChangeData> reviewedBy(Collection<Account.Id> ids) {
+    List<Predicate<ChangeData>> predicates = new ArrayList<>(ids.size());
+    for (Account.Id id : ids) {
+      predicates.add(new ChangeIndexPredicate(ChangeField.REVIEWEDBY, id.toString()));
+    }
+    return Predicate.or(predicates);
+  }
+
+  /** Returns a predicate that matches changes that were not yet reviewed. */
+  public static Predicate<ChangeData> unreviewed() {
+    return Predicate.not(
+        new ChangeIndexPredicate(ChangeField.REVIEWEDBY, ChangeField.NOT_REVIEWED.toString()));
+  }
+
+  /** Returns a predicate that matches the change with the provided {@link Change.Id}. */
+  public static Predicate<ChangeData> id(Change.Id id) {
+    return new ChangeIndexPredicate(
+        ChangeField.LEGACY_ID, ChangeQueryBuilder.FIELD_CHANGE, id.toString());
+  }
+
+  /** Returns a predicate that matches changes owned by the provided {@link Account.Id}. */
+  public static Predicate<ChangeData> owner(Account.Id id) {
+    return new ChangeIndexPredicate(ChangeField.OWNER, id.toString());
+  }
+
+  /**
+   * Returns a predicate that matches changes that are a cherry pick of the provided {@link
+   * Change.Id}.
+   */
+  public static Predicate<ChangeData> cherryPickOf(Change.Id id) {
+    return new ChangeIndexPredicate(ChangeField.CHERRY_PICK_OF_CHANGE, id.toString());
+  }
+
+  /**
+   * Returns a predicate that matches changes that are a cherry pick of the provided {@link
+   * PatchSet.Id}.
+   */
+  public static Predicate<ChangeData> cherryPickOf(PatchSet.Id psId) {
+    return Predicate.and(
+        cherryPickOf(psId.changeId()),
+        new ChangeIndexPredicate(ChangeField.CHERRY_PICK_OF_PATCHSET, String.valueOf(psId.get())));
+  }
+}
diff --git a/java/com/google/gerrit/server/query/change/ChangeQueryBuilder.java b/java/com/google/gerrit/server/query/change/ChangeQueryBuilder.java
index 6e2f49c..7ebaec7 100644
--- a/java/com/google/gerrit/server/query/change/ChangeQueryBuilder.java
+++ b/java/com/google/gerrit/server/query/change/ChangeQueryBuilder.java
@@ -533,7 +533,7 @@
       Integer id = Ints.tryParse(query);
       if (id != null) {
         return args.getSchema().useLegacyNumericFields()
-            ? new LegacyChangeIdPredicate(Change.id(id))
+            ? ChangePredicates.id(Change.id(id))
             : new LegacyChangeIdStrPredicate(Change.id(id));
       }
     } else if (PAT_CHANGE_ID.matcher(query).matches()) {
@@ -551,7 +551,7 @@
   @Operator
   public Predicate<ChangeData> status(String statusName) {
     if ("reviewed".equalsIgnoreCase(statusName)) {
-      return IsReviewedPredicate.create();
+      return ChangePredicates.unreviewed();
     }
     return ChangeStatusPredicate.parse(statusName);
   }
@@ -576,7 +576,7 @@
     }
 
     if ("edit".equalsIgnoreCase(value)) {
-      return new EditByPredicate(self());
+      return ChangePredicates.editBy(self());
     }
 
     if ("unresolved".equalsIgnoreCase(value)) {
@@ -610,11 +610,11 @@
     }
 
     if ("reviewed".equalsIgnoreCase(value)) {
-      return IsReviewedPredicate.create();
+      return ChangePredicates.unreviewed();
     }
 
     if ("owner".equalsIgnoreCase(value)) {
-      return new OwnerPredicate(self());
+      return ChangePredicates.owner(self());
     }
 
     if ("reviewer".equalsIgnoreCase(value)) {
@@ -653,11 +653,11 @@
     }
 
     if ("assigned".equalsIgnoreCase(value)) {
-      return Predicate.not(new AssigneePredicate(Account.id(ChangeField.NO_ASSIGNEE)));
+      return Predicate.not(ChangePredicates.assignee(Account.id(ChangeField.NO_ASSIGNEE)));
     }
 
     if ("unassigned".equalsIgnoreCase(value)) {
-      return new AssigneePredicate(Account.id(ChangeField.NO_ASSIGNEE));
+      return ChangePredicates.assignee(Account.id(ChangeField.NO_ASSIGNEE));
     }
 
     if ("submittable".equalsIgnoreCase(value)) {
@@ -1060,7 +1060,7 @@
   }
 
   private Predicate<ChangeData> draftby(Account.Id who) {
-    return new HasDraftByPredicate(who);
+    return ChangePredicates.draftBy(who);
   }
 
   @Operator
@@ -1119,9 +1119,9 @@
   }
 
   private Predicate<ChangeData> owner(Set<Account.Id> who) {
-    List<OwnerPredicate> p = Lists.newArrayListWithCapacity(who.size());
+    List<Predicate<ChangeData>> p = Lists.newArrayListWithCapacity(who.size());
     for (Account.Id id : who) {
-      p.add(new OwnerPredicate(id));
+      p.add(ChangePredicates.owner(id));
     }
     return Predicate.or(p);
   }
@@ -1146,7 +1146,7 @@
   }
 
   private Predicate<ChangeData> attention(Set<Account.Id> who) {
-    return Predicate.or(who.stream().map(AttentionSetPredicate::new).collect(toImmutableSet()));
+    return Predicate.or(who.stream().map(ChangePredicates::attentionSet).collect(toImmutableSet()));
   }
 
   @Operator
@@ -1156,9 +1156,9 @@
   }
 
   private Predicate<ChangeData> assignee(Set<Account.Id> who) {
-    List<AssigneePredicate> p = Lists.newArrayListWithCapacity(who.size());
+    List<Predicate<ChangeData>> p = Lists.newArrayListWithCapacity(who.size());
     for (Account.Id id : who) {
-      p.add(new AssigneePredicate(id));
+      p.add(ChangePredicates.assignee(id));
     }
     return Predicate.or(p);
   }
@@ -1177,9 +1177,9 @@
     }
 
     Set<Account.Id> accounts = getMembers(groupId);
-    List<OwnerPredicate> p = Lists.newArrayListWithCapacity(accounts.size());
+    List<Predicate<ChangeData>> p = Lists.newArrayListWithCapacity(accounts.size());
     for (Account.Id id : accounts) {
-      p.add(new OwnerPredicate(id));
+      p.add(ChangePredicates.owner(id));
     }
     return Predicate.or(p);
   }
@@ -1275,9 +1275,9 @@
   }
 
   private Predicate<ChangeData> commentby(Set<Account.Id> who) {
-    List<CommentByPredicate> p = Lists.newArrayListWithCapacity(who.size());
+    List<Predicate<ChangeData>> p = Lists.newArrayListWithCapacity(who.size());
     for (Account.Id id : who) {
-      p.add(new CommentByPredicate(id));
+      p.add(ChangePredicates.commentBy(id));
     }
     return Predicate.or(p);
   }
@@ -1337,7 +1337,7 @@
   @Operator
   public Predicate<ChangeData> reviewedby(String who)
       throws QueryParseException, IOException, ConfigInvalidException {
-    return IsReviewedPredicate.create(parseAccount(who));
+    return ChangePredicates.reviewedBy(parseAccount(who));
   }
 
   @Operator
@@ -1420,8 +1420,11 @@
 
   @Operator
   public Predicate<ChangeData> revertof(String value) throws QueryParseException {
+    if (value == null || Ints.tryParse(value) == null) {
+      throw new QueryParseException("'revertof' must be an integer");
+    }
     if (args.getSchema().hasField(ChangeField.REVERT_OF)) {
-      return new RevertOfPredicate(value);
+      return ChangePredicates.revertOf(Change.id(Ints.tryParse(value)));
     }
     throw new QueryParseException("'revertof' operator is not supported by change index version");
   }
@@ -1440,13 +1443,11 @@
     if (args.getSchema().hasField(ChangeField.CHERRY_PICK_OF_CHANGE)
         && args.getSchema().hasField(ChangeField.CHERRY_PICK_OF_PATCHSET)) {
       if (Ints.tryParse(value) != null) {
-        return new CherryPickOfChangePredicate(value);
+        return ChangePredicates.cherryPickOf(Change.id(Ints.tryParse(value)));
       }
       try {
         PatchSet.Id patchSetId = PatchSet.Id.parse(value);
-        return Predicate.and(
-            new CherryPickOfChangePredicate(patchSetId.changeId().toString()),
-            new CherryPickOfPatchSetPredicate(patchSetId.getId()));
+        return ChangePredicates.cherryPickOf(patchSetId);
       } catch (IllegalArgumentException e) {
         throw new QueryParseException(
             "'"
diff --git a/java/com/google/gerrit/server/query/change/ChangeStatusPredicate.java b/java/com/google/gerrit/server/query/change/ChangeStatusPredicate.java
index 88e93d9..0721433 100644
--- a/java/com/google/gerrit/server/query/change/ChangeStatusPredicate.java
+++ b/java/com/google/gerrit/server/query/change/ChangeStatusPredicate.java
@@ -124,11 +124,6 @@
   }
 
   @Override
-  public int getCost() {
-    return 0;
-  }
-
-  @Override
   public int hashCode() {
     return Objects.hashCode(status);
   }
diff --git a/java/com/google/gerrit/server/query/change/CherryPickOfChangePredicate.java b/java/com/google/gerrit/server/query/change/CherryPickOfChangePredicate.java
deleted file mode 100644
index d452017..0000000
--- a/java/com/google/gerrit/server/query/change/CherryPickOfChangePredicate.java
+++ /dev/null
@@ -1,36 +0,0 @@
-// Copyright (C) 2019 The Android Open Source Project
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-// http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-
-package com.google.gerrit.server.query.change;
-
-import com.google.gerrit.server.index.change.ChangeField;
-
-public class CherryPickOfChangePredicate extends ChangeIndexPredicate {
-  public CherryPickOfChangePredicate(String cherryPickOfChange) {
-    super(ChangeField.CHERRY_PICK_OF_CHANGE, cherryPickOfChange);
-  }
-
-  @Override
-  public boolean match(ChangeData cd) {
-    if (cd.change().getCherryPickOf() == null) {
-      return false;
-    }
-    return Integer.toString(cd.change().getCherryPickOf().changeId().get()).equals(value);
-  }
-
-  @Override
-  public int getCost() {
-    return 1;
-  }
-}
diff --git a/java/com/google/gerrit/server/query/change/CherryPickOfPatchSetPredicate.java b/java/com/google/gerrit/server/query/change/CherryPickOfPatchSetPredicate.java
deleted file mode 100644
index 888f45d..0000000
--- a/java/com/google/gerrit/server/query/change/CherryPickOfPatchSetPredicate.java
+++ /dev/null
@@ -1,36 +0,0 @@
-// Copyright (C) 2019 The Android Open Source Project
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-// http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-
-package com.google.gerrit.server.query.change;
-
-import com.google.gerrit.server.index.change.ChangeField;
-
-public class CherryPickOfPatchSetPredicate extends ChangeIndexPredicate {
-  public CherryPickOfPatchSetPredicate(String cherryPickOfPatchSet) {
-    super(ChangeField.CHERRY_PICK_OF_PATCHSET, cherryPickOfPatchSet);
-  }
-
-  @Override
-  public boolean match(ChangeData cd) {
-    if (cd.change().getCherryPickOf() == null) {
-      return false;
-    }
-    return cd.change().getCherryPickOf().getId().equals(value);
-  }
-
-  @Override
-  public int getCost() {
-    return 1;
-  }
-}
diff --git a/java/com/google/gerrit/server/query/change/CommentByPredicate.java b/java/com/google/gerrit/server/query/change/CommentByPredicate.java
deleted file mode 100644
index b8cf100..0000000
--- a/java/com/google/gerrit/server/query/change/CommentByPredicate.java
+++ /dev/null
@@ -1,54 +0,0 @@
-// Copyright (C) 2015 The Android Open Source Project
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-// http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-
-package com.google.gerrit.server.query.change;
-
-import com.google.gerrit.entities.Account;
-import com.google.gerrit.entities.ChangeMessage;
-import com.google.gerrit.entities.HumanComment;
-import com.google.gerrit.server.index.change.ChangeField;
-import java.util.Objects;
-
-public class CommentByPredicate extends ChangeIndexPredicate {
-  protected final Account.Id id;
-
-  public CommentByPredicate(Account.Id id) {
-    super(ChangeField.COMMENTBY, id.toString());
-    this.id = id;
-  }
-
-  Account.Id getAccountId() {
-    return id;
-  }
-
-  @Override
-  public boolean match(ChangeData cd) {
-    for (ChangeMessage m : cd.messages()) {
-      if (Objects.equals(m.getAuthor(), id)) {
-        return true;
-      }
-    }
-    for (HumanComment c : cd.publishedComments()) {
-      if (Objects.equals(c.author.getId(), id)) {
-        return true;
-      }
-    }
-    return false;
-  }
-
-  @Override
-  public int getCost() {
-    return 1;
-  }
-}
diff --git a/java/com/google/gerrit/server/query/change/CommentPredicate.java b/java/com/google/gerrit/server/query/change/CommentPredicate.java
index 4b14f08..0abe45d 100644
--- a/java/com/google/gerrit/server/query/change/CommentPredicate.java
+++ b/java/com/google/gerrit/server/query/change/CommentPredicate.java
@@ -37,7 +37,7 @@
       Predicate<ChangeData> p =
           Predicate.and(
               index.getSchema().useLegacyNumericFields()
-                  ? new LegacyChangeIdPredicate(id)
+                  ? ChangePredicates.id(id)
                   : new LegacyChangeIdStrPredicate(id),
               this);
       for (ChangeData cData : index.getSource(p, IndexedChangeQuery.oneResult()).read()) {
@@ -51,9 +51,4 @@
 
     return false;
   }
-
-  @Override
-  public int getCost() {
-    return 1;
-  }
 }
diff --git a/java/com/google/gerrit/server/query/change/CommitPredicate.java b/java/com/google/gerrit/server/query/change/CommitPredicate.java
index b54ee64..2b3b345 100644
--- a/java/com/google/gerrit/server/query/change/CommitPredicate.java
+++ b/java/com/google/gerrit/server/query/change/CommitPredicate.java
@@ -51,9 +51,4 @@
     }
     return matchesAbbreviation(p.commitId(), id);
   }
-
-  @Override
-  public int getCost() {
-    return 1;
-  }
 }
diff --git a/java/com/google/gerrit/server/query/change/CommitterPredicate.java b/java/com/google/gerrit/server/query/change/CommitterPredicate.java
index 1dcf97f..65034a2 100644
--- a/java/com/google/gerrit/server/query/change/CommitterPredicate.java
+++ b/java/com/google/gerrit/server/query/change/CommitterPredicate.java
@@ -28,9 +28,4 @@
   public boolean match(ChangeData object) {
     return ChangeField.getCommitterParts(object).contains(getValue().toLowerCase());
   }
-
-  @Override
-  public int getCost() {
-    return 1;
-  }
 }
diff --git a/java/com/google/gerrit/server/query/change/ConflictsPredicate.java b/java/com/google/gerrit/server/query/change/ConflictsPredicate.java
index 16f85b1..80e3cb9 100644
--- a/java/com/google/gerrit/server/query/change/ConflictsPredicate.java
+++ b/java/com/google/gerrit/server/query/change/ConflictsPredicate.java
@@ -90,7 +90,7 @@
     and.add(
         Predicate.not(
             args.getSchema().useLegacyNumericFields()
-                ? new LegacyChangeIdPredicate(c.getId())
+                ? ChangePredicates.id(c.getId())
                 : new LegacyChangeIdStrPredicate(c.getId())));
     and.add(Predicate.or(filePredicates));
 
diff --git a/java/com/google/gerrit/server/query/change/DirectoryPredicate.java b/java/com/google/gerrit/server/query/change/DirectoryPredicate.java
index 3ab3e26..9249137 100644
--- a/java/com/google/gerrit/server/query/change/DirectoryPredicate.java
+++ b/java/com/google/gerrit/server/query/change/DirectoryPredicate.java
@@ -31,9 +31,4 @@
   public boolean match(ChangeData cd) {
     return ChangeField.getDirectories(cd).contains(value);
   }
-
-  @Override
-  public int getCost() {
-    return 0;
-  }
 }
diff --git a/java/com/google/gerrit/server/query/change/EditByPredicate.java b/java/com/google/gerrit/server/query/change/EditByPredicate.java
deleted file mode 100644
index 0fd66f8..0000000
--- a/java/com/google/gerrit/server/query/change/EditByPredicate.java
+++ /dev/null
@@ -1,37 +0,0 @@
-// Copyright (C) 2015 The Android Open Source Project
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-// http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-
-package com.google.gerrit.server.query.change;
-
-import com.google.gerrit.entities.Account;
-import com.google.gerrit.server.index.change.ChangeField;
-
-public class EditByPredicate extends ChangeIndexPredicate {
-  protected final Account.Id id;
-
-  public EditByPredicate(Account.Id id) {
-    super(ChangeField.EDITBY, id.toString());
-    this.id = id;
-  }
-
-  @Override
-  public boolean match(ChangeData cd) {
-    return cd.editsByUser().contains(id);
-  }
-
-  @Override
-  public int getCost() {
-    return 1;
-  }
-}
diff --git a/java/com/google/gerrit/server/query/change/EqualsFilePredicate.java b/java/com/google/gerrit/server/query/change/EqualsFilePredicate.java
index 9c033b6..4e454fa 100644
--- a/java/com/google/gerrit/server/query/change/EqualsFilePredicate.java
+++ b/java/com/google/gerrit/server/query/change/EqualsFilePredicate.java
@@ -35,9 +35,4 @@
   public boolean match(ChangeData object) {
     return ChangeField.getFileParts(object).contains(value);
   }
-
-  @Override
-  public int getCost() {
-    return 1;
-  }
 }
diff --git a/java/com/google/gerrit/server/query/change/EqualsLabelPredicate.java b/java/com/google/gerrit/server/query/change/EqualsLabelPredicate.java
index 3e9209b..30d5e2f 100644
--- a/java/com/google/gerrit/server/query/change/EqualsLabelPredicate.java
+++ b/java/com/google/gerrit/server/query/change/EqualsLabelPredicate.java
@@ -108,7 +108,15 @@
       return false;
     }
 
-    if (account != null && !account.equals(approver)) {
+    if (account != null
+        && !account.equals(approver)
+        && !account.equals(ChangeQueryBuilder.OWNER_ACCOUNT_ID)) {
+      return false;
+    }
+
+    if (account != null
+        && account.equals(ChangeQueryBuilder.OWNER_ACCOUNT_ID)
+        && !cd.change().getOwner().equals(approver)) {
       return false;
     }
 
diff --git a/java/com/google/gerrit/server/query/change/EqualsPathPredicate.java b/java/com/google/gerrit/server/query/change/EqualsPathPredicate.java
index 76936fa..63975d0 100644
--- a/java/com/google/gerrit/server/query/change/EqualsPathPredicate.java
+++ b/java/com/google/gerrit/server/query/change/EqualsPathPredicate.java
@@ -26,9 +26,4 @@
   public boolean match(ChangeData object) {
     return Collections.binarySearch(object.currentFilePaths(), value) >= 0;
   }
-
-  @Override
-  public int getCost() {
-    return 1;
-  }
 }
diff --git a/java/com/google/gerrit/server/query/change/ExactAuthorPredicate.java b/java/com/google/gerrit/server/query/change/ExactAuthorPredicate.java
index c1b6928..3b3cb90 100644
--- a/java/com/google/gerrit/server/query/change/ExactAuthorPredicate.java
+++ b/java/com/google/gerrit/server/query/change/ExactAuthorPredicate.java
@@ -29,9 +29,4 @@
   public boolean match(ChangeData object) {
     return ChangeField.getAuthorNameAndEmail(object).contains(getValue());
   }
-
-  @Override
-  public int getCost() {
-    return 1;
-  }
 }
diff --git a/java/com/google/gerrit/server/query/change/ExactCommitterPredicate.java b/java/com/google/gerrit/server/query/change/ExactCommitterPredicate.java
index dac63af..390d4ab 100644
--- a/java/com/google/gerrit/server/query/change/ExactCommitterPredicate.java
+++ b/java/com/google/gerrit/server/query/change/ExactCommitterPredicate.java
@@ -29,9 +29,4 @@
   public boolean match(ChangeData object) {
     return ChangeField.getCommitterNameAndEmail(object).contains(getValue());
   }
-
-  @Override
-  public int getCost() {
-    return 1;
-  }
 }
diff --git a/java/com/google/gerrit/server/query/change/ExactHashtagPredicate.java b/java/com/google/gerrit/server/query/change/ExactHashtagPredicate.java
index a6526f7..76ced90 100644
--- a/java/com/google/gerrit/server/query/change/ExactHashtagPredicate.java
+++ b/java/com/google/gerrit/server/query/change/ExactHashtagPredicate.java
@@ -37,9 +37,4 @@
     }
     return false;
   }
-
-  @Override
-  public int getCost() {
-    return 1;
-  }
 }
diff --git a/java/com/google/gerrit/server/query/change/ExactTopicPredicate.java b/java/com/google/gerrit/server/query/change/ExactTopicPredicate.java
index 6683c91..5d8d2c0 100644
--- a/java/com/google/gerrit/server/query/change/ExactTopicPredicate.java
+++ b/java/com/google/gerrit/server/query/change/ExactTopicPredicate.java
@@ -31,9 +31,4 @@
     }
     return getValue().equals(change.getTopic());
   }
-
-  @Override
-  public int getCost() {
-    return 1;
-  }
 }
diff --git a/java/com/google/gerrit/server/query/change/FileExtensionListPredicate.java b/java/com/google/gerrit/server/query/change/FileExtensionListPredicate.java
index bddd2ec..c16bc83 100644
--- a/java/com/google/gerrit/server/query/change/FileExtensionListPredicate.java
+++ b/java/com/google/gerrit/server/query/change/FileExtensionListPredicate.java
@@ -36,9 +36,4 @@
   public boolean match(ChangeData cd) {
     return ChangeField.getAllExtensionsAsList(cd).equals(value);
   }
-
-  @Override
-  public int getCost() {
-    return 0;
-  }
 }
diff --git a/java/com/google/gerrit/server/query/change/FileExtensionPredicate.java b/java/com/google/gerrit/server/query/change/FileExtensionPredicate.java
index ee573a7..39715cf 100644
--- a/java/com/google/gerrit/server/query/change/FileExtensionPredicate.java
+++ b/java/com/google/gerrit/server/query/change/FileExtensionPredicate.java
@@ -33,9 +33,4 @@
   public boolean match(ChangeData object) {
     return ChangeField.getExtensions(object).contains(value);
   }
-
-  @Override
-  public int getCost() {
-    return 0;
-  }
 }
diff --git a/java/com/google/gerrit/server/query/change/FooterPredicate.java b/java/com/google/gerrit/server/query/change/FooterPredicate.java
index 4d7588c..37bd6b1 100644
--- a/java/com/google/gerrit/server/query/change/FooterPredicate.java
+++ b/java/com/google/gerrit/server/query/change/FooterPredicate.java
@@ -37,9 +37,4 @@
   public boolean match(ChangeData cd) {
     return ChangeField.getFooters(cd).contains(value);
   }
-
-  @Override
-  public int getCost() {
-    return 0;
-  }
 }
diff --git a/java/com/google/gerrit/server/query/change/FuzzyHashtagPredicate.java b/java/com/google/gerrit/server/query/change/FuzzyHashtagPredicate.java
index 35c96ef..b4d6b5f 100644
--- a/java/com/google/gerrit/server/query/change/FuzzyHashtagPredicate.java
+++ b/java/com/google/gerrit/server/query/change/FuzzyHashtagPredicate.java
@@ -30,9 +30,4 @@
   public boolean match(ChangeData cd) {
     return cd.hashtags().stream().anyMatch(ht -> ht.toLowerCase().contains(getValue()));
   }
-
-  @Override
-  public int getCost() {
-    return 1;
-  }
 }
diff --git a/java/com/google/gerrit/server/query/change/FuzzyTopicPredicate.java b/java/com/google/gerrit/server/query/change/FuzzyTopicPredicate.java
index d558b0f..47652b8 100644
--- a/java/com/google/gerrit/server/query/change/FuzzyTopicPredicate.java
+++ b/java/com/google/gerrit/server/query/change/FuzzyTopicPredicate.java
@@ -45,7 +45,7 @@
     try {
       Predicate<ChangeData> thisId =
           index.getSchema().useLegacyNumericFields()
-              ? new LegacyChangeIdPredicate(cd.getId())
+              ? ChangePredicates.id(cd.getId())
               : new LegacyChangeIdStrPredicate(cd.getId());
       Iterable<ChangeData> results =
           index.getSource(and(thisId, this), IndexedChangeQuery.oneResult()).read();
@@ -54,9 +54,4 @@
       throw new StorageException(e);
     }
   }
-
-  @Override
-  public int getCost() {
-    return 1;
-  }
 }
diff --git a/java/com/google/gerrit/server/query/change/GroupPredicate.java b/java/com/google/gerrit/server/query/change/GroupPredicate.java
index 99f37d6..f470cf9 100644
--- a/java/com/google/gerrit/server/query/change/GroupPredicate.java
+++ b/java/com/google/gerrit/server/query/change/GroupPredicate.java
@@ -33,9 +33,4 @@
     }
     return false;
   }
-
-  @Override
-  public int getCost() {
-    return 1;
-  }
 }
diff --git a/java/com/google/gerrit/server/query/change/HasDraftByPredicate.java b/java/com/google/gerrit/server/query/change/HasDraftByPredicate.java
deleted file mode 100644
index 6d1576f..0000000
--- a/java/com/google/gerrit/server/query/change/HasDraftByPredicate.java
+++ /dev/null
@@ -1,37 +0,0 @@
-// Copyright (C) 2010 The Android Open Source Project
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-// http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-
-package com.google.gerrit.server.query.change;
-
-import com.google.gerrit.entities.Account;
-import com.google.gerrit.server.index.change.ChangeField;
-
-public class HasDraftByPredicate extends ChangeIndexPredicate {
-  protected final Account.Id accountId;
-
-  public HasDraftByPredicate(Account.Id accountId) {
-    super(ChangeField.DRAFTBY, accountId.toString());
-    this.accountId = accountId;
-  }
-
-  @Override
-  public boolean match(ChangeData cd) {
-    return cd.draftsByUser().contains(accountId);
-  }
-
-  @Override
-  public int getCost() {
-    return 1;
-  }
-}
diff --git a/java/com/google/gerrit/server/query/change/HasStarsPredicate.java b/java/com/google/gerrit/server/query/change/HasStarsPredicate.java
index 2fbd1e8..6482a19 100644
--- a/java/com/google/gerrit/server/query/change/HasStarsPredicate.java
+++ b/java/com/google/gerrit/server/query/change/HasStarsPredicate.java
@@ -31,11 +31,6 @@
   }
 
   @Override
-  public int getCost() {
-    return 1;
-  }
-
-  @Override
   public String toString() {
     return ChangeQueryBuilder.FIELD_STARBY + ":" + accountId;
   }
diff --git a/java/com/google/gerrit/server/query/change/InternalChangeQuery.java b/java/com/google/gerrit/server/query/change/InternalChangeQuery.java
index e0f7d91..ed0f237 100644
--- a/java/com/google/gerrit/server/query/change/InternalChangeQuery.java
+++ b/java/com/google/gerrit/server/query/change/InternalChangeQuery.java
@@ -99,7 +99,7 @@
     predicateFactory =
         (id) ->
             schema().useLegacyNumericFields()
-                ? new LegacyChangeIdPredicate(id)
+                ? ChangePredicates.id(id)
                 : new LegacyChangeIdStrPredicate(id);
   }
 
diff --git a/java/com/google/gerrit/server/query/change/IsReviewedPredicate.java b/java/com/google/gerrit/server/query/change/IsReviewedPredicate.java
deleted file mode 100644
index 4b32b06..0000000
--- a/java/com/google/gerrit/server/query/change/IsReviewedPredicate.java
+++ /dev/null
@@ -1,59 +0,0 @@
-// Copyright (C) 2015 The Android Open Source Project
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-// http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-
-package com.google.gerrit.server.query.change;
-
-import static com.google.gerrit.server.index.change.ChangeField.REVIEWEDBY;
-
-import com.google.gerrit.entities.Account;
-import com.google.gerrit.index.query.Predicate;
-import com.google.gerrit.server.index.change.ChangeField;
-import java.util.ArrayList;
-import java.util.Collection;
-import java.util.List;
-import java.util.Set;
-
-public class IsReviewedPredicate extends ChangeIndexPredicate {
-  protected static final Account.Id NOT_REVIEWED = Account.id(ChangeField.NOT_REVIEWED);
-
-  public static Predicate<ChangeData> create() {
-    return Predicate.not(new IsReviewedPredicate(NOT_REVIEWED));
-  }
-
-  public static Predicate<ChangeData> create(Collection<Account.Id> ids) {
-    List<Predicate<ChangeData>> predicates = new ArrayList<>(ids.size());
-    for (Account.Id id : ids) {
-      predicates.add(new IsReviewedPredicate(id));
-    }
-    return Predicate.or(predicates);
-  }
-
-  protected final Account.Id id;
-
-  private IsReviewedPredicate(Account.Id id) {
-    super(REVIEWEDBY, Integer.toString(id.get()));
-    this.id = id;
-  }
-
-  @Override
-  public boolean match(ChangeData cd) {
-    Set<Account.Id> reviewedBy = cd.reviewedBy();
-    return !reviewedBy.isEmpty() ? reviewedBy.contains(id) : id.equals(NOT_REVIEWED);
-  }
-
-  @Override
-  public int getCost() {
-    return 1;
-  }
-}
diff --git a/java/com/google/gerrit/server/query/change/LegacyChangeIdPredicate.java b/java/com/google/gerrit/server/query/change/LegacyChangeIdPredicate.java
deleted file mode 100644
index d531236..0000000
--- a/java/com/google/gerrit/server/query/change/LegacyChangeIdPredicate.java
+++ /dev/null
@@ -1,39 +0,0 @@
-// Copyright (C) 2010 The Android Open Source Project
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-// http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-
-package com.google.gerrit.server.query.change;
-
-import static com.google.gerrit.server.index.change.ChangeField.LEGACY_ID;
-
-import com.google.gerrit.entities.Change;
-
-/** Predicate over change number (aka legacy ID or Change.Id). */
-public class LegacyChangeIdPredicate extends ChangeIndexPredicate {
-  protected final Change.Id id;
-
-  public LegacyChangeIdPredicate(Change.Id id) {
-    super(LEGACY_ID, ChangeQueryBuilder.FIELD_CHANGE, id.toString());
-    this.id = id;
-  }
-
-  @Override
-  public boolean match(ChangeData object) {
-    return id.equals(object.getId());
-  }
-
-  @Override
-  public int getCost() {
-    return 1;
-  }
-}
diff --git a/java/com/google/gerrit/server/query/change/LegacyChangeIdStrPredicate.java b/java/com/google/gerrit/server/query/change/LegacyChangeIdStrPredicate.java
index bae9c0d..60cfd8f 100644
--- a/java/com/google/gerrit/server/query/change/LegacyChangeIdStrPredicate.java
+++ b/java/com/google/gerrit/server/query/change/LegacyChangeIdStrPredicate.java
@@ -31,9 +31,4 @@
   public boolean match(ChangeData object) {
     return id.equals(object.getId());
   }
-
-  @Override
-  public int getCost() {
-    return 1;
-  }
 }
diff --git a/java/com/google/gerrit/server/query/change/MessagePredicate.java b/java/com/google/gerrit/server/query/change/MessagePredicate.java
index 44cbd8e..caf751e 100644
--- a/java/com/google/gerrit/server/query/change/MessagePredicate.java
+++ b/java/com/google/gerrit/server/query/change/MessagePredicate.java
@@ -36,7 +36,7 @@
       Predicate<ChangeData> p =
           Predicate.and(
               index.getSchema().useLegacyNumericFields()
-                  ? new LegacyChangeIdPredicate(object.getId())
+                  ? ChangePredicates.id(object.getId())
                   : new LegacyChangeIdStrPredicate(object.getId()),
               this);
       for (ChangeData cData : index.getSource(p, IndexedChangeQuery.oneResult()).read()) {
@@ -50,9 +50,4 @@
 
     return false;
   }
-
-  @Override
-  public int getCost() {
-    return 1;
-  }
 }
diff --git a/java/com/google/gerrit/server/query/change/OwnerPredicate.java b/java/com/google/gerrit/server/query/change/OwnerPredicate.java
deleted file mode 100644
index 923a9ca..0000000
--- a/java/com/google/gerrit/server/query/change/OwnerPredicate.java
+++ /dev/null
@@ -1,43 +0,0 @@
-// Copyright (C) 2010 The Android Open Source Project
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-// http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-
-package com.google.gerrit.server.query.change;
-
-import com.google.gerrit.entities.Account;
-import com.google.gerrit.entities.Change;
-import com.google.gerrit.server.index.change.ChangeField;
-
-public class OwnerPredicate extends ChangeIndexPredicate {
-  protected final Account.Id id;
-
-  public OwnerPredicate(Account.Id id) {
-    super(ChangeField.OWNER, id.toString());
-    this.id = id;
-  }
-
-  protected Account.Id getAccountId() {
-    return id;
-  }
-
-  @Override
-  public boolean match(ChangeData object) {
-    Change change = object.change();
-    return change != null && id.equals(change.getOwner());
-  }
-
-  @Override
-  public int getCost() {
-    return 1;
-  }
-}
diff --git a/java/com/google/gerrit/server/query/change/ProjectPredicate.java b/java/com/google/gerrit/server/query/change/ProjectPredicate.java
index db5a932..b76207c 100644
--- a/java/com/google/gerrit/server/query/change/ProjectPredicate.java
+++ b/java/com/google/gerrit/server/query/change/ProjectPredicate.java
@@ -37,9 +37,4 @@
     Project.NameKey p = change.getDest().project();
     return p.equals(getValueKey());
   }
-
-  @Override
-  public int getCost() {
-    return 1;
-  }
 }
diff --git a/java/com/google/gerrit/server/query/change/ProjectPrefixPredicate.java b/java/com/google/gerrit/server/query/change/ProjectPrefixPredicate.java
index c23a175..b89fffe 100644
--- a/java/com/google/gerrit/server/query/change/ProjectPrefixPredicate.java
+++ b/java/com/google/gerrit/server/query/change/ProjectPrefixPredicate.java
@@ -27,9 +27,4 @@
     Change c = object.change();
     return c != null && c.getDest().project().get().startsWith(getValue());
   }
-
-  @Override
-  public int getCost() {
-    return 1;
-  }
 }
diff --git a/java/com/google/gerrit/server/query/change/RefPredicate.java b/java/com/google/gerrit/server/query/change/RefPredicate.java
index 1c70a62..8dced69 100644
--- a/java/com/google/gerrit/server/query/change/RefPredicate.java
+++ b/java/com/google/gerrit/server/query/change/RefPredicate.java
@@ -30,9 +30,4 @@
     }
     return getValue().equals(change.getDest().branch());
   }
-
-  @Override
-  public int getCost() {
-    return 1;
-  }
 }
diff --git a/java/com/google/gerrit/server/query/change/RevertOfPredicate.java b/java/com/google/gerrit/server/query/change/RevertOfPredicate.java
deleted file mode 100644
index eea1b1e..0000000
--- a/java/com/google/gerrit/server/query/change/RevertOfPredicate.java
+++ /dev/null
@@ -1,36 +0,0 @@
-// Copyright (C) 2017 The Android Open Source Project
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-// http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-
-package com.google.gerrit.server.query.change;
-
-import com.google.gerrit.server.index.change.ChangeField;
-
-public class RevertOfPredicate extends ChangeIndexPredicate {
-  public RevertOfPredicate(String revertOf) {
-    super(ChangeField.REVERT_OF, revertOf);
-  }
-
-  @Override
-  public boolean match(ChangeData cd) {
-    if (cd.change().getRevertOf() == null) {
-      return false;
-    }
-    return cd.change().getRevertOf().toString().equals(value);
-  }
-
-  @Override
-  public int getCost() {
-    return 1;
-  }
-}
diff --git a/java/com/google/gerrit/server/query/change/ReviewerByEmailPredicate.java b/java/com/google/gerrit/server/query/change/ReviewerByEmailPredicate.java
index 62fe9e8..3a51972 100644
--- a/java/com/google/gerrit/server/query/change/ReviewerByEmailPredicate.java
+++ b/java/com/google/gerrit/server/query/change/ReviewerByEmailPredicate.java
@@ -45,9 +45,4 @@
   public boolean match(ChangeData cd) {
     return cd.reviewersByEmail().asTable().get(state, adr) != null;
   }
-
-  @Override
-  public int getCost() {
-    return 1;
-  }
 }
diff --git a/java/com/google/gerrit/server/query/change/ReviewerPredicate.java b/java/com/google/gerrit/server/query/change/ReviewerPredicate.java
index d783f76..142e956 100644
--- a/java/com/google/gerrit/server/query/change/ReviewerPredicate.java
+++ b/java/com/google/gerrit/server/query/change/ReviewerPredicate.java
@@ -52,9 +52,4 @@
   public boolean match(ChangeData cd) {
     return cd.reviewers().asTable().get(state, id) != null;
   }
-
-  @Override
-  public int getCost() {
-    return 1;
-  }
 }
diff --git a/java/com/google/gerrit/server/query/change/StarPredicate.java b/java/com/google/gerrit/server/query/change/StarPredicate.java
index 788f1a3..4a8fe43 100644
--- a/java/com/google/gerrit/server/query/change/StarPredicate.java
+++ b/java/com/google/gerrit/server/query/change/StarPredicate.java
@@ -34,11 +34,6 @@
   }
 
   @Override
-  public int getCost() {
-    return 1;
-  }
-
-  @Override
   public String toString() {
     return ChangeQueryBuilder.FIELD_STAR + ":" + label;
   }
diff --git a/java/com/google/gerrit/server/query/change/SubmissionIdPredicate.java b/java/com/google/gerrit/server/query/change/SubmissionIdPredicate.java
index 093447e..b653eb5 100644
--- a/java/com/google/gerrit/server/query/change/SubmissionIdPredicate.java
+++ b/java/com/google/gerrit/server/query/change/SubmissionIdPredicate.java
@@ -33,9 +33,4 @@
     }
     return getValue().equals(change.getSubmissionId());
   }
-
-  @Override
-  public int getCost() {
-    return 1;
-  }
 }
diff --git a/java/com/google/gerrit/server/query/change/SubmitRecordPredicate.java b/java/com/google/gerrit/server/query/change/SubmitRecordPredicate.java
index 4ca684a..ecddbb6 100644
--- a/java/com/google/gerrit/server/query/change/SubmitRecordPredicate.java
+++ b/java/com/google/gerrit/server/query/change/SubmitRecordPredicate.java
@@ -43,9 +43,4 @@
   public boolean match(ChangeData in) {
     return ChangeField.formatSubmitRecordValues(in).contains(getValue());
   }
-
-  @Override
-  public int getCost() {
-    return 1;
-  }
 }
diff --git a/java/com/google/gerrit/server/query/change/SubmittablePredicate.java b/java/com/google/gerrit/server/query/change/SubmittablePredicate.java
index 2018fbc..060a92e 100644
--- a/java/com/google/gerrit/server/query/change/SubmittablePredicate.java
+++ b/java/com/google/gerrit/server/query/change/SubmittablePredicate.java
@@ -30,9 +30,4 @@
     return cd.submitRecords(ChangeField.SUBMIT_RULE_OPTIONS_STRICT).stream()
         .anyMatch(r -> r.status == status);
   }
-
-  @Override
-  public int getCost() {
-    return 1;
-  }
 }
diff --git a/java/com/google/gerrit/server/query/change/TrackingIdPredicate.java b/java/com/google/gerrit/server/query/change/TrackingIdPredicate.java
index 622fa2c..4f58be2 100644
--- a/java/com/google/gerrit/server/query/change/TrackingIdPredicate.java
+++ b/java/com/google/gerrit/server/query/change/TrackingIdPredicate.java
@@ -25,9 +25,4 @@
   public boolean match(ChangeData cd) {
     return cd.trackingFooters().containsValue(getValue());
   }
-
-  @Override
-  public int getCost() {
-    return 1;
-  }
 }
diff --git a/java/com/google/gerrit/server/query/group/GroupPredicates.java b/java/com/google/gerrit/server/query/group/GroupPredicates.java
index 992f60d..9d8171c 100644
--- a/java/com/google/gerrit/server/query/group/GroupPredicates.java
+++ b/java/com/google/gerrit/server/query/group/GroupPredicates.java
@@ -19,6 +19,7 @@
 import com.google.gerrit.entities.InternalGroup;
 import com.google.gerrit.index.FieldDef;
 import com.google.gerrit.index.query.IndexPredicate;
+import com.google.gerrit.index.query.Matchable;
 import com.google.gerrit.index.query.Predicate;
 import com.google.gerrit.server.index.group.GroupField;
 import java.util.Locale;
@@ -44,7 +45,7 @@
   }
 
   public static Predicate<InternalGroup> name(String name) {
-    return new GroupPredicate(GroupField.NAME, GroupQueryBuilder.FIELD_NAME, name);
+    return new NameGroupPredicate(name);
   }
 
   public static Predicate<InternalGroup> owner(AccountGroup.UUID ownerUuid) {
@@ -75,5 +76,25 @@
     }
   }
 
+  // TODO(hiesel): This is just a one-off to make index tests work. Remove in favor of a more
+  // generic solution.
+  // This is required because Gerrit needs to look up groups by name on every request.
+  static class NameGroupPredicate extends IndexPredicate<InternalGroup>
+      implements Matchable<InternalGroup> {
+    NameGroupPredicate(String value) {
+      super(GroupField.NAME, value);
+    }
+
+    @Override
+    public boolean match(InternalGroup group) {
+      return group.getName().equals(getValue());
+    }
+
+    @Override
+    public int getCost() {
+      return 1;
+    }
+  }
+
   private GroupPredicates() {}
 }
diff --git a/java/com/google/gerrit/server/restapi/account/DeleteDraftComments.java b/java/com/google/gerrit/server/restapi/account/DeleteDraftComments.java
index ec82e1a..d225798 100644
--- a/java/com/google/gerrit/server/restapi/account/DeleteDraftComments.java
+++ b/java/com/google/gerrit/server/restapi/account/DeleteDraftComments.java
@@ -41,8 +41,8 @@
 import com.google.gerrit.server.change.ChangeJson;
 import com.google.gerrit.server.permissions.PermissionBackendException;
 import com.google.gerrit.server.query.change.ChangeData;
+import com.google.gerrit.server.query.change.ChangePredicates;
 import com.google.gerrit.server.query.change.ChangeQueryBuilder;
-import com.google.gerrit.server.query.change.HasDraftByPredicate;
 import com.google.gerrit.server.query.change.InternalChangeQuery;
 import com.google.gerrit.server.restapi.change.CommentJson;
 import com.google.gerrit.server.restapi.change.CommentJson.HumanCommentFormatter;
@@ -147,7 +147,7 @@
 
   private Predicate<ChangeData> predicate(Account.Id accountId, DeleteDraftCommentsInput input)
       throws BadRequestException {
-    Predicate<ChangeData> hasDraft = new HasDraftByPredicate(accountId);
+    Predicate<ChangeData> hasDraft = ChangePredicates.draftBy(accountId);
     if (CharMatcher.whitespace().trimFrom(Strings.nullToEmpty(input.query)).isEmpty()) {
       return hasDraft;
     }
diff --git a/java/com/google/gerrit/testing/BUILD b/java/com/google/gerrit/testing/BUILD
index 93c996e8..be32138 100644
--- a/java/com/google/gerrit/testing/BUILD
+++ b/java/com/google/gerrit/testing/BUILD
@@ -12,6 +12,7 @@
         "//lib:junit",
         "//lib/mockito",
     ],
+    runtime_deps = ["//java/com/google/gerrit/index/testing"],
     deps = [
         "//java/com/google/gerrit/acceptance/config",
         "//java/com/google/gerrit/acceptance/testsuite/project",
diff --git a/java/com/google/gerrit/testing/InMemoryModule.java b/java/com/google/gerrit/testing/InMemoryModule.java
index e93c921..7ca763a1 100644
--- a/java/com/google/gerrit/testing/InMemoryModule.java
+++ b/java/com/google/gerrit/testing/InMemoryModule.java
@@ -242,6 +242,8 @@
       install(luceneIndexModule());
     } else if (indexType.isElasticsearch()) {
       install(elasticIndexModule());
+    } else if (indexType.isFake()) {
+      install(fakeIndexModule());
     }
     bind(ServerInformationImpl.class);
     bind(ServerInformation.class).to(ServerInformationImpl.class);
@@ -317,6 +319,10 @@
     return indexModule("com.google.gerrit.elasticsearch.ElasticIndexModule");
   }
 
+  private Module fakeIndexModule() {
+    return indexModule("com.google.gerrit.index.testing.FakeIndexModule");
+  }
+
   private Module indexModule(String moduleClassName) {
     try {
       Class<?> clazz = Class.forName(moduleClassName);
diff --git a/java/com/google/gerrit/testing/IndexConfig.java b/java/com/google/gerrit/testing/IndexConfig.java
index a8ed5be..daef2b3 100644
--- a/java/com/google/gerrit/testing/IndexConfig.java
+++ b/java/com/google/gerrit/testing/IndexConfig.java
@@ -50,4 +50,8 @@
 
     return cfg;
   }
+
+  public static Config createForFake() {
+    return create();
+  }
 }
diff --git a/javatests/com/google/gerrit/elasticsearch/ElasticContainer.java b/javatests/com/google/gerrit/elasticsearch/ElasticContainer.java
index 8cd09e6..4d7468f 100644
--- a/javatests/com/google/gerrit/elasticsearch/ElasticContainer.java
+++ b/javatests/com/google/gerrit/elasticsearch/ElasticContainer.java
@@ -39,8 +39,6 @@
 
   private static String getImageName(ElasticVersion version) {
     switch (version) {
-      case V7_4:
-        return "blacktop/elasticsearch:7.4.2";
       case V7_5:
         return "blacktop/elasticsearch:7.5.2";
       case V7_6:
diff --git a/javatests/com/google/gerrit/elasticsearch/ElasticVersionTest.java b/javatests/com/google/gerrit/elasticsearch/ElasticVersionTest.java
index 508dc84..75e9636 100644
--- a/javatests/com/google/gerrit/elasticsearch/ElasticVersionTest.java
+++ b/javatests/com/google/gerrit/elasticsearch/ElasticVersionTest.java
@@ -22,9 +22,6 @@
 public class ElasticVersionTest {
   @Test
   public void supportedVersion() throws Exception {
-    assertThat(ElasticVersion.forVersion("7.4.0")).isEqualTo(ElasticVersion.V7_4);
-    assertThat(ElasticVersion.forVersion("7.4.1")).isEqualTo(ElasticVersion.V7_4);
-
     assertThat(ElasticVersion.forVersion("7.5.0")).isEqualTo(ElasticVersion.V7_5);
     assertThat(ElasticVersion.forVersion("7.5.1")).isEqualTo(ElasticVersion.V7_5);
 
diff --git a/javatests/com/google/gerrit/entities/PatchSetTest.java b/javatests/com/google/gerrit/entities/PatchSetTest.java
index 61e1b4c..7e04fe8 100644
--- a/javatests/com/google/gerrit/entities/PatchSetTest.java
+++ b/javatests/com/google/gerrit/entities/PatchSetTest.java
@@ -96,6 +96,10 @@
   public void parseId() {
     assertThat(PatchSet.Id.parse("1,2")).isEqualTo(PatchSet.id(Change.id(1), 2));
     assertThat(PatchSet.Id.parse("01,02")).isEqualTo(PatchSet.id(Change.id(1), 2));
+    Change.Id cId = Change.id(321);
+    assertThat(
+            PatchSet.Id.fromEditRef(RefNames.refsEdit(Account.id(123), cId, PatchSet.id(cId, 6))))
+        .isEqualTo(PatchSet.id(cId, 6));
     assertInvalidId(null);
     assertInvalidId("");
     assertInvalidId("1");
diff --git a/javatests/com/google/gerrit/server/query/account/AbstractQueryAccountsTest.java b/javatests/com/google/gerrit/server/query/account/AbstractQueryAccountsTest.java
index b3ef1ea..f6b3317 100644
--- a/javatests/com/google/gerrit/server/query/account/AbstractQueryAccountsTest.java
+++ b/javatests/com/google/gerrit/server/query/account/AbstractQueryAccountsTest.java
@@ -146,6 +146,8 @@
 
   protected abstract Injector createInjector();
 
+  protected void validateAssumptions() {}
+
   @Before
   public void setUpInjector() throws Exception {
     lifecycle = new LifecycleManager();
@@ -155,6 +157,7 @@
     lifecycle.start();
     initAfterLifecycleStart();
     setUpDatabase();
+    validateAssumptions();
   }
 
   @After
diff --git a/javatests/com/google/gerrit/server/query/account/BUILD b/javatests/com/google/gerrit/server/query/account/BUILD
index 5c910a0..4ae2039 100644
--- a/javatests/com/google/gerrit/server/query/account/BUILD
+++ b/javatests/com/google/gerrit/server/query/account/BUILD
@@ -32,8 +32,7 @@
     name = "lucene_query_test",
     size = "large",
     srcs = glob(
-        ["*.java"],
-        exclude = ABSTRACT_QUERY_TEST,
+        ["LuceneQueryAccountsTest.java"],
     ),
     visibility = ["//visibility:public"],
     deps = [
@@ -44,3 +43,21 @@
         "//lib/guice",
     ],
 )
+
+junit_tests(
+    name = "fake_query_test",
+    size = "large",
+    srcs = glob(
+        ["FakeQueryAccountsTest.java"],
+    ),
+    visibility = ["//visibility:public"],
+    deps = [
+        ":abstract_query_tests",
+        "//java/com/google/gerrit/entities",
+        "//java/com/google/gerrit/server",
+        "//java/com/google/gerrit/testing:gerrit-test-util",
+        "//lib:jgit",
+        "//lib/guice",
+        "@truth//jar",
+    ],
+)
diff --git a/javatests/com/google/gerrit/server/query/account/FakeQueryAccountsTest.java b/javatests/com/google/gerrit/server/query/account/FakeQueryAccountsTest.java
new file mode 100644
index 0000000..b742bd8
--- /dev/null
+++ b/javatests/com/google/gerrit/server/query/account/FakeQueryAccountsTest.java
@@ -0,0 +1,67 @@
+// Copyright (C) 2021 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package com.google.gerrit.server.query.account;
+
+import static org.junit.Assume.assumeFalse;
+
+import com.google.gerrit.entities.Account;
+import com.google.gerrit.server.account.AccountState;
+import com.google.gerrit.server.index.account.AccountSchemaDefinitions;
+import com.google.gerrit.testing.ConfigSuite;
+import com.google.gerrit.testing.InMemoryModule;
+import com.google.gerrit.testing.IndexConfig;
+import com.google.gerrit.testing.IndexVersions;
+import com.google.inject.Guice;
+import com.google.inject.Injector;
+import java.sql.Timestamp;
+import java.util.List;
+import java.util.Map;
+import org.eclipse.jgit.lib.Config;
+
+public class FakeQueryAccountsTest extends AbstractQueryAccountsTest {
+  @ConfigSuite.Default
+  public static Config defaultConfig() {
+    return IndexConfig.createForFake();
+  }
+
+  @ConfigSuite.Configs
+  public static Map<String, Config> againstPreviousIndexVersion() {
+    // the current schema version is already tested by the inherited default config suite
+    List<Integer> schemaVersions =
+        IndexVersions.getWithoutLatest(AccountSchemaDefinitions.INSTANCE);
+    return IndexVersions.asConfigMap(
+        AccountSchemaDefinitions.INSTANCE, schemaVersions, "againstIndexVersion", defaultConfig());
+  }
+
+  @Override
+  protected Injector createInjector() {
+    Config fakeConfig = new Config(config);
+    InMemoryModule.setDefaults(fakeConfig);
+    fakeConfig.setString("index", null, "type", "fake");
+    return Guice.createInjector(new InMemoryModule(fakeConfig));
+  }
+
+  @Override
+  protected void validateAssumptions() {
+    // TODO(hiesel): Account predicates are always matching (they return true on match), so we need
+    // to skip all tests here. We are doing this to document existing behavior. We want to remove
+    // this assume statement and make group predicates matchable.
+    assumeFalse(
+        AccountPredicates.equalsName("test")
+            .asMatchable()
+            .match(
+                AccountState.forAccount(Account.builder(Account.id(1), new Timestamp(0)).build())));
+  }
+}
diff --git a/javatests/com/google/gerrit/server/query/change/AbstractQueryChangesTest.java b/javatests/com/google/gerrit/server/query/change/AbstractQueryChangesTest.java
index 4e84b3c..6c8026b 100644
--- a/javatests/com/google/gerrit/server/query/change/AbstractQueryChangesTest.java
+++ b/javatests/com/google/gerrit/server/query/change/AbstractQueryChangesTest.java
@@ -1905,7 +1905,7 @@
     assertQuery("-added:<=4");
 
     assertQuery("added:3", change1);
-    assertQuery("-(added:<3 OR added>3)", change1);
+    assertQuery("-(added:<3 OR added:>3)", change1);
 
     assertQuery("added:>2", change1);
     assertQuery("-added:<=2", change1);
@@ -1923,7 +1923,7 @@
     assertQuery("-deleted:<=3");
 
     assertQuery("deleted:2", change2);
-    assertQuery("-(deleted:<2 OR deleted>2)", change2);
+    assertQuery("-(deleted:<2 OR deleted:>2)", change2);
 
     assertQuery("deleted:>1", change2);
     assertQuery("-deleted:<=1", change2);
@@ -2039,7 +2039,7 @@
     assertQuery("user@example.com", expected);
     assertQuery("repo", expected);
 
-    assertQuery("Code-Review:+1", change4);
+    assertQuery("Code-Review=+1", change4);
   }
 
   @Test
diff --git a/javatests/com/google/gerrit/server/query/change/BUILD b/javatests/com/google/gerrit/server/query/change/BUILD
index 43b9690..0f102a8 100644
--- a/javatests/com/google/gerrit/server/query/change/BUILD
+++ b/javatests/com/google/gerrit/server/query/change/BUILD
@@ -4,6 +4,7 @@
 ABSTRACT_QUERY_TEST = [
     "AbstractQueryChangesTest.java",
     "LuceneQueryChangesTest.java",
+    "FakeQueryChangesTest.java",
 ]
 
 java_library(
@@ -24,6 +25,7 @@
         "//java/com/google/gerrit/httpd",
         "//java/com/google/gerrit/index",
         "//java/com/google/gerrit/index:query_exception",
+        "//java/com/google/gerrit/index/testing",
         "//java/com/google/gerrit/lifecycle",
         "//java/com/google/gerrit/server",
         "//java/com/google/gerrit/server/project/testing:project-test-util",
@@ -38,9 +40,11 @@
     ],
 )
 
-LUCENE_QUERY_TEST = [
+QUERY_TEST = [
     "LuceneQueryChangesLatestIndexVersionTest.java",
     "LuceneQueryChangesPreviousIndexVersionTest.java",
+    "FakeQueryChangesLatestIndexVersionTest.java",
+    "FakeQueryChangesPreviousIndexVersionTest.java",
 ]
 
 [junit_tests(
@@ -60,14 +64,14 @@
         "//lib/guice",
         "//lib/truth",
     ],
-) for f in LUCENE_QUERY_TEST]
+) for f in QUERY_TEST]
 
 junit_tests(
     name = "small_tests",
     size = "small",
     srcs = glob(
         ["*.java"],
-        exclude = ABSTRACT_QUERY_TEST + LUCENE_QUERY_TEST,
+        exclude = ABSTRACT_QUERY_TEST + QUERY_TEST,
     ),
     visibility = ["//visibility:public"],
     deps = [
diff --git a/javatests/com/google/gerrit/server/query/change/FakeQueryChangesLatestIndexVersionTest.java b/javatests/com/google/gerrit/server/query/change/FakeQueryChangesLatestIndexVersionTest.java
new file mode 100644
index 0000000..5496f56
--- /dev/null
+++ b/javatests/com/google/gerrit/server/query/change/FakeQueryChangesLatestIndexVersionTest.java
@@ -0,0 +1,29 @@
+// Copyright (C) 2021 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package com.google.gerrit.server.query.change;
+
+import com.google.gerrit.testing.ConfigSuite;
+import com.google.gerrit.testing.IndexConfig;
+import org.eclipse.jgit.lib.Config;
+
+/**
+ * Test against {@link com.google.gerrit.index.testing.AbstractFakeIndex} using the latest schema.
+ */
+public class FakeQueryChangesLatestIndexVersionTest extends FakeQueryChangesTest {
+  @ConfigSuite.Default
+  public static Config defaultConfig() {
+    return IndexConfig.createForFake();
+  }
+}
diff --git a/javatests/com/google/gerrit/server/query/change/FakeQueryChangesPreviousIndexVersionTest.java b/javatests/com/google/gerrit/server/query/change/FakeQueryChangesPreviousIndexVersionTest.java
new file mode 100644
index 0000000..1610eca
--- /dev/null
+++ b/javatests/com/google/gerrit/server/query/change/FakeQueryChangesPreviousIndexVersionTest.java
@@ -0,0 +1,39 @@
+// Copyright (C) 2021 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package com.google.gerrit.server.query.change;
+
+import com.google.common.collect.Iterables;
+import com.google.gerrit.server.index.change.ChangeSchemaDefinitions;
+import com.google.gerrit.testing.ConfigSuite;
+import com.google.gerrit.testing.IndexConfig;
+import com.google.gerrit.testing.IndexVersions;
+import org.eclipse.jgit.lib.Config;
+
+/**
+ * Test against {@link com.google.gerrit.index.testing.AbstractFakeIndex} using the current schema.
+ */
+public class FakeQueryChangesPreviousIndexVersionTest extends FakeQueryChangesTest {
+  @ConfigSuite.Default
+  public static Config againstPreviousIndexVersion() {
+    // the current schema version is already tested by the inherited default config suite
+    return Iterables.getOnlyElement(
+        IndexVersions.asConfigMap(
+                ChangeSchemaDefinitions.INSTANCE,
+                IndexVersions.getWithoutLatest(ChangeSchemaDefinitions.INSTANCE),
+                "againstIndexVersion",
+                IndexConfig.createForFake())
+            .values());
+  }
+}
diff --git a/javatests/com/google/gerrit/server/query/change/FakeQueryChangesTest.java b/javatests/com/google/gerrit/server/query/change/FakeQueryChangesTest.java
new file mode 100644
index 0000000..385d4b2
--- /dev/null
+++ b/javatests/com/google/gerrit/server/query/change/FakeQueryChangesTest.java
@@ -0,0 +1,189 @@
+// Copyright (C) 2021 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package com.google.gerrit.server.query.change;
+
+import com.google.gerrit.testing.InMemoryModule;
+import com.google.inject.Guice;
+import com.google.inject.Injector;
+import org.eclipse.jgit.lib.Config;
+import org.junit.Ignore;
+import org.junit.Test;
+
+/**
+ * Test against {@link com.google.gerrit.index.testing.AbstractFakeIndex}. This test might seem
+ * obsolete, but it makes sure that the fake index implementation used in tests gives the same
+ * results as production indices.
+ */
+public abstract class FakeQueryChangesTest extends AbstractQueryChangesTest {
+  @Override
+  protected Injector createInjector() {
+    Config fakeConfig = new Config(config);
+    InMemoryModule.setDefaults(fakeConfig);
+    fakeConfig.setString("index", null, "type", "fake");
+    return Guice.createInjector(new InMemoryModule(fakeConfig));
+  }
+
+  @Ignore
+  @Test
+  @Override
+  public void byDefault() throws Exception {
+    // TODO(hiesel): Fix bug in predicate and remove @Ignore.
+    super.byDefault();
+  }
+
+  @Ignore
+  @Test
+  @Override
+  public void byMergedBefore() throws Exception {
+    // TODO(hiesel): Used predicate is not a matchable. Fix.
+    super.byMergedBefore();
+  }
+
+  @Ignore
+  @Test
+  @Override
+  public void reviewerAndCcByEmail() throws Exception {
+    // TODO(hiesel): Fix bug in predicate and remove @Ignore.
+    super.reviewerAndCcByEmail();
+  }
+
+  @Ignore
+  @Test
+  @Override
+  public void byMessageExact() throws Exception {
+    // TODO(hiesel): Existing #match function uses the index causing a StackOverflowError. Fix.
+    super.byMessageExact();
+  }
+
+  @Ignore
+  @Test
+  @Override
+  public void fullTextWithNumbers() throws Exception {
+    // TODO(hiesel): Existing #match function uses the index causing a StackOverflowError. Fix.
+    super.fullTextWithNumbers();
+  }
+
+  @Ignore
+  @Test
+  @Override
+  public void byTriplet() throws Exception {
+    // TODO(hiesel): Fix bug in predicate and remove @Ignore.
+    super.byTriplet();
+  }
+
+  @Ignore
+  @Test
+  @Override
+  public void byAge() throws Exception {
+    // TODO(hiesel): Existing #match function uses the index causing a StackOverflowError. Fix.
+    super.byAge();
+  }
+
+  @Ignore
+  @Test
+  @Override
+  public void byMessageSubstring() throws Exception {
+    // TODO(hiesel): Existing #match function uses the index causing a StackOverflowError. Fix.
+    super.byMessageSubstring();
+  }
+
+  @Ignore
+  @Test
+  @Override
+  public void byBeforeUntil() throws Exception {
+    // TODO(hiesel): Used predicate is not a matchable. Fix.
+    super.byBeforeUntil();
+  }
+
+  @Ignore
+  @Test
+  @Override
+  public void byTopic() throws Exception {
+    // TODO(hiesel): Existing #match function uses the index causing a StackOverflowError. Fix.
+    super.byTopic();
+  }
+
+  @Ignore
+  @Test
+  @Override
+  public void userQuery() throws Exception {
+    // TODO(hiesel): Account name predicate is always returning true in #match. Fix.
+    super.userQuery();
+  }
+
+  @Ignore
+  @Test
+  @Override
+  public void visible() throws Exception {
+    // TODO(hiesel): Account name predicate is always returning true in #match. Fix.
+    super.visible();
+  }
+
+  @Ignore
+  @Test
+  @Override
+  public void userDestination() throws Exception {
+    // TODO(hiesel): Account name predicate is always returning true in #match. Fix.
+    super.userDestination();
+  }
+
+  @Ignore
+  @Test
+  @Override
+  public void byAfterSince() throws Exception {
+    // TODO(hiesel): Used predicate is not a matchable. Fix.
+    super.byAfterSince();
+  }
+
+  @Ignore
+  @Test
+  @Override
+  public void byMessageMixedCase() throws Exception {
+    // TODO(hiesel): Used predicate is not a matchable. Fix.
+    super.byMessageMixedCase();
+  }
+
+  @Ignore
+  @Test
+  @Override
+  public void byCommit() throws Exception {
+    // TODO(hiesel): Existing #match function uses the index causing a StackOverflowError. Fix.
+    super.byCommit();
+  }
+
+  @Ignore
+  @Test
+  @Override
+  public void byComment() throws Exception {
+    // TODO(hiesel): Existing #match function uses the index causing a StackOverflowError. Fix.
+    super.byComment();
+  }
+
+  @Ignore
+  @Test
+  @Override
+  public void byMergedAfter() throws Exception {
+    // TODO(hiesel): Used predicate is not a matchable. Fix.
+    super.byMergedAfter();
+  }
+
+  @Ignore
+  @Test
+  @Override
+  public void byOwnerInvalidQuery() throws Exception {
+    // TODO(hiesel): Account name predicate is always returning true in #match. Fix.
+    super.byMergedAfter();
+  }
+}
diff --git a/javatests/com/google/gerrit/server/query/group/AbstractQueryGroupsTest.java b/javatests/com/google/gerrit/server/query/group/AbstractQueryGroupsTest.java
index a822417..f392747 100644
--- a/javatests/com/google/gerrit/server/query/group/AbstractQueryGroupsTest.java
+++ b/javatests/com/google/gerrit/server/query/group/AbstractQueryGroupsTest.java
@@ -115,6 +115,8 @@
 
   protected abstract Injector createInjector();
 
+  protected void validateAssumptions() {}
+
   @Before
   public void setUpInjector() throws Exception {
     lifecycle = new LifecycleManager();
@@ -124,6 +126,7 @@
     lifecycle.start();
     initAfterLifecycleStart();
     setUpDatabase();
+    validateAssumptions();
   }
 
   @After
diff --git a/javatests/com/google/gerrit/server/query/group/BUILD b/javatests/com/google/gerrit/server/query/group/BUILD
index e14350f..4b74325 100644
--- a/javatests/com/google/gerrit/server/query/group/BUILD
+++ b/javatests/com/google/gerrit/server/query/group/BUILD
@@ -29,8 +29,7 @@
     name = "lucene_query_test",
     size = "large",
     srcs = glob(
-        ["*.java"],
-        exclude = ABSTRACT_QUERY_TEST,
+        ["LuceneQueryGroupsTest.java"],
     ),
     visibility = ["//visibility:public"],
     deps = [
@@ -41,3 +40,20 @@
         "//lib/guice",
     ],
 )
+
+junit_tests(
+    name = "fake_query_test",
+    size = "large",
+    srcs = glob(
+        ["FakeQueryGroupsTest.java"],
+    ),
+    visibility = ["//visibility:public"],
+    deps = [
+        ":abstract_query_tests",
+        "//java/com/google/gerrit/server",
+        "//java/com/google/gerrit/testing:gerrit-test-util",
+        "//lib:jgit",
+        "//lib/guice",
+        "@truth//jar",
+    ],
+)
diff --git a/javatests/com/google/gerrit/server/query/group/FakeQueryGroupsTest.java b/javatests/com/google/gerrit/server/query/group/FakeQueryGroupsTest.java
new file mode 100644
index 0000000..8bc1c30
--- /dev/null
+++ b/javatests/com/google/gerrit/server/query/group/FakeQueryGroupsTest.java
@@ -0,0 +1,59 @@
+// Copyright (C) 2021 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package com.google.gerrit.server.query.group;
+
+import static org.junit.Assume.assumeTrue;
+
+import com.google.gerrit.server.index.group.GroupSchemaDefinitions;
+import com.google.gerrit.testing.ConfigSuite;
+import com.google.gerrit.testing.InMemoryModule;
+import com.google.gerrit.testing.IndexConfig;
+import com.google.gerrit.testing.IndexVersions;
+import com.google.inject.Guice;
+import com.google.inject.Injector;
+import java.util.List;
+import java.util.Map;
+import org.eclipse.jgit.lib.Config;
+
+public class FakeQueryGroupsTest extends AbstractQueryGroupsTest {
+  @ConfigSuite.Default
+  public static Config defaultConfig() {
+    return IndexConfig.createForFake();
+  }
+
+  @ConfigSuite.Configs
+  public static Map<String, Config> againstPreviousIndexVersion() {
+    // the current schema version is already tested by the inherited default config suite
+    List<Integer> schemaVersions = IndexVersions.getWithoutLatest(GroupSchemaDefinitions.INSTANCE);
+    return IndexVersions.asConfigMap(
+        GroupSchemaDefinitions.INSTANCE, schemaVersions, "againstIndexVersion", defaultConfig());
+  }
+
+  @Override
+  protected Injector createInjector() {
+    Config fakeConfig = new Config(config);
+    InMemoryModule.setDefaults(fakeConfig);
+    fakeConfig.setString("index", null, "type", "fake");
+    return Guice.createInjector(new InMemoryModule(fakeConfig));
+  }
+
+  @Override
+  protected void validateAssumptions() {
+    // TODO(hiesel): Group predicates are not matchable, so we need to skip all tests here.
+    // We are doing this to document existing behavior. We want to remove this assume statement and
+    // make group predicates matchable.
+    assumeTrue(GroupPredicates.inname("test").isMatchable());
+  }
+}
diff --git a/javatests/com/google/gerrit/server/query/project/AbstractQueryProjectsTest.java b/javatests/com/google/gerrit/server/query/project/AbstractQueryProjectsTest.java
index dfd7928..2317c7e 100644
--- a/javatests/com/google/gerrit/server/query/project/AbstractQueryProjectsTest.java
+++ b/javatests/com/google/gerrit/server/query/project/AbstractQueryProjectsTest.java
@@ -111,6 +111,8 @@
 
   protected abstract Injector createInjector();
 
+  protected void validateAssumptions() {}
+
   @Before
   public void setUpInjector() throws Exception {
     lifecycle = new LifecycleManager();
@@ -120,6 +122,7 @@
     lifecycle.start();
     initAfterLifecycleStart();
     setUpDatabase();
+    validateAssumptions();
   }
 
   @After
diff --git a/javatests/com/google/gerrit/server/query/project/BUILD b/javatests/com/google/gerrit/server/query/project/BUILD
index 984d824..a65306c 100644
--- a/javatests/com/google/gerrit/server/query/project/BUILD
+++ b/javatests/com/google/gerrit/server/query/project/BUILD
@@ -29,8 +29,7 @@
     name = "lucene_query_test",
     size = "large",
     srcs = glob(
-        ["*.java"],
-        exclude = ABSTRACT_QUERY_TEST,
+        ["LuceneQueryProjectsTest.java"],
     ),
     visibility = ["//visibility:public"],
     deps = [
@@ -41,3 +40,21 @@
         "//lib/guice",
     ],
 )
+
+junit_tests(
+    name = "fake_query_test",
+    size = "large",
+    srcs = glob(
+        ["FakeQueryProjectsTest.java"],
+    ),
+    visibility = ["//visibility:public"],
+    deps = [
+        ":abstract_query_tests",
+        "//java/com/google/gerrit/index/project",
+        "//java/com/google/gerrit/server",
+        "//java/com/google/gerrit/testing:gerrit-test-util",
+        "//lib:jgit",
+        "//lib/guice",
+        "@truth//jar",
+    ],
+)
diff --git a/javatests/com/google/gerrit/server/query/project/FakeQueryProjectsTest.java b/javatests/com/google/gerrit/server/query/project/FakeQueryProjectsTest.java
new file mode 100644
index 0000000..8517ad2
--- /dev/null
+++ b/javatests/com/google/gerrit/server/query/project/FakeQueryProjectsTest.java
@@ -0,0 +1,61 @@
+// Copyright (C) 2021 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package com.google.gerrit.server.query.project;
+
+import static org.junit.Assume.assumeTrue;
+
+import com.google.gerrit.index.project.ProjectSchemaDefinitions;
+import com.google.gerrit.testing.ConfigSuite;
+import com.google.gerrit.testing.InMemoryModule;
+import com.google.gerrit.testing.IndexConfig;
+import com.google.gerrit.testing.IndexVersions;
+import com.google.inject.Guice;
+import com.google.inject.Injector;
+import java.util.List;
+import java.util.Map;
+import org.eclipse.jgit.lib.Config;
+
+public class FakeQueryProjectsTest extends AbstractQueryProjectsTest {
+  @ConfigSuite.Default
+  public static Config defaultConfig() {
+    return IndexConfig.createForFake();
+  }
+
+  @ConfigSuite.Configs
+  public static Map<String, Config> againstPreviousIndexVersion() {
+    // the current schema version is already tested by the inherited default config suite
+    List<Integer> schemaVersions =
+        IndexVersions.getWithoutLatest(
+            com.google.gerrit.index.project.ProjectSchemaDefinitions.INSTANCE);
+    return IndexVersions.asConfigMap(
+        ProjectSchemaDefinitions.INSTANCE, schemaVersions, "againstIndexVersion", defaultConfig());
+  }
+
+  @Override
+  protected Injector createInjector() {
+    Config fakeConfig = new Config(config);
+    InMemoryModule.setDefaults(fakeConfig);
+    fakeConfig.setString("index", null, "type", "fake");
+    return Guice.createInjector(new InMemoryModule(fakeConfig));
+  }
+
+  @Override
+  protected void validateAssumptions() {
+    // TODO(hiesel): Project predicates are not matchable, so we need to skip all tests here.
+    // We are doing this to document existing behavior. We want to remove this assume statement and
+    // make group predicates matchable.
+    assumeTrue(ProjectPredicates.inname("test").isMatchable());
+  }
+}
diff --git a/polygerrit-ui/app/api/checks.ts b/polygerrit-ui/app/api/checks.ts
index e74eee1..454b3d5 100644
--- a/polygerrit-ui/app/api/checks.ts
+++ b/polygerrit-ui/app/api/checks.ts
@@ -225,8 +225,6 @@
   name: string;
   tooltip?: string;
   /**
-   * TODO: Maybe drop this property? Do we really need it?
-   *
    * Primary actions will get a more prominent treatment in the UI. For example
    * primary actions might be rendered as buttons versus just menu entries in
    * an overflow menu.
@@ -424,8 +422,6 @@
   url: string;
   tooltip?: string;
   /**
-   * TODO: Maybe drop this property? Do we really need it?
-   *
    * Primary links will get a more prominent treatment in the UI, e.g. being
    * always visible in the results table or also showing up in the change page
    * summary of checks.
diff --git a/polygerrit-ui/app/elements/checks/gr-checks-action.ts b/polygerrit-ui/app/elements/checks/gr-checks-action.ts
index 33e52a7..82680aa 100644
--- a/polygerrit-ui/app/elements/checks/gr-checks-action.ts
+++ b/polygerrit-ui/app/elements/checks/gr-checks-action.ts
@@ -59,7 +59,10 @@
         @click="${(e: Event) => this.handleClick(e)}"
       >
         ${this.action.name}
-        <paper-tooltip ?hidden="${!this.action.tooltip}" offset="5"
+        <paper-tooltip
+          ?hidden="${!this.action.tooltip}"
+          offset="5"
+          fit-to-visible-bounds="true"
           >${this.action.tooltip}</paper-tooltip
         >
       </gr-button>
diff --git a/polygerrit-ui/app/elements/checks/gr-checks-results.ts b/polygerrit-ui/app/elements/checks/gr-checks-results.ts
index b77912d..4b7aec5 100644
--- a/polygerrit-ui/app/elements/checks/gr-checks-results.ts
+++ b/polygerrit-ui/app/elements/checks/gr-checks-results.ts
@@ -28,7 +28,6 @@
 } from 'lit-element';
 import {GrLitElement} from '../lit/gr-lit-element';
 import './gr-checks-action';
-import './gr-checks-attempt';
 import '@polymer/paper-tooltip/paper-tooltip';
 import {
   Action,
@@ -53,6 +52,8 @@
   hasCompletedWithoutResults,
   iconForCategory,
   iconForLink,
+  otherLinks,
+  primaryLink,
   primaryRunAction,
   tooltipForLink,
 } from '../../services/checks/checks-util';
@@ -299,14 +300,13 @@
           <div class="flex">
             <gr-hovercard-run .run="${this.result}"></gr-hovercard-run>
             <div class="name">${this.result.checkName}</div>
-            <gr-checks-attempt .run="${this.result}"></gr-checks-attempt>
             <div class="space"></div>
             ${this.renderPrimaryRunAction()}
           </div>
         </td>
         <td class="summaryCol">
           <div class="summary-cell">
-            ${(this.result.links?.slice(0, 1) ?? []).map(this.renderLink)}
+            ${this.renderLink(primaryLink(this.result))}
             ${this.renderSummary(this.result.summary)}
             <div class="message" @click="${this.toggleExpanded}">
               ${this.isExpanded ? '' : this.result.message}
@@ -386,6 +386,7 @@
     if (category !== Category.ERROR && category !== Category.WARNING) return;
     const label = this.result?.labelName;
     if (!label) return;
+    if (!this.result?.isLatestAttempt) return;
     const info = this.labels?.[label];
     const status = getLabelStatus(info).toLowerCase();
     const value = valueString(getRepresentativeValue(info));
@@ -396,12 +397,13 @@
   }
 
   renderLinks() {
-    const links = (this.result?.links ?? []).slice(1);
+    const links = otherLinks(this.result);
     if (links.length === 0) return;
     return html`<div class="links">${links.map(this.renderLink)}</div>`;
   }
 
-  renderLink(link: Link) {
+  renderLink(link?: Link) {
+    if (!link) return;
     const tooltipText = link.tooltip ?? tooltipForLink(link.icon);
     return html`<a href="${link.url}" target="_blank"
       ><iron-icon
@@ -667,8 +669,15 @@
           display: flex;
           align-items: center;
         }
-        .headerBottomRow .links iron-icon {
+        .headerBottomRow iron-icon {
           color: var(--link-color);
+        }
+        .headerBottomRow .space {
+          display: inline-block;
+          width: var(--spacing-xl);
+          height: var(--line-height-normal);
+        }
+        .headerBottomRow a {
           margin-right: var(--spacing-l);
         }
         #moreActions iron-icon {
@@ -831,7 +840,11 @@
         </div>
         <div class="headerBottomRow">
           <div class="left">${this.renderFilter()}</div>
-          <div class="right">${this.renderLinks()}${this.renderActions()}</div>
+          <div class="right">
+            ${this.renderLinks()}
+            <div class="space"></div>
+            ${this.renderActions()}
+          </div>
         </div>
       </div>
       <div class="body">
@@ -844,12 +857,43 @@
   }
 
   private renderLinks() {
-    const links = (this.links ?? []).slice(0, 4);
+    const links = this.links ?? [];
     if (links.length === 0) return;
-    return html`<div class="links">${links.map(this.renderLink)}</div>`;
+    const primaryLinks = links.filter(a => a.primary).slice(0, 4);
+    const overflowLinks = links.filter(a => !primaryLinks.includes(a));
+    return html`
+      ${primaryLinks.map(this.renderLink)}
+      ${this.renderOverflowLinks(overflowLinks)}
+    `;
   }
 
-  private renderLink(link: Link) {
+  private renderOverflowLinks(overflowLinks: Link[]) {
+    const items = overflowLinks.map(link => {
+      return {
+        ...link,
+        id: link.tooltip,
+        name: link.tooltip,
+        target: '_blank',
+        tooltip: undefined,
+      };
+    });
+    return html`
+      <gr-dropdown
+        id="moreLinks"
+        link=""
+        vertical-offset="32"
+        horizontal-align="right"
+        .items="${items}"
+      >
+        <iron-icon icon="gr-icons:more-vert" aria-labelledby="moreMessage">
+        </iron-icon>
+        <span id="moreMessage">More</span>
+      </gr-dropdown>
+    `;
+  }
+
+  private renderLink(link?: Link) {
+    if (!link) return;
     const tooltipText = link.tooltip ?? tooltipForLink(link.icon);
     return html`<a href="${link.url}" target="_blank"
       ><iron-icon
@@ -862,23 +906,33 @@
   }
 
   private renderActions() {
-    const overflowItems = this.actions.slice(2).map(action => {
+    const actions = this.actions ?? [];
+    if (actions.length === 0) return;
+    const primaryActions = actions.filter(a => a.primary).slice(0, 2);
+    const overflowActions = actions.filter(a => !primaryActions.includes(a));
+    return html`
+      ${this.renderAction(primaryActions[0])}
+      ${this.renderAction(primaryActions[1])}
+      ${this.renderOverflowActions(overflowActions)}
+    `;
+  }
+
+  private renderOverflowActions(overflowActions: Action[]) {
+    const items = overflowActions.map(action => {
       return {...action, id: action.name};
     });
-    const disabledItems = overflowItems
+    if (!items || items.length === 0) return;
+    const disabledItems = items
       .filter(action => action.disabled)
       .map(action => action.id);
     return html`
-      ${this.renderAction(this.actions[0])}
-      ${this.renderAction(this.actions[1])}
       <gr-dropdown
         id="moreActions"
         link=""
         vertical-offset="32"
         horizontal-align="right"
         @tap-item="${this.handleAction}"
-        ?hidden="${overflowItems.length === 0}"
-        .items="${overflowItems}"
+        .items="${items}"
         .disabledIds="${disabledItems}"
       >
         <iron-icon icon="gr-icons:more-vert" aria-labelledby="moreMessage">
diff --git a/polygerrit-ui/app/elements/checks/gr-checks-runs.ts b/polygerrit-ui/app/elements/checks/gr-checks-runs.ts
index 175a0b5..edcc856 100644
--- a/polygerrit-ui/app/elements/checks/gr-checks-runs.ts
+++ b/polygerrit-ui/app/elements/checks/gr-checks-runs.ts
@@ -61,6 +61,8 @@
 } from './gr-checks-util';
 import {ChecksTabState} from '../../types/events';
 import {charsOnly} from '../../utils/string-util';
+import {appContext} from '../../services/app-context';
+import {KnownExperimentId} from '../../services/flags/flags';
 
 @customElement('gr-checks-run')
 export class GrChecksRun extends GrLitElement {
@@ -327,6 +329,8 @@
 
   private isSectionExpanded = new Map<RunStatus, boolean>();
 
+  private flagService = appContext.flagsService;
+
   constructor() {
     super();
     this.subscribe('runs', allRuns$);
@@ -425,34 +429,7 @@
       />
       ${this.renderSection(RunStatus.COMPLETED)}
       ${this.renderSection(RunStatus.RUNNING)}
-      ${this.renderSection(RunStatus.RUNNABLE)}
-      <div class="testing">
-        <div>Toggle fake runs by clicking buttons:</div>
-        <gr-button link @click="${this.none}">none</gr-button>
-        <gr-button
-          link
-          @click="${() =>
-            this.toggle('f0', [fakeRun0], fakeActions, fakeLinks)}"
-          >0</gr-button
-        >
-        <gr-button link @click="${() => this.toggle('f1', [fakeRun1])}"
-          >1</gr-button
-        >
-        <gr-button link @click="${() => this.toggle('f2', [fakeRun2])}"
-          >2</gr-button
-        >
-        <gr-button link @click="${() => this.toggle('f3', [fakeRun3])}"
-          >3</gr-button
-        >
-        <gr-button
-          link
-          @click="${() => {
-            this.toggle('f4', [fakeRun4_1, fakeRun4_2, fakeRun4_3, fakeRun4_4]);
-          }}"
-          >4</gr-button
-        >
-        <gr-button link @click="${this.all}">all</gr-button>
-      </div>
+      ${this.renderSection(RunStatus.RUNNABLE)} ${this.renderFakeControls()}
     `;
   }
 
@@ -541,6 +518,39 @@
     }
     return show;
   }
+
+  renderFakeControls() {
+    if (!this.flagService.isEnabled(KnownExperimentId.CHECKS_DEVELOPER)) return;
+    return html`
+      <div class="testing">
+        <div>Toggle fake runs by clicking buttons:</div>
+        <gr-button link @click="${this.none}">none</gr-button>
+        <gr-button
+          link
+          @click="${() =>
+            this.toggle('f0', [fakeRun0], fakeActions, fakeLinks)}"
+          >0</gr-button
+        >
+        <gr-button link @click="${() => this.toggle('f1', [fakeRun1])}"
+          >1</gr-button
+        >
+        <gr-button link @click="${() => this.toggle('f2', [fakeRun2])}"
+          >2</gr-button
+        >
+        <gr-button link @click="${() => this.toggle('f3', [fakeRun3])}"
+          >3</gr-button
+        >
+        <gr-button
+          link
+          @click="${() => {
+            this.toggle('f4', [fakeRun4_1, fakeRun4_2, fakeRun4_3, fakeRun4_4]);
+          }}"
+          >4</gr-button
+        >
+        <gr-button link @click="${this.all}">all</gr-button>
+      </div>
+    `;
+  }
 }
 
 declare global {
diff --git a/polygerrit-ui/app/elements/diff/gr-diff-cursor/gr-diff-cursor.ts b/polygerrit-ui/app/elements/diff/gr-diff-cursor/gr-diff-cursor.ts
index 9b7c25a..69c6139 100644
--- a/polygerrit-ui/app/elements/diff/gr-diff-cursor/gr-diff-cursor.ts
+++ b/polygerrit-ui/app/elements/diff/gr-diff-cursor/gr-diff-cursor.ts
@@ -35,7 +35,6 @@
 import {PolymerDomWrapper} from '../../../types/types';
 import {GrDiffGroupType} from '../gr-diff/gr-diff-group';
 import {GrDiff} from '../gr-diff/gr-diff';
-import {fireAlert, fireEvent} from '../../../utils/event-util';
 import {Subscription} from 'rxjs';
 import {toggleClass} from '../../../utils/dom-util';
 
@@ -44,9 +43,6 @@
 const LEFT_SIDE_CLASS = 'target-side-left';
 const RIGHT_SIDE_CLASS = 'target-side-right';
 
-// Time in which pressing n key again after the toast navigates to next file
-const NAVIGATE_TO_NEXT_FILE_TIMEOUT_MS = 5000;
-
 export interface GrDiffCursor {
   $: {};
 }
@@ -59,8 +55,6 @@
 
   private preventAutoScrollOnManualScroll = false;
 
-  private lastDisplayedNavigateToFileToast: Map<string, number> = new Map();
-
   @property({type: String})
   side = Side.RIGHT;
 
@@ -190,66 +184,28 @@
     }
   }
 
-  private showToastAndFireEvent(direction: string, shortcut: string) {
-    /*
-     * If user presses p/n on the first/last diff chunk, show a toast informing
-     * user that pressing it again will navigate them to previous/next
-     * unreviewedfile if click happens within the time limit
-     */
-    if (
-      this.lastDisplayedNavigateToFileToast.get(direction) &&
-      Date.now() - this.lastDisplayedNavigateToFileToast.get(direction)! <=
-        NAVIGATE_TO_NEXT_FILE_TIMEOUT_MS
-    ) {
-      // reset for next file
-      this.lastDisplayedNavigateToFileToast.delete(direction);
-      fireEvent(this, `navigate-to-${direction}-unreviewed-file`);
-    } else {
-      this.lastDisplayedNavigateToFileToast.set(direction, Date.now());
-      fireAlert(
-        this,
-        `Press ${shortcut} again to navigate to ${direction} unreviewed file`
-      );
-    }
-  }
-
-  moveToNextChunk(
-    clipToTop?: boolean,
-    navigateToNextFile?: boolean
-  ): CursorMoveResult {
+  moveToNextChunk(clipToTop?: boolean): CursorMoveResult {
     const result = this.cursorManager.next({
       filter: (row: HTMLElement) => this._isFirstRowOfChunk(row),
       getTargetHeight: target =>
         (target?.parentNode as HTMLElement)?.scrollHeight || 0,
       clipToTop,
     });
-    if (
-      navigateToNextFile &&
-      result === CursorMoveResult.CLIPPED &&
-      this.isAtEnd()
-    ) {
-      this.showToastAndFireEvent('next', 'n');
-    }
-
     this._fixSide();
     return result;
   }
 
-  moveToPreviousChunk(navigateToPreviousFile?: boolean): CursorMoveResult {
+  moveToPreviousChunk(): CursorMoveResult {
     const result = this.cursorManager.previous({
       filter: (row: HTMLElement) => this._isFirstRowOfChunk(row),
     });
-    if (navigateToPreviousFile && this.isAtStart()) {
-      this.showToastAndFireEvent('previous', 'p');
-    }
     this._fixSide();
     return result;
   }
 
-  moveToNextCommentThread(): CursorMoveResult | undefined {
+  moveToNextCommentThread(): CursorMoveResult {
     if (this.isAtEnd()) {
-      fireEvent(this, 'navigate-to-next-file-with-comments');
-      return;
+      return CursorMoveResult.CLIPPED;
     }
     const result = this.cursorManager.next({
       filter: (row: HTMLElement) => this._rowHasThread(row),
diff --git a/polygerrit-ui/app/elements/diff/gr-diff-cursor/gr-diff-cursor_test.js b/polygerrit-ui/app/elements/diff/gr-diff-cursor/gr-diff-cursor_test.js
index 901f72a..7b72da8 100644
--- a/polygerrit-ui/app/elements/diff/gr-diff-cursor/gr-diff-cursor_test.js
+++ b/polygerrit-ui/app/elements/diff/gr-diff-cursor/gr-diff-cursor_test.js
@@ -445,21 +445,6 @@
     });
   });
 
-  test('navigate to next unreviewed file via moveToNextChunk', () => {
-    const cursorManager = cursorElement.cursorManager;
-    cursorManager.index = cursorManager.stops.length - 1;
-    const dispatchEventStub = sinon.stub(cursorElement, 'dispatchEvent');
-    cursorElement.moveToNextChunk(/* opt_clipToTop = */false,
-        /* opt_navigateToNextFile = */true);
-    assert.isTrue(dispatchEventStub.called);
-    assert.equal(dispatchEventStub.getCall(1).args[0].type, 'show-alert');
-
-    cursorElement.moveToNextChunk(/* opt_clipToTop = */false,
-        /* opt_navigateToNextFile = */true);
-    assert.equal(dispatchEventStub.getCall(2).args[0].type,
-        'navigate-to-next-unreviewed-file');
-  });
-
   test('initialLineNumber not provided', done => {
     let scrollBehaviorDuringMove;
     const moveToNumStub = sinon.stub(cursorElement, 'moveToLineNumber');
diff --git a/polygerrit-ui/app/elements/diff/gr-diff-highlight/gr-diff-highlight.ts b/polygerrit-ui/app/elements/diff/gr-diff-highlight/gr-diff-highlight.ts
index ca003f3..6216644 100644
--- a/polygerrit-ui/app/elements/diff/gr-diff-highlight/gr-diff-highlight.ts
+++ b/polygerrit-ui/app/elements/diff/gr-diff-highlight/gr-diff-highlight.ts
@@ -123,7 +123,10 @@
    * because isMouseUp === true combined with an existing selection must
    * mean that this is the end of a double-click.
    */
-  handleSelectionChange(selection: Selection | null, isMouseUp: boolean) {
+  handleSelectionChange(
+    selection: Selection | Range | null,
+    isMouseUp: boolean
+  ) {
     if (selection === null) return;
     // Debounce is not just nice for waiting until the selection has settled,
     // it is also vital for being able to click on the action box before it is
@@ -262,7 +265,7 @@
    * syntax highligh, convert native DOM Range objects to Gerrit concepts
    * (line, side, etc).
    */
-  _getNormalizedRange(selection: Selection) {
+  _getNormalizedRange(selection: Selection | Range) {
     /* On Safari the ShadowRoot.getSelection() isn't there and the only thing
        we can get is a single Range */
     if (selection instanceof Range) {
@@ -425,7 +428,7 @@
     );
   }
 
-  _handleSelection(selection: Selection, isMouseUp: boolean) {
+  _handleSelection(selection: Selection | Range, isMouseUp: boolean) {
     /* On Safari, the selection events may return a null range that should
        be ignored */
     if (!selection) {
diff --git a/polygerrit-ui/app/elements/diff/gr-diff-view/gr-diff-view.ts b/polygerrit-ui/app/elements/diff/gr-diff-view/gr-diff-view.ts
index 638b49e..b7ac0de 100644
--- a/polygerrit-ui/app/elements/diff/gr-diff-view/gr-diff-view.ts
+++ b/polygerrit-ui/app/elements/diff/gr-diff-view/gr-diff-view.ts
@@ -106,10 +106,15 @@
 import {GerritView} from '../../../services/router/router-model';
 import {assertIsDefined} from '../../../utils/common-util';
 import {toggleClass, getKeyboardEvent} from '../../../utils/dom-util';
+import {CursorMoveResult} from '../../shared/gr-cursor-manager/gr-cursor-manager';
+
 const ERR_REVIEW_STATUS = 'Couldn’t change file review status.';
 const MSG_LOADING_BLAME = 'Loading blame...';
 const MSG_LOADED_BLAME = 'Blame loaded';
 
+// Time in which pressing n key again after the toast navigates to next file
+const NAVIGATE_TO_NEXT_FILE_TIMEOUT_MS = 5000;
+
 interface Files {
   sortedFileList: string[];
   changeFilesByPath: {[path: string]: FileInfo};
@@ -623,17 +628,62 @@
 
     e.preventDefault();
     if (e.detail.keyboardEvent?.shiftKey) {
-      this.$.cursor.moveToNextCommentThread();
+      const result = this.$.cursor.moveToNextCommentThread();
+      if (result === CursorMoveResult.CLIPPED) {
+        this._navigateToNextFileWithCommentThread();
+      }
     } else {
       if (this.modifierPressed(e)) return;
+      const result = this.$.cursor.moveToNextChunk();
       // navigate to next file if key is not being held down
-      this.$.cursor.moveToNextChunk(
-        /* opt_clipToTop = */ false,
-        /* opt_navigateToNextFile = */ !e.detail.keyboardEvent?.repeat
+      if (
+        !e.detail.keyboardEvent?.repeat &&
+        result === CursorMoveResult.CLIPPED &&
+        this.$.cursor.isAtEnd()
+      ) {
+        this.showToastAndNavigateFile('next', 'n');
+      }
+    }
+  }
+
+  private lastDisplayedNavigateToFileToast: Map<string, number> = new Map();
+
+  private showToastAndNavigateFile(direction: string, shortcut: string) {
+    /*
+     * If user presses p/n on the first/last diff chunk, show a toast informing
+     * user that pressing it again will navigate them to previous/next
+     * unreviewedfile if click happens within the time limit
+     */
+    if (
+      this.lastDisplayedNavigateToFileToast.get(direction) &&
+      Date.now() - this.lastDisplayedNavigateToFileToast.get(direction)! <=
+        NAVIGATE_TO_NEXT_FILE_TIMEOUT_MS
+    ) {
+      // reset for next file
+      this.lastDisplayedNavigateToFileToast.delete(direction);
+      this.navigateToUnreviewedFile(direction);
+    } else {
+      this.lastDisplayedNavigateToFileToast.set(direction, Date.now());
+      fireAlert(
+        this,
+        `Press ${shortcut} again to navigate to ${direction} unreviewed file`
       );
     }
   }
 
+  private navigateToUnreviewedFile(direction: string) {
+    if (!this._path) return;
+    if (!this._fileList) return;
+    if (!this._reviewedFiles) return;
+    // Ensure that the currently viewed file always appears in unreviewedFiles
+    // so we resolve the right "next" file.
+    const unreviewedFiles = this._fileList.filter(
+      file => file === this._path || !this._reviewedFiles.has(file)
+    );
+
+    this._navToFile(this._path, unreviewedFiles, direction === 'next' ? 1 : -1);
+  }
+
   _handlePrevChunkOrCommentThread(e: CustomKeyboardEvent) {
     if (this.shouldSuppressKeyboardShortcut(e)) return;
 
@@ -642,7 +692,10 @@
       this.$.cursor.moveToPreviousCommentThread();
     } else {
       if (this.modifierPressed(e)) return;
-      this.$.cursor.moveToPreviousChunk(!e.detail.keyboardEvent?.repeat);
+      this.$.cursor.moveToPreviousChunk();
+      if (!e.detail.keyboardEvent?.repeat && this.$.cursor.isAtStart()) {
+        this.showToastAndNavigateFile('previous', 'p');
+      }
     }
   }
 
@@ -1753,34 +1806,10 @@
     return disableDiffPrefs || !loggedIn;
   }
 
-  _navigateToNextUnreviewedFile() {
-    if (!this._path) return;
-    if (!this._fileList) return;
-    if (!this._reviewedFiles) return;
-    // Ensure that the currently viewed file always appears in unreviewedFiles
-    // so we resolve the right "next" file.
-    const unreviewedFiles = this._fileList.filter(
-      file => file === this._path || !this._reviewedFiles.has(file)
-    );
-    this._navToFile(this._path, unreviewedFiles, 1);
-  }
-
-  _navigateToPreviousUnreviewedFile() {
-    if (!this._path) return;
-    if (!this._fileList) return;
-    if (!this._reviewedFiles) return;
-    // Ensure that the currently viewed file always appears in unreviewedFiles
-    // so we resolve the right "next" file.
-    const unreviewedFiles = this._fileList.filter(
-      file => file === this._path || !this._reviewedFiles.has(file)
-    );
-    this._navToFile(this._path, unreviewedFiles, -1);
-  }
-
   _handleNextUnreviewedFile(e: CustomKeyboardEvent) {
     if (this.shouldSuppressKeyboardShortcut(e)) return;
     this._setReviewed(true);
-    this._navigateToNextUnreviewedFile();
+    this.navigateToUnreviewedFile('next');
   }
 
   _navigateToNextFileWithCommentThread() {
diff --git a/polygerrit-ui/app/elements/diff/gr-diff-view/gr-diff-view_html.ts b/polygerrit-ui/app/elements/diff/gr-diff-view/gr-diff-view_html.ts
index 63bf74e..7897a4a 100644
--- a/polygerrit-ui/app/elements/diff/gr-diff-view/gr-diff-view_html.ts
+++ b/polygerrit-ui/app/elements/diff/gr-diff-view/gr-diff-view_html.ts
@@ -429,11 +429,6 @@
     on-reload-diff-preference="_handleReloadingDiffPreference"
   >
   </gr-diff-preferences-dialog>
-  <gr-diff-cursor
-    id="cursor"
-    on-navigate-to-next-unreviewed-file="_navigateToNextUnreviewedFile"
-    on-navigate-to-previous-unreviewed-file="_navigateToPreviousUnreviewedFile"
-    on-navigate-to-next-file-with-comments="_navigateToNextFileWithCommentThread"
-  ></gr-diff-cursor>
+  <gr-diff-cursor id="cursor"></gr-diff-cursor>
   <gr-comment-api id="commentAPI"></gr-comment-api>
 `;
diff --git a/polygerrit-ui/app/elements/diff/gr-diff-view/gr-diff-view_test.js b/polygerrit-ui/app/elements/diff/gr-diff-view/gr-diff-view_test.js
index 244bafb..39ec384 100644
--- a/polygerrit-ui/app/elements/diff/gr-diff-view/gr-diff-view_test.js
+++ b/polygerrit-ui/app/elements/diff/gr-diff-view/gr-diff-view_test.js
@@ -29,6 +29,8 @@
   createComment,
 } from '../../../test/test-data-generators.js';
 import {EditPatchSetNum} from '../../../types/common.js';
+import sinon from 'sinon/pkg/sinon-esm';
+import {CursorMoveResult} from '../../shared/gr-cursor-manager/gr-cursor-manager.js';
 
 const basicFixture = fixtureFromElement('gr-diff-view');
 
@@ -1735,6 +1737,133 @@
       });
     });
 
+    suite('switching files', () => {
+      let dispatchEventStub;
+      let navToFileStub;
+      let moveToPreviousChunkStub;
+      let moveToNextChunkStub;
+      let isAtStartStub;
+      let isAtEndStub;
+      let nowStub;
+
+      setup(() => {
+        dispatchEventStub = sinon.stub(
+            element, 'dispatchEvent').callThrough();
+        navToFileStub = sinon.stub(element, '_navToFile');
+        moveToPreviousChunkStub =
+            sinon.stub(element.$.cursor, 'moveToPreviousChunk');
+        moveToNextChunkStub =
+            sinon.stub(element.$.cursor, 'moveToNextChunk');
+        isAtStartStub = sinon.stub(element.$.cursor, 'isAtStart');
+        isAtEndStub = sinon.stub(element.$.cursor, 'isAtEnd');
+        nowStub = sinon.stub(Date, 'now');
+      });
+
+      test('shows toast when at the end of file', () => {
+        moveToNextChunkStub.returns(CursorMoveResult.CLIPPED);
+        isAtEndStub.returns(true);
+
+        MockInteractions.pressAndReleaseKeyOn(element, 78, null, 'n');
+
+        assert.isTrue(moveToNextChunkStub.called);
+        assert.equal(dispatchEventStub.lastCall.args[0].type, 'show-alert');
+        assert.isFalse(navToFileStub.called);
+      });
+
+      test('navigates to next file when n is tapped again', () => {
+        moveToNextChunkStub.returns(CursorMoveResult.CLIPPED);
+        isAtEndStub.returns(true);
+
+        element._files = getFilesFromFileList(['file1', 'file2', 'file3']);
+        element._reviewedFiles = new Set(['file2']);
+        element._path = 'file1';
+
+        nowStub.returns(5);
+        MockInteractions.pressAndReleaseKeyOn(element, 78, null, 'n');
+        nowStub.returns(10);
+        MockInteractions.pressAndReleaseKeyOn(element, 78, null, 'n');
+
+        assert.isTrue(navToFileStub.called);
+        assert.deepEqual(navToFileStub.lastCall.args, [
+          'file1',
+          ['file1', 'file3'],
+          1,
+        ]);
+      });
+
+      test('does not navigate if n is tapped twice too slow', () => {
+        moveToNextChunkStub.returns(CursorMoveResult.CLIPPED);
+        isAtEndStub.returns(true);
+
+        nowStub.returns(5);
+        MockInteractions.pressAndReleaseKeyOn(element, 78, null, 'n');
+        nowStub.returns(6000);
+        MockInteractions.pressAndReleaseKeyOn(element, 78, null, 'n');
+
+        assert.isFalse(navToFileStub.called);
+      });
+
+      test('shows toast when at the start of file', () => {
+        moveToPreviousChunkStub.returns(CursorMoveResult.CLIPPED);
+        isAtStartStub.returns(true);
+
+        MockInteractions.pressAndReleaseKeyOn(element, 80, null, 'p');
+
+        assert.isTrue(moveToPreviousChunkStub.called);
+        assert.equal(dispatchEventStub.lastCall.args[0].type, 'show-alert');
+        assert.isFalse(navToFileStub.called);
+      });
+
+      test('navigates to prev file when p is tapped again', () => {
+        moveToPreviousChunkStub.returns(CursorMoveResult.CLIPPED);
+        isAtStartStub.returns(true);
+
+        element._files = getFilesFromFileList(['file1', 'file2', 'file3']);
+        element._reviewedFiles = new Set(['file2']);
+        element._path = 'file3';
+
+        nowStub.returns(5);
+        MockInteractions.pressAndReleaseKeyOn(element, 80, null, 'p');
+        nowStub.returns(10);
+        MockInteractions.pressAndReleaseKeyOn(element, 80, null, 'p');
+
+        assert.isTrue(navToFileStub.called);
+        assert.deepEqual(navToFileStub.lastCall.args, [
+          'file3',
+          ['file1', 'file3'],
+          -1,
+        ]);
+      });
+
+      test('does not navigate if p is tapped twice too slow', () => {
+        moveToPreviousChunkStub.returns(CursorMoveResult.CLIPPED);
+        isAtStartStub.returns(true);
+
+        nowStub.returns(5);
+        MockInteractions.pressAndReleaseKeyOn(element, 80, null, 'p');
+        nowStub.returns(6000);
+        MockInteractions.pressAndReleaseKeyOn(element, 80, null, 'p');
+
+        assert.isFalse(navToFileStub.called);
+      });
+
+      test('does not navigate when tapping n then p', () => {
+        moveToNextChunkStub.returns(CursorMoveResult.CLIPPED);
+        isAtEndStub.returns(true);
+
+        nowStub.returns(5);
+        MockInteractions.pressAndReleaseKeyOn(element, 78, null, 'n');
+
+        moveToPreviousChunkStub.returns(CursorMoveResult.CLIPPED);
+        isAtStartStub.returns(true);
+
+        nowStub.returns(10);
+        MockInteractions.pressAndReleaseKeyOn(element, 80, null, 'p');
+
+        assert.isFalse(navToFileStub.called);
+      });
+    });
+
     test('shift+m navigates to next unreviewed file', () => {
       element._files = getFilesFromFileList(['file1', 'file2', 'file3']);
       element._reviewedFiles = new Set(['file1', 'file2']);
@@ -1894,7 +2023,7 @@
     });
   });
 
-  suite('gr-diff-view tests unmodified files with comments', () => {
+  suite('unmodified files with comments', () => {
     let element;
     setup(() => {
       const changedFiles = {
diff --git a/polygerrit-ui/app/elements/diff/gr-diff/gr-diff.ts b/polygerrit-ui/app/elements/diff/gr-diff/gr-diff.ts
index 3b76698..486bf3a 100644
--- a/polygerrit-ui/app/elements/diff/gr-diff/gr-diff.ts
+++ b/polygerrit-ui/app/elements/diff/gr-diff/gr-diff.ts
@@ -65,9 +65,7 @@
 import {AbortStop} from '../../shared/gr-cursor-manager/gr-cursor-manager';
 import {fireAlert, fireEvent} from '../../../utils/event-util';
 import {MovedLinkClickedEvent} from '../../../types/events';
-// TODO(davido): See: https://github.com/GoogleChromeLabs/shadow-selection-polyfill/issues/9
-// @ts-ignore
-import * as shadow from 'shadow-selection-polyfill/shadow.js';
+import {getContentEditableRange} from '../../../utils/safari-selection-util';
 
 import {
   CreateCommentEventDetail as CreateCommentEventDetailApi,
@@ -228,6 +226,14 @@
   revisionImage?: ImageInfo;
 
   /**
+   * In order to allow multi-select in Safari browsers, a workaround is required
+   * to trigger 'beforeinput' events to get a list of static ranges. This is
+   * obtained by making the content of the diff table "contentEditable".
+   */
+  @property({type: Boolean})
+  isContentEditable = isSafari();
+
+  /**
    * Whether the safety check for large diffs when whole-file is set has
    * been bypassed. If the value is null, then the safety has not been
    * bypassed. If the value is a number, then that number represents the
@@ -336,14 +342,11 @@
   @observe('loggedIn', 'isAttached')
   _enableSelectionObserver(loggedIn: boolean, isAttached: boolean) {
     if (loggedIn && isAttached) {
-      document.addEventListener(
-        '-shadow-selectionchange',
-        this.handleSelectionChange
-      );
+      document.addEventListener('selectionchange', this.handleSelectionChange);
       document.addEventListener('mouseup', this.handleMouseUp);
     } else {
       document.removeEventListener(
-        '-shadow-selectionchange',
+        'selectionchange',
         this.handleSelectionChange
       );
       document.removeEventListener('mouseup', this.handleMouseUp);
@@ -375,7 +378,7 @@
     return this.root instanceof ShadowRoot && this.root.getSelection
       ? this.root.getSelection()
       : isSafari()
-      ? shadow.getRange(this.root)
+      ? getContentEditableRange()
       : document.getSelection();
   }
 
diff --git a/polygerrit-ui/app/elements/diff/gr-diff/gr-diff_html.ts b/polygerrit-ui/app/elements/diff/gr-diff/gr-diff_html.ts
index e2bc312..9da3bf1 100644
--- a/polygerrit-ui/app/elements/diff/gr-diff/gr-diff_html.ts
+++ b/polygerrit-ui/app/elements/diff/gr-diff/gr-diff_html.ts
@@ -97,6 +97,10 @@
       height: 100%;
       background-color: var(--diff-blank-background-color);
     }
+    td.lineNum {
+      vertical-align: top;
+    }
+
     /*
       The only way to focus this (clicking) will apply our own focus styling,
       so this default styling is not needed and distracting.
@@ -358,6 +362,9 @@
       color: var(--link-color);
       padding: var(--spacing-m) 0 var(--spacing-m) 48px;
     }
+    #diffTable:focus {
+      outline: none;
+    }
     #loadingError,
     #sizeWarning {
       display: none;
@@ -558,6 +565,7 @@
             id="diffTable"
             class$="[[_diffTableClass]]"
             role="presentation"
+            contenteditable$="[[isContentEditable]]"
           ></table>
 
           <template
diff --git a/polygerrit-ui/app/elements/shared/gr-textarea/gr-textarea.ts b/polygerrit-ui/app/elements/shared/gr-textarea/gr-textarea.ts
index 6125d33..b3d1578 100644
--- a/polygerrit-ui/app/elements/shared/gr-textarea/gr-textarea.ts
+++ b/polygerrit-ui/app/elements/shared/gr-textarea/gr-textarea.ts
@@ -122,7 +122,7 @@
   _currentSearchString?: string;
 
   @property({type: Boolean})
-  _hideAutocomplete = true;
+  _hideEmojiAutocomplete = true;
 
   @property({type: Number})
   _index?: number;
@@ -141,7 +141,7 @@
   get keyBindings() {
     return {
       esc: '_handleEscKey',
-      tab: '_handleEnterByKey',
+      tab: '_handleTabKey',
       enter: '_handleEnterByKey',
       up: '_handleUpKey',
       down: '_handleDownKey',
@@ -186,7 +186,7 @@
   }
 
   _handleEscKey(e: KeyboardEvent) {
-    if (this._hideAutocomplete) {
+    if (this._hideEmojiAutocomplete) {
       return;
     }
     e.preventDefault();
@@ -195,7 +195,7 @@
   }
 
   _handleUpKey(e: KeyboardEvent) {
-    if (this._hideAutocomplete) {
+    if (this._hideEmojiAutocomplete) {
       return;
     }
     e.preventDefault();
@@ -206,7 +206,7 @@
   }
 
   _handleDownKey(e: KeyboardEvent) {
-    if (this._hideAutocomplete) {
+    if (this._hideEmojiAutocomplete) {
       return;
     }
     e.preventDefault();
@@ -216,8 +216,10 @@
     this.disableEnterKeyForSelectingEmoji = false;
   }
 
-  _handleEnterByKey(e: KeyboardEvent) {
-    if (this._hideAutocomplete || this.disableEnterKeyForSelectingEmoji) {
+  _handleTabKey(e: KeyboardEvent) {
+    // Tab should have normal behavior if the picker is closed or if the user
+    // has only typed ':'.
+    if (this._hideEmojiAutocomplete || this.disableEnterKeyForSelectingEmoji) {
       return;
     }
     e.preventDefault();
@@ -225,6 +227,19 @@
     this._setEmoji(this.$.emojiSuggestions.getCurrentText());
   }
 
+  _handleEnterByKey(e: KeyboardEvent) {
+    // Enter should have newline behavior if the picker is closed or if the user
+    // has only typed ':'.
+    if (this._hideEmojiAutocomplete || this.disableEnterKeyForSelectingEmoji) {
+      this.indent(e);
+      return;
+    }
+
+    e.preventDefault();
+    e.stopPropagation();
+    this._setEmoji(this.$.emojiSuggestions.getCurrentText());
+  }
+
   _handleEmojiSelect(e: CustomEvent) {
     this._setEmoji(e.detail.selected.dataset['value']);
   }
@@ -257,7 +272,7 @@
    * this allows the dropdown to appear near where the user is typing.
    */
   _updateCaratPosition() {
-    this._hideAutocomplete = false;
+    this._hideEmojiAutocomplete = false;
     if (typeof this.$.textarea.value === 'string') {
       this.$.hiddenText.textContent = this.$.textarea.value.substr(
         0,
@@ -375,7 +390,7 @@
     // hide and reset the autocomplete dropdown.
     flush();
     this._currentSearchString = '';
-    this._hideAutocomplete = true;
+    this._hideEmojiAutocomplete = true;
     this.closeDropdown();
     this._colonIndex = null;
     this.$.textarea.textarea.focus();
@@ -386,6 +401,34 @@
       new CustomEvent('value-changed', {detail: {value: text}})
     );
   }
+
+  private indent(e: KeyboardEvent): void {
+    if (!document.queryCommandSupported('insertText')) {
+      return;
+    }
+    // When nothing is selected, selectionStart is the caret position. We want
+    // the indentation level of the current line, not the end of the text which
+    // may be different.
+    const currentLine = this.$.textarea.textarea.value
+      .substr(0, this.$.textarea.selectionStart)
+      .split('\n')
+      .pop();
+    const currentLineIndentation = currentLine?.match(/^\s*/)?.[0];
+    if (!currentLineIndentation) {
+      return;
+    }
+
+    // Stops the normal newline being added afterwards since we are adding it
+    // ourselves.
+    e.preventDefault();
+
+    // MDN says that execCommand is deprecated, but the replacements are still
+    // WIP (Input Events Level 2). The queryCommandSupported check should ensure
+    // that entering newlines will work even if this indent feature breaks.
+    // Directly replacing the text is possible, but would destroy the undo/redo
+    // queue.
+    document.execCommand('insertText', false, '\n' + currentLineIndentation);
+  }
 }
 
 declare global {
diff --git a/polygerrit-ui/app/elements/shared/gr-textarea/gr-textarea_test.js b/polygerrit-ui/app/elements/shared/gr-textarea/gr-textarea_test.js
index 5b3a2b2..1747fce 100644
--- a/polygerrit-ui/app/elements/shared/gr-textarea/gr-textarea_test.js
+++ b/polygerrit-ui/app/elements/shared/gr-textarea/gr-textarea_test.js
@@ -71,7 +71,7 @@
         flush();
         assert.isFalse(element.$.emojiSuggestions.isHidden);
         assert.equal(element._colonIndex, 0);
-        assert.isFalse(element._hideAutocomplete);
+        assert.isFalse(element._hideEmojiAutocomplete);
         assert.equal(element._currentSearchString, '');
       });
 
@@ -86,7 +86,7 @@
         flush();
         assert.isFalse(element.$.emojiSuggestions.isHidden);
         assert.equal(element._colonIndex, 1);
-        assert.isFalse(element._hideAutocomplete);
+        assert.isFalse(element._hideEmojiAutocomplete);
         assert.equal(element._currentSearchString, '');
       });
 
@@ -100,7 +100,7 @@
         element.text = 'test:';
         flush();
         assert.isTrue(element.$.emojiSuggestions.isHidden);
-        assert.isTrue(element._hideAutocomplete);
+        assert.isTrue(element._hideEmojiAutocomplete);
       });
 
   test('emoji selector opens when a colon is typed and some substring',
@@ -117,7 +117,7 @@
         flush();
         assert.isFalse(element.$.emojiSuggestions.isHidden);
         assert.equal(element._colonIndex, 0);
-        assert.isFalse(element._hideAutocomplete);
+        assert.isFalse(element._hideEmojiAutocomplete);
         assert.equal(element._currentSearchString, 't');
       });
 
@@ -142,7 +142,7 @@
         flush();
         assert.isFalse(element.$.emojiSuggestions.isHidden);
         assert.equal(element._colonIndex, 0);
-        assert.isFalse(element._hideAutocomplete);
+        assert.isFalse(element._hideEmojiAutocomplete);
         assert.equal(element._currentSearchString, '');
       });
   test('emoji selector closes when text changes before the colon', () => {
@@ -169,7 +169,7 @@
     const closeSpy = sinon.spy(element, 'closeDropdown');
     element._resetEmojiDropdown();
     assert.equal(element._currentSearchString, '');
-    assert.isTrue(element._hideAutocomplete);
+    assert.isTrue(element._hideEmojiAutocomplete);
     assert.equal(element._colonIndex, null);
 
     element.$.emojiSuggestions.open();
@@ -220,6 +220,16 @@
         element.$.caratSpan.outerHTML);
   });
 
+  test('newline receives matching indentation', async () => {
+    const indentCommand = sinon.stub(document, 'execCommand');
+    element.$.textarea.value = '    a';
+    element._handleEnterByKey(
+        new CustomEvent('keydown', {detail: {keyboardEvent: {keyCode: 13}}})
+    );
+    await flush();
+    assert.deepEqual(indentCommand.args[0], ['insertText', false, '\n    ']);
+  });
+
   test('emoji dropdown is closed when iron-overlay-closed is fired', () => {
     const resetSpy = sinon.spy(element, '_resetEmojiDropdown');
     element.$.emojiSuggestions.dispatchEvent(
diff --git a/polygerrit-ui/app/package.json b/polygerrit-ui/app/package.json
index 6d5e475..4f5acf5 100644
--- a/polygerrit-ui/app/package.json
+++ b/polygerrit-ui/app/package.json
@@ -40,8 +40,7 @@
     "page": "^1.11.6",
     "polymer-bridges": "file:../../polymer-bridges/",
     "polymer-resin": "^2.0.1",
-    "rxjs": "^6.6.7",
-    "shadow-selection-polyfill": "^1.1.0"
+    "rxjs": "^6.6.7"
   },
   "license": "Apache-2.0",
   "private": true
diff --git a/polygerrit-ui/app/services/checks/checks-model.ts b/polygerrit-ui/app/services/checks/checks-model.ts
index e92db53..60cb780 100644
--- a/polygerrit-ui/app/services/checks/checks-model.ts
+++ b/polygerrit-ui/app/services/checks/checks-model.ts
@@ -228,9 +228,9 @@
   privateState$.next(nextState);
 }
 
-// TODO(brohlfs): Remove all fake runs by end of April. They are just making
-// it easier to develop the UI and always see all the different types/states of
-// runs and results.
+// TODO(brohlfs): Remove all fake runs once the Checks UI is fully launched.
+//  They are just making it easier to develop the UI and always see all the
+//  different types/states of runs and results.
 
 export const fakeRun0: CheckRun = {
   internalRunId: 'f0',
@@ -262,7 +262,7 @@
         },
         {
           name: 'Flag',
-          tooltip: 'Flag this result as not useful',
+          tooltip: 'Flag this result as totally absolutely really not useful',
           primary: true,
           disabled: true,
           callback: () => Promise.resolve({message: 'flag "flag" triggered'}),
@@ -448,7 +448,7 @@
 export const fakeActions: Action[] = [
   {
     name: 'Fake Action 1',
-    primary: false,
+    primary: true,
     disabled: true,
     tooltip: 'Tooltip for Fake Action 1',
     callback: () => Promise.resolve({message: 'fake action 1 triggered'}),
@@ -471,7 +471,7 @@
 export const fakeLinks: Link[] = [
   {
     url: 'https://www.google.com',
-    primary: false,
+    primary: true,
     tooltip: 'Tooltip for Bug Report Fake Link',
     icon: LinkIcon.REPORT_BUG,
   },
diff --git a/polygerrit-ui/app/services/checks/checks-util.ts b/polygerrit-ui/app/services/checks/checks-util.ts
index 7eb2a5d..981a1f6 100644
--- a/polygerrit-ui/app/services/checks/checks-util.ts
+++ b/polygerrit-ui/app/services/checks/checks-util.ts
@@ -21,6 +21,7 @@
   CheckResult as CheckResultApi,
   LinkIcon,
   RunStatus,
+  Link,
 } from '../../api/checks';
 import {assertNever} from '../../utils/common-util';
 import {CheckResult, CheckRun} from './checks-model';
@@ -308,3 +309,15 @@
     internalResultId: 'fake',
   };
 }
+
+export function primaryLink(result?: CheckResultApi): Link | undefined {
+  const links = result?.links ?? [];
+  return links.find(link => link.primary);
+}
+
+export function otherLinks(result?: CheckResultApi): Link[] {
+  const primary = primaryLink(result);
+  const links = result?.links ?? [];
+  // Just filter the one primary link, not all primary links.
+  return links.filter(link => link !== primary);
+}
diff --git a/polygerrit-ui/app/services/flags/flags.ts b/polygerrit-ui/app/services/flags/flags.ts
index 1a29055..789ff4e 100644
--- a/polygerrit-ui/app/services/flags/flags.ts
+++ b/polygerrit-ui/app/services/flags/flags.ts
@@ -26,4 +26,5 @@
 export enum KnownExperimentId {
   NEW_IMAGE_DIFF_UI = 'UiFeature__new_image_diff_ui',
   TOKEN_HIGHLIGHTING = 'UiFeature__token_highlighting',
+  CHECKS_DEVELOPER = 'UiFeature__checks_developer',
 }
diff --git a/polygerrit-ui/app/utils/label-util.ts b/polygerrit-ui/app/utils/label-util.ts
index 0cfbbbd..bcc92e8 100644
--- a/polygerrit-ui/app/utils/label-util.ts
+++ b/polygerrit-ui/app/utils/label-util.ts
@@ -66,10 +66,12 @@
 export function getLabelStatus(label?: DetailedLabelInfo): LabelStatus {
   const value = getRepresentativeValue(label);
   const range = getVotingRangeOrDefault(label);
-  if (value === range.min) return LabelStatus.REJECTED;
-  if (value === range.max) return LabelStatus.APPROVED;
-  if (value < 0) return LabelStatus.DISLIKED;
-  if (value > 0) return LabelStatus.RECOMMENDED;
+  if (value < 0) {
+    return value === range.min ? LabelStatus.REJECTED : LabelStatus.DISLIKED;
+  }
+  if (value > 0) {
+    return value === range.max ? LabelStatus.APPROVED : LabelStatus.RECOMMENDED;
+  }
   return LabelStatus.NEUTRAL;
 }
 
diff --git a/polygerrit-ui/app/utils/label-util_test.ts b/polygerrit-ui/app/utils/label-util_test.ts
index aef776d..56941ba 100644
--- a/polygerrit-ui/app/utils/label-util_test.ts
+++ b/polygerrit-ui/app/utils/label-util_test.ts
@@ -33,6 +33,10 @@
   DetailedLabelInfo,
 } from '../types/common';
 
+const VALUES_0 = {
+  '0': 'neutral',
+};
+
 const VALUES_1 = {
   '-1': 'bad',
   '0': 'neutral',
@@ -134,6 +138,10 @@
   test('getLabelStatus', () => {
     let labelInfo: DetailedLabelInfo = {all: [], values: VALUES_2};
     assert.equal(getLabelStatus(labelInfo), LabelStatus.NEUTRAL);
+    labelInfo = {all: [{value: 0}], values: VALUES_0};
+    assert.equal(getLabelStatus(labelInfo), LabelStatus.NEUTRAL);
+    labelInfo = {all: [{value: 0}], values: VALUES_1};
+    assert.equal(getLabelStatus(labelInfo), LabelStatus.NEUTRAL);
     labelInfo = {all: [{value: 0}], values: VALUES_2};
     assert.equal(getLabelStatus(labelInfo), LabelStatus.NEUTRAL);
     labelInfo = {all: [{value: 1}], values: VALUES_2};
diff --git a/polygerrit-ui/app/utils/safari-selection-util.ts b/polygerrit-ui/app/utils/safari-selection-util.ts
new file mode 100644
index 0000000..e38111f
--- /dev/null
+++ b/polygerrit-ui/app/utils/safari-selection-util.ts
@@ -0,0 +1,114 @@
+/**
+ * @license
+ * Copyright (C) 2021 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+import {isSafari, findActiveElement} from './dom-util';
+
+const SUPPORTS_SHADOW_SELECTION =
+  typeof window.ShadowRoot.prototype.getSelection === 'function';
+const SUPPORTS_BEFORE_INPUT =
+  typeof (window.InputEvent.prototype as InputEventExtended).getTargetRanges ===
+  'function';
+
+const TARGET_ID = 'diffTable';
+
+let processing = false;
+let contentEditableRange: Range | null = null;
+
+interface InputEventExtended extends InputEvent {
+  getTargetRanges(): StaticRange[];
+}
+
+if (isSafari() && !SUPPORTS_SHADOW_SELECTION && SUPPORTS_BEFORE_INPUT) {
+  /**
+   * This library aims at extracting the selection range in a content editable
+   * area. It is a hacky solution to work around the fact that Safari does not
+   * allow to get the selection from shadow dom anymore.
+   *
+   * The main idea behind this approach is the following:
+   * - Listen to 'selectionChange' events of 'contentEditable' areas.
+   * - Trigger a 'beforeInput' event by running and immediately terminating
+   *   an arbitrary `execCommand`.
+   * - use the getTargetRanges() method to get a list of static ranges
+   *
+   * This typescript snippet is the porting of that idea (as explained by its
+   * original author [1]).
+   *
+   * [1] https://github.com/GoogleChromeLabs/shadow-selection-polyfill/issues/11
+   */
+
+  window.addEventListener(
+    'selectionchange',
+    () => {
+      if (!processing) {
+        processing = true;
+        const active = findActiveElement(document, true);
+        if (active && active.id === TARGET_ID) {
+          // Safari does not allow to select inside a shadowRoot, so we use an
+          // `execCommand` to trigger a `beforeInput` event in order to
+          // get at the target range from the event.
+          document.execCommand('indent');
+        }
+        processing = false;
+      }
+    },
+    true
+  );
+
+  window.addEventListener(
+    'beforeinput',
+    event => {
+      if (processing) {
+        // selecting
+        const inputEvent = event as InputEventExtended;
+        if (typeof inputEvent.getTargetRanges !== 'function') return;
+        const range = inputEvent.getTargetRanges()[0];
+
+        const newRange = new Range();
+
+        newRange.setStart(range.startContainer, range.startOffset);
+        newRange.setEnd(range.endContainer, range.endOffset);
+
+        contentEditableRange = newRange;
+
+        event.preventDefault();
+        event.stopImmediatePropagation();
+      } else {
+        // typing
+        const active = findActiveElement(document, true);
+        if (active && active.id === TARGET_ID) {
+          // Prevent diff content from actually being edited: Making the diff
+          // table content editable is just a mechanism to allow processing
+          // 'beforeInput' events, but the content itself should not be editable
+          event.preventDefault();
+          event.stopImmediatePropagation();
+        }
+      }
+    },
+    true
+  );
+
+  window.addEventListener(
+    'selectstart',
+    _ => {
+      contentEditableRange = null;
+    },
+    true
+  );
+}
+
+export function getContentEditableRange() {
+  return contentEditableRange;
+}
diff --git a/polygerrit-ui/app/yarn.lock b/polygerrit-ui/app/yarn.lock
index 543017a..fed42a4 100644
--- a/polygerrit-ui/app/yarn.lock
+++ b/polygerrit-ui/app/yarn.lock
@@ -472,11 +472,6 @@
   dependencies:
     tslib "^1.9.0"
 
-shadow-selection-polyfill@^1.1.0:
-  version "1.1.0"
-  resolved "https://registry.yarnpkg.com/shadow-selection-polyfill/-/shadow-selection-polyfill-1.1.0.tgz#87eee5c3cd9c7296f9fec083ba6f4910b1fa6686"
-  integrity sha512-ntz8P6DLEFpx7gikeXZ4gSi3APE2D+BP0rKnnaBzED+Lm8je8nkNcayy6kGWPEDWMFbtm+Yvd1ONFaXcsVWn2w==
-
 tslib@^1.9.0:
   version "1.14.1"
   resolved "https://registry.yarnpkg.com/tslib/-/tslib-1.14.1.tgz#cf2d38bdc34a134bcaf1091c41f6619e2f672d00"