diff --git a/java/com/google/gerrit/entities/SubmitRequirementResult.java b/java/com/google/gerrit/entities/SubmitRequirementResult.java
index 4f2f2f6..b7fa398 100644
--- a/java/com/google/gerrit/entities/SubmitRequirementResult.java
+++ b/java/com/google/gerrit/entities/SubmitRequirementResult.java
@@ -64,6 +64,13 @@
     }
   }
 
+  /** Returns true if the submit requirement is fulfilled and can allow change submission. */
+  @Memoized
+  public boolean fulfilled() {
+    Status s = status();
+    return s == Status.SATISFIED || s == Status.OVERRIDDEN || s == Status.NOT_APPLICABLE;
+  }
+
   public static Builder builder() {
     return new AutoValue_SubmitRequirementResult.Builder();
   }
diff --git a/java/com/google/gerrit/server/CommentsUtil.java b/java/com/google/gerrit/server/CommentsUtil.java
index 3d3603f..ba9f6d6 100644
--- a/java/com/google/gerrit/server/CommentsUtil.java
+++ b/java/com/google/gerrit/server/CommentsUtil.java
@@ -450,6 +450,10 @@
   /**
    * Get NoteDb draft refs for a change.
    *
+   * <p>This is just a simple ref scan, so the results may potentially include refs for zombie draft
+   * comments. A zombie draft is one which has been published but the write to delete the draft ref
+   * from All-Users failed.
+   *
    * @param changeId change ID.
    * @return raw refs from All-Users repo.
    */
diff --git a/java/com/google/gerrit/server/approval/ApprovalInference.java b/java/com/google/gerrit/server/approval/ApprovalInference.java
index 4cb080a..695997a 100644
--- a/java/com/google/gerrit/server/approval/ApprovalInference.java
+++ b/java/com/google/gerrit/server/approval/ApprovalInference.java
@@ -54,6 +54,7 @@
 import java.util.Map;
 import java.util.Optional;
 import org.eclipse.jgit.lib.Config;
+import org.eclipse.jgit.lib.ObjectId;
 import org.eclipse.jgit.revwalk.RevWalk;
 
 /**
@@ -134,8 +135,9 @@
       PatchSet.Id psId,
       ChangeKind kind,
       LabelType type,
-      @Nullable Map<String, FileDiffOutput> modifiedFiles,
-      @Nullable Map<String, FileDiffOutput> modifiedFilesLastPatchset) {
+      @Nullable Map<String, FileDiffOutput> baseVsCurrentDiff,
+      @Nullable Map<String, FileDiffOutput> baseVsPriorDiff,
+      @Nullable Map<String, FileDiffOutput> priorVsCurrentDiff) {
     int n = psa.key().patchSetId().get();
     checkArgument(n != psId.get());
 
@@ -185,7 +187,8 @@
           project.getName());
       return true;
     } else if (type.isCopyAllScoresIfListOfFilesDidNotChange()
-        && listOfFilesUnchangedPredicate.match(modifiedFiles, modifiedFilesLastPatchset)) {
+        && listOfFilesUnchangedPredicate.match(
+            baseVsCurrentDiff, baseVsPriorDiff, priorVsCurrentDiff)) {
       logger.atFine().log(
           "approval %d on label %s of patch set %d of change %d can be copied"
               + " to patch set %d because the label has set "
@@ -402,8 +405,9 @@
         priorPatchSet.getValue().id().changeId(),
         changeKind);
 
-    Map<String, FileDiffOutput> modifiedFiles = null;
-    Map<String, FileDiffOutput> modifiedFilesLastPatchSet = null;
+    Map<String, FileDiffOutput> baseVsCurrent = null;
+    Map<String, FileDiffOutput> baseVsPrior = null;
+    Map<String, FileDiffOutput> priorVsCurrent = null;
     LabelTypes labelTypes = project.getLabelTypes();
     for (PatchSetApproval psa : priorApprovals) {
       if (resultByUser.contains(psa.label(), psa.accountId())) {
@@ -411,11 +415,13 @@
       }
       Optional<LabelType> type = labelTypes.byLabel(psa.labelId());
       // Only compute modified files if there is a relevant label, since this is expensive.
-      if (modifiedFiles == null
+      if (baseVsCurrent == null
           && type.isPresent()
           && type.get().isCopyAllScoresIfListOfFilesDidNotChange()) {
-        modifiedFiles = listModifiedFiles(project, patchSet);
-        modifiedFilesLastPatchSet = listModifiedFiles(project, priorPatchSet.getValue());
+        baseVsCurrent = listModifiedFiles(project, patchSet);
+        baseVsPrior = listModifiedFiles(project, priorPatchSet.getValue());
+        priorVsCurrent =
+            listModifiedFiles(project, priorPatchSet.getValue().commitId(), patchSet.commitId());
       }
       if (!type.isPresent()) {
         logger.atFine().log(
@@ -435,8 +441,9 @@
               patchSet.id(),
               changeKind,
               type.get(),
-              modifiedFiles,
-              modifiedFilesLastPatchSet)
+              baseVsCurrent,
+              baseVsPrior,
+              priorVsCurrent)
           && !canCopyBasedOnCopyCondition(notes, psa, patchSet, type.get(), changeKind)) {
         continue;
       }
@@ -465,4 +472,21 @@
           ex);
     }
   }
+
+  /**
+   * Gets the modified files between two commits corresponding to different patchsets of the same
+   * change.
+   */
+  private Map<String, FileDiffOutput> listModifiedFiles(
+      ProjectState project, ObjectId sourceCommit, ObjectId targetCommit) {
+    try {
+      return diffOperations.listModifiedFiles(project.getNameKey(), sourceCommit, targetCommit);
+    } catch (DiffNotAvailableException ex) {
+      throw new StorageException(
+          "failed to compute difference in files, so won't copy"
+              + " votes on labels even if list of files is the same and "
+              + "copyAllIfListOfFilesDidNotChange",
+          ex);
+    }
+  }
 }
diff --git a/java/com/google/gerrit/server/notedb/ChangeNotes.java b/java/com/google/gerrit/server/notedb/ChangeNotes.java
index f2034af..2d9b014 100644
--- a/java/com/google/gerrit/server/notedb/ChangeNotes.java
+++ b/java/com/google/gerrit/server/notedb/ChangeNotes.java
@@ -32,6 +32,7 @@
 import com.google.common.collect.ListMultimap;
 import com.google.common.collect.Lists;
 import com.google.common.collect.MultimapBuilder;
+import com.google.common.collect.Multimaps;
 import com.google.common.collect.Ordering;
 import com.google.common.collect.Sets;
 import com.google.common.collect.Sets.SetView;
@@ -522,7 +523,12 @@
   public ImmutableListMultimap<ObjectId, HumanComment> getDraftComments(
       Account.Id author, @Nullable Ref ref) {
     loadDraftComments(author, ref);
-    return draftCommentNotes.getComments();
+    // Filter out any zombie draft comments. These are drafts that are also in
+    // the published map, and arise when the update to All-Users to delete them
+    // during the publish operation failed.
+    return ImmutableListMultimap.copyOf(
+        Multimaps.filterEntries(
+            draftCommentNotes.getComments(), e -> !getCommentKeys().contains(e.getValue().key)));
   }
 
   public ImmutableListMultimap<ObjectId, RobotComment> getRobotComments() {
diff --git a/java/com/google/gerrit/server/notedb/CommitRewriter.java b/java/com/google/gerrit/server/notedb/CommitRewriter.java
index 3cbe546..e940b1e 100644
--- a/java/com/google/gerrit/server/notedb/CommitRewriter.java
+++ b/java/com/google/gerrit/server/notedb/CommitRewriter.java
@@ -543,12 +543,16 @@
     Matcher assigneeDeletedMatcher = ASSIGNEE_DELETED_PATTERN.matcher(originalChangeMessage);
     if (assigneeDeletedMatcher.matches()) {
       if (!NON_REPLACE_ACCOUNT_PATTERN.matcher(assigneeDeletedMatcher.group(1)).matches()) {
+        Optional<String> assigneeReplacement =
+            getPossibleAccountReplacement(
+                changeFixProgress,
+                oldAssignee,
+                getAccountInfoFromNameEmail(assigneeDeletedMatcher.group(1)));
+
         return Optional.of(
-            "Assignee deleted: "
-                + getPossibleAccountReplacement(
-                    changeFixProgress,
-                    oldAssignee,
-                    ParsedAccountInfo.create(assigneeDeletedMatcher.group(1))));
+            assigneeReplacement.isPresent()
+                ? "Assignee deleted: " + assigneeReplacement.get()
+                : "Assignee was deleted.");
       }
       return Optional.empty();
     }
@@ -556,12 +560,15 @@
     Matcher assigneeAddedMatcher = ASSIGNEE_ADDED_PATTERN.matcher(originalChangeMessage);
     if (assigneeAddedMatcher.matches()) {
       if (!NON_REPLACE_ACCOUNT_PATTERN.matcher(assigneeAddedMatcher.group(1)).matches()) {
+        Optional<String> assigneeReplacement =
+            getPossibleAccountReplacement(
+                changeFixProgress,
+                newAssignee,
+                getAccountInfoFromNameEmail(assigneeAddedMatcher.group(1)));
         return Optional.of(
-            "Assignee added: "
-                + getPossibleAccountReplacement(
-                    changeFixProgress,
-                    newAssignee,
-                    ParsedAccountInfo.create(assigneeAddedMatcher.group(1))));
+            assigneeReplacement.isPresent()
+                ? "Assignee added: " + assigneeReplacement.get()
+                : "Assignee was added.");
       }
       return Optional.empty();
     }
@@ -569,17 +576,22 @@
     Matcher assigneeChangedMatcher = ASSIGNEE_CHANGED_PATTERN.matcher(originalChangeMessage);
     if (assigneeChangedMatcher.matches()) {
       if (!NON_REPLACE_ACCOUNT_PATTERN.matcher(assigneeChangedMatcher.group(1)).matches()) {
+        Optional<String> oldAssigneeReplacement =
+            getPossibleAccountReplacement(
+                changeFixProgress,
+                oldAssignee,
+                getAccountInfoFromNameEmail(assigneeChangedMatcher.group(1)));
+        Optional<String> newAssigneeReplacement =
+            getPossibleAccountReplacement(
+                changeFixProgress,
+                newAssignee,
+                getAccountInfoFromNameEmail(assigneeChangedMatcher.group(2)));
         return Optional.of(
-            String.format(
-                "Assignee changed from: %s to: %s",
-                getPossibleAccountReplacement(
-                    changeFixProgress,
-                    oldAssignee,
-                    ParsedAccountInfo.create(assigneeChangedMatcher.group(1))),
-                getPossibleAccountReplacement(
-                    changeFixProgress,
-                    newAssignee,
-                    ParsedAccountInfo.create(assigneeChangedMatcher.group(2)))));
+            oldAssigneeReplacement.isPresent() && newAssigneeReplacement.isPresent()
+                ? String.format(
+                    "Assignee changed from: %s to: %s",
+                    oldAssigneeReplacement.get(), newAssigneeReplacement.get())
+                : "Assignee was changed.");
       }
       return Optional.empty();
     }
@@ -610,12 +622,15 @@
 
     Matcher matcher = REMOVED_VOTE_PATTERN.matcher(originalChangeMessage);
     if (matcher.matches() && !NON_REPLACE_ACCOUNT_PATTERN.matcher(matcher.group(2)).matches()) {
-      return Optional.of(
-          String.format(
-              "Removed %s by %s",
-              matcher.group(1),
-              getPossibleAccountReplacement(
-                  changeFixProgress, reviewer, getAccountInfoFromNameEmail(matcher.group(2)))));
+      Optional<String> reviewerReplacement =
+          getPossibleAccountReplacement(
+              changeFixProgress, reviewer, getAccountInfoFromNameEmail(matcher.group(2)));
+      StringBuilder replacement = new StringBuilder();
+      replacement.append("Removed ").append(matcher.group(1));
+      if (reviewerReplacement.isPresent()) {
+        replacement.append(" by ").append(reviewerReplacement.get());
+      }
+      return Optional.of(replacement.toString());
     }
     return Optional.empty();
   }
@@ -637,14 +652,14 @@
       String replacementLine = lines[i];
       if (matcher.matches() && !NON_REPLACE_ACCOUNT_PATTERN.matcher(matcher.group(2)).matches()) {
         anyFixed = true;
-        replacementLine =
-            String.format(
-                "* %s by %s\n",
-                matcher.group(1),
-                getPossibleAccountReplacement(
-                    changeFixProgress,
-                    Optional.empty(),
-                    getAccountInfoFromNameEmail(matcher.group(2))));
+        Optional<String> reviewerReplacement =
+            getPossibleAccountReplacement(
+                changeFixProgress, Optional.empty(), getAccountInfoFromNameEmail(matcher.group(2)));
+        replacementLine = "* " + matcher.group(1);
+        if (reviewerReplacement.isPresent()) {
+          replacementLine += " by " + reviewerReplacement.get();
+        }
+        replacementLine += "\n";
       }
       fixedLines.append(replacementLine);
     }
@@ -708,11 +723,14 @@
     StringBuffer sb = new StringBuffer();
     while (onAddReviewerMatcher.find()) {
       String reviewerName = normalizeOnCodeOwnerAddReviewerMatch(onAddReviewerMatcher.group(1));
-      String replacementName =
+      Optional<String> replacementName =
           getPossibleAccountReplacement(
               changeFixProgress, Optional.empty(), ParsedAccountInfo.create(reviewerName));
       onAddReviewerMatcher.appendReplacement(
-          sb, replacementName + ", who was added as reviewer owns the following files");
+          sb,
+          replacementName.isPresent()
+              ? replacementName.get() + ", who was added as reviewer owns the following files"
+              : "Added reviewer owns the following files");
     }
     onAddReviewerMatcher.appendTail(sb);
     sb.append("\n");
@@ -1071,19 +1089,20 @@
    * <p>If {@code account} is known, replace with {@link AccountTemplateUtil#getAccountTemplate}.
    * Otherwise, try to guess the correct replacement account for {@code accountName} among {@link
    * ChangeFixProgress#parsedAccounts} that appeared in the change. If this fails {@link
-   * #DEFAULT_ACCOUNT_REPLACEMENT} is applied.
+   * Optional#empty} is returned.
    *
    * @param changeFixProgress see {@link ChangeFixProgress}
    * @param account account that should be used for replacement, if known
    * @param accountInfo {@link ParsedAccountInfo} to replace.
-   * @return replacement for {@code accountName}
+   * @return replacement for {@code accountName} or {@link Optional#empty}, if the replacement could
+   *     not be determined.
    */
-  private String getPossibleAccountReplacement(
+  private Optional<String> getPossibleAccountReplacement(
       ChangeFixProgress changeFixProgress,
       Optional<Account.Id> account,
       ParsedAccountInfo accountInfo) {
     if (account.isPresent()) {
-      return AccountTemplateUtil.getAccountTemplate(account.get());
+      return Optional.of(AccountTemplateUtil.getAccountTemplate(account.get()));
     }
     // Retrieve reviewer accounts from cache and try to match by their name.
     Map<Account.Id, AccountState> missingAccountStateReviewers =
@@ -1129,7 +1148,7 @@
                               e.getValue().get().account().getName(), accountInfo.name()))
               .collect(ImmutableMap.toImmutableMap(Map.Entry::getKey, e -> e.getValue().get()));
     }
-    String replacementName = DEFAULT_ACCOUNT_REPLACEMENT;
+    Optional<String> replacementName = Optional.empty();
     if (possibleReplacements.isEmpty()) {
       logger.atWarning().log(
           "Fixing ref %s, could not find reviewer account matching name %s",
@@ -1140,8 +1159,9 @@
           changeFixProgress.changeMetaRef, accountInfo);
     } else {
       replacementName =
-          AccountTemplateUtil.getAccountTemplate(
-              Iterables.getOnlyElement(possibleReplacements.keySet()));
+          Optional.of(
+              AccountTemplateUtil.getAccountTemplate(
+                  Iterables.getOnlyElement(possibleReplacements.keySet())));
     }
     return replacementName;
   }
diff --git a/java/com/google/gerrit/server/notedb/StoreSubmitRequirementsOp.java b/java/com/google/gerrit/server/notedb/StoreSubmitRequirementsOp.java
index 57a3cd7..1a7d5af 100644
--- a/java/com/google/gerrit/server/notedb/StoreSubmitRequirementsOp.java
+++ b/java/com/google/gerrit/server/notedb/StoreSubmitRequirementsOp.java
@@ -50,7 +50,9 @@
     // patchset to the user before it was merged.
     ChangeData changeData = changeDataFactory.create(ctx.getProject(), ctx.getChange().getId());
     ChangeUpdate update = ctx.getUpdate(ctx.getChange().currentPatchSetId());
-    update.putSubmitRequirementResults(evaluator.evaluateAllRequirements(changeData).values());
+    // We do not want to store submit requirements in NoteDb for legacy submit records
+    update.putSubmitRequirementResults(
+        evaluator.evaluateAllRequirements(changeData, /* includeLegacy= */ false).values());
     return !changeData.submitRequirements().isEmpty();
   }
 }
diff --git a/java/com/google/gerrit/server/patch/DiffExecutor.java b/java/com/google/gerrit/server/patch/DiffExecutor.java
index 63d5c50..c9b87ff 100644
--- a/java/com/google/gerrit/server/patch/DiffExecutor.java
+++ b/java/com/google/gerrit/server/patch/DiffExecutor.java
@@ -16,14 +16,11 @@
 
 import static java.lang.annotation.RetentionPolicy.RUNTIME;
 
-import com.google.gerrit.server.patch.filediff.PatchListLoader;
 import com.google.inject.BindingAnnotation;
 import java.lang.annotation.Retention;
 import java.util.concurrent.ExecutorService;
 
-/**
- * Marker on {@link ExecutorService} used by {@link IntraLineLoader} and {@link PatchListLoader}.
- */
+/** Marker on {@link ExecutorService} used by {@link IntraLineLoader}. */
 @Retention(RUNTIME)
 @BindingAnnotation
 public @interface DiffExecutor {}
diff --git a/java/com/google/gerrit/server/patch/PatchListCache.java b/java/com/google/gerrit/server/patch/PatchListCache.java
index 6d42249..b8651e0 100644
--- a/java/com/google/gerrit/server/patch/PatchListCache.java
+++ b/java/com/google/gerrit/server/patch/PatchListCache.java
@@ -16,18 +16,11 @@
 
 import com.google.gerrit.entities.Project;
 
-/** Provides a cached list of {@link PatchListEntry}. */
+/**
+ * Provides a cached list of intra-line and summary diffs. Use {@link DiffOperations} to compute
+ * detailed file diffs.
+ */
 public interface PatchListCache {
-  /**
-   * Returns the patch list - list of modified files - between two commits.
-   *
-   * @param key identifies the old / new commits.
-   * @param project name key identifying a specific git project (repository).
-   * @return patch list containing the modified files between two commits.
-   * @deprecated use {@link DiffOperations} instead.
-   */
-  @Deprecated
-  PatchList get(PatchListKey key, Project.NameKey project) throws PatchListNotAvailableException;
 
   IntraLineDiff getIntraLineDiff(IntraLineDiffKey key, IntraLineDiffArgs args);
 
diff --git a/java/com/google/gerrit/server/patch/PatchListCacheImpl.java b/java/com/google/gerrit/server/patch/PatchListCacheImpl.java
index dd2bb47..eab0c22 100644
--- a/java/com/google/gerrit/server/patch/PatchListCacheImpl.java
+++ b/java/com/google/gerrit/server/patch/PatchListCacheImpl.java
@@ -15,14 +15,12 @@
 
 package com.google.gerrit.server.patch;
 
-import com.google.common.annotations.VisibleForTesting;
 import com.google.common.cache.Cache;
+import com.google.common.flogger.FluentLogger;
 import com.google.common.util.concurrent.UncheckedExecutionException;
 import com.google.gerrit.entities.Project;
-import com.google.gerrit.server.cache.CacheBackend;
 import com.google.gerrit.server.cache.CacheModule;
 import com.google.gerrit.server.config.GerritServerConfig;
-import com.google.gerrit.server.patch.filediff.PatchListLoader;
 import com.google.inject.Inject;
 import com.google.inject.Module;
 import com.google.inject.Singleton;
@@ -30,12 +28,12 @@
 import java.util.concurrent.ExecutionException;
 import org.eclipse.jgit.errors.LargeObjectException;
 import org.eclipse.jgit.lib.Config;
-import org.eclipse.jgit.lib.ObjectId;
 
 /** Provides a cached list of {@link PatchListEntry}. */
 @Singleton
 public class PatchListCacheImpl implements PatchListCache {
-  public static final String FILE_NAME = "diff";
+  public static final FluentLogger logger = FluentLogger.forEnclosingClass();
+
   static final String INTRA_NAME = "diff_intraline";
   static final String DIFF_SUMMARY = "diff_summary";
 
@@ -43,13 +41,6 @@
     return new CacheModule() {
       @Override
       protected void configure() {
-        factory(PatchListLoader.Factory.class);
-        // TODO(davido): Switch off using legacy cache backend, after fixing PatchListLoader
-        // to be recursion free.
-        persist(FILE_NAME, PatchListKey.class, PatchList.class, CacheBackend.GUAVA)
-            .maximumWeight(10 << 20)
-            .weigher(PatchListWeigher.class);
-
         factory(IntraLineLoader.Factory.class);
         persist(INTRA_NAME, IntraLineDiffKey.class, IntraLineDiff.class)
             .maximumWeight(10 << 20)
@@ -67,27 +58,21 @@
     };
   }
 
-  private final Cache<PatchListKey, PatchList> fileCache;
   private final Cache<IntraLineDiffKey, IntraLineDiff> intraCache;
   private final Cache<DiffSummaryKey, DiffSummary> diffSummaryCache;
-  private final PatchListLoader.Factory fileLoaderFactory;
   private final IntraLineLoader.Factory intraLoaderFactory;
   private final DiffSummaryLoader.Factory diffSummaryLoaderFactory;
   private final boolean computeIntraline;
 
   @Inject
   PatchListCacheImpl(
-      @Named(FILE_NAME) Cache<PatchListKey, PatchList> fileCache,
       @Named(INTRA_NAME) Cache<IntraLineDiffKey, IntraLineDiff> intraCache,
       @Named(DIFF_SUMMARY) Cache<DiffSummaryKey, DiffSummary> diffSummaryCache,
-      PatchListLoader.Factory fileLoaderFactory,
       IntraLineLoader.Factory intraLoaderFactory,
       DiffSummaryLoader.Factory diffSummaryLoaderFactory,
       @GerritServerConfig Config cfg) {
-    this.fileCache = fileCache;
     this.intraCache = intraCache;
     this.diffSummaryCache = diffSummaryCache;
-    this.fileLoaderFactory = fileLoaderFactory;
     this.intraLoaderFactory = intraLoaderFactory;
     this.diffSummaryLoaderFactory = diffSummaryLoaderFactory;
 
@@ -97,31 +82,6 @@
   }
 
   @Override
-  public PatchList get(PatchListKey key, Project.NameKey project)
-      throws PatchListNotAvailableException {
-    try {
-      PatchList pl = fileCache.get(key, fileLoaderFactory.create(key, project));
-      if (pl instanceof LargeObjectTombstone) {
-        throw new PatchListObjectTooLargeException(
-            "Error computing " + key + ". Previous attempt failed with LargeObjectException");
-      }
-      return pl;
-    } catch (ExecutionException e) {
-      PatchListLoader.logger.atWarning().withCause(e).log("Error computing %s", key);
-      throw new PatchListNotAvailableException(e);
-    } catch (UncheckedExecutionException e) {
-      if (e.getCause() instanceof LargeObjectException) {
-        // Cache negative result so we don't need to redo expensive computations that would yield
-        // the same result.
-        fileCache.put(key, new LargeObjectTombstone());
-        PatchListLoader.logger.atWarning().withCause(e).log("Error computing %s", key);
-        throw new PatchListNotAvailableException(e);
-      }
-      throw e;
-    }
-  }
-
-  @Override
   public IntraLineDiff getIntraLineDiff(IntraLineDiffKey key, IntraLineDiffArgs args) {
     if (computeIntraline) {
       try {
@@ -140,28 +100,14 @@
     try {
       return diffSummaryCache.get(key, diffSummaryLoaderFactory.create(key, project));
     } catch (ExecutionException e) {
-      PatchListLoader.logger.atWarning().withCause(e).log("Error computing %s", key);
+      logger.atWarning().withCause(e).log("Error computing %s", key);
       throw new PatchListNotAvailableException(e);
     } catch (UncheckedExecutionException e) {
       if (e.getCause() instanceof LargeObjectException) {
-        PatchListLoader.logger.atWarning().withCause(e).log("Error computing %s", key);
+        logger.atWarning().withCause(e).log("Error computing %s", key);
         throw new PatchListNotAvailableException(e);
       }
       throw e;
     }
   }
-
-  /** Used to cache negative results in {@code fileCache}. */
-  @VisibleForTesting
-  public static class LargeObjectTombstone extends PatchList {
-    private static final long serialVersionUID = 1L;
-
-    @VisibleForTesting
-    public LargeObjectTombstone() {
-      // Initialize super class with valid values. We don't care about the inner state, but need to
-      // pass valid values that don't break (de)serialization.
-      super(
-          null, ObjectId.zeroId(), false, ComparisonType.againstAutoMerge(), new PatchListEntry[0]);
-    }
-  }
 }
diff --git a/java/com/google/gerrit/server/patch/PatchListWeigher.java b/java/com/google/gerrit/server/patch/PatchListWeigher.java
deleted file mode 100644
index 942d0e0..0000000
--- a/java/com/google/gerrit/server/patch/PatchListWeigher.java
+++ /dev/null
@@ -1,37 +0,0 @@
-// Copyright (C) 2012 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.patch;
-
-import com.google.common.cache.Weigher;
-
-/** Approximates memory usage for PatchList in bytes of memory used. */
-public class PatchListWeigher implements Weigher<PatchListKey, PatchList> {
-  @Override
-  public int weigh(PatchListKey key, PatchList value) {
-    int size =
-        16
-            + 4 * 8
-            + 2 * 36
-            + 8 // Size of PatchListKey, 64 bit JVM
-            + 16
-            + 3 * 8
-            + 3 * 4
-            + 20; // Size of PatchList, 64 bit JVM
-    for (PatchListEntry e : value.getPatches()) {
-      size += e.weigh();
-    }
-    return size;
-  }
-}
diff --git a/java/com/google/gerrit/server/patch/PatchScriptBuilder.java b/java/com/google/gerrit/server/patch/PatchScriptBuilder.java
index 0b08c4f..33300e3 100644
--- a/java/com/google/gerrit/server/patch/PatchScriptBuilder.java
+++ b/java/com/google/gerrit/server/patch/PatchScriptBuilder.java
@@ -71,28 +71,8 @@
     intralineDiffCalculator = calculator;
   }
 
-  /** Convert into {@link PatchScript} using the old diff cache output. */
-  PatchScript toPatchScriptOld(Repository git, PatchList list, PatchListEntry content)
-      throws IOException {
-
-    PatchFileChange change =
-        new PatchFileChange(
-            content.getEdits(),
-            content.getEditsDueToRebase(),
-            content.getHeaderLines(),
-            content.getOldName(),
-            content.getNewName(),
-            content.getChangeType(),
-            content.getPatchType());
-    SidesResolver sidesResolver = new SidesResolver(git, list.getComparisonType());
-    ResolvedSides sides =
-        resolveSides(
-            git, sidesResolver, oldName(change), newName(change), list.getOldId(), list.getNewId());
-    return build(sides.a, sides.b, change);
-  }
-
   /** Convert into {@link PatchScript} using the new diff cache output. */
-  PatchScript toPatchScriptNew(Repository git, FileDiffOutput content) throws IOException {
+  PatchScript toPatchScript(Repository git, FileDiffOutput content) throws IOException {
     PatchFileChange change =
         new PatchFileChange(
             content.edits().stream().map(TaggedEdit::jgitEdit).collect(toImmutableList()),
diff --git a/java/com/google/gerrit/server/patch/PatchScriptFactory.java b/java/com/google/gerrit/server/patch/PatchScriptFactory.java
index 96b23c8..02f125a 100644
--- a/java/com/google/gerrit/server/patch/PatchScriptFactory.java
+++ b/java/com/google/gerrit/server/patch/PatchScriptFactory.java
@@ -229,7 +229,7 @@
                 notes.getProjectName(), bId, parentNum, fileName, diffPrefs.ignoreWhitespace)
             : diffOperations.getModifiedFile(
                 notes.getProjectName(), aId, bId, fileName, diffPrefs.ignoreWhitespace);
-    return newBuilder().toPatchScriptNew(git, fileDiffOutput);
+    return newBuilder().toPatchScript(git, fileDiffOutput);
   }
 
   private Optional<ObjectId> getAId() {
diff --git a/java/com/google/gerrit/server/patch/filediff/PatchListLoader.java b/java/com/google/gerrit/server/patch/filediff/PatchListLoader.java
deleted file mode 100644
index 031f3db..0000000
--- a/java/com/google/gerrit/server/patch/filediff/PatchListLoader.java
+++ /dev/null
@@ -1,705 +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.patch.filediff;
-
-import static com.google.common.base.Preconditions.checkArgument;
-import static com.google.common.collect.ImmutableList.toImmutableList;
-import static java.nio.charset.StandardCharsets.UTF_8;
-import static java.util.stream.Collectors.toSet;
-import static org.eclipse.jgit.lib.Constants.OBJ_BLOB;
-
-import com.google.auto.value.AutoValue;
-import com.google.common.base.Throwables;
-import com.google.common.collect.ImmutableList;
-import com.google.common.collect.ImmutableMultimap;
-import com.google.common.collect.ImmutableSet;
-import com.google.common.collect.Iterables;
-import com.google.common.collect.Multimap;
-import com.google.common.flogger.FluentLogger;
-import com.google.gerrit.entities.Patch;
-import com.google.gerrit.entities.Project;
-import com.google.gerrit.exceptions.StorageException;
-import com.google.gerrit.extensions.client.DiffPreferencesInfo.Whitespace;
-import com.google.gerrit.metrics.Counter0;
-import com.google.gerrit.metrics.Description;
-import com.google.gerrit.metrics.MetricMaker;
-import com.google.gerrit.server.config.ConfigUtil;
-import com.google.gerrit.server.config.GerritServerConfig;
-import com.google.gerrit.server.git.GitRepositoryManager;
-import com.google.gerrit.server.git.InMemoryInserter;
-import com.google.gerrit.server.git.MergeUtil;
-import com.google.gerrit.server.patch.AutoMerger;
-import com.google.gerrit.server.patch.ComparisonType;
-import com.google.gerrit.server.patch.DiffExecutor;
-import com.google.gerrit.server.patch.PatchList;
-import com.google.gerrit.server.patch.PatchListCache;
-import com.google.gerrit.server.patch.PatchListCacheImpl;
-import com.google.gerrit.server.patch.PatchListEntry;
-import com.google.gerrit.server.patch.PatchListKey;
-import com.google.gerrit.server.patch.PatchListNotAvailableException;
-import com.google.gerrit.server.patch.Text;
-import com.google.gerrit.server.patch.filediff.EditTransformer.ContextAwareEdit;
-import com.google.inject.Inject;
-import com.google.inject.Singleton;
-import com.google.inject.assistedinject.Assisted;
-import java.io.IOException;
-import java.util.ArrayList;
-import java.util.Collection;
-import java.util.HashSet;
-import java.util.List;
-import java.util.Optional;
-import java.util.Set;
-import java.util.concurrent.Callable;
-import java.util.concurrent.ExecutionException;
-import java.util.concurrent.ExecutorService;
-import java.util.concurrent.Future;
-import java.util.concurrent.TimeUnit;
-import java.util.concurrent.TimeoutException;
-import org.eclipse.jgit.diff.DiffEntry;
-import org.eclipse.jgit.diff.DiffEntry.ChangeType;
-import org.eclipse.jgit.diff.DiffFormatter;
-import org.eclipse.jgit.diff.Edit;
-import org.eclipse.jgit.diff.EditList;
-import org.eclipse.jgit.diff.HistogramDiff;
-import org.eclipse.jgit.diff.RawText;
-import org.eclipse.jgit.diff.RawTextComparator;
-import org.eclipse.jgit.lib.AbbreviatedObjectId;
-import org.eclipse.jgit.lib.Config;
-import org.eclipse.jgit.lib.Constants;
-import org.eclipse.jgit.lib.FileMode;
-import org.eclipse.jgit.lib.ObjectId;
-import org.eclipse.jgit.lib.ObjectInserter;
-import org.eclipse.jgit.lib.ObjectReader;
-import org.eclipse.jgit.lib.Repository;
-import org.eclipse.jgit.merge.ThreeWayMergeStrategy;
-import org.eclipse.jgit.patch.FileHeader;
-import org.eclipse.jgit.patch.FileHeader.PatchType;
-import org.eclipse.jgit.revwalk.RevCommit;
-import org.eclipse.jgit.revwalk.RevObject;
-import org.eclipse.jgit.revwalk.RevTree;
-import org.eclipse.jgit.revwalk.RevWalk;
-import org.eclipse.jgit.treewalk.TreeWalk;
-import org.eclipse.jgit.util.io.DisabledOutputStream;
-
-public class PatchListLoader implements Callable<PatchList> {
-  public static final FluentLogger logger = FluentLogger.forEnclosingClass();
-
-  public interface Factory {
-    PatchListLoader create(PatchListKey key, Project.NameKey project);
-  }
-
-  @Singleton
-  static class Metrics {
-    final Counter0 timeouts;
-
-    @Inject
-    Metrics(MetricMaker metricMaker) {
-      // TODO(ghareeb): Remove this metric from documentation once this class is deprecated.
-      timeouts =
-          metricMaker.newCounter(
-              "caches/diff/legacy/timeouts",
-              new Description(
-                      "Total number of git file diff computations that resulted in timeouts.")
-                  .setRate()
-                  .setUnit("count"));
-    }
-  }
-
-  private final GitRepositoryManager repoManager;
-  private final PatchListCache patchListCache;
-  private final ThreeWayMergeStrategy mergeStrategy;
-  private final ExecutorService diffExecutor;
-  private final AutoMerger autoMerger;
-  private final PatchListKey key;
-  private final Metrics metrics;
-  private final Project.NameKey project;
-  private final long timeoutMillis;
-
-  @Inject
-  PatchListLoader(
-      GitRepositoryManager mgr,
-      PatchListCache plc,
-      @GerritServerConfig Config cfg,
-      @DiffExecutor ExecutorService de,
-      AutoMerger am,
-      Metrics metrics,
-      @Assisted PatchListKey k,
-      @Assisted Project.NameKey p) {
-    this.repoManager = mgr;
-    this.patchListCache = plc;
-    this.mergeStrategy = MergeUtil.getMergeStrategy(cfg);
-    this.diffExecutor = de;
-    this.autoMerger = am;
-    this.metrics = metrics;
-    this.key = k;
-    this.project = p;
-    this.timeoutMillis =
-        ConfigUtil.getTimeUnit(
-            cfg,
-            "cache",
-            PatchListCacheImpl.FILE_NAME,
-            "timeout",
-            TimeUnit.MILLISECONDS.convert(5, TimeUnit.SECONDS),
-            TimeUnit.MILLISECONDS);
-  }
-
-  @Override
-  public PatchList call() throws IOException, PatchListNotAvailableException {
-    try (Repository repo = repoManager.openRepository(project);
-        InMemoryInserter ins = new InMemoryInserter(repo);
-        ObjectReader reader = ins.newReader();
-        RevWalk rw = new RevWalk(reader)) {
-      return readPatchList(repo, rw, ins);
-    }
-  }
-
-  private static RawTextComparator comparatorFor(Whitespace ws) {
-    switch (ws) {
-      case IGNORE_ALL:
-        return RawTextComparator.WS_IGNORE_ALL;
-
-      case IGNORE_TRAILING:
-        return RawTextComparator.WS_IGNORE_TRAILING;
-
-      case IGNORE_LEADING_AND_TRAILING:
-        return RawTextComparator.WS_IGNORE_CHANGE;
-
-      case IGNORE_NONE:
-      default:
-        return RawTextComparator.DEFAULT;
-    }
-  }
-
-  private PatchList readPatchList(Repository repo, RevWalk rw, InMemoryInserter ins)
-      throws IOException, PatchListNotAvailableException {
-    ObjectReader reader = rw.getObjectReader();
-    checkArgument(reader.getCreatedFromInserter() == ins);
-    RawTextComparator cmp = comparatorFor(key.getWhitespace());
-    try (DiffFormatter df = new DiffFormatter(DisabledOutputStream.INSTANCE)) {
-      RevCommit b = rw.parseCommit(key.getNewId());
-      RevObject a = aFor(key, repo, rw, ins, b);
-
-      if (a == null) {
-        // TODO(sop) Remove this case.
-        // This is an octopus merge commit which should be compared against the
-        // auto-merge. However since we don't support computing the auto-merge
-        // for octopus merge commits, we fall back to diffing against the first
-        // parent, even though this wasn't what was requested.
-        //
-        ComparisonType comparisonType = ComparisonType.againstParent(1);
-        PatchListEntry[] entries = new PatchListEntry[2];
-        entries[0] = newCommitMessage(cmp, reader, null, b);
-        entries[1] = newMergeList(cmp, reader, null, b, comparisonType);
-        return new PatchList(a, b, true, comparisonType, entries);
-      }
-
-      ComparisonType comparisonType = getComparisonType(a, b);
-
-      RevCommit aCommit = a instanceof RevCommit ? (RevCommit) a : null;
-      RevTree aTree = rw.parseTree(a);
-      RevTree bTree = b.getTree();
-
-      df.setReader(reader, repo.getConfig());
-      df.setDiffComparator(cmp);
-      df.setDetectRenames(true);
-      List<DiffEntry> diffEntries = df.scan(aTree, bTree);
-
-      EditsDueToRebaseResult editsDueToRebaseResult =
-          determineEditsDueToRebase(aCommit, b, diffEntries, df, rw);
-      diffEntries = editsDueToRebaseResult.getRelevantOriginalDiffEntries();
-      Multimap<String, ContextAwareEdit> editsDueToRebasePerFilePath =
-          editsDueToRebaseResult.getEditsDueToRebasePerFilePath();
-
-      List<PatchListEntry> entries = new ArrayList<>();
-      entries.add(
-          newCommitMessage(
-              cmp, reader, comparisonType.isAgainstParentOrAutoMerge() ? null : aCommit, b));
-      boolean isMerge = b.getParentCount() > 1;
-      if (isMerge) {
-        entries.add(
-            newMergeList(
-                cmp,
-                reader,
-                comparisonType.isAgainstParentOrAutoMerge() ? null : aCommit,
-                b,
-                comparisonType));
-      }
-      for (DiffEntry diffEntry : diffEntries) {
-        Set<ContextAwareEdit> editsDueToRebase =
-            getEditsDueToRebase(editsDueToRebasePerFilePath, diffEntry);
-        Optional<PatchListEntry> patchListEntry =
-            getPatchListEntry(reader, df, diffEntry, aTree, bTree, editsDueToRebase);
-        patchListEntry.ifPresent(entries::add);
-      }
-      return new PatchList(
-          a, b, isMerge, comparisonType, entries.toArray(new PatchListEntry[entries.size()]));
-    }
-  }
-
-  /**
-   * Identifies the edits which are present between {@code commitA} and {@code commitB} due to other
-   * commits in between those two. Edits which cannot be clearly attributed to those other commits
-   * (because they overlap with modifications introduced by {@code commitA} or {@code commitB}) are
-   * omitted from the result. The edits are expressed as differences between {@code treeA} of {@code
-   * commitA} and {@code treeB} of {@code commitB}.
-   *
-   * <p><b>Note:</b> If one of the commits is a merge commit, an empty {@code Multimap} will be
-   * returned.
-   *
-   * <p><b>Warning:</b> This method assumes that commitA and commitB are either a parent and child
-   * commit or represent two patch sets which belong to the same change. No checks are made to
-   * confirm this assumption! Passing arbitrary commits to this method may lead to strange results
-   * or take very long.
-   *
-   * <p>This logic could be expanded to arbitrary commits if the following adjustments were applied:
-   *
-   * <ul>
-   *   <li>If {@code commitA} is an ancestor of {@code commitB} (or the other way around), {@code
-   *       commitA} (or {@code commitB}) is used instead of its parent in this method.
-   *   <li>Special handling for merge commits is added. If only one of them is a merge commit, the
-   *       whole computation has to be done between the single parent and all parents of the merge
-   *       commit. If both of them are merge commits, all combinations of parents have to be
-   *       considered. Alternatively, we could decide to not support this feature for merge commits
-   *       (or just for specific types of merge commits).
-   * </ul>
-   *
-   * @param commitA the commit defining {@code treeA}
-   * @param commitB the commit defining {@code treeB}
-   * @param diffEntries the list of {@code DiffEntries} for the diff between {@code commitA} and
-   *     {@code commitB}
-   * @param df the {@code DiffFormatter}
-   * @param rw the current {@code RevWalk}
-   * @return an aggregated result of the computation
-   * @throws PatchListNotAvailableException if the edits can't be identified
-   * @throws IOException if an error occurred while accessing the repository
-   */
-  private EditsDueToRebaseResult determineEditsDueToRebase(
-      RevCommit commitA,
-      RevCommit commitB,
-      List<DiffEntry> diffEntries,
-      DiffFormatter df,
-      RevWalk rw)
-      throws PatchListNotAvailableException, IOException {
-    if (commitA == null
-        || isRootOrMergeCommit(commitA)
-        || isRootOrMergeCommit(commitB)
-        || areParentChild(commitA, commitB)
-        || haveCommonParent(commitA, commitB)) {
-      return EditsDueToRebaseResult.create(diffEntries, ImmutableMultimap.of());
-    }
-
-    PatchListKey oldKey = PatchListKey.againstDefaultBase(key.getOldId(), key.getWhitespace());
-    PatchList oldPatchList = patchListCache.get(oldKey, project);
-    PatchListKey newKey = PatchListKey.againstDefaultBase(key.getNewId(), key.getWhitespace());
-    PatchList newPatchList = patchListCache.get(newKey, project);
-
-    List<PatchListEntry> oldPatches = oldPatchList.getPatches();
-    List<PatchListEntry> newPatches = newPatchList.getPatches();
-    // TODO(aliceks): Have separate but more limited lists for parents and patch sets (but don't
-    // mess up renames/copies).
-    Set<String> touchedFilePaths = new HashSet<>();
-    for (PatchListEntry patchListEntry : oldPatches) {
-      touchedFilePaths.addAll(getTouchedFilePaths(patchListEntry));
-    }
-    for (PatchListEntry patchListEntry : newPatches) {
-      touchedFilePaths.addAll(getTouchedFilePaths(patchListEntry));
-    }
-
-    List<DiffEntry> relevantDiffEntries =
-        diffEntries.stream()
-            .filter(diffEntry -> isTouched(touchedFilePaths, diffEntry))
-            .collect(toImmutableList());
-
-    RevCommit parentCommitA = commitA.getParent(0);
-    rw.parseBody(parentCommitA);
-    RevCommit parentCommitB = commitB.getParent(0);
-    rw.parseBody(parentCommitB);
-    List<DiffEntry> parentDiffEntries = df.scan(parentCommitA, parentCommitB);
-    // TODO(aliceks): Find a way to not construct a PatchListEntry as it contains many unnecessary
-    // details and we don't fill all of them properly.
-    List<PatchListEntry> parentPatchListEntries =
-        getRelevantPatchListEntries(
-            parentDiffEntries, parentCommitA, parentCommitB, touchedFilePaths, df);
-
-    EditTransformer editTransformer = new EditTransformer(toFileEditsList(parentPatchListEntries));
-    editTransformer.transformReferencesOfSideA(toFileEditsList(oldPatches));
-    editTransformer.transformReferencesOfSideB(toFileEditsList(newPatches));
-    return EditsDueToRebaseResult.create(
-        relevantDiffEntries, editTransformer.getEditsPerFilePath());
-  }
-
-  private ImmutableList<FileEdits> toFileEditsList(List<PatchListEntry> entries) {
-    return entries.stream().map(PatchListLoader::toFileEdits).collect(toImmutableList());
-  }
-
-  private static FileEdits toFileEdits(PatchListEntry patchListEntry) {
-    Optional<String> oldName = Optional.empty();
-    Optional<String> newName = Optional.empty();
-    switch (patchListEntry.getChangeType()) {
-      case DELETED:
-        oldName = Optional.of(patchListEntry.getNewName());
-        break;
-      case ADDED:
-      case MODIFIED:
-      case REWRITE:
-        newName = Optional.of(patchListEntry.getNewName());
-        break;
-
-      case COPIED:
-      case RENAMED:
-        oldName = Optional.of(patchListEntry.getOldName());
-        newName = Optional.of(patchListEntry.getNewName());
-        break;
-    }
-    return FileEdits.createFromJgitEdits(patchListEntry.getEdits(), oldName, newName);
-  }
-
-  private static boolean isRootOrMergeCommit(RevCommit commit) {
-    return commit.getParentCount() != 1;
-  }
-
-  private static boolean areParentChild(RevCommit commitA, RevCommit commitB) {
-    return ObjectId.isEqual(commitA.getParent(0), commitB)
-        || ObjectId.isEqual(commitB.getParent(0), commitA);
-  }
-
-  private static boolean haveCommonParent(RevCommit commitA, RevCommit commitB) {
-    return ObjectId.isEqual(commitA.getParent(0), commitB.getParent(0));
-  }
-
-  private static Set<String> getTouchedFilePaths(PatchListEntry patchListEntry) {
-    String oldFilePath = patchListEntry.getOldName();
-    String newFilePath = patchListEntry.getNewName();
-
-    return oldFilePath == null
-        ? ImmutableSet.of(newFilePath)
-        : ImmutableSet.of(oldFilePath, newFilePath);
-  }
-
-  private static boolean isTouched(Set<String> touchedFilePaths, DiffEntry diffEntry) {
-    String oldFilePath = diffEntry.getOldPath();
-    String newFilePath = diffEntry.getNewPath();
-    // One of the above file paths could be /dev/null but we need not explicitly check for this
-    // value as the set of file paths shouldn't contain it.
-    return touchedFilePaths.contains(oldFilePath) || touchedFilePaths.contains(newFilePath);
-  }
-
-  private List<PatchListEntry> getRelevantPatchListEntries(
-      List<DiffEntry> parentDiffEntries,
-      RevCommit parentCommitA,
-      RevCommit parentCommitB,
-      Set<String> touchedFilePaths,
-      DiffFormatter diffFormatter)
-      throws IOException {
-    List<PatchListEntry> parentPatchListEntries = new ArrayList<>(parentDiffEntries.size());
-    for (DiffEntry parentDiffEntry : parentDiffEntries) {
-      if (!isTouched(touchedFilePaths, parentDiffEntry)) {
-        continue;
-      }
-      FileHeader fileHeader = toFileHeader(parentCommitB, diffFormatter, parentDiffEntry);
-      // The code which uses this PatchListEntry doesn't care about the last three parameters. As
-      // they are expensive to compute, we use arbitrary values for them.
-      PatchListEntry patchListEntry =
-          newEntry(parentCommitA.getTree(), fileHeader, ImmutableSet.of(), 0, 0);
-      parentPatchListEntries.add(patchListEntry);
-    }
-    return parentPatchListEntries;
-  }
-
-  private static Set<ContextAwareEdit> getEditsDueToRebase(
-      Multimap<String, ContextAwareEdit> editsDueToRebasePerFilePath, DiffEntry diffEntry) {
-    if (editsDueToRebasePerFilePath.isEmpty()) {
-      return ImmutableSet.of();
-    }
-
-    String filePath = diffEntry.getNewPath();
-    if (diffEntry.getChangeType() == ChangeType.DELETE) {
-      filePath = diffEntry.getOldPath();
-    }
-    return ImmutableSet.copyOf(editsDueToRebasePerFilePath.get(filePath));
-  }
-
-  private Optional<PatchListEntry> getPatchListEntry(
-      ObjectReader objectReader,
-      DiffFormatter diffFormatter,
-      DiffEntry diffEntry,
-      RevTree treeA,
-      RevTree treeB,
-      Set<ContextAwareEdit> editsDueToRebase)
-      throws IOException {
-    FileHeader fileHeader = toFileHeader(key.getNewId(), diffFormatter, diffEntry);
-    long oldSize =
-        getFileSize(
-            objectReader,
-            diffEntry.getOldId(),
-            diffEntry.getOldMode(),
-            diffEntry.getOldPath(),
-            treeA);
-    long newSize =
-        getFileSize(
-            objectReader,
-            diffEntry.getNewId(),
-            diffEntry.getNewMode(),
-            diffEntry.getNewPath(),
-            treeB);
-    Set<Edit> contentEditsDueToRebase = getContentEdits(editsDueToRebase);
-    PatchListEntry patchListEntry =
-        newEntry(treeA, fileHeader, contentEditsDueToRebase, newSize, newSize - oldSize);
-    // All edits in a file are due to rebase -> exclude the file from the diff.
-    if (EditTransformer.toEdits(toFileEdits(patchListEntry)).allMatch(editsDueToRebase::contains)) {
-      return Optional.empty();
-    }
-    return Optional.of(patchListEntry);
-  }
-
-  private static Set<Edit> getContentEdits(Set<ContextAwareEdit> editsDueToRebase) {
-    return editsDueToRebase.stream()
-        .map(ContextAwareEdit::toEdit)
-        .filter(Optional::isPresent)
-        .map(Optional::get)
-        .collect(toSet());
-  }
-
-  private ComparisonType getComparisonType(RevObject a, RevCommit b) {
-    for (int i = 0; i < b.getParentCount(); i++) {
-      if (b.getParent(i).equals(a)) {
-        return ComparisonType.againstParent(i + 1);
-      }
-    }
-
-    if (key.getOldId() == null && b.getParentCount() > 0) {
-      return ComparisonType.againstAutoMerge();
-    }
-
-    return ComparisonType.againstOtherPatchSet();
-  }
-
-  private static long getFileSize(
-      ObjectReader reader, AbbreviatedObjectId abbreviatedId, FileMode mode, String path, RevTree t)
-      throws IOException {
-    if (!isBlob(mode)) {
-      return 0;
-    }
-    ObjectId fileId =
-        toObjectId(reader, abbreviatedId).orElseGet(() -> lookupObjectId(reader, path, t));
-    if (ObjectId.zeroId().equals(fileId)) {
-      return 0;
-    }
-    return reader.getObjectSize(fileId, OBJ_BLOB);
-  }
-
-  private static boolean isBlob(FileMode mode) {
-    int t = mode.getBits() & FileMode.TYPE_MASK;
-    return t == FileMode.TYPE_FILE || t == FileMode.TYPE_SYMLINK;
-  }
-
-  private static Optional<ObjectId> toObjectId(
-      ObjectReader reader, AbbreviatedObjectId abbreviatedId) throws IOException {
-    if (abbreviatedId == null) {
-      // In theory, DiffEntry#getOldId or DiffEntry#getNewId can be null for pure renames or pure
-      // mode changes (e.g. DiffEntry#modify doesn't set the IDs). However, the method we call
-      // for diffs (DiffFormatter#scan) seems to always produce DiffEntries with set IDs, even for
-      // pure renames.
-      return Optional.empty();
-    }
-    if (abbreviatedId.isComplete()) {
-      // With the current JGit version and the method we call for diffs (DiffFormatter#scan), this
-      // is the only code path taken right now.
-      return Optional.ofNullable(abbreviatedId.toObjectId());
-    }
-    Collection<ObjectId> objectIds = reader.resolve(abbreviatedId);
-    // It seems very unlikely that an ObjectId which was just abbreviated by the diff computation
-    // now can't be resolved to exactly one ObjectId. The API allows this possibility, though.
-    return objectIds.size() == 1
-        ? Optional.of(Iterables.getOnlyElement(objectIds))
-        : Optional.empty();
-  }
-
-  private static ObjectId lookupObjectId(ObjectReader reader, String path, RevTree tree) {
-    // This variant is very expensive.
-    try (TreeWalk treeWalk = TreeWalk.forPath(reader, path, tree)) {
-      return treeWalk != null ? treeWalk.getObjectId(0) : ObjectId.zeroId();
-    } catch (IOException e) {
-      throw new StorageException(e);
-    }
-  }
-
-  private FileHeader toFileHeader(
-      ObjectId commitB, DiffFormatter diffFormatter, DiffEntry diffEntry) throws IOException {
-
-    Future<FileHeader> result =
-        diffExecutor.submit(
-            () -> {
-              synchronized (diffEntry) {
-                return diffFormatter.toFileHeader(diffEntry);
-              }
-            });
-
-    try {
-      return result.get(timeoutMillis, TimeUnit.MILLISECONDS);
-    } catch (InterruptedException | TimeoutException e) {
-      metrics.timeouts.increment();
-      logger.atWarning().log(
-          "%s ms timeout reached for Diff loader in project %s"
-              + " on commit %s on path %s comparing %s..%s",
-          timeoutMillis,
-          project,
-          commitB.name(),
-          diffEntry.getNewPath(),
-          diffEntry.getOldId().name(),
-          diffEntry.getNewId().name());
-      result.cancel(true);
-      synchronized (diffEntry) {
-        return toFileHeaderWithoutMyersDiff(diffFormatter, diffEntry);
-      }
-    } catch (ExecutionException e) {
-      // If there was an error computing the result, carry it
-      // up to the caller so the cache knows this key is invalid.
-      Throwables.throwIfInstanceOf(e.getCause(), IOException.class);
-      throw new IOException(e.getMessage(), e.getCause());
-    }
-  }
-
-  private FileHeader toFileHeaderWithoutMyersDiff(DiffFormatter diffFormatter, DiffEntry diffEntry)
-      throws IOException {
-    HistogramDiff histogramDiff = new HistogramDiff();
-    histogramDiff.setFallbackAlgorithm(null);
-    diffFormatter.setDiffAlgorithm(histogramDiff);
-    return diffFormatter.toFileHeader(diffEntry);
-  }
-
-  private PatchListEntry newCommitMessage(
-      RawTextComparator cmp, ObjectReader reader, RevCommit aCommit, RevCommit bCommit)
-      throws IOException {
-    Text aText = aCommit != null ? Text.forCommit(reader, aCommit) : Text.EMPTY;
-    Text bText = Text.forCommit(reader, bCommit);
-    return createPatchListEntry(cmp, aCommit, aText, bText, Patch.COMMIT_MSG);
-  }
-
-  private PatchListEntry newMergeList(
-      RawTextComparator cmp,
-      ObjectReader reader,
-      RevCommit aCommit,
-      RevCommit bCommit,
-      ComparisonType comparisonType)
-      throws IOException {
-    Text aText = aCommit != null ? Text.forMergeList(comparisonType, reader, aCommit) : Text.EMPTY;
-    Text bText = Text.forMergeList(comparisonType, reader, bCommit);
-    return createPatchListEntry(cmp, aCommit, aText, bText, Patch.MERGE_LIST);
-  }
-
-  private static PatchListEntry createPatchListEntry(
-      RawTextComparator cmp, RevCommit aCommit, Text aText, Text bText, String fileName) {
-    byte[] rawHdr = getRawHeader(aCommit != null, fileName);
-    byte[] aContent = aText.getContent();
-    byte[] bContent = bText.getContent();
-    long size = bContent.length;
-    long sizeDelta = size - aContent.length;
-    RawText aRawText = new RawText(aContent);
-    RawText bRawText = new RawText(bContent);
-    EditList edits = new HistogramDiff().diff(cmp, aRawText, bRawText);
-    FileHeader fh = new FileHeader(rawHdr, edits, PatchType.UNIFIED);
-    return new PatchListEntry(fh, edits, ImmutableSet.of(), size, sizeDelta);
-  }
-
-  private static byte[] getRawHeader(boolean hasA, String fileName) {
-    StringBuilder hdr = new StringBuilder();
-    hdr.append("diff --git");
-    if (hasA) {
-      hdr.append(" a/").append(fileName);
-    } else {
-      hdr.append(" ").append(FileHeader.DEV_NULL);
-    }
-    hdr.append(" b/").append(fileName);
-    hdr.append("\n");
-
-    if (hasA) {
-      hdr.append("--- a/").append(fileName).append("\n");
-    } else {
-      hdr.append("--- ").append(FileHeader.DEV_NULL).append("\n");
-    }
-    hdr.append("+++ b/").append(fileName).append("\n");
-    return hdr.toString().getBytes(UTF_8);
-  }
-
-  private static PatchListEntry newEntry(
-      RevTree aTree, FileHeader fileHeader, Set<Edit> editsDueToRebase, long size, long sizeDelta) {
-    if (aTree == null // want combined diff
-        || fileHeader.getPatchType() != PatchType.UNIFIED
-        || fileHeader.getHunks().isEmpty()) {
-      return new PatchListEntry(fileHeader, ImmutableList.of(), ImmutableSet.of(), size, sizeDelta);
-    }
-
-    List<Edit> edits = fileHeader.toEditList();
-    if (edits.isEmpty()) {
-      return new PatchListEntry(fileHeader, ImmutableList.of(), ImmutableSet.of(), size, sizeDelta);
-    }
-    return new PatchListEntry(fileHeader, edits, editsDueToRebase, size, sizeDelta);
-  }
-
-  private RevObject aFor(
-      PatchListKey key, Repository repo, RevWalk rw, InMemoryInserter ins, RevCommit b)
-      throws IOException {
-    if (key.getOldId() != null) {
-      return rw.parseAny(key.getOldId());
-    }
-
-    switch (b.getParentCount()) {
-      case 0:
-        return rw.parseAny(emptyTree(ins));
-      case 1:
-        {
-          RevCommit r = b.getParent(0);
-          rw.parseBody(r);
-          return r;
-        }
-      default:
-        if (key.getParentNum() != null) {
-          RevCommit r = b.getParent(key.getParentNum() - 1);
-          rw.parseBody(r);
-          return r;
-        }
-        // Only support auto-merge for 2 parents, not octopus merges
-        if (b.getParentCount() == 2) {
-          return autoMerger.lookupFromGitOrMergeInMemory(repo, rw, ins, b, mergeStrategy);
-        }
-        return null;
-    }
-  }
-
-  private static ObjectId emptyTree(ObjectInserter ins) throws IOException {
-    ObjectId id = ins.insert(Constants.OBJ_TREE, new byte[] {});
-    ins.flush();
-    return id;
-  }
-
-  @AutoValue
-  abstract static class EditsDueToRebaseResult {
-    public static EditsDueToRebaseResult create(
-        List<DiffEntry> relevantDiffEntries,
-        Multimap<String, ContextAwareEdit> editsDueToRebasePerFilePath) {
-      return new AutoValue_PatchListLoader_EditsDueToRebaseResult(
-          relevantDiffEntries, editsDueToRebasePerFilePath);
-    }
-
-    public abstract List<DiffEntry> getRelevantOriginalDiffEntries();
-
-    /** Returns the edits per file path they modify in {@code treeB}. */
-    public abstract Multimap<String, ContextAwareEdit> getEditsDueToRebasePerFilePath();
-  }
-}
diff --git a/java/com/google/gerrit/server/project/SubmitRequirementsAdapter.java b/java/com/google/gerrit/server/project/SubmitRequirementsAdapter.java
index f028def..63a29cc 100644
--- a/java/com/google/gerrit/server/project/SubmitRequirementsAdapter.java
+++ b/java/com/google/gerrit/server/project/SubmitRequirementsAdapter.java
@@ -25,8 +25,12 @@
 import com.google.gerrit.entities.SubmitRequirementExpressionResult;
 import com.google.gerrit.entities.SubmitRequirementExpressionResult.Status;
 import com.google.gerrit.entities.SubmitRequirementResult;
+import com.google.gerrit.server.query.change.ChangeData;
 import com.google.gerrit.server.query.change.ChangeQueryBuilder;
 import java.util.List;
+import java.util.Map;
+import java.util.function.Function;
+import java.util.stream.Collectors;
 import org.eclipse.jgit.lib.ObjectId;
 
 /**
@@ -38,7 +42,25 @@
 
   private SubmitRequirementsAdapter() {}
 
-  public static List<SubmitRequirementResult> createResult(
+  /**
+   * Retrieve legacy submit records (created by label functions and other {@link
+   * com.google.gerrit.server.rules.SubmitRule}s) and convert them to submit requirement results.
+   */
+  public static Map<SubmitRequirement, SubmitRequirementResult> getLegacyRequirements(
+      SubmitRuleEvaluator.Factory evaluator, ChangeData cd) {
+    // We use SubmitRuleOptions.defaults() which does not recompute submit rules for closed changes.
+    // This doesn't have an effect since we never call this class (i.e. to evaluate submit
+    // requirements) for closed changes.
+    List<SubmitRecord> records = evaluator.create(SubmitRuleOptions.defaults()).evaluate(cd);
+    List<LabelType> labelTypes = cd.getLabelTypes().getLabelTypes();
+    ObjectId commitId = cd.currentPatchSet().commitId();
+    return records.stream()
+        .map(r -> createResult(r, labelTypes, commitId))
+        .flatMap(List::stream)
+        .collect(Collectors.toMap(sr -> sr.submitRequirement(), Function.identity()));
+  }
+
+  static List<SubmitRequirementResult> createResult(
       SubmitRecord record, List<LabelType> labelTypes, ObjectId psCommitId) {
     List<SubmitRequirementResult> results;
     if (record.ruleName.equals("gerrit~DefaultSubmitRule")) {
diff --git a/java/com/google/gerrit/server/project/SubmitRequirementsEvaluator.java b/java/com/google/gerrit/server/project/SubmitRequirementsEvaluator.java
index b3ac380..402bb51 100644
--- a/java/com/google/gerrit/server/project/SubmitRequirementsEvaluator.java
+++ b/java/com/google/gerrit/server/project/SubmitRequirementsEvaluator.java
@@ -26,8 +26,13 @@
   /**
    * Evaluate and return all submit requirement results for a change. Submit requirements are read
    * from the project config of the project containing the change as well as parent projects.
+   *
+   * @param cd change data corresponding to a specific gerrit change
+   * @param includeLegacy if set to true, evaluate legacy {@link
+   *     com.google.gerrit.entities.SubmitRecord}s and convert them to submit requirements.
    */
-  Map<SubmitRequirement, SubmitRequirementResult> evaluateAllRequirements(ChangeData cd);
+  Map<SubmitRequirement, SubmitRequirementResult> evaluateAllRequirements(
+      ChangeData cd, boolean includeLegacy);
 
   /** Evaluate a single {@link SubmitRequirement} using change data. */
   SubmitRequirementResult evaluateRequirement(SubmitRequirement sr, ChangeData cd);
diff --git a/java/com/google/gerrit/server/project/SubmitRequirementsEvaluatorImpl.java b/java/com/google/gerrit/server/project/SubmitRequirementsEvaluatorImpl.java
index 9be50c7..de637b4 100644
--- a/java/com/google/gerrit/server/project/SubmitRequirementsEvaluatorImpl.java
+++ b/java/com/google/gerrit/server/project/SubmitRequirementsEvaluatorImpl.java
@@ -17,8 +17,6 @@
 import static com.google.gerrit.server.project.ProjectCache.illegalState;
 
 import com.google.common.collect.ImmutableMap;
-import com.google.gerrit.entities.LabelType;
-import com.google.gerrit.entities.SubmitRecord;
 import com.google.gerrit.entities.SubmitRequirement;
 import com.google.gerrit.entities.SubmitRequirementExpression;
 import com.google.gerrit.entities.SubmitRequirementExpressionResult;
@@ -36,12 +34,8 @@
 import com.google.inject.Provider;
 import com.google.inject.Scopes;
 import java.util.HashMap;
-import java.util.List;
 import java.util.Map;
 import java.util.Optional;
-import java.util.function.Function;
-import java.util.stream.Collectors;
-import org.eclipse.jgit.lib.ObjectId;
 
 /** Evaluates submit requirements for different change data. */
 public class SubmitRequirementsEvaluatorImpl implements SubmitRequirementsEvaluator {
@@ -81,12 +75,19 @@
   }
 
   @Override
-  public Map<SubmitRequirement, SubmitRequirementResult> evaluateAllRequirements(ChangeData cd) {
-    Map<SubmitRequirement, SubmitRequirementResult> result = getRequirements(cd);
-    if (experimentFeatures.isFeatureEnabled(
-        ExperimentFeaturesConstants
-            .GERRIT_BACKEND_REQUEST_FEATURE_ENABLE_LEGACY_SUBMIT_REQUIREMENTS)) {
-      result.putAll(getLegacyRequirements(cd));
+  public Map<SubmitRequirement, SubmitRequirementResult> evaluateAllRequirements(
+      ChangeData cd, boolean includeLegacy) {
+    Map<SubmitRequirement, SubmitRequirementResult> projectConfigRequirements = getRequirements(cd);
+    Map<SubmitRequirement, SubmitRequirementResult> result = projectConfigRequirements;
+    if (includeLegacy
+        && experimentFeatures.isFeatureEnabled(
+            ExperimentFeaturesConstants
+                .GERRIT_BACKEND_REQUEST_FEATURE_ENABLE_LEGACY_SUBMIT_REQUIREMENTS)) {
+      Map<SubmitRequirement, SubmitRequirementResult> legacyReqs =
+          SubmitRequirementsAdapter.getLegacyRequirements(legacyEvaluator, cd);
+      result =
+          SubmitRequirementsUtil.mergeLegacyAndNonLegacyRequirements(
+              projectConfigRequirements, legacyReqs);
     }
     return ImmutableMap.copyOf(result);
   }
@@ -140,23 +141,6 @@
     return result;
   }
 
-  /**
-   * Convert and return legacy submit records (created by label functions and other {@link
-   * com.google.gerrit.server.rules.SubmitRule}s to submit requirement results.
-   */
-  private Map<SubmitRequirement, SubmitRequirementResult> getLegacyRequirements(ChangeData cd) {
-    // We use SubmitRuleOptions.defaults() which does not recompute submit rules for closed changes.
-    // This doesn't have an effect since we never call this class (i.e. to evaluate submit
-    // requirements) for closed changes.
-    List<SubmitRecord> records = legacyEvaluator.create(SubmitRuleOptions.defaults()).evaluate(cd);
-    List<LabelType> labelTypes = cd.getLabelTypes().getLabelTypes();
-    ObjectId commitId = cd.currentPatchSet().commitId();
-    return records.stream()
-        .map(r -> SubmitRequirementsAdapter.createResult(r, labelTypes, commitId))
-        .flatMap(List::stream)
-        .collect(Collectors.toMap(sr -> sr.submitRequirement(), Function.identity()));
-  }
-
   /** Evaluate the predicate recursively using change data. */
   private PredicateResult evaluatePredicateTree(
       Predicate<ChangeData> predicate, ChangeData changeData) {
diff --git a/java/com/google/gerrit/server/project/SubmitRequirementsUtil.java b/java/com/google/gerrit/server/project/SubmitRequirementsUtil.java
new file mode 100644
index 0000000..2e43eac
--- /dev/null
+++ b/java/com/google/gerrit/server/project/SubmitRequirementsUtil.java
@@ -0,0 +1,71 @@
+// 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.project;
+
+import com.google.gerrit.entities.SubmitRequirement;
+import com.google.gerrit.entities.SubmitRequirementResult;
+import java.util.HashMap;
+import java.util.Map;
+import java.util.stream.Collectors;
+
+/**
+ * A utility class for different operations related to {@link
+ * com.google.gerrit.entities.SubmitRequirement}s.
+ */
+public class SubmitRequirementsUtil {
+
+  private SubmitRequirementsUtil() {}
+
+  /**
+   * Merge legacy and non-legacy submit requirement results. If both input maps have submit
+   * requirements with the same name and fulfillment status (according to {@link
+   * SubmitRequirementResult#fulfilled()}), we eliminate the entry from the {@code
+   * legacyRequirements} input map and only include the one from the {@code
+   * projectConfigRequirements} in the result.
+   *
+   * @param projectConfigRequirements map of {@link SubmitRequirement} to {@link
+   *     SubmitRequirementResult} containing results for submit requirements stored in the
+   *     project.config.
+   * @param legacyRequirements map of {@link SubmitRequirement} to {@link SubmitRequirementResult}
+   *     containing the results of converting legacy submit records to submit requirements.
+   * @return a map that is the result of merging both input maps, while eliminating requirements
+   *     with the same name and status.
+   */
+  public static Map<SubmitRequirement, SubmitRequirementResult> mergeLegacyAndNonLegacyRequirements(
+      Map<SubmitRequirement, SubmitRequirementResult> projectConfigRequirements,
+      Map<SubmitRequirement, SubmitRequirementResult> legacyRequirements) {
+    Map<SubmitRequirement, SubmitRequirementResult> result = new HashMap<>();
+    result.putAll(projectConfigRequirements);
+    Map<String, SubmitRequirementResult> requirementsByName =
+        projectConfigRequirements.entrySet().stream()
+            .collect(Collectors.toMap(sr -> sr.getKey().name(), sr -> sr.getValue()));
+    for (Map.Entry<SubmitRequirement, SubmitRequirementResult> legacy :
+        legacyRequirements.entrySet()) {
+      String name = legacy.getKey().name();
+      SubmitRequirementResult projectConfigResult = requirementsByName.get(name);
+      SubmitRequirementResult legacyResult = legacy.getValue();
+      if (projectConfigResult != null && matchByStatus(projectConfigResult, legacyResult)) {
+        continue;
+      }
+      result.put(legacy.getKey(), legacy.getValue());
+    }
+    return result;
+  }
+
+  /** Returns true if both input results are equal in allowing/disallowing change submission. */
+  private static boolean matchByStatus(SubmitRequirementResult r1, SubmitRequirementResult r2) {
+    return r1.fulfilled() == r2.fulfilled();
+  }
+}
diff --git a/java/com/google/gerrit/server/query/approval/ListOfFilesUnchangedPredicate.java b/java/com/google/gerrit/server/query/approval/ListOfFilesUnchangedPredicate.java
index 55c27be..de7dd0a 100644
--- a/java/com/google/gerrit/server/query/approval/ListOfFilesUnchangedPredicate.java
+++ b/java/com/google/gerrit/server/query/approval/ListOfFilesUnchangedPredicate.java
@@ -58,13 +58,18 @@
     Integer parentNum =
         isInitialCommit(ctx.changeNotes().getProjectName(), targetPatchSet.commitId()) ? 0 : 1;
     try {
-      Map<String, FileDiffOutput> modifiedTargetPatchSet =
+      Map<String, FileDiffOutput> baseVsCurrent =
           diffOperations.listModifiedFilesAgainstParent(
               ctx.changeNotes().getProjectName(), targetPatchSet.commitId(), parentNum);
-      Map<String, FileDiffOutput> modifiedSourcePatchSet =
+      Map<String, FileDiffOutput> baseVsPrior =
           diffOperations.listModifiedFilesAgainstParent(
               ctx.changeNotes().getProjectName(), sourcePatchSet.commitId(), parentNum);
-      return match(modifiedTargetPatchSet, modifiedSourcePatchSet);
+      Map<String, FileDiffOutput> priorVsCurrent =
+          diffOperations.listModifiedFiles(
+              ctx.changeNotes().getProjectName(),
+              sourcePatchSet.commitId(),
+              targetPatchSet.commitId());
+      return match(baseVsCurrent, baseVsPrior, priorVsCurrent);
     } catch (DiffNotAvailableException ex) {
       throw new StorageException(
           "failed to compute difference in files, so won't copy"
@@ -79,16 +84,23 @@
    * {@link ChangeType} matches for each modified file.
    */
   public boolean match(
-      Map<String, FileDiffOutput> modifiedFiles1, Map<String, FileDiffOutput> modifiedFiles2) {
+      Map<String, FileDiffOutput> baseVsCurrent,
+      Map<String, FileDiffOutput> baseVsPrior,
+      Map<String, FileDiffOutput> priorVsCurrent) {
     Set<String> allFiles = new HashSet<>();
-    allFiles.addAll(modifiedFiles1.keySet());
-    allFiles.addAll(modifiedFiles2.keySet());
+    allFiles.addAll(baseVsCurrent.keySet());
+    allFiles.addAll(baseVsPrior.keySet());
     for (String file : allFiles) {
       if (Patch.isMagic(file)) {
         continue;
       }
-      FileDiffOutput fileDiffOutput1 = modifiedFiles1.get(file);
-      FileDiffOutput fileDiffOutput2 = modifiedFiles2.get(file);
+      FileDiffOutput fileDiffOutput1 = baseVsCurrent.get(file);
+      FileDiffOutput fileDiffOutput2 = baseVsPrior.get(file);
+      if (!priorVsCurrent.containsKey(file)) {
+        // If the file is not modified between prior and current patchsets, then scan safely skip
+        // it. The file might has been modified due to rebase.
+        continue;
+      }
       if (fileDiffOutput1 == null || fileDiffOutput2 == null) {
         return false;
       }
diff --git a/java/com/google/gerrit/server/query/change/ChangeData.java b/java/com/google/gerrit/server/query/change/ChangeData.java
index c551cd2..b8c8c07 100644
--- a/java/com/google/gerrit/server/query/change/ChangeData.java
+++ b/java/com/google/gerrit/server/query/change/ChangeData.java
@@ -75,6 +75,8 @@
 import com.google.gerrit.server.change.PureRevert;
 import com.google.gerrit.server.config.AllUsersName;
 import com.google.gerrit.server.config.TrackingFooters;
+import com.google.gerrit.server.experiments.ExperimentFeatures;
+import com.google.gerrit.server.experiments.ExperimentFeaturesConstants;
 import com.google.gerrit.server.git.GitRepositoryManager;
 import com.google.gerrit.server.git.MergeUtil;
 import com.google.gerrit.server.notedb.ChangeNotes;
@@ -87,7 +89,9 @@
 import com.google.gerrit.server.project.NoSuchChangeException;
 import com.google.gerrit.server.project.ProjectCache;
 import com.google.gerrit.server.project.ProjectState;
+import com.google.gerrit.server.project.SubmitRequirementsAdapter;
 import com.google.gerrit.server.project.SubmitRequirementsEvaluator;
+import com.google.gerrit.server.project.SubmitRequirementsUtil;
 import com.google.gerrit.server.project.SubmitRuleEvaluator;
 import com.google.gerrit.server.project.SubmitRuleOptions;
 import com.google.gerrit.server.util.time.TimeUtil;
@@ -268,7 +272,7 @@
     ChangeData cd =
         new ChangeData(
             null, null, null, null, null, null, null, null, null, null, null, null, null, null,
-            null, null, project, id, null, null);
+            null, null, null, project, id, null, null);
     cd.currentPatchSet =
         PatchSet.builder()
             .id(PatchSet.id(id, currentPatchSetId))
@@ -286,6 +290,7 @@
   private final ChangeMessagesUtil cmUtil;
   private final ChangeNotes.Factory notesFactory;
   private final CommentsUtil commentsUtil;
+  private final ExperimentFeatures experimentFeatures;
   private final GitRepositoryManager repoManager;
   private final MergeUtil.Factory mergeUtilFactory;
   private final MergeabilityCache mergeabilityCache;
@@ -367,6 +372,7 @@
       ChangeMessagesUtil cmUtil,
       ChangeNotes.Factory notesFactory,
       CommentsUtil commentsUtil,
+      ExperimentFeatures experimentFeatures,
       GitRepositoryManager repoManager,
       MergeUtil.Factory mergeUtilFactory,
       MergeabilityCache mergeabilityCache,
@@ -386,6 +392,7 @@
     this.cmUtil = cmUtil;
     this.notesFactory = notesFactory;
     this.commentsUtil = commentsUtil;
+    this.experimentFeatures = experimentFeatures;
     this.repoManager = repoManager;
     this.mergeUtilFactory = mergeUtilFactory;
     this.mergeabilityCache = mergeabilityCache;
@@ -946,13 +953,28 @@
         return Collections.emptyMap();
       }
       Change c = change();
-      if (c != null && c.isClosed()) {
+      if (c == null || !c.isClosed()) {
+        // Open changes: Evaluate submit requirements online.
         submitRequirements =
-            notes().getSubmitRequirementsResult().stream()
-                .collect(Collectors.toMap(r -> r.submitRequirement(), Function.identity()));
-      } else {
-        submitRequirements = submitRequirementsEvaluator.evaluateAllRequirements(this);
+            submitRequirementsEvaluator.evaluateAllRequirements(this, /* includeLegacy= */ true);
+        return submitRequirements;
       }
+      // Closed changes: Load submit requirement results from NoteDb.
+      Map<SubmitRequirement, SubmitRequirementResult> projectConfigRequirements =
+          notes().getSubmitRequirementsResult().stream()
+              .filter(r -> !r.legacy())
+              .collect(Collectors.toMap(r -> r.submitRequirement(), Function.identity()));
+      if (!experimentFeatures.isFeatureEnabled(
+          ExperimentFeaturesConstants
+              .GERRIT_BACKEND_REQUEST_FEATURE_ENABLE_LEGACY_SUBMIT_REQUIREMENTS)) {
+        submitRequirements = projectConfigRequirements;
+        return submitRequirements;
+      }
+      Map<SubmitRequirement, SubmitRequirementResult> legacyRequirements =
+          SubmitRequirementsAdapter.getLegacyRequirements(submitRuleEvaluatorFactory, this);
+      submitRequirements =
+          SubmitRequirementsUtil.mergeLegacyAndNonLegacyRequirements(
+              projectConfigRequirements, legacyRequirements);
     }
     return submitRequirements;
   }
@@ -1347,7 +1369,14 @@
       draftsByUser = new HashMap<>();
       for (Ref ref : commentsUtil.getDraftRefs(notes().getChangeId())) {
         Account.Id account = Account.Id.fromRefSuffix(ref.getName());
-        if (account != null) {
+        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());
         }
       }
diff --git a/javatests/com/google/gerrit/acceptance/api/change/ChangeIT.java b/javatests/com/google/gerrit/acceptance/api/change/ChangeIT.java
index 59011f6..52202d7 100644
--- a/javatests/com/google/gerrit/acceptance/api/change/ChangeIT.java
+++ b/javatests/com/google/gerrit/acceptance/api/change/ChangeIT.java
@@ -184,8 +184,6 @@
 import com.google.gerrit.server.patch.DiffSummaryKey;
 import com.google.gerrit.server.patch.IntraLineDiff;
 import com.google.gerrit.server.patch.IntraLineDiffKey;
-import com.google.gerrit.server.patch.PatchList;
-import com.google.gerrit.server.patch.PatchListKey;
 import com.google.gerrit.server.project.testing.TestLabels;
 import com.google.gerrit.server.query.change.ChangeData;
 import com.google.gerrit.server.query.change.ChangeQueryBuilder.ChangeOperatorFactory;
@@ -243,10 +241,6 @@
   @Inject private ExtensionRegistry extensionRegistry;
 
   @Inject
-  @Named("diff")
-  private Cache<PatchListKey, PatchList> fileCache;
-
-  @Inject
   @Named("diff_intraline")
   private Cache<IntraLineDiffKey, IntraLineDiff> intraCache;
 
@@ -307,13 +301,10 @@
     String fileContent = "First line\nSecond line\n";
     PushOneCommit.Result result = createChange("Add a file", fileName, fileContent);
     String triplet = project.get() + "~master~" + result.getChangeId();
-    CacheStats startPatch = cloneStats(fileCache.stats());
     CacheStats startIntra = cloneStats(intraCache.stats());
     CacheStats startSummary = cloneStats(diffSummaryCache.stats());
     gApi.changes().id(triplet).get(ImmutableList.of(ListChangesOption.SKIP_DIFFSTAT));
 
-    assertThat(fileCache.stats()).since(startPatch).hasMissCount(0);
-    assertThat(fileCache.stats()).since(startPatch).hasHitCount(0);
     assertThat(intraCache.stats()).since(startIntra).hasMissCount(0);
     assertThat(intraCache.stats()).since(startIntra).hasHitCount(0);
     assertThat(diffSummaryCache.stats()).since(startSummary).hasMissCount(0);
@@ -4548,6 +4539,129 @@
       value =
           ExperimentFeaturesConstants
               .GERRIT_BACKEND_REQUEST_FEATURE_ENABLE_LEGACY_SUBMIT_REQUIREMENTS)
+  public void
+      submitRequirements_returnOneEntryForMatchingLegacyAndNonLegacyResultsWithTheSameName_ifLegacySubmitRecordsAreEnabled()
+          throws Exception {
+    // Configure a legacy submit requirement: label with a max with block function
+    configLabel("build-cop-override", LabelFunction.MAX_WITH_BLOCK);
+    projectOperations
+        .project(project)
+        .forUpdate()
+        .add(
+            allowLabel("build-cop-override")
+                .ref("refs/heads/master")
+                .group(REGISTERED_USERS)
+                .range(-1, 1))
+        .update();
+
+    // Configure a submit requirement with the same name.
+    configSubmitRequirement(
+        project,
+        SubmitRequirement.builder()
+            .setName("build-cop-override")
+            .setSubmittabilityExpression(
+                SubmitRequirementExpression.create(
+                    "label:build-cop-override=MAX -label:build-cop-override=MIN"))
+            .setAllowOverrideInChildProjects(false)
+            .build());
+
+    // Create a change. Vote to fulfill all requirements.
+    PushOneCommit.Result r = createChange();
+    String changeId = r.getChangeId();
+    voteLabel(changeId, "build-cop-override", 1);
+    voteLabel(changeId, "Code-Review", 2);
+
+    // Project has two legacy requirements: Code-Review and bco, and a non-legacy requirement: bco.
+    // Only non-legacy bco is returned.
+    ChangeInfo change = gApi.changes().id(changeId).get();
+    assertThat(change.submitRequirements).hasSize(2);
+    assertSubmitRequirementStatus(
+        change.submitRequirements, "Code-Review", Status.SATISFIED, /* isLegacy= */ true);
+    assertSubmitRequirementStatus(
+        change.submitRequirements,
+        "build-cop-override",
+        Status.SATISFIED,
+        /* isLegacy= */ false,
+        /* submittabilityCondition= */ "label:build-cop-override=MAX -label:build-cop-override=MIN");
+
+    // Merge the change. Submit requirements are still the same.
+    gApi.changes().id(changeId).current().submit();
+    change = gApi.changes().id(changeId).get();
+    assertThat(change.submitRequirements).hasSize(2);
+    assertSubmitRequirementStatus(
+        change.submitRequirements, "Code-Review", Status.SATISFIED, /* isLegacy= */ true);
+    assertSubmitRequirementStatus(
+        change.submitRequirements,
+        "build-cop-override",
+        Status.SATISFIED,
+        /* isLegacy= */ false,
+        /* submittabilityCondition= */ "label:build-cop-override=MAX -label:build-cop-override=MIN");
+  }
+
+  @Test
+  @GerritConfig(
+      name = "experiments.enabled",
+      value =
+          ExperimentFeaturesConstants
+              .GERRIT_BACKEND_REQUEST_FEATURE_ENABLE_LEGACY_SUBMIT_REQUIREMENTS)
+  public void
+      submitRequirements_returnTwoEntriesForMismatchingLegacyAndNonLegacyResultsWithTheSameName_ifLegacySubmitRecordsAreEnabled()
+          throws Exception {
+    // Configure a legacy submit requirement: label with a max with block function
+    configLabel("build-cop-override", LabelFunction.MAX_WITH_BLOCK);
+    projectOperations
+        .project(project)
+        .forUpdate()
+        .add(
+            allowLabel("build-cop-override")
+                .ref("refs/heads/master")
+                .group(REGISTERED_USERS)
+                .range(-1, 1))
+        .update();
+
+    // Configure a submit requirement with the same name.
+    configSubmitRequirement(
+        project,
+        SubmitRequirement.builder()
+            .setName("build-cop-override")
+            .setSubmittabilityExpression(
+                SubmitRequirementExpression.create("label:build-cop-override=MIN"))
+            .setAllowOverrideInChildProjects(false)
+            .build());
+
+    // Create a change
+    PushOneCommit.Result r = createChange();
+    String changeId = r.getChangeId();
+    voteLabel(changeId, "build-cop-override", 1);
+    voteLabel(changeId, "Code-Review", 2);
+
+    // Project has two legacy requirements: Code-Review and bco, and a non-legacy requirement: bco.
+    // Two instances of bco will be returned since their status is not matching.
+    ChangeInfo change = gApi.changes().id(changeId).get();
+    assertThat(change.submitRequirements).hasSize(3);
+    assertSubmitRequirementStatus(
+        change.submitRequirements, "Code-Review", Status.SATISFIED, /* isLegacy= */ true);
+    assertSubmitRequirementStatus(
+        change.submitRequirements,
+        "build-cop-override",
+        Status.SATISFIED,
+        /* isLegacy= */ true,
+        // MAX_WITH_BLOCK function was translated to a submittability expression.
+        /* submittabilityCondition= */ "label:build-cop-override=MAX -label:build-cop-override=MIN");
+    assertSubmitRequirementStatus(
+        change.submitRequirements,
+        "build-cop-override",
+        Status.UNSATISFIED,
+        /* isLegacy= */ false,
+        /* submittabilityCondition= */ "label:build-cop-override=MIN");
+  }
+
+  @Test
+  @GerritConfig(
+      name = "experiments.enabled",
+      value =
+          ExperimentFeaturesConstants
+              .GERRIT_BACKEND_REQUEST_FEATURE_ENABLE_LEGACY_SUBMIT_REQUIREMENTS)
   public void submitRequirements_returnForLegacySubmitRecords_ifEnabled() throws Exception {
     configLabel("build-cop-override", LabelFunction.MAX_WITH_BLOCK);
     projectOperations
@@ -4591,6 +4705,7 @@
     // 4. Merge the change. Submit requirements status is presented from NoteDb.
     gApi.changes().id(changeId).current().submit();
     change = gApi.changes().id(changeId).get();
+    // Legacy submit records are returned as submit requirements.
     assertThat(change.submitRequirements).hasSize(2);
     assertSubmitRequirementStatus(
         change.submitRequirements, "Code-Review", Status.SATISFIED, /* isLegacy= */ true);
@@ -5205,6 +5320,30 @@
       Collection<SubmitRequirementResultInfo> results,
       String requirementName,
       SubmitRequirementResultInfo.Status status,
+      boolean isLegacy,
+      String submittabilityCondition) {
+    for (SubmitRequirementResultInfo result : results) {
+      if (result.name.equals(requirementName)
+          && result.status == status
+          && result.isLegacy == isLegacy
+          && result.submittabilityExpressionResult.expression.equals(submittabilityCondition)) {
+        return;
+      }
+    }
+    throw new AssertionError(
+        String.format(
+            "Could not find submit requirement %s with status %s (results = %s)",
+            requirementName,
+            status,
+            results.stream()
+                .map(r -> String.format("%s=%s", r.name, r.status))
+                .collect(toImmutableList())));
+  }
+
+  private void assertSubmitRequirementStatus(
+      Collection<SubmitRequirementResultInfo> results,
+      String requirementName,
+      SubmitRequirementResultInfo.Status status,
       boolean isLegacy) {
     for (SubmitRequirementResultInfo result : results) {
       if (result.name.equals(requirementName)
diff --git a/javatests/com/google/gerrit/acceptance/api/change/StickyApprovalsIT.java b/javatests/com/google/gerrit/acceptance/api/change/StickyApprovalsIT.java
index cd9e876..3888679 100644
--- a/javatests/com/google/gerrit/acceptance/api/change/StickyApprovalsIT.java
+++ b/javatests/com/google/gerrit/acceptance/api/change/StickyApprovalsIT.java
@@ -43,6 +43,7 @@
 import com.google.gerrit.acceptance.testsuite.change.ChangeOperations;
 import com.google.gerrit.acceptance.testsuite.project.ProjectOperations;
 import com.google.gerrit.acceptance.testsuite.request.RequestScopeOperations;
+import com.google.gerrit.common.RawInputUtil;
 import com.google.gerrit.entities.Change;
 import com.google.gerrit.entities.LabelId;
 import com.google.gerrit.entities.LabelType;
@@ -557,6 +558,46 @@
   }
 
   @Test
+  public void
+      stickyWithCopyAllScoresIfListOfFilesDidNotChangeWhenFileIsModifiedDueToRebase_withoutCopyCondition()
+          throws Exception {
+    try (ProjectConfigUpdate u = updateProject(project)) {
+      u.getConfig()
+          .updateLabelType(
+              LabelId.CODE_REVIEW, b -> b.setCopyAllScoresIfListOfFilesDidNotChange(true));
+      u.save();
+    }
+    // Create two changes both with the same parent
+    PushOneCommit.Result r = createChange();
+    testRepo.reset("HEAD~1");
+    PushOneCommit.Result r2 = createChange();
+
+    // Modify f.txt in change 1. Approve and submit the first change
+    gApi.changes().id(r.getChangeId()).edit().modifyFile("f.txt", RawInputUtil.create("content"));
+    gApi.changes().id(r.getChangeId()).edit().publish();
+    RevisionApi revision = gApi.changes().id(r.getChangeId()).current();
+    revision.review(ReviewInput.approve().label(LabelId.VERIFIED, 1));
+    revision.submit();
+
+    // Add an approval whose score should be copied on change 2.
+    gApi.changes().id(r2.getChangeId()).current().review(ReviewInput.recommend());
+
+    // Rebase the second change. The rebase adds f1.txt.
+    gApi.changes().id(r2.getChangeId()).rebase();
+
+    // The code-review approval is copied for the second change between PS1 and PS2 since the only
+    // modified file is due to rebase.
+    List<PatchSetApproval> patchSetApprovals =
+        r2.getChange().notes().getApprovalsWithCopied().values().stream()
+            .sorted(comparing(a -> a.patchSetId().get()))
+            .collect(toImmutableList());
+    PatchSetApproval nonCopied = patchSetApprovals.get(0);
+    PatchSetApproval copied = patchSetApprovals.get(1);
+    assertCopied(nonCopied, /* psId= */ 1, LabelId.CODE_REVIEW, (short) 1, false);
+    assertCopied(copied, /* psId= */ 2, LabelId.CODE_REVIEW, (short) 1, true);
+  }
+
+  @Test
   public void stickyWithCopyAllScoresIfListOfFilesDidNotChangeWhenFileIsModified_withCopyCondition()
       throws Exception {
     try (ProjectConfigUpdate u = updateProject(project)) {
@@ -1072,17 +1113,9 @@
             .sorted(comparing(a -> a.patchSetId().get()))
             .collect(toImmutableList());
     PatchSetApproval nonCopied = patchSetApprovals.get(0);
-
-    assertThat(nonCopied.patchSetId().get()).isEqualTo(1);
-    assertThat(nonCopied.label()).isEqualTo(LabelId.CODE_REVIEW);
-    assertThat(nonCopied.value()).isEqualTo((short) 1);
-    assertThat(nonCopied.copied()).isFalse();
-
     PatchSetApproval copied = patchSetApprovals.get(1);
-    assertThat(copied.patchSetId().get()).isEqualTo(2);
-    assertThat(copied.label()).isEqualTo(LabelId.CODE_REVIEW);
-    assertThat(copied.value()).isEqualTo((short) 1);
-    assertThat(copied.copied()).isTrue();
+    assertCopied(nonCopied, 1, LabelId.CODE_REVIEW, (short) 1, /* copied= */ false);
+    assertCopied(copied, 2, LabelId.CODE_REVIEW, (short) 1, /* copied= */ true);
   }
 
   @Test
@@ -1311,4 +1344,12 @@
     }
     assertWithMessage(name).that(vote).isEqualTo(expectedVote);
   }
+
+  private void assertCopied(
+      PatchSetApproval approval, int psId, String label, short value, boolean copied) {
+    assertThat(approval.patchSetId().get()).isEqualTo(psId);
+    assertThat(approval.label()).isEqualTo(label);
+    assertThat(approval.value()).isEqualTo(value);
+    assertThat(approval.copied()).isEqualTo(copied);
+  }
 }
diff --git a/javatests/com/google/gerrit/server/notedb/ChangeNotesTest.java b/javatests/com/google/gerrit/server/notedb/ChangeNotesTest.java
index 4e7b3f3..c524c94 100644
--- a/javatests/com/google/gerrit/server/notedb/ChangeNotesTest.java
+++ b/javatests/com/google/gerrit/server/notedb/ChangeNotesTest.java
@@ -76,6 +76,8 @@
 import org.junit.Test;
 
 public class ChangeNotesTest extends AbstractChangeNotesTest {
+  @Inject private DraftCommentNotes.Factory draftNotesFactory;
+
   @Inject private ChangeNoteJson changeNoteJson;
 
   @Test
@@ -2978,6 +2980,86 @@
   }
 
   @Test
+  public void filterOutAndFixUpZombieDraftComments() throws Exception {
+    Change c = newChange();
+    ObjectId commitId1 = ObjectId.fromString("abcd1234abcd1234abcd1234abcd1234abcd1234");
+    CommentRange range = new CommentRange(1, 1, 2, 1);
+    PatchSet.Id ps1 = c.currentPatchSetId();
+    short side = (short) 1;
+
+    ChangeUpdate update = newUpdate(c, otherUser);
+    Timestamp now = TimeUtil.nowTs();
+    HumanComment comment1 =
+        newComment(
+            ps1,
+            "file1",
+            "uuid1",
+            range,
+            range.getEndLine(),
+            otherUser,
+            null,
+            now,
+            "comment on ps1",
+            side,
+            commitId1,
+            false);
+    HumanComment comment2 =
+        newComment(
+            ps1,
+            "file2",
+            "uuid2",
+            range,
+            range.getEndLine(),
+            otherUser,
+            null,
+            now,
+            "another comment",
+            side,
+            commitId1,
+            false);
+    update.putComment(HumanComment.Status.DRAFT, comment1);
+    update.putComment(HumanComment.Status.DRAFT, comment2);
+    update.commit();
+
+    String refName = refsDraftComments(c.getId(), otherUserId);
+    ObjectId oldDraftId = exactRefAllUsers(refName);
+
+    update = newUpdate(c, otherUser);
+    update.setPatchSetId(ps1);
+    update.putComment(HumanComment.Status.PUBLISHED, comment2);
+    update.commit();
+    assertThat(exactRefAllUsers(refName)).isNotNull();
+    assertThat(exactRefAllUsers(refName)).isNotEqualTo(oldDraftId);
+
+    // Re-add draft version of comment2 back to draft ref without updating
+    // change ref. Simulates the case where deleting the draft failed
+    // non-atomically after adding the published comment succeeded.
+    ChangeDraftUpdate draftUpdate = newUpdate(c, otherUser).createDraftUpdateIfNull();
+    draftUpdate.putComment(comment2);
+    try (NoteDbUpdateManager manager = updateManagerFactory.create(c.getProject())) {
+      manager.add(draftUpdate);
+      manager.execute();
+    }
+
+    // Looking at drafts directly shows the zombie comment.
+    DraftCommentNotes draftNotes = draftNotesFactory.create(c.getId(), otherUserId);
+    assertThat(draftNotes.load().getComments().get(commitId1)).containsExactly(comment1, comment2);
+
+    // Zombie comment is filtered out of drafts via ChangeNotes.
+    ChangeNotes notes = newNotes(c);
+    assertThat(notes.getDraftComments(otherUserId).get(commitId1)).containsExactly(comment1);
+    assertThat(notes.getHumanComments().get(commitId1)).containsExactly(comment2);
+
+    update = newUpdate(c, otherUser);
+    update.setPatchSetId(ps1);
+    update.putComment(HumanComment.Status.PUBLISHED, comment1);
+    update.commit();
+
+    // Updating an unrelated comment causes the zombie comment to get fixed up.
+    assertThat(exactRefAllUsers(refName)).isNull();
+  }
+
+  @Test
   public void updateCommentsInSequentialUpdates() throws Exception {
     Change c = newChange();
     CommentRange range = new CommentRange(1, 1, 2, 1);
diff --git a/javatests/com/google/gerrit/server/notedb/CommitRewriterTest.java b/javatests/com/google/gerrit/server/notedb/CommitRewriterTest.java
index 19c2bcf..7f16cc4 100644
--- a/javatests/com/google/gerrit/server/notedb/CommitRewriterTest.java
+++ b/javatests/com/google/gerrit/server/notedb/CommitRewriterTest.java
@@ -785,7 +785,7 @@
         .containsExactly(
             "@@ -6 +6 @@\n"
                 + "-Removed Verified+2 by Other Account <other@account.com>\n"
-                + "+Removed Verified+2 by Gerrit Account\n");
+                + "+Removed Verified+2\n");
     BackfillResult secondRunResult = rewriter.backfillProject(project, repo, options);
     assertThat(secondRunResult.fixedRefDiff.keySet()).isEmpty();
     assertThat(secondRunResult.refsFailedToFix).isEmpty();
@@ -1671,10 +1671,9 @@
                 + "   * file1.java\n"
                 + "\n<GERRIT_ACCOUNT_2>, who was added as reviewer owns the following files:\n"
                 + "   * file3.js\n"
-                + "\nGerrit Account, who was added as reviewer owns the following files:\n"
+                + "\nAdded reviewer owns the following files:\n"
                 + "   * file4.java\n",
-            "Gerrit Account, who was added as reviewer owns the following files:\n"
-                + "   * file6.java\n",
+            "Added reviewer owns the following files:\n" + "   * file6.java\n",
             "Gerrit Account who was added as reviewer owns the following files:\n"
                 + "   * file1.java\n"
                 + "\n<GERRIT_ACCOUNT_1> who was added as reviewer owns the following files:\n"
@@ -1701,10 +1700,10 @@
                 + "+<GERRIT_ACCOUNT_2>, who was added as reviewer owns the following files:\n"
                 + "@@ -12 +12 @@\n"
                 + "-Missing Reviewer who was added as reviewer owns the following files:\n"
-                + "+Gerrit Account, who was added as reviewer owns the following files:\n",
+                + "+Added reviewer owns the following files:\n",
             "@@ -6 +6 @@\n"
                 + "-Reviewer User who was added as reviewer owns the following files:\n"
-                + "+Gerrit Account, who was added as reviewer owns the following files:\n");
+                + "+Added reviewer owns the following files:\n");
     BackfillResult secondRunResult = rewriter.backfillProject(project, repo, options);
     assertThat(secondRunResult.fixedRefDiff.keySet()).isEmpty();
     assertThat(secondRunResult.refsFailedToFix).isEmpty();
@@ -2051,7 +2050,8 @@
         getChangeUpdateBody(
             c,
             String.format(
-                "Assignee changed from: %s to: %s", changeOwner.getName(), otherUser.getName())),
+                "Assignee changed from: %s to: %s",
+                changeOwner.getNameEmail(), otherUser.getNameEmail())),
         getAuthorIdent(otherUser.getAccount()));
     writeUpdate(
         RefNames.changeMetaRef(c.getId()),
@@ -2086,14 +2086,12 @@
                 + "-Assignee added: Change Owner\n"
                 + "+Assignee added: <GERRIT_ACCOUNT_1>\n",
             "@@ -6 +6 @@\n"
-                + "-Assignee changed from: Change Owner to: Other Account\n"
+                + "-Assignee changed from: Change Owner <change@owner.com> to: Other Account <other@account.com>\n"
                 + "+Assignee changed from: <GERRIT_ACCOUNT_1> to: <GERRIT_ACCOUNT_2>\n",
             "@@ -6 +6 @@\n"
                 + "-Assignee deleted: Other Account\n"
                 + "+Assignee deleted: <GERRIT_ACCOUNT_2>\n",
-            "@@ -6 +6 @@\n"
-                + "-Assignee added: Reviewer User\n"
-                + "+Assignee added: Gerrit Account\n");
+            "@@ -6 +6 @@\n" + "-Assignee added: Reviewer User\n" + "+Assignee was added.\n");
     BackfillResult secondRunResult = rewriter.backfillProject(project, repo, options);
     assertThat(secondRunResult.fixedRefDiff.keySet()).isEmpty();
     assertThat(secondRunResult.refsFailedToFix).isEmpty();
diff --git a/javatests/com/google/gerrit/server/patch/PatchListTest.java b/javatests/com/google/gerrit/server/patch/PatchListTest.java
deleted file mode 100644
index 182ce49..0000000
--- a/javatests/com/google/gerrit/server/patch/PatchListTest.java
+++ /dev/null
@@ -1,97 +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.patch;
-
-import static com.google.common.truth.Truth.assertThat;
-
-import com.google.gerrit.entities.Patch;
-import com.google.gerrit.entities.Patch.ChangeType;
-import com.google.gerrit.server.patch.PatchList.ChangeTypeCmp;
-import java.io.ByteArrayInputStream;
-import java.io.ByteArrayOutputStream;
-import java.io.InputStream;
-import java.io.ObjectInputStream;
-import java.io.ObjectOutputStream;
-import java.util.Arrays;
-import java.util.List;
-import org.junit.Test;
-
-public class PatchListTest {
-
-  @Test
-  public void fileOrder() {
-    String[] names = {
-      "zzz",
-      "def/g",
-      "/!xxx",
-      "abc",
-      Patch.MERGE_LIST,
-      "qrx",
-      Patch.COMMIT_MSG,
-      Patch.PATCHSET_LEVEL
-    };
-    String[] want = {
-      Patch.COMMIT_MSG,
-      Patch.MERGE_LIST,
-      Patch.PATCHSET_LEVEL,
-      "/!xxx",
-      "abc",
-      "def/g",
-      "qrx",
-      "zzz",
-    };
-    Arrays.sort(names, 0, names.length, PatchList.FILE_PATH_CMP);
-    assertThat(names).isEqualTo(want);
-  }
-
-  @Test
-  public void fileOrderNoMerge() {
-    String[] names = {
-      "zzz", "def/g", "/!xxx", "abc", "qrx", Patch.COMMIT_MSG,
-    };
-    String[] want = {
-      Patch.COMMIT_MSG, "/!xxx", "abc", "def/g", "qrx", "zzz",
-    };
-
-    Arrays.sort(names, 0, names.length, PatchList.FILE_PATH_CMP);
-    assertThat(names).isEqualTo(want);
-  }
-
-  @Test
-  public void changeTypeOrderIsComplete() {
-    List<ChangeType> changeTypeOrder = ChangeTypeCmp.order;
-    ChangeType[] allTypes = ChangeType.values();
-
-    Arrays.sort(allTypes, PatchList.CHANGE_TYPE_CMP);
-    assertThat(changeTypeOrder).containsExactlyElementsIn(allTypes).inOrder();
-  }
-
-  @Test
-  public void largeObjectTombstoneCanBeSerializedAndDeserialized() throws Exception {
-    // Serialize
-    byte[] serializedObject;
-    try (ByteArrayOutputStream baos = new ByteArrayOutputStream();
-        ObjectOutputStream objectStream = new ObjectOutputStream(baos)) {
-      objectStream.writeObject(new PatchListCacheImpl.LargeObjectTombstone());
-      serializedObject = baos.toByteArray();
-      assertThat(serializedObject).isNotNull();
-    }
-    // Deserialize
-    try (InputStream is = new ByteArrayInputStream(serializedObject);
-        ObjectInputStream ois = new ObjectInputStream(is)) {
-      assertThat(ois.readObject()).isInstanceOf(PatchListCacheImpl.LargeObjectTombstone.class);
-    }
-  }
-}
diff --git a/javatests/com/google/gerrit/server/query/change/AbstractQueryChangesTest.java b/javatests/com/google/gerrit/server/query/change/AbstractQueryChangesTest.java
index 2663853..9ebee9c 100644
--- a/javatests/com/google/gerrit/server/query/change/AbstractQueryChangesTest.java
+++ b/javatests/com/google/gerrit/server/query/change/AbstractQueryChangesTest.java
@@ -69,6 +69,7 @@
 import com.google.gerrit.extensions.api.changes.DraftInput;
 import com.google.gerrit.extensions.api.changes.HashtagsInput;
 import com.google.gerrit.extensions.api.changes.ReviewInput;
+import com.google.gerrit.extensions.api.changes.ReviewInput.DraftHandling;
 import com.google.gerrit.extensions.api.changes.ReviewerInput;
 import com.google.gerrit.extensions.api.groups.GroupInput;
 import com.google.gerrit.extensions.api.projects.ConfigInput;
@@ -2333,6 +2334,44 @@
   }
 
   @Test
+  public void byHasDraftExcludesZombieDrafts() throws Exception {
+    Project.NameKey project = Project.nameKey("repo");
+    TestRepository<Repo> repo = createProject(project.get());
+    Change change = insert(repo, newChange(repo));
+    Change.Id id = change.getId();
+
+    DraftInput in = new DraftInput();
+    in.line = 1;
+    in.message = "nit: trailing whitespace";
+    in.path = Patch.COMMIT_MSG;
+    gApi.changes().id(id.get()).current().createDraft(in);
+
+    assertQuery("has:draft", change);
+    assertQuery("commentby:" + userId);
+
+    try (TestRepository<Repo> allUsers =
+        new TestRepository<>(repoManager.openRepository(allUsersName))) {
+      Ref draftsRef = allUsers.getRepository().exactRef(RefNames.refsDraftComments(id, userId));
+      assertThat(draftsRef).isNotNull();
+
+      ReviewInput rin = ReviewInput.dislike();
+      rin.drafts = DraftHandling.PUBLISH_ALL_REVISIONS;
+      gApi.changes().id(id.get()).current().review(rin);
+
+      assertQuery("has:draft");
+      assertQuery("commentby:" + userId, change);
+      assertThat(allUsers.getRepository().exactRef(draftsRef.getName())).isNull();
+
+      // Re-add drafts ref and ensure it gets filtered out during indexing.
+      allUsers.update(draftsRef.getName(), draftsRef.getObjectId());
+      assertThat(allUsers.getRepository().exactRef(draftsRef.getName())).isNotNull();
+    }
+
+    indexer.index(project, id);
+    assertQuery("has:draft");
+  }
+
+  @Test
   public void byStarredBy() throws Exception {
     TestRepository<Repo> repo = createProject("repo");
     Change change1 = insert(repo, newChange(repo));
diff --git a/polygerrit-ui/app/elements/change/gr-change-metadata/gr-change-metadata.ts b/polygerrit-ui/app/elements/change/gr-change-metadata/gr-change-metadata.ts
index ba62ec3..8b46cd8 100644
--- a/polygerrit-ui/app/elements/change/gr-change-metadata/gr-change-metadata.ts
+++ b/polygerrit-ui/app/elements/change/gr-change-metadata/gr-change-metadata.ts
@@ -752,6 +752,16 @@
           })
       );
   }
+
+  _showNewSubmitRequirements(change?: ParsedChangeInfo) {
+    if (!this._isSubmitRequirementsUiEnabled) return false;
+    return (change?.submit_requirements ?? []).length > 0;
+  }
+
+  _showNewSubmitRequirementWarning(change?: ParsedChangeInfo) {
+    if (!this._isSubmitRequirementsUiEnabled) return false;
+    return (change?.submit_requirements ?? []).length === 0;
+  }
 }
 
 declare global {
diff --git a/polygerrit-ui/app/elements/change/gr-change-metadata/gr-change-metadata_html.ts b/polygerrit-ui/app/elements/change/gr-change-metadata/gr-change-metadata_html.ts
index 26d1277..97101f6 100644
--- a/polygerrit-ui/app/elements/change/gr-change-metadata/gr-change-metadata_html.ts
+++ b/polygerrit-ui/app/elements/change/gr-change-metadata/gr-change-metadata_html.ts
@@ -113,6 +113,10 @@
       --iron-icon-height: 18px;
       --iron-icon-width: 18px;
     }
+    .submit-requirement-error {
+      color: var(--deemphasized-text-color);
+      padding-left: var(--metadata-horizontal-padding);
+    }
   </style>
   <gr-external-style id="externalStyle" name="change-metadata">
     <div class="metadata-header">
@@ -480,20 +484,25 @@
       </span>
     </section>
     <div class="separatedSection">
-      <template is="dom-if" if="[[_isSubmitRequirementsUiEnabled]]">
+      <template is="dom-if" if="[[_showNewSubmitRequirements(change)]]">
         <gr-submit-requirements
           change="[[change]]"
           account="[[account]]"
           mutable="[[_mutable]]"
         ></gr-submit-requirements>
       </template>
-      <template is="dom-if" if="[[!_isSubmitRequirementsUiEnabled]]">
+      <template is="dom-if" if="[[!_showNewSubmitRequirements(change)]]">
         <gr-change-requirements
           change="{{change}}"
           account="[[account]]"
           mutable="[[_mutable]]"
         ></gr-change-requirements>
       </template>
+      <template is="dom-if" if="[[_showNewSubmitRequirementWarning(change)]]">
+        <div class="submit-requirement-error">
+          New Submit Requirements don't work on this change.
+        </div>
+      </template>
     </div>
     <section
       id="webLinks"
diff --git a/polygerrit-ui/app/elements/change/gr-change-view/gr-change-view.ts b/polygerrit-ui/app/elements/change/gr-change-view/gr-change-view.ts
index fd7b5d1..fc2cbe5 100644
--- a/polygerrit-ui/app/elements/change/gr-change-view/gr-change-view.ts
+++ b/polygerrit-ui/app/elements/change/gr-change-view/gr-change-view.ts
@@ -1824,7 +1824,7 @@
       changeIsOpen(change)
     ) {
       fireAlert(this, 'Change edit not found. Please create a change edit.');
-      GerritNav.navigateToChange(change);
+      fireReload(this, true);
       return;
     }
 
@@ -1837,7 +1837,7 @@
         this,
         'Change edits cannot be created if change is merged or abandoned. Redirected to non edit mode.'
       );
-      GerritNav.navigateToChange(change);
+      fireReload(this, true);
       return;
     }
 
diff --git a/polygerrit-ui/app/elements/change/gr-submit-requirement-hovercard/gr-submit-requirement-hovercard.ts b/polygerrit-ui/app/elements/change/gr-submit-requirement-hovercard/gr-submit-requirement-hovercard.ts
index 2e00034..4b1dba6 100644
--- a/polygerrit-ui/app/elements/change/gr-submit-requirement-hovercard/gr-submit-requirement-hovercard.ts
+++ b/polygerrit-ui/app/elements/change/gr-submit-requirement-hovercard/gr-submit-requirement-hovercard.ts
@@ -15,7 +15,8 @@
  * limitations under the License.
  */
 import '../../../styles/gr-font-styles';
-import '../../shared/gr-hovercard/gr-hovercard-shared-style';
+import '../../../styles/gr-hovercard-styles';
+import '../../../styles/shared-styles';
 import '../../shared/gr-button/gr-button';
 import {PolymerElement} from '@polymer/polymer/polymer-element';
 import {customElement, property} from '@polymer/decorators';
diff --git a/polygerrit-ui/app/elements/change/gr-submit-requirement-hovercard/gr-submit-requirement-hovercard_html.ts b/polygerrit-ui/app/elements/change/gr-submit-requirement-hovercard/gr-submit-requirement-hovercard_html.ts
index b7b4d9c..5023895 100644
--- a/polygerrit-ui/app/elements/change/gr-submit-requirement-hovercard/gr-submit-requirement-hovercard_html.ts
+++ b/polygerrit-ui/app/elements/change/gr-submit-requirement-hovercard/gr-submit-requirement-hovercard_html.ts
@@ -20,7 +20,10 @@
   <style include="gr-font-styles">
     /* Workaround for empty style block - see https://github.com/Polymer/tools/issues/408 */
   </style>
-  <style include="gr-hovercard-shared-style">
+  <style include="shared-styles">
+    /* Workaround for empty style block - see https://github.com/Polymer/tools/issues/408 */
+  </style>
+  <style include="gr-hovercard-styles">
     #container {
       min-width: 356px;
       max-width: 356px;
diff --git a/polygerrit-ui/app/elements/checks/gr-checks-results.ts b/polygerrit-ui/app/elements/checks/gr-checks-results.ts
index 48ccf2c..9c27cdb 100644
--- a/polygerrit-ui/app/elements/checks/gr-checks-results.ts
+++ b/polygerrit-ui/app/elements/checks/gr-checks-results.ts
@@ -293,7 +293,13 @@
   override firstUpdated() {
     const loading = this.shadowRoot?.querySelector('.container');
     assertIsDefined(loading, '"Loading" element');
-    whenVisible(loading, () => this.setAttribute('shouldRender', 'true'), 200);
+    whenVisible(
+      loading,
+      () => {
+        this.shouldRender = true;
+      },
+      200
+    );
   }
 
   override render() {
diff --git a/polygerrit-ui/app/elements/checks/gr-hovercard-run.ts b/polygerrit-ui/app/elements/checks/gr-hovercard-run.ts
index d26856c..57eac3b 100644
--- a/polygerrit-ui/app/elements/checks/gr-hovercard-run.ts
+++ b/polygerrit-ui/app/elements/checks/gr-hovercard-run.ts
@@ -16,6 +16,8 @@
  */
 import './gr-checks-styles';
 import '../../styles/gr-font-styles';
+import '../../styles/gr-hovercard-styles';
+import '../../styles/shared-styles';
 import {HovercardBehaviorMixin} from '../shared/gr-hovercard/gr-hovercard-behavior';
 import {PolymerElement} from '@polymer/polymer/polymer-element';
 import {htmlTemplate} from './gr-hovercard-run_html';
diff --git a/polygerrit-ui/app/elements/checks/gr-hovercard-run_html.ts b/polygerrit-ui/app/elements/checks/gr-hovercard-run_html.ts
index 49a1416..52dbb9c 100644
--- a/polygerrit-ui/app/elements/checks/gr-hovercard-run_html.ts
+++ b/polygerrit-ui/app/elements/checks/gr-hovercard-run_html.ts
@@ -23,7 +23,10 @@
   <style include="gr-checks-styles">
     /* Workaround for empty style block - see https://github.com/Polymer/tools/issues/408 */
   </style>
-  <style include="gr-hovercard-shared-style">
+  <style include="shared-styles">
+    /* Workaround for empty style block - see https://github.com/Polymer/tools/issues/408 */
+  </style>
+  <style include="gr-hovercard-styles">
     #container {
       min-width: 356px;
       max-width: 356px;
diff --git a/polygerrit-ui/app/elements/core/gr-search-bar/gr-search-bar.ts b/polygerrit-ui/app/elements/core/gr-search-bar/gr-search-bar.ts
index 78c1ebd..aaeb924 100644
--- a/polygerrit-ui/app/elements/core/gr-search-bar/gr-search-bar.ts
+++ b/polygerrit-ui/app/elements/core/gr-search-bar/gr-search-bar.ts
@@ -55,7 +55,6 @@
   'commentby:',
   'commit:',
   'committer:',
-  'conflicts:',
   'deleted:',
   'delta:',
   'dir:',
diff --git a/polygerrit-ui/app/elements/diff/gr-diff-host/gr-diff-host.ts b/polygerrit-ui/app/elements/diff/gr-diff-host/gr-diff-host.ts
index 4641897..b1bad1c 100644
--- a/polygerrit-ui/app/elements/diff/gr-diff-host/gr-diff-host.ts
+++ b/polygerrit-ui/app/elements/diff/gr-diff-host/gr-diff-host.ts
@@ -56,6 +56,7 @@
   PatchRange,
   PatchSetNum,
   RepoName,
+  UrlEncodedCommentId,
 } from '../../../types/common';
 import {
   DiffInfo,
@@ -730,11 +731,24 @@
   }
 
   _threadsChanged(threads: CommentThread[]) {
-    const threadEls = new Set<Object>();
+    const threadEls = new Set<GrCommentThread>();
+    const rootIdToThreadEl = new Map<UrlEncodedCommentId, GrCommentThread>();
+    for (const threadEl of this.getThreadEls()) {
+      if (threadEl.rootId) {
+        rootIdToThreadEl.set(threadEl.rootId, threadEl);
+      }
+    }
     for (const thread of threads) {
-      const threadEl = this._createThreadElement(thread);
-      this._attachThreadElement(threadEl);
-      threadEls.add(threadEl);
+      const existingThreadEl =
+        thread.rootId && rootIdToThreadEl.get(thread.rootId);
+      if (existingThreadEl) {
+        this._updateThreadElement(existingThreadEl, thread);
+        threadEls.add(existingThreadEl);
+      } else {
+        const threadEl = this._createThreadElement(thread);
+        this._attachThreadElement(threadEl);
+        threadEls.add(threadEl);
+      }
     }
     // Remove all threads that are no longer existing.
     for (const threadEl of this.getThreadEls()) {
diff --git a/polygerrit-ui/app/elements/diff/gr-diff-host/gr-diff-host_test.js b/polygerrit-ui/app/elements/diff/gr-diff-host/gr-diff-host_test.js
index ed3ffe0..8901636 100644
--- a/polygerrit-ui/app/elements/diff/gr-diff-host/gr-diff-host_test.js
+++ b/polygerrit-ui/app/elements/diff/gr-diff-host/gr-diff-host_test.js
@@ -1145,11 +1145,19 @@
           .queryDistributedElements('gr-comment-thread');
 
       assert.equal(threads.length, 1);
-
       element.threads= [...element.threads, thread];
 
       threads = dom(element.$.diff)
           .queryDistributedElements('gr-comment-thread');
+      // Threads have same rootId so element is reused
+      assert.equal(threads.length, 1);
+
+      const newThread = {...thread};
+      newThread.rootId = 'differentRootId';
+      element.threads= [...element.threads, newThread];
+      threads = dom(element.$.diff)
+          .queryDistributedElements('gr-comment-thread');
+      // New thread has a different rootId
       assert.equal(threads.length, 2);
     });
 
diff --git a/polygerrit-ui/app/elements/diff/gr-diff-image-viewer/gr-image-viewer.ts b/polygerrit-ui/app/elements/diff/gr-diff-image-viewer/gr-image-viewer.ts
index 3a05e7d..32f5f39 100644
--- a/polygerrit-ui/app/elements/diff/gr-diff-image-viewer/gr-image-viewer.ts
+++ b/polygerrit-ui/app/elements/diff/gr-diff-image-viewer/gr-image-viewer.ts
@@ -422,25 +422,23 @@
       />
     `;
 
-    const sourceImageWithHighlight = this.diffHighlightSrc
-      ? html`
-          <div id="source-plus-highlight-container">
-            ${sourceImage}
-            <img
-              id="highlight-image"
-              style="${styleMap({
-                opacity: this.showHighlight ? '1' : '0',
-                // When the highlight layer is not being shown, saving the image or
-                // opening it in a new tab from the context menu, e.g. for external
-                // comparison, should give back the source image, not the highlight
-                // layer.
-                'pointer-events': this.showHighlight ? 'auto' : 'none',
-              })}"
-              src="${this.diffHighlightSrc}"
-            />
-          </div>
-        `
-      : '';
+    const sourceImageWithHighlight = html`
+      <div id="source-plus-highlight-container">
+        ${sourceImage}
+        <img
+          id="highlight-image"
+          style="${styleMap({
+            opacity: this.showHighlight ? '1' : '0',
+            // When the highlight layer is not being shown, saving the image or
+            // opening it in a new tab from the context menu, e.g. for external
+            // comparison, should give back the source image, not the highlight
+            // layer.
+            'pointer-events': this.showHighlight ? 'auto' : 'none',
+          })}"
+          src="${this.diffHighlightSrc}"
+        />
+      </div>
+    `;
 
     const versionExplanation = html`
       <div id="version-explanation">
diff --git a/polygerrit-ui/app/elements/edit/gr-edit-controls/gr-edit-controls.ts b/polygerrit-ui/app/elements/edit/gr-edit-controls/gr-edit-controls.ts
index d87b573..1615a23 100644
--- a/polygerrit-ui/app/elements/edit/gr-edit-controls/gr-edit-controls.ts
+++ b/polygerrit-ui/app/elements/edit/gr-edit-controls/gr-edit-controls.ts
@@ -36,7 +36,7 @@
 } from '../../shared/gr-autocomplete/gr-autocomplete';
 import {appContext} from '../../../services/app-context';
 import {IronInputElement} from '@polymer/iron-input';
-import {fireAlert} from '../../../utils/event-util';
+import {fireAlert, fireReload} from '../../../utils/event-util';
 
 export interface GrEditControls {
   $: {
@@ -237,7 +237,7 @@
           return;
         }
         this._closeDialog(this.$.openDialog);
-        GerritNav.navigateToChange(this.change);
+        fireReload(this, true);
       });
   }
 
@@ -257,7 +257,7 @@
           return;
         }
         this._closeDialog(dialog);
-        GerritNav.navigateToChange(this.change);
+        fireReload(this);
       });
   }
 
@@ -275,7 +275,7 @@
           return;
         }
         this._closeDialog(dialog);
-        GerritNav.navigateToChange(this.change);
+        fireReload(this);
       });
   }
 
@@ -293,7 +293,7 @@
           return;
         }
         this._closeDialog(dialog);
-        GerritNav.navigateToChange(this.change);
+        fireReload(this, true);
       });
   }
 
diff --git a/polygerrit-ui/app/elements/edit/gr-edit-controls/gr-edit-controls_test.ts b/polygerrit-ui/app/elements/edit/gr-edit-controls/gr-edit-controls_test.ts
index 0ba68e2..6198f17 100644
--- a/polygerrit-ui/app/elements/edit/gr-edit-controls/gr-edit-controls_test.ts
+++ b/polygerrit-ui/app/elements/edit/gr-edit-controls/gr-edit-controls_test.ts
@@ -122,12 +122,12 @@
   });
 
   suite('delete button CUJ', () => {
-    let navStub: sinon.SinonStub;
+    let eventStub: sinon.SinonStub;
     let deleteStub: sinon.SinonStub;
     let deleteAutocomplete: GrAutocomplete;
 
     setup(() => {
-      navStub = sinon.stub(GerritNav, 'navigateToChange');
+      eventStub = sinon.stub(element, 'dispatchEvent');
       deleteStub = stubRestApi('deleteFileInChangeEdit');
       deleteAutocomplete =
         element.$.deleteDialog!.querySelector('gr-autocomplete')!;
@@ -155,7 +155,7 @@
       assert.isTrue(deleteStub.called);
       await deleteStub.lastCall.returnValue;
       assert.equal(element._path, '');
-      assert.isTrue(navStub.called);
+      assert.equal(eventStub.firstCall.args[0].type, 'reload');
       assert.isTrue(closeDialogSpy.called);
     });
 
@@ -181,7 +181,7 @@
       assert.isTrue(deleteStub.called);
 
       await deleteStub.lastCall.returnValue;
-      assert.isFalse(navStub.called);
+      assert.isFalse(eventStub.called);
       assert.isFalse(closeDialogSpy.called);
     });
 
@@ -195,7 +195,7 @@
         MockInteractions.tap(
           queryAndAssert(element.$.deleteDialog, 'gr-button')
         );
-        assert.isFalse(navStub.called);
+        assert.isFalse(eventStub.called);
         assert.isTrue(closeDialogSpy.called);
         assert.equal(element._path, '');
       });
@@ -203,12 +203,12 @@
   });
 
   suite('rename button CUJ', () => {
-    let navStub: sinon.SinonStub;
+    let eventStub: sinon.SinonStub;
     let renameStub: sinon.SinonStub;
     let renameAutocomplete: GrAutocomplete;
 
     setup(() => {
-      navStub = sinon.stub(GerritNav, 'navigateToChange');
+      eventStub = sinon.stub(element, 'dispatchEvent');
       renameStub = stubRestApi('renameFileInChangeEdit');
       renameAutocomplete =
         element.$.renameDialog!.querySelector('gr-autocomplete')!;
@@ -241,7 +241,7 @@
 
       await renameStub.lastCall.returnValue;
       assert.equal(element._path, '');
-      assert.isTrue(navStub.called);
+      assert.equal(eventStub.firstCall.args[0].type, 'reload');
       assert.isTrue(closeDialogSpy.called);
     });
 
@@ -272,7 +272,7 @@
       assert.isTrue(renameStub.called);
 
       await renameStub.lastCall.returnValue;
-      assert.isFalse(navStub.called);
+      assert.isFalse(eventStub.called);
       assert.isFalse(closeDialogSpy.called);
     });
 
@@ -287,7 +287,7 @@
         MockInteractions.tap(
           queryAndAssert(element.$.renameDialog, 'gr-button')
         );
-        assert.isFalse(navStub.called);
+        assert.isFalse(eventStub.called);
         assert.isTrue(closeDialogSpy.called);
         assert.equal(element._path, '');
         assert.equal(element._newPath, '');
@@ -296,11 +296,11 @@
   });
 
   suite('restore button CUJ', () => {
-    let navStub: sinon.SinonStub;
+    let eventStub: sinon.SinonStub;
     let restoreStub: sinon.SinonStub;
 
     setup(() => {
-      navStub = sinon.stub(GerritNav, 'navigateToChange');
+      eventStub = sinon.stub(element, 'dispatchEvent');
       restoreStub = stubRestApi('restoreFileInChangeEdit');
     });
 
@@ -324,7 +324,7 @@
         assert.equal(restoreStub.lastCall.args[1], 'src/test.cpp');
         return restoreStub.lastCall.returnValue.then(() => {
           assert.equal(element._path, '');
-          assert.isTrue(navStub.called);
+          assert.equal(eventStub.firstCall.args[0].type, 'reload');
           assert.isTrue(closeDialogSpy.called);
         });
       });
@@ -343,7 +343,7 @@
         assert.isTrue(restoreStub.called);
         assert.equal(restoreStub.lastCall.args[1], 'src/test.cpp');
         return restoreStub.lastCall.returnValue.then(() => {
-          assert.isFalse(navStub.called);
+          assert.isFalse(eventStub.called);
           assert.isFalse(closeDialogSpy.called);
         });
       });
@@ -356,7 +356,7 @@
         MockInteractions.tap(
           queryAndAssert(element.$.restoreDialog, 'gr-button')
         );
-        assert.isFalse(navStub.called);
+        assert.isFalse(eventStub.called);
         assert.isTrue(closeDialogSpy.called);
         assert.equal(element._path, '');
       });
diff --git a/polygerrit-ui/app/elements/gr-app-element.ts b/polygerrit-ui/app/elements/gr-app-element.ts
index 3b93bea..38f55bd 100644
--- a/polygerrit-ui/app/elements/gr-app-element.ts
+++ b/polygerrit-ui/app/elements/gr-app-element.ts
@@ -242,7 +242,7 @@
     this.addEventListener(EventType.DIALOG_CHANGE, e => {
       this._handleDialogChange(e as CustomEvent<DialogChangeEventDetail>);
     });
-    this.addEventListener('location-change', e =>
+    this.addEventListener(EventType.LOCATION_CHANGE, e =>
       this._handleLocationChange(e)
     );
     this.addEventListener(EventType.RECREATE_CHANGE_VIEW, () =>
@@ -251,7 +251,7 @@
     this.addEventListener(EventType.RECREATE_DIFF_VIEW, () =>
       this.handleRecreateView(GerritView.DIFF)
     );
-    document.addEventListener('gr-rpc-log', e => this._handleRpcLog(e));
+    document.addEventListener(EventType.GR_RPC_LOG, e => this._handleRpcLog(e));
   }
 
   override ready() {
diff --git a/polygerrit-ui/app/elements/shared/gr-hovercard-account/gr-hovercard-account.ts b/polygerrit-ui/app/elements/shared/gr-hovercard-account/gr-hovercard-account.ts
index 06272ed..3988095 100644
--- a/polygerrit-ui/app/elements/shared/gr-hovercard-account/gr-hovercard-account.ts
+++ b/polygerrit-ui/app/elements/shared/gr-hovercard-account/gr-hovercard-account.ts
@@ -18,6 +18,7 @@
 import '@polymer/iron-icon/iron-icon';
 import '../../../styles/gr-font-styles';
 import '../../../styles/shared-styles';
+import '../../../styles/gr-hovercard-styles';
 import '../gr-avatar/gr-avatar';
 import '../gr-button/gr-button';
 import {HovercardBehaviorMixin} from '../gr-hovercard/gr-hovercard-behavior';
diff --git a/polygerrit-ui/app/elements/shared/gr-hovercard-account/gr-hovercard-account_html.ts b/polygerrit-ui/app/elements/shared/gr-hovercard-account/gr-hovercard-account_html.ts
index adca888..cba7293 100644
--- a/polygerrit-ui/app/elements/shared/gr-hovercard-account/gr-hovercard-account_html.ts
+++ b/polygerrit-ui/app/elements/shared/gr-hovercard-account/gr-hovercard-account_html.ts
@@ -14,14 +14,17 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
-import '../gr-hovercard/gr-hovercard-shared-style';
+import '../../../styles/gr-hovercard-styles';
 import {html} from '@polymer/polymer/lib/utils/html-tag';
 
 export const htmlTemplate = html`
   <style include="gr-font-styles">
     /* Workaround for empty style block - see https://github.com/Polymer/tools/issues/408 */
   </style>
-  <style include="gr-hovercard-shared-style">
+  <style include="shared-styles">
+    /* Workaround for empty style block - see https://github.com/Polymer/tools/issues/408 */
+  </style>
+  <style include="gr-hovercard-styles">
     .top,
     .attention,
     .status,
diff --git a/polygerrit-ui/app/elements/shared/gr-hovercard/gr-hovercard-behavior.ts b/polygerrit-ui/app/elements/shared/gr-hovercard/gr-hovercard-behavior.ts
index 82af365..3d8702b 100644
--- a/polygerrit-ui/app/elements/shared/gr-hovercard/gr-hovercard-behavior.ts
+++ b/polygerrit-ui/app/elements/shared/gr-hovercard/gr-hovercard-behavior.ts
@@ -129,12 +129,8 @@
       super.connectedCallback();
       if (!this._target) {
         this._target = this.target;
+        this.addTargetEventListeners();
       }
-      this._target.addEventListener('mouseenter', this.debounceShow);
-      this._target.addEventListener('focus', this.debounceShow);
-      this._target.addEventListener('mouseleave', this.debounceHide);
-      this._target.addEventListener('blur', this.debounceHide);
-      this._target.addEventListener('click', this.hide);
 
       // show the hovercard if mouse moves to hovercard
       // this will cancel pending hide as well
@@ -149,12 +145,23 @@
       this.cancelShowTask();
       this.cancelHideTask();
       this.unlock();
+      super.disconnectedCallback();
+    }
+
+    addTargetEventListeners() {
+      this._target?.addEventListener('mouseenter', this.debounceShow);
+      this._target?.addEventListener('focus', this.debounceShow);
+      this._target?.addEventListener('mouseleave', this.debounceHide);
+      this._target?.addEventListener('blur', this.debounceHide);
+      this._target?.addEventListener('click', this.hide);
+    }
+
+    removeTargetEventListeners() {
       this._target?.removeEventListener('mouseenter', this.debounceShow);
       this._target?.removeEventListener('focus', this.debounceShow);
       this._target?.removeEventListener('mouseleave', this.debounceHide);
       this._target?.removeEventListener('blur', this.debounceHide);
       this._target?.removeEventListener('click', this.hide);
-      super.disconnectedCallback();
     }
 
     override ready() {
@@ -457,7 +464,9 @@
      */
     @observe('for')
     _forChanged() {
+      this.removeTargetEventListeners();
       this._target = this.target;
+      this.addTargetEventListeners();
     }
   }
 
diff --git a/polygerrit-ui/app/elements/shared/gr-hovercard/gr-hovercard-shared-style.ts b/polygerrit-ui/app/elements/shared/gr-hovercard/gr-hovercard-shared-style.ts
deleted file mode 100644
index aa92654..0000000
--- a/polygerrit-ui/app/elements/shared/gr-hovercard/gr-hovercard-shared-style.ts
+++ /dev/null
@@ -1,51 +0,0 @@
-/**
- * @license
- * 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.
- */
-
-// Mark the file as a module. Otherwise typescript assumes this is a script
-// and $_documentContainer is a global variable.
-// See: https://www.typescriptlang.org/docs/handbook/modules.html
-export {};
-
-/** The shared styles for all hover cards. */
-const GrHoverCardSharedStyle = document.createElement('dom-module');
-GrHoverCardSharedStyle.innerHTML = `<template>
-    <style include="shared-styles">
-      :host {
-        position: absolute;
-        display: none;
-        z-index: 200;
-        max-width: 600px;
-        outline: none;
-      }
-      :host(.hovered) {
-        display: block;
-      }
-      :host(.hide) {
-        visibility: hidden;
-      }
-      /* You have to use a <div class="container"> in your hovercard in order
-         to pick up this consistent styling. */
-      #container {
-        background: var(--dialog-background-color);
-        border: 1px solid var(--border-color);
-        border-radius: var(--border-radius);
-        box-shadow: var(--elevation-level-5);
-      }
-    </style>
-  </template>`;
-
-GrHoverCardSharedStyle.register('gr-hovercard-shared-style');
diff --git a/polygerrit-ui/app/elements/shared/gr-hovercard/gr-hovercard.ts b/polygerrit-ui/app/elements/shared/gr-hovercard/gr-hovercard.ts
index acc5e15..5fc53e6 100644
--- a/polygerrit-ui/app/elements/shared/gr-hovercard/gr-hovercard.ts
+++ b/polygerrit-ui/app/elements/shared/gr-hovercard/gr-hovercard.ts
@@ -15,20 +15,35 @@
  * limitations under the License.
  */
 
-import '../../../styles/shared-styles';
-import {PolymerElement} from '@polymer/polymer/polymer-element';
-import {htmlTemplate} from './gr-hovercard_html';
-import {HovercardBehaviorMixin} from './gr-hovercard-behavior';
-import './gr-hovercard-shared-style';
-import {customElement} from '@polymer/decorators';
+import {customElement} from 'lit/decorators';
+import {HovercardMixin} from '../../../mixins/hovercard-mixin/hovercard-mixin';
+import {css, html, LitElement} from 'lit';
+import {hovercardStyles} from '../../../styles/gr-hovercard-styles';
+import {sharedStyles} from '../../../styles/shared-styles';
 
 // This avoids JSC_DYNAMIC_EXTENDS_WITHOUT_JSDOC closure compiler error.
-const base = HovercardBehaviorMixin(PolymerElement);
+const base = HovercardMixin(LitElement);
 
 @customElement('gr-hovercard')
 export class GrHovercard extends base {
-  static get template() {
-    return htmlTemplate;
+  static override get styles() {
+    return [
+      sharedStyles,
+      hovercardStyles,
+      css`
+        #container {
+          padding: var(--spacing-l);
+        }
+      `,
+    ];
+  }
+
+  override render() {
+    return html`
+      <div id="container" role="tooltip" tabindex="-1">
+        <slot></slot>
+      </div>
+    `;
   }
 }
 
diff --git a/polygerrit-ui/app/elements/shared/gr-hovercard/gr-hovercard_html.ts b/polygerrit-ui/app/elements/shared/gr-hovercard/gr-hovercard_html.ts
deleted file mode 100644
index 830cbd878..0000000
--- a/polygerrit-ui/app/elements/shared/gr-hovercard/gr-hovercard_html.ts
+++ /dev/null
@@ -1,28 +0,0 @@
-/**
- * @license
- * 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.
- */
-import {html} from '@polymer/polymer/lib/utils/html-tag';
-
-export const htmlTemplate = html`
-  <style include="gr-hovercard-shared-style">
-    #container {
-      padding: var(--spacing-l);
-    }
-  </style>
-  <div id="container" role="tooltip" tabindex="-1">
-    <slot></slot>
-  </div>
-`;
diff --git a/polygerrit-ui/app/elements/shared/gr-hovercard/gr-hovercard_test.js b/polygerrit-ui/app/elements/shared/gr-hovercard/gr-hovercard_test.js
deleted file mode 100644
index d5e0061..0000000
--- a/polygerrit-ui/app/elements/shared/gr-hovercard/gr-hovercard_test.js
+++ /dev/null
@@ -1,168 +0,0 @@
-/**
- * @license
- * Copyright (C) 2018 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 '../../../test/common-test-setup-karma.js';
-import './gr-hovercard.js';
-import {html} from '@polymer/polymer/lib/utils/html-tag.js';
-
-const basicFixture = fixtureFromTemplate(html`
-<gr-hovercard for="foo" id="bar"></gr-hovercard>
-`);
-
-suite('gr-hovercard tests', () => {
-  let element;
-
-  let button;
-  let testResolve;
-  let testPromise;
-
-  setup(() => {
-    testResolve = undefined;
-    testPromise = new Promise(r => testResolve = r);
-    button = document.createElement('button');
-    button.innerHTML = 'Hello';
-    button.setAttribute('id', 'foo');
-    document.body.appendChild(button);
-
-    element = basicFixture.instantiate();
-  });
-
-  teardown(() => {
-    element.hide({});
-    button.remove();
-  });
-
-  test('updatePosition', () => {
-    // Test that the correct style properties have at least been set.
-    element.position = 'bottom';
-    element.updatePosition();
-    assert.typeOf(element.style.getPropertyValue('left'), 'string');
-    assert.typeOf(element.style.getPropertyValue('top'), 'string');
-    assert.typeOf(element.style.getPropertyValue('paddingTop'), 'string');
-    assert.typeOf(element.style.getPropertyValue('marginTop'), 'string');
-
-    const parentRect = document.documentElement.getBoundingClientRect();
-    const targetRect = element._target.getBoundingClientRect();
-    const thisRect = element.getBoundingClientRect();
-
-    const targetLeft = targetRect.left - parentRect.left;
-    const targetTop = targetRect.top - parentRect.top;
-
-    const pixelCompare = pixel =>
-      Math.round(parseInt(pixel.substring(0, pixel.length - 1)), 10);
-
-    assert.equal(
-        pixelCompare(element.style.left),
-        pixelCompare(
-            (targetLeft + (targetRect.width - thisRect.width) / 2) + 'px'));
-    assert.equal(
-        pixelCompare(element.style.top),
-        pixelCompare(
-            (targetTop + targetRect.height + element.offset) + 'px'));
-  });
-
-  test('hide', () => {
-    element.hide({});
-    const style = getComputedStyle(element);
-    assert.isFalse(element._isShowing);
-    assert.isFalse(element.classList.contains('hovered'));
-    assert.equal(style.display, 'none');
-    assert.notEqual(element.container, element.parentNode);
-  });
-
-  test('show', async () => {
-    await element.show({});
-    const style = getComputedStyle(element);
-    assert.isTrue(element._isShowing);
-    assert.isTrue(element.classList.contains('hovered'));
-    assert.equal(style.opacity, '1');
-    assert.equal(style.visibility, 'visible');
-  });
-
-  test('debounceShow does not show immediately', async () => {
-    element.debounceShowBy(100);
-    setTimeout(testResolve, 0);
-    await testPromise;
-    assert.isFalse(element._isShowing);
-  });
-
-  test('debounceShow shows after delay', async () => {
-    element.debounceShowBy(1);
-    setTimeout(testResolve, 10);
-    await testPromise;
-    assert.isTrue(element._isShowing);
-  });
-
-  test('card is scheduled to show on enter and hides on leave', async () => {
-    const button = document.querySelector('button');
-    let enterResolve = undefined;
-    const enterPromise = new Promise(r => enterResolve = r);
-    button.addEventListener('mouseenter', enterResolve);
-    let leaveResolve = undefined;
-    const leavePromise = new Promise(r => leaveResolve = r);
-    button.addEventListener('mouseleave', leaveResolve);
-
-    assert.isFalse(element._isShowing);
-    button.dispatchEvent(new CustomEvent('mouseenter'));
-
-    await enterPromise;
-    await flush();
-    assert.isTrue(element.isScheduledToShow);
-    element.showTask.flush();
-    assert.isTrue(element._isShowing);
-    assert.isFalse(element.isScheduledToShow);
-
-    button.dispatchEvent(new CustomEvent('mouseleave'));
-
-    await leavePromise;
-    assert.isTrue(element.isScheduledToHide);
-    assert.isTrue(element._isShowing);
-    element.hideTask.flush();
-    assert.isFalse(element.isScheduledToShow);
-    assert.isFalse(element._isShowing);
-
-    button.removeEventListener('mouseenter', enterResolve);
-    button.removeEventListener('mouseleave', leaveResolve);
-  });
-
-  test('card should disappear on click', async () => {
-    const button = document.querySelector('button');
-    let enterResolve = undefined;
-    const enterPromise = new Promise(r => enterResolve = r);
-    button.addEventListener('mouseenter', enterResolve);
-    let clickResolve = undefined;
-    const clickPromise = new Promise(r => clickResolve = r);
-    button.addEventListener('click', clickResolve);
-
-    assert.isFalse(element._isShowing);
-
-    button.dispatchEvent(new CustomEvent('mouseenter'));
-
-    await enterPromise;
-    await flush();
-    assert.isTrue(element.isScheduledToShow);
-    MockInteractions.tap(button);
-
-    await clickPromise;
-    assert.isFalse(element.isScheduledToShow);
-    assert.isFalse(element._isShowing);
-
-    button.removeEventListener('mouseenter', enterResolve);
-    button.removeEventListener('click', clickResolve);
-  });
-});
-
diff --git a/polygerrit-ui/app/elements/shared/gr-label-info/gr-label-info.ts b/polygerrit-ui/app/elements/shared/gr-label-info/gr-label-info.ts
index 5a6d821..2df2ccb 100644
--- a/polygerrit-ui/app/elements/shared/gr-label-info/gr-label-info.ts
+++ b/polygerrit-ui/app/elements/shared/gr-label-info/gr-label-info.ts
@@ -24,7 +24,6 @@
 import '../gr-label/gr-label';
 import '../gr-tooltip-content/gr-tooltip-content';
 import {dom, EventApi} from '@polymer/polymer/lib/legacy/polymer.dom';
-import {GerritNav} from '../../core/gr-navigation/gr-navigation';
 import {
   AccountInfo,
   LabelInfo,
@@ -44,6 +43,7 @@
 import {sharedStyles} from '../../../styles/shared-styles';
 import {votingStyles} from '../../../styles/gr-voting-styles';
 import {ifDefined} from 'lit/directives/if-defined';
+import {fireReload} from '../../../utils/event-util';
 
 declare global {
   interface HTMLElementTagNameMap {
@@ -349,7 +349,7 @@
           return;
         }
         if (this.change) {
-          GerritNav.navigateToChange(this.change);
+          fireReload(this);
         }
       })
       .catch(err => {
diff --git a/polygerrit-ui/app/mixins/hovercard-mixin/hovercard-mixin.ts b/polygerrit-ui/app/mixins/hovercard-mixin/hovercard-mixin.ts
new file mode 100644
index 0000000..793e5d6
--- /dev/null
+++ b/polygerrit-ui/app/mixins/hovercard-mixin/hovercard-mixin.ts
@@ -0,0 +1,488 @@
+/**
+ * @license
+ * 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.
+ */
+import {getRootElement} from '../../scripts/rootElement';
+import {Constructor} from '../../utils/common-util';
+import {LitElement, PropertyValues} from 'lit';
+import {property, query} from 'lit/decorators';
+import {ShowAlertEventDetail} from '../../types/events';
+import {debounce, DelayedTask} from '../../utils/async-util';
+import {hovercardStyles} from '../../styles/gr-hovercard-styles';
+import {sharedStyles} from '../../styles/shared-styles';
+
+interface ReloadEventDetail {
+  clearPatchset?: boolean;
+}
+
+const HOVER_CLASS = 'hovered';
+const HIDE_CLASS = 'hide';
+
+/**
+ * ID for the container element.
+ */
+const containerId = 'gr-hovercard-container';
+
+export function getHovercardContainer(
+  options: {createIfNotExists: boolean} = {createIfNotExists: false}
+): HTMLElement | null {
+  let container = getRootElement().querySelector<HTMLElement>(
+    `#${containerId}`
+  );
+  if (!container && options.createIfNotExists) {
+    // If it does not exist, create and initialize the hovercard container.
+    container = document.createElement('div');
+    container.setAttribute('id', containerId);
+    getRootElement().appendChild(container);
+  }
+  return container;
+}
+
+/**
+ * How long should we wait before showing the hovercard when the user hovers
+ * over the element?
+ */
+const SHOW_DELAY_MS = 550;
+
+/**
+ * How long should we wait before hiding the hovercard when the user moves from
+ * target to the hovercard.
+ *
+ * Note: this should be lower than SHOW_DELAY_MS to avoid flickering.
+ */
+const HIDE_DELAY_MS = 500;
+
+/**
+ * The mixin for hovercard behavior.
+ *
+ * @example
+ *
+ * class YourComponent extends hovercardBehaviorMixin(
+ *  LitElement)
+ *
+ * @see gr-hovercard.ts
+ *
+ * // following annotations are required for polylint
+ * @lit
+ * @mixinFunction
+ */
+export const HovercardMixin = <T extends Constructor<LitElement>>(
+  superClass: T
+) => {
+  /**
+   * @lit
+   * @mixinClass
+   */
+  class Mixin extends superClass {
+    @query('#container')
+    topElement?: HTMLElement;
+
+    @property({type: Object})
+    _target: HTMLElement | null = null;
+
+    // Determines whether or not the hovercard is visible.
+    @property({type: Boolean})
+    _isShowing = false;
+
+    // The `id` of the element that the hovercard is anchored to.
+    @property({type: String})
+    for?: string;
+
+    /**
+     * The spacing between the top of the hovercard and the element it is
+     * anchored to.
+     */
+    @property({type: Number})
+    offset = 14;
+
+    /**
+     * Positions the hovercard to the top, right, bottom, left, bottom-left,
+     * bottom-right, top-left, or top-right of its content.
+     */
+    @property({type: String})
+    position = 'right';
+
+    @property({type: Object})
+    container: HTMLElement | null = null;
+
+    // Private but used in tests.
+    hideTask?: DelayedTask;
+
+    showTask?: DelayedTask;
+
+    isScheduledToShow?: boolean;
+
+    isScheduledToHide?: boolean;
+
+    static get styles() {
+      return [sharedStyles, hovercardStyles];
+    }
+
+    // eslint-disable-next-line @typescript-eslint/no-explicit-any
+    constructor(...args: any[]) {
+      super(...args);
+      // show the hovercard if mouse moves to hovercard
+      // this will cancel pending hide as well
+      this.addEventListener('mouseenter', this.show);
+      // when leave hovercard, hide it immediately
+      this.addEventListener('mouseleave', this.hide);
+    }
+
+    override connectedCallback() {
+      super.connectedCallback();
+      // We have to cache the target because when we this.container.appendChild
+      // in show we can not pick the container as target when we reconnect.
+      if (!this._target) {
+        this._target = this.target;
+        this.addTargetEventListeners();
+      }
+
+      this.container = getHovercardContainer({createIfNotExists: true});
+    }
+
+    override disconnectedCallback() {
+      this.cancelShowTask();
+      this.cancelHideTask();
+      super.disconnectedCallback();
+    }
+
+    private addTargetEventListeners() {
+      this._target?.addEventListener('mouseenter', this.debounceShow);
+      this._target?.addEventListener('focus', this.debounceShow);
+      this._target?.addEventListener('mouseleave', this.debounceHide);
+      this._target?.addEventListener('blur', this.debounceHide);
+      this._target?.addEventListener('click', this.hide);
+    }
+
+    private removeTargetEventListeners() {
+      this._target?.removeEventListener('mouseenter', this.debounceShow);
+      this._target?.removeEventListener('focus', this.debounceShow);
+      this._target?.removeEventListener('mouseleave', this.debounceHide);
+      this._target?.removeEventListener('blur', this.debounceHide);
+      this._target?.removeEventListener('click', this.hide);
+    }
+
+    /**
+     * Responds to a change in the `for` value and gets the updated `target`
+     * element for the hovercard.
+     */
+    override updated(changedProperties: PropertyValues) {
+      super.updated(changedProperties);
+      if (changedProperties.has('for')) {
+        this.removeTargetEventListeners();
+        this._target = this.target;
+        this.addTargetEventListeners();
+      }
+    }
+
+    readonly debounceHide = () => {
+      this.cancelShowTask();
+      if (!this._isShowing || this.isScheduledToHide) return;
+      this.isScheduledToHide = true;
+      this.hideTask = debounce(
+        this.hideTask,
+        () => {
+          // This happens when hide immediately through click or mouse leave
+          // on the hovercard
+          if (!this.isScheduledToHide) return;
+          this.hide();
+        },
+        HIDE_DELAY_MS
+      );
+    };
+
+    cancelHideTask() {
+      if (!this.hideTask) return;
+      this.hideTask.cancel();
+      this.isScheduledToHide = false;
+      this.hideTask = undefined;
+    }
+
+    /**
+     * Hovercard elements are created outside of <gr-app>, so if you want to fire
+     * events, then you probably want to do that through the target element.
+     */
+
+    dispatchEventThroughTarget(eventName: string): void;
+
+    dispatchEventThroughTarget(
+      eventName: 'show-alert',
+      detail: ShowAlertEventDetail
+    ): void;
+
+    dispatchEventThroughTarget(
+      eventName: 'reload',
+      detail: ReloadEventDetail
+    ): void;
+
+    dispatchEventThroughTarget(eventName: string, detail?: unknown) {
+      if (!detail) detail = {};
+      if (this._target)
+        this._target.dispatchEvent(
+          new CustomEvent(eventName, {
+            detail,
+            bubbles: true,
+            composed: true,
+          })
+        );
+    }
+
+    /**
+     * Returns the target element that the hovercard is anchored to (the `id` of
+     * the `for` property).
+     */
+    get target(): HTMLElement {
+      const parentNode = this.parentNode;
+      // If the parentNode is a document fragment, then we need to use the host.
+      const ownerRoot = this.getRootNode() as ShadowRoot;
+      let target;
+      if (this.for) {
+        target = ownerRoot.querySelector('#' + this.for);
+      } else {
+        target =
+          !parentNode || parentNode.nodeType === Node.DOCUMENT_FRAGMENT_NODE
+            ? ownerRoot.host
+            : parentNode;
+      }
+      return target as HTMLElement;
+    }
+
+    /**
+     * Hides/closes the hovercard. This occurs when the user triggers the
+     * `mouseleave` event on the hovercard's `target` element (as long as the
+     * user is not hovering over the hovercard).
+     *
+     */
+    readonly hide = (e?: MouseEvent) => {
+      this.cancelHideTask();
+      this.cancelShowTask();
+      if (!this._isShowing) {
+        return;
+      }
+
+      // If the user is now hovering over the hovercard or the user is returning
+      // from the hovercard but now hovering over the target (to stop an annoying
+      // flicker effect), just return.
+      if (e) {
+        if (
+          e.relatedTarget === this ||
+          (e.target === this && e.relatedTarget === this._target)
+        ) {
+          return;
+        }
+      }
+
+      // Mark that the hovercard is not visible and do not allow focusing
+      this._isShowing = false;
+
+      // Clear styles in preparation for the next time we need to show the card
+      this.classList.remove(HOVER_CLASS);
+
+      // Reset and remove the hovercard from the DOM
+      this.style.cssText = '';
+      this.topElement?.setAttribute('tabindex', '-1');
+
+      // Remove the hovercard from the container, given that it is still a child
+      // of the container.
+      if (this.container?.contains(this)) {
+        this.container.removeChild(this);
+      }
+    };
+
+    /**
+     * Shows/opens the hovercard with a fixed delay.
+     */
+    readonly debounceShow = () => {
+      this.debounceShowBy(SHOW_DELAY_MS);
+    };
+
+    /**
+     * Shows/opens the hovercard with the given delay.
+     */
+    debounceShowBy(delayMs: number) {
+      this.cancelHideTask();
+      if (this._isShowing || this.isScheduledToShow) return;
+      this.isScheduledToShow = true;
+      this.showTask = debounce(
+        this.showTask,
+        () => {
+          // This happens when the mouse leaves the target before the delay is over.
+          if (!this.isScheduledToShow) return;
+          this.show();
+        },
+        delayMs
+      );
+    }
+
+    cancelShowTask() {
+      if (!this.showTask) return;
+      this.showTask.cancel();
+      this.isScheduledToShow = false;
+      this.showTask = undefined;
+    }
+
+    /**
+     * Shows/opens the hovercard. This occurs when the user triggers the
+     * `mousenter` event on the hovercard's `target` element.
+     */
+    readonly show = async () => {
+      this.cancelHideTask();
+      this.cancelShowTask();
+      if (this._isShowing || !this.container) {
+        return;
+      }
+
+      // Mark that the hovercard is now visible
+      this._isShowing = true;
+      this.setAttribute('tabindex', '0');
+
+      // Add it to the DOM and calculate its position
+      this.container.appendChild(this);
+      // We temporarily hide the hovercard until we have found the correct
+      // position for it.
+      this.classList.add(HIDE_CLASS);
+      this.classList.add(HOVER_CLASS);
+      // Make sure that the hovercard actually rendered and all dom-if
+      // statements processed, so that we can measure the (invisible)
+      // hovercard properly in updatePosition().
+      await new Promise<void>(r => {
+        setTimeout(r, 0);
+      });
+      this.updatePosition();
+      this.classList.remove(HIDE_CLASS);
+    };
+
+    updatePosition() {
+      const positionsToTry = new Set([
+        this.position,
+        'right',
+        'bottom-right',
+        'top-right',
+        'bottom',
+        'top',
+        'bottom-left',
+        'top-left',
+        'left',
+      ]);
+      for (const position of positionsToTry) {
+        this.updatePositionTo(position);
+        if (this._isInsideViewport()) return;
+      }
+      console.warn('Could not find a visible position for the hovercard.');
+    }
+
+    _isInsideViewport() {
+      const thisRect = this.getBoundingClientRect();
+      if (thisRect.top < 0) return false;
+      if (thisRect.left < 0) return false;
+      const docuRect = document.documentElement.getBoundingClientRect();
+      if (thisRect.bottom > docuRect.height) return false;
+      if (thisRect.right > docuRect.width) return false;
+      return true;
+    }
+
+    /**
+     * Updates the hovercard's position based the current position of the `target`
+     * element.
+     *
+     * The hovercard is supposed to stay open if the user hovers over it.
+     * To keep it open when the user moves away from the target, the bounding
+     * rects of the target and hovercard must touch or overlap.
+     *
+     * NOTE: You do not need to directly call this method unless you need to
+     * update the position of the tooltip while it is already visible (the
+     * target element has moved and the tooltip is still open).
+     */
+    updatePositionTo(position: string) {
+      if (!this._target) {
+        return;
+      }
+
+      // Make sure that thisRect will not get any paddings and such included
+      // in the width and height of the bounding client rect.
+      this.style.cssText = '';
+
+      const docuRect = document.documentElement.getBoundingClientRect();
+      const targetRect = this._target.getBoundingClientRect();
+      const thisRect = this.getBoundingClientRect();
+
+      const targetLeft = targetRect.left - docuRect.left;
+      const targetTop = targetRect.top - docuRect.top;
+
+      let hovercardLeft;
+      let hovercardTop;
+
+      switch (position) {
+        case 'top':
+          hovercardLeft = targetLeft + (targetRect.width - thisRect.width) / 2;
+          hovercardTop = targetTop - thisRect.height - this.offset;
+          break;
+        case 'bottom':
+          hovercardLeft = targetLeft + (targetRect.width - thisRect.width) / 2;
+          hovercardTop = targetTop + targetRect.height + this.offset;
+          break;
+        case 'left':
+          hovercardLeft = targetLeft - thisRect.width - this.offset;
+          hovercardTop = targetTop + (targetRect.height - thisRect.height) / 2;
+          break;
+        case 'right':
+          hovercardLeft = targetLeft + targetRect.width + this.offset;
+          hovercardTop = targetTop + (targetRect.height - thisRect.height) / 2;
+          break;
+        case 'bottom-right':
+          hovercardLeft = targetLeft + targetRect.width + this.offset;
+          hovercardTop = targetTop;
+          break;
+        case 'bottom-left':
+          hovercardLeft = targetLeft - thisRect.width - this.offset;
+          hovercardTop = targetTop;
+          break;
+        case 'top-left':
+          hovercardLeft = targetLeft - thisRect.width - this.offset;
+          hovercardTop = targetTop + targetRect.height - thisRect.height;
+          break;
+        case 'top-right':
+          hovercardLeft = targetLeft + targetRect.width + this.offset;
+          hovercardTop = targetTop + targetRect.height - thisRect.height;
+          break;
+      }
+
+      this.style.left = `${hovercardLeft}px`;
+      this.style.top = `${hovercardTop}px`;
+    }
+  }
+
+  return Mixin as T & Constructor<HovercardMixinInterface>;
+};
+
+export interface HovercardMixinInterface {
+  for?: string;
+  offset: number;
+  _target: HTMLElement | null;
+  _isShowing: boolean;
+  dispatchEventThroughTarget(eventName: string, detail?: unknown): void;
+  show(): void;
+
+  // Used for tests
+  hide(e: MouseEvent): void;
+  container: HTMLElement | null;
+  hideTask?: DelayedTask;
+  showTask?: DelayedTask;
+  position: string;
+  debounceShowBy(delayMs: number): void;
+  updatePosition(): void;
+  isScheduledToShow?: boolean;
+  isScheduledToHide?: boolean;
+}
diff --git a/polygerrit-ui/app/mixins/hovercard-mixin/hovercard-mixin_test.ts b/polygerrit-ui/app/mixins/hovercard-mixin/hovercard-mixin_test.ts
new file mode 100644
index 0000000..bd12789
--- /dev/null
+++ b/polygerrit-ui/app/mixins/hovercard-mixin/hovercard-mixin_test.ts
@@ -0,0 +1,177 @@
+/**
+ * @license
+ * Copyright (C) 2018 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 '../../test/common-test-setup-karma.js';
+import {HovercardMixin} from './hovercard-mixin.js';
+import {html, LitElement} from 'lit';
+import {customElement} from 'lit/decorators';
+import {MockPromise, mockPromise} from '../../test/test-utils.js';
+
+const base = HovercardMixin(LitElement);
+
+declare global {
+  interface HTMLElementTagNameMap {
+    'hovercard-mixin-test': HovercardMixinTest;
+  }
+}
+
+@customElement('hovercard-mixin-test')
+class HovercardMixinTest extends base {
+  constructor() {
+    super();
+    this.for = 'foo';
+  }
+
+  override render() {
+    return html`<div id="container"><slot></slot></div>`;
+  }
+}
+
+const basicFixture = fixtureFromElement('hovercard-mixin-test');
+
+suite('gr-hovercard tests', () => {
+  let element: HovercardMixinTest;
+
+  let button: HTMLElement;
+  let testPromise: MockPromise;
+
+  setup(() => {
+    testPromise = mockPromise();
+    button = document.createElement('button');
+    button.innerHTML = 'Hello';
+    button.setAttribute('id', 'foo');
+    document.body.appendChild(button);
+
+    element = basicFixture.instantiate();
+  });
+
+  teardown(() => {
+    element.hide(new MouseEvent('click'));
+    button?.remove();
+  });
+
+  test('updatePosition', async () => {
+    // Test that the correct style properties have at least been set.
+    element.position = 'bottom';
+    element.updatePosition();
+    await element.updateComplete;
+    assert.typeOf(element.style.getPropertyValue('left'), 'string');
+    assert.typeOf(element.style.getPropertyValue('top'), 'string');
+    assert.typeOf(element.style.getPropertyValue('paddingTop'), 'string');
+    assert.typeOf(element.style.getPropertyValue('marginTop'), 'string');
+
+    const parentRect = document.documentElement.getBoundingClientRect();
+    const targetRect = element!._target!.getBoundingClientRect();
+    const thisRect = element.getBoundingClientRect();
+
+    const targetLeft = targetRect.left - parentRect.left;
+    const targetTop = targetRect.top - parentRect.top;
+
+    const pixelCompare = (pixel: string) =>
+      Math.round(parseInt(pixel.substring(0, pixel.length - 1), 10));
+
+    assert.equal(
+      pixelCompare(element.style.left),
+      pixelCompare(`${targetLeft + (targetRect.width - thisRect.width) / 2}px`)
+    );
+    assert.equal(
+      pixelCompare(element.style.top),
+      pixelCompare(`${targetTop + targetRect.height + element.offset}px`)
+    );
+  });
+
+  test('hide', () => {
+    element.hide(new MouseEvent('click'));
+    const style = getComputedStyle(element);
+    assert.isFalse(element._isShowing);
+    assert.isFalse(element.classList.contains('hovered'));
+    assert.equal(style.display, 'none');
+    assert.notEqual(element.container, element.parentNode);
+  });
+
+  test('show', async () => {
+    await element.show();
+    await element.updateComplete;
+    const style = getComputedStyle(element);
+    assert.isTrue(element._isShowing);
+    assert.isTrue(element.classList.contains('hovered'));
+    assert.equal(style.opacity, '1');
+    assert.equal(style.visibility, 'visible');
+  });
+
+  test('debounceShow does not show immediately', async () => {
+    element.debounceShowBy(100);
+    setTimeout(() => testPromise.resolve(), 0);
+    await testPromise;
+    assert.isFalse(element._isShowing);
+  });
+
+  test('debounceShow shows after delay', async () => {
+    element.debounceShowBy(1);
+    setTimeout(() => testPromise.resolve(), 10);
+    await testPromise;
+    assert.isTrue(element._isShowing);
+  });
+
+  test('card is scheduled to show on enter and hides on leave', async () => {
+    const button = document.querySelector('button');
+    const enterPromise = mockPromise();
+    button!.addEventListener('mouseenter', () => enterPromise.resolve());
+    const leavePromise = mockPromise();
+    button!.addEventListener('mouseleave', () => leavePromise.resolve());
+
+    assert.isFalse(element._isShowing);
+    button!.dispatchEvent(new CustomEvent('mouseenter'));
+
+    await enterPromise;
+    await flush();
+    assert.isTrue(element.isScheduledToShow);
+    element!.showTask!.flush();
+    assert.isTrue(element._isShowing);
+    assert.isFalse(element.isScheduledToShow);
+
+    button!.dispatchEvent(new CustomEvent('mouseleave'));
+
+    await leavePromise;
+    assert.isTrue(element.isScheduledToHide);
+    assert.isTrue(element._isShowing);
+    element!.hideTask!.flush();
+    assert.isFalse(element.isScheduledToShow);
+    assert.isFalse(element._isShowing);
+  });
+
+  test('card should disappear on click', async () => {
+    const button = document.querySelector('button');
+    const enterPromise = mockPromise();
+    const clickPromise = mockPromise();
+    button!.addEventListener('mouseenter', () => enterPromise.resolve());
+    button!.addEventListener('click', () => clickPromise.resolve());
+
+    assert.isFalse(element._isShowing);
+
+    button!.dispatchEvent(new CustomEvent('mouseenter'));
+
+    await enterPromise;
+    await flush();
+    assert.isTrue(element.isScheduledToShow);
+    button!.click();
+
+    await clickPromise;
+    assert.isFalse(element.isScheduledToShow);
+    assert.isFalse(element._isShowing);
+  });
+});
diff --git a/polygerrit-ui/app/package.json b/polygerrit-ui/app/package.json
index 4be6241..2ad4e79 100644
--- a/polygerrit-ui/app/package.json
+++ b/polygerrit-ui/app/package.json
@@ -38,7 +38,7 @@
     "ba-linkify": "^1.0.1",
     "codemirror-minified": "^5.62.2",
     "immer": "^9.0.5",
-    "lit": "2.0.0-rc.3",
+    "lit": "2.0.2",
     "page": "^1.11.6",
     "polymer-bridges": "file:../../polymer-bridges/",
     "polymer-resin": "^2.0.1",
diff --git a/polygerrit-ui/app/styles/gr-hovercard-styles.ts b/polygerrit-ui/app/styles/gr-hovercard-styles.ts
new file mode 100644
index 0000000..f214a9c
--- /dev/null
+++ b/polygerrit-ui/app/styles/gr-hovercard-styles.ts
@@ -0,0 +1,51 @@
+/**
+ * @license
+ * 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.
+ */
+import {css} from 'lit';
+
+export const hovercardStyles = css`
+  :host {
+    position: absolute;
+    display: none;
+    z-index: 200;
+    max-width: 600px;
+    outline: none;
+  }
+  :host(.hovered) {
+    display: block;
+  }
+  :host(.hide) {
+    visibility: hidden;
+  }
+  /* You have to use a <div class="container"> in your hovercard in order
+      to pick up this consistent styling. */
+  #container {
+    background: var(--dialog-background-color);
+    border: 1px solid var(--border-color);
+    border-radius: var(--border-radius);
+    box-shadow: var(--elevation-level-5);
+  }
+`;
+
+const $_documentContainer = document.createElement('template');
+$_documentContainer.innerHTML = `<dom-module id="gr-hovercard-styles">
+  <template>
+    <style>
+    ${hovercardStyles.cssText}
+    </style>
+  </template>
+</dom-module>`;
+document.head.appendChild($_documentContainer.content);
diff --git a/polygerrit-ui/app/yarn.lock b/polygerrit-ui/app/yarn.lock
index 395ef64..bfca566 100644
--- a/polygerrit-ui/app/yarn.lock
+++ b/polygerrit-ui/app/yarn.lock
@@ -2,10 +2,10 @@
 # yarn lockfile v1
 
 
-"@lit/reactive-element@^1.0.0-rc.2":
-  version "1.0.0-rc.3"
-  resolved "https://registry.yarnpkg.com/@lit/reactive-element/-/reactive-element-1.0.0-rc.3.tgz#5032f493fbf39781b187a7e2dd5d256537c8760c"
-  integrity sha512-Rs2px1keOQUNJUo5B+WExl5v244ZNCiN/iMVNO9evFdJjAdWCIupR/p14zRPkNHsciRBELLTcOZ379cI9O6PDg==
+"@lit/reactive-element@^1.0.0":
+  version "1.0.1"
+  resolved "https://registry.yarnpkg.com/@lit/reactive-element/-/reactive-element-1.0.1.tgz#853cacd4d78d79059f33f66f8e7b0e5c34bee294"
+  integrity sha512-nSD5AA2AZkKuXuvGs8IK7K5ZczLAogfDd26zT9l6S7WzvqALdVWcW5vMUiTnZyj5SPcNwNNANj0koeV1ieqTFQ==
 
 "@mapbox/node-pre-gyp@^1.0.0":
   version "1.0.5"
@@ -425,10 +425,10 @@
   resolved "https://registry.yarnpkg.com/@types/resize-observer-browser/-/resize-observer-browser-0.1.6.tgz#d8e6c2f830e2650dc06fe74464472ff64b54a302"
   integrity sha512-61IfTac0s9jvNtBCpyo86QeaN8qqpMGHdK0uGKCCIy2dt5/Yk84VduHIdWAcmkC5QvdkPL0p5eWYgUZtHKKUVg==
 
-"@types/trusted-types@^1.0.1":
-  version "1.0.6"
-  resolved "https://registry.yarnpkg.com/@types/trusted-types/-/trusted-types-1.0.6.tgz#569b8a08121d3203398290d602d84d73c8dcf5da"
-  integrity sha512-230RC8sFeHoT6sSUlRO6a8cAnclO06eeiq1QDfiv2FGCLWFvvERWgwIQD4FWqD9A69BN7Lzee4OXwoMVnnsWDw==
+"@types/trusted-types@^2.0.2":
+  version "2.0.2"
+  resolved "https://registry.yarnpkg.com/@types/trusted-types/-/trusted-types-2.0.2.tgz#fc25ad9943bcac11cceb8168db4f275e0e72e756"
+  integrity sha512-F5DIZ36YVLE+PN+Zwws4kJogq47hNgX3Nx6WyDJ3kcplxyke3XIzB8uK5n/Lpm1HBsbGzd6nmGehL8cPekP+Tg==
 
 "@webcomponents/shadycss@^1.10.2", "@webcomponents/shadycss@^1.9.1":
   version "1.11.0"
@@ -473,9 +473,9 @@
   integrity sha512-Y9J6ZjXtoYh8RnXVCMOU/ttDmk1aBjunq9vO0ta5x85WDQiQfUF9sIPBITdbiiIVcBo03Hi3jMxigBtsddlXRw==
 
 are-we-there-yet@~1.1.2:
-  version "1.1.5"
-  resolved "https://registry.yarnpkg.com/are-we-there-yet/-/are-we-there-yet-1.1.5.tgz#4b35c2944f062a8bfcda66410760350fe9ddfc21"
-  integrity sha512-5hYdAkZlcG8tOLujVDTgCT+uPX0VnpAH28gWsLfzpXYm7wP6mp5Q/gYyR7YQ0cKVJcXJnl3j2kpBan13PtQf6w==
+  version "1.1.7"
+  resolved "https://registry.yarnpkg.com/are-we-there-yet/-/are-we-there-yet-1.1.7.tgz#b15474a932adab4ff8a50d9adfa7e4e926f21146"
+  integrity sha512-nxwy40TuMiUGqMyRHgCSWZ9FM4VAoRP4xUYSTv5ImRog+h9yISPbVH7H8fASCIzYn9wlEv4zvFL7uKDMCFQm3g==
   dependencies:
     delegates "^1.0.0"
     readable-stream "^2.0.6"
@@ -518,9 +518,9 @@
   integrity sha1-DQcLTQQ6W+ozovGkDi7bPZpMz3c=
 
 codemirror-minified@^5.62.2:
-  version "5.62.2"
-  resolved "https://registry.yarnpkg.com/codemirror-minified/-/codemirror-minified-5.62.2.tgz#37d866f5f39bbd4482c60b1607c669bcb7190388"
-  integrity sha512-lQpyiEaqyEln1YDiHqq8lJcX8GkTJamecZAn0DkgdteFIVCRHnVmllOXPF+d159OSNkMi1UcKRObcU6ueBHe1A==
+  version "5.63.0"
+  resolved "https://registry.yarnpkg.com/codemirror-minified/-/codemirror-minified-5.63.0.tgz#29d1a78713a633c933a27853679afdc0bfea49cc"
+  integrity sha512-dMN2w0Qg5Zwn2p7UW3sYAoyrJ+QRBkiF5bfbQAvQ1bfqhEjGnZ++/zvOG7NivfnUbYRhSULz8lsFtzt4ldBNyQ==
 
 concat-map@0.0.1:
   version "0.0.1"
@@ -533,9 +533,9 @@
   integrity sha1-PXz0Rk22RG6mRL9LOVB/mFEAjo4=
 
 core-util-is@~1.0.0:
-  version "1.0.2"
-  resolved "https://registry.yarnpkg.com/core-util-is/-/core-util-is-1.0.2.tgz#b5fd54220aa2bc5ab57aab7140c940754503c1a7"
-  integrity sha1-tf1UIgqivFq1eqtxQMlAdUUDwac=
+  version "1.0.3"
+  resolved "https://registry.yarnpkg.com/core-util-is/-/core-util-is-1.0.3.tgz#a6042d3634c2b27e9328f837b965fac83808db85"
+  integrity sha512-ZQBvi1DcpJ4GDqanjucZ2Hj3wEO5pZDS89BWbkcrvdxksJorwUDDZamX9ldFkp9aw2lmBDLgkObEA4DWNJ9FYQ==
 
 debug@4:
   version "4.3.2"
@@ -588,9 +588,9 @@
     wide-align "^1.1.0"
 
 glob@^7.1.3:
-  version "7.1.7"
-  resolved "https://registry.yarnpkg.com/glob/-/glob-7.1.7.tgz#3b193e9233f01d42d0b3f78294bbeeb418f94a90"
-  integrity sha512-OvD9ENzPLbegENnYP5UUfJIirTg4+XwMWGaQfQTY0JenxNvvIKP3U3/tAQSPIu/lHxXYSZmpXlUHeqAIdKzBLQ==
+  version "7.2.0"
+  resolved "https://registry.yarnpkg.com/glob/-/glob-7.2.0.tgz#d15535af7732e02e948f4c41628bd910293f6023"
+  integrity sha512-lmLf6gtyrPq8tTjSmrO94wBeQbFR3HbLHbuyD69wuyQkImp2hWqMGB47OX65FBkPffO641IP9jWa1z4ivqG26Q==
   dependencies:
     fs.realpath "^1.0.0"
     inflight "^1.0.4"
@@ -613,9 +613,9 @@
     debug "4"
 
 immer@^9.0.5:
-  version "9.0.5"
-  resolved "https://registry.yarnpkg.com/immer/-/immer-9.0.5.tgz#a7154f34fe7064f15f00554cc94c66cc0bf453ec"
-  integrity sha512-2WuIehr2y4lmYz9gaQzetPR2ECniCifk4ORaQbU3g5EalLt+0IVTosEPJ5BoYl/75ky2mivzdRzV8wWgQGOSYQ==
+  version "9.0.6"
+  resolved "https://registry.yarnpkg.com/immer/-/immer-9.0.6.tgz#7a96bf2674d06c8143e327cbf73539388ddf1a73"
+  integrity sha512-G95ivKpy+EvVAnAab4fVa4YGYn24J1SpEktnJX7JJ45Bd7xqME/SCplFzYFmTbrkwZbQ4xJK1xMTUYBkN6pWsQ==
 
 inflight@^1.0.4:
   version "1.0.6"
@@ -652,29 +652,29 @@
   resolved "https://registry.yarnpkg.com/isarray/-/isarray-1.0.0.tgz#bb935d48582cba168c06834957a54a3e07124f11"
   integrity sha1-u5NdSFgsuhaMBoNJV6VKPgcSTxE=
 
-lit-element@^3.0.0-rc.2:
-  version "3.0.0-rc.3"
-  resolved "https://registry.yarnpkg.com/lit-element/-/lit-element-3.0.0-rc.3.tgz#cece8f092d28eb6f9c6b23e4138ff5d7260897ef"
-  integrity sha512-NDe7yjW18gfYQb1GIEQr1T8sB1GUAb1HB62pdAEw+SK6lUW7OFPKQqCOlRhZ6qJXsw9KxMnyYIprLZT4FZdYdQ==
+lit-element@^3.0.0:
+  version "3.0.1"
+  resolved "https://registry.yarnpkg.com/lit-element/-/lit-element-3.0.1.tgz#3c545af17d8a46268bc1dd5623a47486e6ff76f4"
+  integrity sha512-vs9uybH9ORyK49CFjoNGN85HM9h5bmisU4TQ63phe/+GYlwvY/3SIFYKdjV6xNvzz8v2MnVC+9+QOkPqh+Q3Ew==
   dependencies:
-    "@lit/reactive-element" "^1.0.0-rc.2"
-    lit-html "^2.0.0-rc.4"
+    "@lit/reactive-element" "^1.0.0"
+    lit-html "^2.0.0"
 
-lit-html@^2.0.0-rc.4:
-  version "2.0.0-rc.4"
-  resolved "https://registry.yarnpkg.com/lit-html/-/lit-html-2.0.0-rc.4.tgz#1015fa8f1f7c8c5b79999ed0bc11c3b79ff1aab5"
-  integrity sha512-WSLGu3vxq7y8q/oOd9I3zxyBELNLLiDk6gAYoKK4PGctI5fbh6lhnO/jVBdy0PV/vTc+cLJCA/occzx3YoNPeg==
+lit-html@^2.0.0:
+  version "2.0.1"
+  resolved "https://registry.yarnpkg.com/lit-html/-/lit-html-2.0.1.tgz#63241015efa07bc9259b6f96f04abd052d2a1f95"
+  integrity sha512-KF5znvFdXbxTYM/GjpdOOnMsjgRcFGusTnB54ixnCTya5zUR0XqrDRj29ybuLS+jLXv1jji6Y8+g4W7WP8uL4w==
   dependencies:
-    "@types/trusted-types" "^1.0.1"
+    "@types/trusted-types" "^2.0.2"
 
-lit@2.0.0-rc.3:
-  version "2.0.0-rc.3"
-  resolved "https://registry.yarnpkg.com/lit/-/lit-2.0.0-rc.3.tgz#8b6a85268aba287c11125dfe57e88e0bc09beaff"
-  integrity sha512-UZDLWuspl7saA+WvS0e+TE3NdGGE05hOIwUPTWiibs34c5QupcEzpjB/aElt79V9bELQVNbUUwa0Ow7D1Wuszw==
+lit@2.0.2:
+  version "2.0.2"
+  resolved "https://registry.yarnpkg.com/lit/-/lit-2.0.2.tgz#5e6f422924e0732258629fb379556b6d23f7179c"
+  integrity sha512-hKA/1YaSB+P+DvKWuR2q1Xzy/iayhNrJ3aveD0OQ9CKn6wUjsdnF/7LavDOJsKP/K5jzW/kXsuduPgRvTFrFJw==
   dependencies:
-    "@lit/reactive-element" "^1.0.0-rc.2"
-    lit-element "^3.0.0-rc.2"
-    lit-html "^2.0.0-rc.4"
+    "@lit/reactive-element" "^1.0.0"
+    lit-element "^3.0.0"
+    lit-html "^2.0.0"
 
 lru-cache@^6.0.0:
   version "6.0.0"
@@ -703,9 +703,9 @@
     brace-expansion "^1.1.7"
 
 minipass@^3.0.0:
-  version "3.1.3"
-  resolved "https://registry.yarnpkg.com/minipass/-/minipass-3.1.3.tgz#7d42ff1f39635482e15f9cdb53184deebd5815fd"
-  integrity sha512-Mgd2GdMVzY+x3IJ+oHnVM+KG3lA5c8tnabyJKmHSaG2kAGpudxuOf8ToDkhumF7UzME7DecbQE9uOZhNm7PuJg==
+  version "3.1.5"
+  resolved "https://registry.yarnpkg.com/minipass/-/minipass-3.1.5.tgz#71f6251b0a33a49c01b3cf97ff77eda030dff732"
+  integrity sha512-+8NzxD82XQoNKNrl1d/FSi+X8wAEWR+sbYAfIvub4Nz0d22plFG72CEVVaufV8PNf4qSslFTD8VMOxNVhHCjTw==
   dependencies:
     yallist "^4.0.0"
 
@@ -733,9 +733,11 @@
   integrity sha512-8ZtvEnA2c5aYCZYd1cvgdnU6cqwixRoYg70xPLWUws5ORTa/lnw+u4amixRS/Ac5U5mQVgp9pnlSUnbNWFaWZQ==
 
 node-fetch@^2.6.1:
-  version "2.6.1"
-  resolved "https://registry.yarnpkg.com/node-fetch/-/node-fetch-2.6.1.tgz#045bd323631f76ed2e2b55573394416b639a0052"
-  integrity sha512-V4aYg89jEoVRxRb2fJdAg8FHvI7cEyYdVAh94HH0UIK8oJxUfkjlDQN9RbMx+bEjP7+ggMiFRprSti032Oipxw==
+  version "2.6.5"
+  resolved "https://registry.yarnpkg.com/node-fetch/-/node-fetch-2.6.5.tgz#42735537d7f080a7e5f78b6c549b7146be1742fd"
+  integrity sha512-mmlIVHJEu5rnIxgEgez6b9GgWXbkZj5YZ7fx+2r94a2E+Uirsp6HsPTPlomfdHtpt/B0cdKviwkoaM6pyvUOpQ==
+  dependencies:
+    whatwg-url "^5.0.0"
 
 nopt@^5.0.0:
   version "5.0.0"
@@ -863,9 +865,9 @@
   integrity sha1-BF+XgtARrppoA93TgrJDkrPYkPc=
 
 signal-exit@^3.0.0:
-  version "3.0.3"
-  resolved "https://registry.yarnpkg.com/signal-exit/-/signal-exit-3.0.3.tgz#a1410c2edd8f077b08b4e253c8eacfcaf057461c"
-  integrity sha512-VUJ49FC8U1OxwZLxIbTTrDvLnf/6TDgxZcK8wxR8zs13xpx7xbG60ndBlhNrFi2EMuFRoeDoJO7wthSLq42EjA==
+  version "3.0.5"
+  resolved "https://registry.yarnpkg.com/signal-exit/-/signal-exit-3.0.5.tgz#9e3e8cc0c75a99472b44321033a7702e7738252f"
+  integrity sha512-KWcOiKeQj6ZyXx7zq4YxSMgHRlod4czeBQZrPb8OKcohcqAXShm7E20kEMle9WBt26hFcAf0qLOcp5zmY7kOqQ==
 
 simple-concat@^1.0.0:
   version "1.0.1"
@@ -920,9 +922,9 @@
     ansi-regex "^3.0.0"
 
 tar@^6.1.0:
-  version "6.1.8"
-  resolved "https://registry.yarnpkg.com/tar/-/tar-6.1.8.tgz#4fc50cfe56511c538ce15b71e05eebe66530cbd4"
-  integrity sha512-sb9b0cp855NbkMJcskdSYA7b11Q8JsX4qe4pyUAfHp+Y6jBjJeek2ZVlwEfWayshEIwlIzXx0Fain3QG9JPm2A==
+  version "6.1.11"
+  resolved "https://registry.yarnpkg.com/tar/-/tar-6.1.11.tgz#6760a38f003afa1b2ffd0ffe9e9abbd0eab3d621"
+  integrity sha512-an/KZQzQUkZCkuoAA64hM92X0Urb6VpRhAFllDzz44U2mcD5scmT3zBc4VgVpkugF580+DQn8eAFSyoQt0tznA==
   dependencies:
     chownr "^2.0.0"
     fs-minipass "^2.0.0"
@@ -931,6 +933,11 @@
     mkdirp "^1.0.3"
     yallist "^4.0.0"
 
+tr46@~0.0.3:
+  version "0.0.3"
+  resolved "https://registry.yarnpkg.com/tr46/-/tr46-0.0.3.tgz#8184fd347dac9cdc185992f3a6622e14b9d9ab6a"
+  integrity sha1-gYT9NH2snNwYWZLzpmIuFLnZq2o=
+
 tslib@^1.9.0:
   version "1.14.1"
   resolved "https://registry.yarnpkg.com/tslib/-/tslib-1.14.1.tgz#cf2d38bdc34a134bcaf1091c41f6619e2f672d00"
@@ -941,6 +948,19 @@
   resolved "https://registry.yarnpkg.com/util-deprecate/-/util-deprecate-1.0.2.tgz#450d4dc9fa70de732762fbd2d4a28981419a0ccf"
   integrity sha1-RQ1Nyfpw3nMnYvvS1KKJgUGaDM8=
 
+webidl-conversions@^3.0.0:
+  version "3.0.1"
+  resolved "https://registry.yarnpkg.com/webidl-conversions/-/webidl-conversions-3.0.1.tgz#24534275e2a7bc6be7bc86611cc16ae0a5654871"
+  integrity sha1-JFNCdeKnvGvnvIZhHMFq4KVlSHE=
+
+whatwg-url@^5.0.0:
+  version "5.0.0"
+  resolved "https://registry.yarnpkg.com/whatwg-url/-/whatwg-url-5.0.0.tgz#966454e8765462e37644d3626f6742ce8b70965d"
+  integrity sha1-lmRU6HZUYuN2RNNib2dCzotwll0=
+  dependencies:
+    tr46 "~0.0.3"
+    webidl-conversions "^3.0.0"
+
 wide-align@^1.1.0:
   version "1.1.3"
   resolved "https://registry.yarnpkg.com/wide-align/-/wide-align-1.1.3.tgz#ae074e6bdc0c14a431e804e624549c633b000457"