diff --git a/java/com/google/gerrit/acceptance/InMemoryTestingDatabaseModule.java b/java/com/google/gerrit/acceptance/InMemoryTestingDatabaseModule.java
index 05e88a4..e15d162 100644
--- a/java/com/google/gerrit/acceptance/InMemoryTestingDatabaseModule.java
+++ b/java/com/google/gerrit/acceptance/InMemoryTestingDatabaseModule.java
@@ -28,8 +28,6 @@
 import com.google.gerrit.server.config.TrackingFooters;
 import com.google.gerrit.server.config.TrackingFootersProvider;
 import com.google.gerrit.server.git.GitRepositoryManager;
-import com.google.gerrit.server.notedb.ChangeBundleReader;
-import com.google.gerrit.server.notedb.GwtormChangeBundleReader;
 import com.google.gerrit.server.notedb.NotesMigration;
 import com.google.gerrit.server.schema.NotesMigrationSchemaFactory;
 import com.google.gerrit.server.schema.ReviewDbFactory;
@@ -83,7 +81,6 @@
     bind(schemaFactory).to(NotesMigrationSchemaFactory.class);
     bind(Key.get(schemaFactory, ReviewDbFactory.class)).to(InMemoryDatabase.class);
     bind(InMemoryDatabase.class).in(SINGLETON);
-    bind(ChangeBundleReader.class).to(GwtormChangeBundleReader.class);
 
     listener().to(CreateDatabase.class);
 
diff --git a/java/com/google/gerrit/pgm/util/BatchProgramModule.java b/java/com/google/gerrit/pgm/util/BatchProgramModule.java
index 54d2dea..ca4b6f3 100644
--- a/java/com/google/gerrit/pgm/util/BatchProgramModule.java
+++ b/java/com/google/gerrit/pgm/util/BatchProgramModule.java
@@ -50,7 +50,6 @@
 import com.google.gerrit.server.config.DefaultUrlFormatter;
 import com.google.gerrit.server.config.DisableReverseDnsLookup;
 import com.google.gerrit.server.config.DisableReverseDnsLookupProvider;
-import com.google.gerrit.server.config.GerritServerConfig;
 import com.google.gerrit.server.config.GitReceivePackGroups;
 import com.google.gerrit.server.config.GitUploadPackGroups;
 import com.google.gerrit.server.config.SysExecutorModule;
@@ -87,16 +86,13 @@
 import java.util.Collections;
 import java.util.List;
 import java.util.Set;
-import org.eclipse.jgit.lib.Config;
 
 /** Module for programs that perform batch operations on a site. */
 public class BatchProgramModule extends FactoryModule {
-  private final Config cfg;
   private final Module reviewDbModule;
 
   @Inject
-  BatchProgramModule(@GerritServerConfig Config cfg, PerThreadReviewDbModule reviewDbModule) {
-    this.cfg = cfg;
+  BatchProgramModule(PerThreadReviewDbModule reviewDbModule) {
     this.reviewDbModule = reviewDbModule;
   }
 
@@ -168,7 +164,7 @@
     install(new H2CacheModule());
     install(new ExternalIdModule());
     install(new GroupModule());
-    install(new NoteDbModule(cfg));
+    install(new NoteDbModule());
     install(AccountCacheImpl.module());
     install(GroupCacheImpl.module());
     install(GroupIncludeCacheImpl.module());
diff --git a/java/com/google/gerrit/server/config/GerritGlobalModule.java b/java/com/google/gerrit/server/config/GerritGlobalModule.java
index b26e875..6eb4ad9 100644
--- a/java/com/google/gerrit/server/config/GerritGlobalModule.java
+++ b/java/com/google/gerrit/server/config/GerritGlobalModule.java
@@ -246,7 +246,7 @@
     install(new GitModule());
     install(new GroupDbModule());
     install(new GroupModule());
-    install(new NoteDbModule(cfg));
+    install(new NoteDbModule());
     install(new PrologModule());
     install(new DefaultSubmitRule.Module());
     install(new IgnoreSelfApprovalRule.Module());
diff --git a/java/com/google/gerrit/server/notedb/ChangeBundle.java b/java/com/google/gerrit/server/notedb/ChangeBundle.java
deleted file mode 100644
index c4d6a91..0000000
--- a/java/com/google/gerrit/server/notedb/ChangeBundle.java
+++ /dev/null
@@ -1,976 +0,0 @@
-// Copyright (C) 2016 The Android Open Source Project
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-// http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-
-package com.google.gerrit.server.notedb;
-
-import static com.google.common.base.MoreObjects.firstNonNull;
-import static com.google.common.base.Preconditions.checkArgument;
-import static com.google.common.collect.ImmutableList.toImmutableList;
-import static com.google.common.collect.ImmutableSortedMap.toImmutableSortedMap;
-import static com.google.gerrit.reviewdb.server.ReviewDbUtil.checkColumns;
-import static com.google.gerrit.reviewdb.server.ReviewDbUtil.intKeyOrdering;
-import static com.google.gerrit.server.notedb.ChangeBundle.Source.NOTE_DB;
-import static com.google.gerrit.server.notedb.ChangeBundle.Source.REVIEW_DB;
-import static com.google.gerrit.server.util.time.TimeUtil.truncateToSecond;
-import static java.util.Comparator.comparing;
-import static java.util.Comparator.naturalOrder;
-import static java.util.Comparator.nullsFirst;
-import static java.util.Objects.requireNonNull;
-import static java.util.stream.Collectors.toList;
-
-import com.google.auto.value.AutoValue;
-import com.google.common.base.CharMatcher;
-import com.google.common.base.Function;
-import com.google.common.base.Predicate;
-import com.google.common.base.Predicates;
-import com.google.common.base.Strings;
-import com.google.common.collect.Collections2;
-import com.google.common.collect.ImmutableCollection;
-import com.google.common.collect.ImmutableList;
-import com.google.common.collect.ImmutableMap;
-import com.google.common.collect.ImmutableSortedMap;
-import com.google.common.collect.Iterables;
-import com.google.common.collect.LinkedListMultimap;
-import com.google.common.collect.ListMultimap;
-import com.google.common.collect.Lists;
-import com.google.common.collect.Maps;
-import com.google.common.collect.Ordering;
-import com.google.common.collect.Sets;
-import com.google.common.collect.Streams;
-import com.google.gerrit.common.Nullable;
-import com.google.gerrit.reviewdb.client.Account;
-import com.google.gerrit.reviewdb.client.Change;
-import com.google.gerrit.reviewdb.client.ChangeMessage;
-import com.google.gerrit.reviewdb.client.PatchLineComment;
-import com.google.gerrit.reviewdb.client.PatchSet;
-import com.google.gerrit.reviewdb.client.PatchSet.Id;
-import com.google.gerrit.reviewdb.client.PatchSetApproval;
-import com.google.gerrit.server.ChangeUtil;
-import com.google.gerrit.server.CommentsUtil;
-import com.google.gerrit.server.ReviewerSet;
-import com.google.gerrit.server.notedb.rebuild.ChangeRebuilderImpl;
-import com.google.gwtorm.client.Column;
-import com.google.gwtorm.server.OrmException;
-import java.lang.reflect.Field;
-import java.sql.Timestamp;
-import java.util.ArrayList;
-import java.util.Arrays;
-import java.util.Collection;
-import java.util.Comparator;
-import java.util.Iterator;
-import java.util.LinkedList;
-import java.util.List;
-import java.util.Map;
-import java.util.Objects;
-import java.util.Optional;
-import java.util.Set;
-
-/**
- * A bundle of all entities rooted at a single {@link Change} entity.
- *
- * <p>See the {@link Change} Javadoc for a depiction of this tree. Bundles may be compared using
- * {@link #differencesFrom(ChangeBundle)}, which normalizes out the minor implementation differences
- * between ReviewDb and NoteDb.
- */
-public class ChangeBundle {
-  public enum Source {
-    REVIEW_DB,
-    NOTE_DB;
-  }
-
-  public static ChangeBundle fromNotes(CommentsUtil commentsUtil, ChangeNotes notes)
-      throws OrmException {
-    return new ChangeBundle(
-        notes.getChange(),
-        notes.getChangeMessages(),
-        notes.getPatchSets().values(),
-        notes.getApprovals().values(),
-        Iterables.concat(
-            CommentsUtil.toPatchLineComments(
-                notes.getChangeId(),
-                PatchLineComment.Status.DRAFT,
-                commentsUtil.draftByChange(null, notes)),
-            CommentsUtil.toPatchLineComments(
-                notes.getChangeId(),
-                PatchLineComment.Status.PUBLISHED,
-                commentsUtil.publishedByChange(null, notes))),
-        notes.getReviewers(),
-        Source.NOTE_DB);
-  }
-
-  private static ImmutableSortedMap<ChangeMessage.Key, ChangeMessage> changeMessageMap(
-      Collection<ChangeMessage> in) {
-    return in.stream()
-        .collect(
-            toImmutableSortedMap(
-                comparing((ChangeMessage.Key k) -> k.getParentKey().get())
-                    .thenComparing(k -> k.get()),
-                cm -> cm.getKey(),
-                cm -> cm));
-  }
-
-  // Unlike the *Map comparators, which are intended to make key lists diffable,
-  // this comparator sorts first on timestamp, then on every other field.
-  private static final Comparator<ChangeMessage> CHANGE_MESSAGE_COMPARATOR =
-      comparing(ChangeMessage::getWrittenOn)
-          .thenComparing(m -> m.getKey().getParentKey().get())
-          .thenComparing(
-              m -> m.getPatchSetId() != null ? m.getPatchSetId().get() : null,
-              nullsFirst(naturalOrder()))
-          .thenComparing(ChangeMessage::getAuthor, intKeyOrdering())
-          .thenComparing(ChangeMessage::getMessage, nullsFirst(naturalOrder()));
-
-  private static ImmutableList<ChangeMessage> changeMessageList(Iterable<ChangeMessage> in) {
-    return Streams.stream(in).sorted(CHANGE_MESSAGE_COMPARATOR).collect(toImmutableList());
-  }
-
-  private static ImmutableSortedMap<Id, PatchSet> patchSetMap(Iterable<PatchSet> in) {
-    return Streams.stream(in)
-        .collect(toImmutableSortedMap(patchSetIdComparator(), PatchSet::getId, ps -> ps));
-  }
-
-  private static ImmutableSortedMap<PatchSetApproval.Key, PatchSetApproval> patchSetApprovalMap(
-      Iterable<PatchSetApproval> in) {
-    return Streams.stream(in)
-        .collect(
-            toImmutableSortedMap(
-                comparing(PatchSetApproval.Key::getParentKey, patchSetIdComparator())
-                    .thenComparing(PatchSetApproval.Key::getAccountId, intKeyOrdering())
-                    .thenComparing(PatchSetApproval.Key::getLabelId),
-                PatchSetApproval::getKey,
-                a -> a));
-  }
-
-  private static ImmutableSortedMap<PatchLineComment.Key, PatchLineComment> patchLineCommentMap(
-      Iterable<PatchLineComment> in) {
-    return Streams.stream(in)
-        .collect(
-            toImmutableSortedMap(
-                comparing(
-                        (PatchLineComment.Key k) -> k.getParentKey().getParentKey(),
-                        patchSetIdComparator())
-                    .thenComparing(PatchLineComment.Key::getParentKey)
-                    .thenComparing(PatchLineComment.Key::get),
-                PatchLineComment::getKey,
-                c -> c));
-  }
-
-  private static Comparator<PatchSet.Id> patchSetIdComparator() {
-    return comparing((PatchSet.Id id) -> id.getParentKey().get()).thenComparing(id -> id.get());
-  }
-
-  static {
-    // Initialization-time checks that the column set hasn't changed since the
-    // last time this file was updated.
-    checkColumns(Change.Id.class, 1);
-
-    checkColumns(
-        Change.class, 1, 2, 3, 4, 5, 7, 8, 10, 12, 13, 14, 17, 18, 19, 20, 21, 22, 23, 101);
-    checkColumns(ChangeMessage.Key.class, 1, 2);
-    checkColumns(ChangeMessage.class, 1, 2, 3, 4, 5, 6, 7);
-    checkColumns(PatchSet.Id.class, 1, 2);
-    checkColumns(PatchSet.class, 1, 2, 3, 4, 6, 8, 9);
-    checkColumns(PatchSetApproval.Key.class, 1, 2, 3);
-    checkColumns(PatchSetApproval.class, 1, 2, 3, 6, 7, 8);
-    checkColumns(PatchLineComment.Key.class, 1, 2);
-    checkColumns(PatchLineComment.class, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12);
-  }
-
-  private final Change change;
-  private final ImmutableList<ChangeMessage> changeMessages;
-  private final ImmutableSortedMap<PatchSet.Id, PatchSet> patchSets;
-  private final ImmutableMap<PatchSetApproval.Key, PatchSetApproval> patchSetApprovals;
-  private final ImmutableMap<PatchLineComment.Key, PatchLineComment> patchLineComments;
-  private final ReviewerSet reviewers;
-  private final Source source;
-
-  public ChangeBundle(
-      Change change,
-      Iterable<ChangeMessage> changeMessages,
-      Iterable<PatchSet> patchSets,
-      Iterable<PatchSetApproval> patchSetApprovals,
-      Iterable<PatchLineComment> patchLineComments,
-      ReviewerSet reviewers,
-      Source source) {
-    this.change = requireNonNull(change);
-    this.changeMessages = changeMessageList(changeMessages);
-    this.patchSets = ImmutableSortedMap.copyOfSorted(patchSetMap(patchSets));
-    this.patchSetApprovals = ImmutableMap.copyOf(patchSetApprovalMap(patchSetApprovals));
-    this.patchLineComments = ImmutableMap.copyOf(patchLineCommentMap(patchLineComments));
-    this.reviewers = requireNonNull(reviewers);
-    this.source = requireNonNull(source);
-
-    for (ChangeMessage m : this.changeMessages) {
-      checkArgument(m.getKey().getParentKey().equals(change.getId()));
-    }
-    for (PatchSet.Id id : this.patchSets.keySet()) {
-      checkArgument(id.getParentKey().equals(change.getId()));
-    }
-    for (PatchSetApproval.Key k : this.patchSetApprovals.keySet()) {
-      checkArgument(k.getParentKey().getParentKey().equals(change.getId()));
-    }
-    for (PatchLineComment.Key k : this.patchLineComments.keySet()) {
-      checkArgument(k.getParentKey().getParentKey().getParentKey().equals(change.getId()));
-    }
-  }
-
-  public Change getChange() {
-    return change;
-  }
-
-  public ImmutableCollection<ChangeMessage> getChangeMessages() {
-    return changeMessages;
-  }
-
-  public ImmutableCollection<PatchSet> getPatchSets() {
-    return patchSets.values();
-  }
-
-  public ImmutableCollection<PatchSetApproval> getPatchSetApprovals() {
-    return patchSetApprovals.values();
-  }
-
-  public ImmutableCollection<PatchLineComment> getPatchLineComments() {
-    return patchLineComments.values();
-  }
-
-  public ReviewerSet getReviewers() {
-    return reviewers;
-  }
-
-  public Source getSource() {
-    return source;
-  }
-
-  public ImmutableList<String> differencesFrom(ChangeBundle o) {
-    List<String> diffs = new ArrayList<>();
-    diffChanges(diffs, this, o);
-    diffChangeMessages(diffs, this, o);
-    diffPatchSets(diffs, this, o);
-    diffPatchSetApprovals(diffs, this, o);
-    diffReviewers(diffs, this, o);
-    diffPatchLineComments(diffs, this, o);
-    return ImmutableList.copyOf(diffs);
-  }
-
-  private Timestamp getFirstPatchSetTime() {
-    if (patchSets.isEmpty()) {
-      return change.getCreatedOn();
-    }
-    return patchSets.firstEntry().getValue().getCreatedOn();
-  }
-
-  private Timestamp getLatestTimestamp() {
-    Ordering<Timestamp> o = Ordering.natural().nullsFirst();
-    Timestamp ts = null;
-    for (ChangeMessage cm : filterChangeMessages()) {
-      ts = o.max(ts, cm.getWrittenOn());
-    }
-    for (PatchSet ps : getPatchSets()) {
-      ts = o.max(ts, ps.getCreatedOn());
-    }
-    for (PatchSetApproval psa : filterPatchSetApprovals().values()) {
-      ts = o.max(ts, psa.getGranted());
-    }
-    for (PatchLineComment plc : filterPatchLineComments().values()) {
-      // Ignore draft comments, as they do not show up in the change meta graph.
-      if (plc.getStatus() != PatchLineComment.Status.DRAFT) {
-        ts = o.max(ts, plc.getWrittenOn());
-      }
-    }
-    return firstNonNull(ts, change.getLastUpdatedOn());
-  }
-
-  private Map<PatchSetApproval.Key, PatchSetApproval> filterPatchSetApprovals() {
-    return limitToValidPatchSets(patchSetApprovals, PatchSetApproval.Key::getParentKey);
-  }
-
-  private Map<PatchLineComment.Key, PatchLineComment> filterPatchLineComments() {
-    return limitToValidPatchSets(patchLineComments, k -> k.getParentKey().getParentKey());
-  }
-
-  private <K, V> Map<K, V> limitToValidPatchSets(Map<K, V> in, Function<K, PatchSet.Id> func) {
-    return Maps.filterKeys(in, Predicates.compose(validPatchSetPredicate(), func));
-  }
-
-  private Predicate<PatchSet.Id> validPatchSetPredicate() {
-    return patchSets::containsKey;
-  }
-
-  private Collection<ChangeMessage> filterChangeMessages() {
-    final Predicate<PatchSet.Id> validPatchSet = validPatchSetPredicate();
-    return Collections2.filter(
-        changeMessages,
-        m -> {
-          PatchSet.Id psId = m.getPatchSetId();
-          if (psId == null) {
-            return true;
-          }
-          return validPatchSet.apply(psId);
-        });
-  }
-
-  private static void diffChanges(List<String> diffs, ChangeBundle bundleA, ChangeBundle bundleB) {
-    Change a = bundleA.change;
-    Change b = bundleB.change;
-    String desc = a.getId().equals(b.getId()) ? describe(a.getId()) : "Changes";
-
-    boolean excludeCreatedOn = false;
-    boolean excludeCurrentPatchSetId = false;
-    boolean excludeTopic = false;
-    Timestamp aCreated = a.getCreatedOn();
-    Timestamp bCreated = b.getCreatedOn();
-    Timestamp aUpdated = a.getLastUpdatedOn();
-    Timestamp bUpdated = b.getLastUpdatedOn();
-
-    boolean excludeSubject = false;
-    boolean excludeOrigSubj = false;
-    // Subject is not technically a nullable field, but we observed some null
-    // subjects in the wild on googlesource.com, so treat null as empty.
-    String aSubj = Strings.nullToEmpty(a.getSubject());
-    String bSubj = Strings.nullToEmpty(b.getSubject());
-
-    // Allow created timestamp in NoteDb to be any of:
-    //  - The created timestamp of the change.
-    //  - The timestamp of the first remaining patch set.
-    //  - The last updated timestamp, if it is less than the created timestamp.
-    //
-    // Ignore subject if the NoteDb subject starts with the ReviewDb subject.
-    // The NoteDb subject is read directly from the commit, whereas the ReviewDb
-    // subject historically may have been truncated to fit in a SQL varchar
-    // column.
-    //
-    // Ignore original subject on the ReviewDb side when comparing to NoteDb.
-    // This field may have any number of values:
-    //  - It may be null, if the change has had no new patch sets pushed since
-    //    migrating to schema 103.
-    //  - It may match the first patch set subject, if the change was created
-    //    after migrating to schema 103.
-    //  - It may match the subject of the first patch set that was pushed after
-    //    the migration to schema 103, even though that is neither the subject
-    //    of the first patch set nor the subject of the last patch set. (See
-    //    Change#setCurrentPatchSet as of 43b10f86 for this behavior.) This
-    //    subject of an intermediate patch set is not available to the
-    //    ChangeBundle; we would have to get the subject from the repo, which is
-    //    inconvenient at this point.
-    //
-    // Ignore original subject on the ReviewDb side if it equals the subject of
-    // the current patch set.
-    //
-    // For all of the above subject comparisons, first trim any leading spaces
-    // from the NoteDb strings. (We actually do represent the leading spaces
-    // faithfully during conversion, but JGit's FooterLine parser trims them
-    // when reading.)
-    //
-    // Ignore empty topic on the ReviewDb side if it is null on the NoteDb side.
-    //
-    // Ignore currentPatchSetId on NoteDb side if ReviewDb does not point to a
-    // valid patch set.
-    //
-    // Use max timestamp of all ReviewDb entities when comparing with NoteDb.
-    if (bundleA.source == REVIEW_DB && bundleB.source == NOTE_DB) {
-      boolean createdOnMatchesFirstPs =
-          !timestampsDiffer(bundleA, bundleA.getFirstPatchSetTime(), bundleB, bCreated);
-      boolean createdOnMatchesLastUpdatedOn =
-          !timestampsDiffer(bundleA, aUpdated, bundleB, bCreated);
-      boolean createdAfterUpdated = aCreated.compareTo(aUpdated) > 0;
-      excludeCreatedOn =
-          createdOnMatchesFirstPs || (createdAfterUpdated && createdOnMatchesLastUpdatedOn);
-
-      aSubj = cleanReviewDbSubject(aSubj);
-      bSubj = cleanNoteDbSubject(bSubj);
-      excludeCurrentPatchSetId = !bundleA.validPatchSetPredicate().apply(a.currentPatchSetId());
-      excludeSubject = bSubj.startsWith(aSubj) || excludeCurrentPatchSetId;
-      excludeOrigSubj = true;
-      String aTopic = trimOrNull(a.getTopic());
-      excludeTopic =
-          Objects.equals(aTopic, b.getTopic()) || ("".equals(aTopic) && b.getTopic() == null);
-      aUpdated = bundleA.getLatestTimestamp();
-    } else if (bundleA.source == NOTE_DB && bundleB.source == REVIEW_DB) {
-      boolean createdOnMatchesFirstPs =
-          !timestampsDiffer(bundleA, aCreated, bundleB, bundleB.getFirstPatchSetTime());
-      boolean createdOnMatchesLastUpdatedOn =
-          !timestampsDiffer(bundleA, aCreated, bundleB, bUpdated);
-      boolean createdAfterUpdated = bCreated.compareTo(bUpdated) > 0;
-      excludeCreatedOn =
-          createdOnMatchesFirstPs || (createdAfterUpdated && createdOnMatchesLastUpdatedOn);
-
-      aSubj = cleanNoteDbSubject(aSubj);
-      bSubj = cleanReviewDbSubject(bSubj);
-      excludeCurrentPatchSetId = !bundleB.validPatchSetPredicate().apply(b.currentPatchSetId());
-      excludeSubject = aSubj.startsWith(bSubj) || excludeCurrentPatchSetId;
-      excludeOrigSubj = true;
-      String bTopic = trimOrNull(b.getTopic());
-      excludeTopic =
-          Objects.equals(bTopic, a.getTopic()) || (a.getTopic() == null && "".equals(bTopic));
-      bUpdated = bundleB.getLatestTimestamp();
-    }
-
-    String subjectField = "subject";
-    String updatedField = "lastUpdatedOn";
-    List<String> exclude =
-        Lists.newArrayList(subjectField, updatedField, "noteDbState", "rowVersion");
-    if (excludeCreatedOn) {
-      exclude.add("createdOn");
-    }
-    if (excludeCurrentPatchSetId) {
-      exclude.add("currentPatchSetId");
-    }
-    if (excludeOrigSubj) {
-      exclude.add("originalSubject");
-    }
-    if (excludeTopic) {
-      exclude.add("topic");
-    }
-    diffColumnsExcluding(diffs, Change.class, desc, bundleA, a, bundleB, b, exclude);
-
-    // Allow last updated timestamps to either be exactly equal (within slop),
-    // or the NoteDb timestamp to be equal to the latest entity timestamp in the
-    // whole ReviewDb bundle (within slop).
-    if (timestampsDiffer(bundleA, a.getLastUpdatedOn(), bundleB, b.getLastUpdatedOn())) {
-      diffTimestamps(
-          diffs, desc, bundleA, aUpdated, bundleB, bUpdated, "effective last updated time");
-    }
-    if (!excludeSubject) {
-      diffValues(diffs, desc, aSubj, bSubj, subjectField);
-    }
-  }
-
-  private static String trimOrNull(String s) {
-    return s != null ? CharMatcher.whitespace().trimFrom(s) : null;
-  }
-
-  private static String cleanReviewDbSubject(String s) {
-    s = CharMatcher.is(' ').trimLeadingFrom(s);
-
-    // An old JGit bug failed to extract subjects from commits with "\r\n"
-    // terminators: https://bugs.eclipse.org/bugs/show_bug.cgi?id=400707
-    // Changes created with this bug may have "\r\n" converted to "\r " and the
-    // entire commit in the subject. The version of JGit used to read NoteDb
-    // changes parses these subjects correctly, so we need to clean up old
-    // ReviewDb subjects before comparing.
-    int rn = s.indexOf("\r \r ");
-    if (rn >= 0) {
-      s = s.substring(0, rn);
-    }
-    return NoteDbUtil.sanitizeFooter(s);
-  }
-
-  private static String cleanNoteDbSubject(String s) {
-    return NoteDbUtil.sanitizeFooter(s);
-  }
-
-  /**
-   * Set of fields that must always exactly match between ReviewDb and NoteDb.
-   *
-   * <p>Used to limit the worst-case quadratic search when pairing off matching messages below.
-   */
-  @AutoValue
-  abstract static class ChangeMessageCandidate {
-    static ChangeMessageCandidate create(ChangeMessage cm) {
-      return new AutoValue_ChangeBundle_ChangeMessageCandidate(
-          cm.getAuthor(), cm.getMessage(), cm.getTag());
-    }
-
-    @Nullable
-    abstract Account.Id author();
-
-    @Nullable
-    abstract String message();
-
-    @Nullable
-    abstract String tag();
-
-    // Exclude:
-    //  - patch set, which may be null on ReviewDb side but not NoteDb
-    //  - UUID, which is always different between ReviewDb and NoteDb
-    //  - writtenOn, which is fuzzy
-  }
-
-  private static void diffChangeMessages(
-      List<String> diffs, ChangeBundle bundleA, ChangeBundle bundleB) {
-    if (bundleA.source == REVIEW_DB && bundleB.source == REVIEW_DB) {
-      // Both came from ReviewDb: check all fields exactly.
-      Map<ChangeMessage.Key, ChangeMessage> as = changeMessageMap(bundleA.filterChangeMessages());
-      Map<ChangeMessage.Key, ChangeMessage> bs = changeMessageMap(bundleB.filterChangeMessages());
-
-      for (ChangeMessage.Key k : diffKeySets(diffs, as, bs)) {
-        ChangeMessage a = as.get(k);
-        ChangeMessage b = bs.get(k);
-        String desc = describe(k);
-        diffColumns(diffs, ChangeMessage.class, desc, bundleA, a, bundleB, b);
-      }
-      return;
-    }
-    Change.Id id = bundleA.getChange().getId();
-    checkArgument(id.equals(bundleB.getChange().getId()));
-
-    // Try to pair up matching ChangeMessages from each side, and succeed only
-    // if both collections are empty at the end. Quadratic in the worst case,
-    // but easy to reason about.
-    List<ChangeMessage> as = new LinkedList<>(bundleA.filterChangeMessages());
-
-    ListMultimap<ChangeMessageCandidate, ChangeMessage> bs = LinkedListMultimap.create();
-    for (ChangeMessage b : bundleB.filterChangeMessages()) {
-      bs.put(ChangeMessageCandidate.create(b), b);
-    }
-
-    Iterator<ChangeMessage> ait = as.iterator();
-    A:
-    while (ait.hasNext()) {
-      ChangeMessage a = ait.next();
-      Iterator<ChangeMessage> bit = bs.get(ChangeMessageCandidate.create(a)).iterator();
-      while (bit.hasNext()) {
-        ChangeMessage b = bit.next();
-        if (changeMessagesMatch(bundleA, a, bundleB, b)) {
-          ait.remove();
-          bit.remove();
-          continue A;
-        }
-      }
-    }
-
-    if (as.isEmpty() && bs.isEmpty()) {
-      return;
-    }
-    StringBuilder sb =
-        new StringBuilder("ChangeMessages differ for Change.Id ").append(id).append('\n');
-    if (!as.isEmpty()) {
-      sb.append("Only in A:");
-      for (ChangeMessage cm : as) {
-        sb.append("\n  ").append(cm);
-      }
-      if (!bs.isEmpty()) {
-        sb.append('\n');
-      }
-    }
-    if (!bs.isEmpty()) {
-      sb.append("Only in B:");
-      bs.values()
-          .stream()
-          .sorted(CHANGE_MESSAGE_COMPARATOR)
-          .forEach(cm -> sb.append("\n  ").append(cm));
-    }
-    diffs.add(sb.toString());
-  }
-
-  private static boolean changeMessagesMatch(
-      ChangeBundle bundleA, ChangeMessage a, ChangeBundle bundleB, ChangeMessage b) {
-    List<String> tempDiffs = new ArrayList<>();
-    String temp = "temp";
-
-    // ReviewDb allows timestamps before patch set was created, but NoteDb
-    // truncates this to the patch set creation timestamp.
-    Timestamp ta = a.getWrittenOn();
-    Timestamp tb = b.getWrittenOn();
-    PatchSet psa = bundleA.patchSets.get(a.getPatchSetId());
-    PatchSet psb = bundleB.patchSets.get(b.getPatchSetId());
-    boolean excludePatchSet = false;
-    boolean excludeWrittenOn = false;
-    if (bundleA.source == REVIEW_DB && bundleB.source == NOTE_DB) {
-      excludePatchSet = a.getPatchSetId() == null;
-      excludeWrittenOn =
-          psa != null
-              && psb != null
-              && ta.before(psa.getCreatedOn())
-              && tb.equals(psb.getCreatedOn());
-    } else if (bundleA.source == NOTE_DB && bundleB.source == REVIEW_DB) {
-      excludePatchSet = b.getPatchSetId() == null;
-      excludeWrittenOn =
-          psa != null
-              && psb != null
-              && tb.before(psb.getCreatedOn())
-              && ta.equals(psa.getCreatedOn());
-    }
-
-    List<String> exclude = Lists.newArrayList("key");
-    if (excludePatchSet) {
-      exclude.add("patchset");
-    }
-    if (excludeWrittenOn) {
-      exclude.add("writtenOn");
-    }
-
-    diffColumnsExcluding(tempDiffs, ChangeMessage.class, temp, bundleA, a, bundleB, b, exclude);
-    return tempDiffs.isEmpty();
-  }
-
-  private static void diffPatchSets(
-      List<String> diffs, ChangeBundle bundleA, ChangeBundle bundleB) {
-    Map<PatchSet.Id, PatchSet> as = bundleA.patchSets;
-    Map<PatchSet.Id, PatchSet> bs = bundleB.patchSets;
-    Optional<PatchSet.Id> minA = as.keySet().stream().min(intKeyOrdering());
-    Optional<PatchSet.Id> minB = bs.keySet().stream().min(intKeyOrdering());
-    Set<PatchSet.Id> ids = diffKeySets(diffs, as, bs);
-
-    // Old versions of Gerrit had a bug that created patch sets during
-    // rebase or submission with a createdOn timestamp earlier than the patch
-    // set it was replacing. (In the cases I examined, it was equal to createdOn
-    // for the change, but we're not counting on this exact behavior.)
-    //
-    // ChangeRebuilder ensures patch set events come out in order, but it's hard
-    // to predict what the resulting timestamps would look like. So, completely
-    // ignore the createdOn timestamps if both:
-    //   * ReviewDb timestamps are non-monotonic.
-    //   * NoteDb timestamps are monotonic.
-    //
-    // Allow the timestamp of the first patch set to match the creation time of
-    // the change.
-    boolean excludeAllCreatedOn = false;
-    if (bundleA.source == REVIEW_DB && bundleB.source == NOTE_DB) {
-      excludeAllCreatedOn = !createdOnIsMonotonic(as, ids) && createdOnIsMonotonic(bs, ids);
-    } else if (bundleA.source == NOTE_DB && bundleB.source == REVIEW_DB) {
-      excludeAllCreatedOn = createdOnIsMonotonic(as, ids) && !createdOnIsMonotonic(bs, ids);
-    }
-
-    for (PatchSet.Id id : ids) {
-      PatchSet a = as.get(id);
-      PatchSet b = bs.get(id);
-      String desc = describe(id);
-      String pushCertField = "pushCertificate";
-
-      boolean excludeCreatedOn = excludeAllCreatedOn;
-      boolean excludeDesc = false;
-      if (bundleA.source == REVIEW_DB && bundleB.source == NOTE_DB) {
-        excludeDesc = Objects.equals(trimOrNull(a.getDescription()), b.getDescription());
-        excludeCreatedOn |=
-            Optional.of(id).equals(minB) && b.getCreatedOn().equals(bundleB.change.getCreatedOn());
-      } else if (bundleA.source == NOTE_DB && bundleB.source == REVIEW_DB) {
-        excludeDesc = Objects.equals(a.getDescription(), trimOrNull(b.getDescription()));
-        excludeCreatedOn |=
-            Optional.of(id).equals(minA) && a.getCreatedOn().equals(bundleA.change.getCreatedOn());
-      }
-
-      List<String> exclude = Lists.newArrayList(pushCertField);
-      if (excludeCreatedOn) {
-        exclude.add("createdOn");
-      }
-      if (excludeDesc) {
-        exclude.add("description");
-      }
-
-      diffColumnsExcluding(diffs, PatchSet.class, desc, bundleA, a, bundleB, b, exclude);
-      diffValues(diffs, desc, trimPushCert(a), trimPushCert(b), pushCertField);
-    }
-  }
-
-  private static String trimPushCert(PatchSet ps) {
-    if (ps.getPushCertificate() == null) {
-      return null;
-    }
-    return CharMatcher.is('\n').trimTrailingFrom(ps.getPushCertificate());
-  }
-
-  private static boolean createdOnIsMonotonic(
-      Map<?, PatchSet> patchSets, Set<PatchSet.Id> limitToIds) {
-    List<PatchSet> orderedById =
-        patchSets
-            .values()
-            .stream()
-            .filter(ps -> limitToIds.contains(ps.getId()))
-            .sorted(ChangeUtil.PS_ID_ORDER)
-            .collect(toList());
-    return Ordering.natural().onResultOf(PatchSet::getCreatedOn).isOrdered(orderedById);
-  }
-
-  private static void diffPatchSetApprovals(
-      List<String> diffs, ChangeBundle bundleA, ChangeBundle bundleB) {
-    Map<PatchSetApproval.Key, PatchSetApproval> as = bundleA.filterPatchSetApprovals();
-    Map<PatchSetApproval.Key, PatchSetApproval> bs = bundleB.filterPatchSetApprovals();
-    for (PatchSetApproval.Key k : diffKeySets(diffs, as, bs)) {
-      PatchSetApproval a = as.get(k);
-      PatchSetApproval b = bs.get(k);
-      String desc = describe(k);
-
-      // ReviewDb allows timestamps before patch set was created, but NoteDb
-      // truncates this to the patch set creation timestamp.
-      //
-      // ChangeRebuilder ensures all post-submit approvals happen after the
-      // actual submit, so the timestamps may not line up. This shouldn't really
-      // happen, because postSubmit shouldn't be set in ReviewDb until after the
-      // change is submitted in ReviewDb, but you never know.
-      //
-      // Due to a quirk of PostReview, post-submit 0 votes might not have the
-      // postSubmit bit set in ReviewDb. As these are only used for tombstone
-      // purposes, ignore the postSubmit bit in NoteDb in this case.
-      Timestamp ta = a.getGranted();
-      Timestamp tb = b.getGranted();
-      PatchSet psa = requireNonNull(bundleA.patchSets.get(a.getPatchSetId()));
-      PatchSet psb = requireNonNull(bundleB.patchSets.get(b.getPatchSetId()));
-      boolean excludeGranted = false;
-      boolean excludePostSubmit = false;
-      List<String> exclude = new ArrayList<>(1);
-      if (bundleA.source == REVIEW_DB && bundleB.source == NOTE_DB) {
-        excludeGranted =
-            (ta.before(psa.getCreatedOn()) && tb.equals(psb.getCreatedOn()))
-                || ta.compareTo(tb) < 0;
-        excludePostSubmit = a.getValue() == 0 && b.isPostSubmit();
-      } else if (bundleA.source == NOTE_DB && bundleB.source == REVIEW_DB) {
-        excludeGranted =
-            (tb.before(psb.getCreatedOn()) && ta.equals(psa.getCreatedOn()))
-                || (tb.compareTo(ta) < 0);
-        excludePostSubmit = b.getValue() == 0 && a.isPostSubmit();
-      }
-
-      // Legacy submit approvals may or may not have tags associated with them,
-      // depending on whether ChangeRebuilder happened to group them with the
-      // status change.
-      boolean excludeTag =
-          bundleA.source != bundleB.source && a.isLegacySubmit() && b.isLegacySubmit();
-
-      if (excludeGranted) {
-        exclude.add("granted");
-      }
-      if (excludePostSubmit) {
-        exclude.add("postSubmit");
-      }
-      if (excludeTag) {
-        exclude.add("tag");
-      }
-
-      diffColumnsExcluding(diffs, PatchSetApproval.class, desc, bundleA, a, bundleB, b, exclude);
-    }
-  }
-
-  private static void diffReviewers(
-      List<String> diffs, ChangeBundle bundleA, ChangeBundle bundleB) {
-    diffSets(diffs, bundleA.reviewers.all(), bundleB.reviewers.all(), "reviewer");
-  }
-
-  private static void diffPatchLineComments(
-      List<String> diffs, ChangeBundle bundleA, ChangeBundle bundleB) {
-    Map<PatchLineComment.Key, PatchLineComment> as = bundleA.filterPatchLineComments();
-    Map<PatchLineComment.Key, PatchLineComment> bs = bundleB.filterPatchLineComments();
-    for (PatchLineComment.Key k : diffKeySets(diffs, as, bs)) {
-      PatchLineComment a = as.get(k);
-      PatchLineComment b = bs.get(k);
-      String desc = describe(k);
-      diffColumns(diffs, PatchLineComment.class, desc, bundleA, a, bundleB, b);
-    }
-  }
-
-  private static <T> Set<T> diffKeySets(List<String> diffs, Map<T, ?> a, Map<T, ?> b) {
-    if (a.isEmpty() && b.isEmpty()) {
-      return a.keySet();
-    }
-    String clazz = keyClass((!a.isEmpty() ? a.keySet() : b.keySet()).iterator().next());
-    return diffSets(diffs, a.keySet(), b.keySet(), clazz);
-  }
-
-  private static <T> Set<T> diffSets(List<String> diffs, Set<T> as, Set<T> bs, String desc) {
-    if (as.isEmpty() && bs.isEmpty()) {
-      return as;
-    }
-
-    Set<T> aNotB = Sets.difference(as, bs);
-    Set<T> bNotA = Sets.difference(bs, as);
-    if (aNotB.isEmpty() && bNotA.isEmpty()) {
-      return as;
-    }
-    diffs.add(desc + " sets differ: " + aNotB + " only in A; " + bNotA + " only in B");
-    return Sets.intersection(as, bs);
-  }
-
-  private static <T> void diffColumns(
-      List<String> diffs,
-      Class<T> clazz,
-      String desc,
-      ChangeBundle bundleA,
-      T a,
-      ChangeBundle bundleB,
-      T b) {
-    diffColumnsExcluding(diffs, clazz, desc, bundleA, a, bundleB, b);
-  }
-
-  private static <T> void diffColumnsExcluding(
-      List<String> diffs,
-      Class<T> clazz,
-      String desc,
-      ChangeBundle bundleA,
-      T a,
-      ChangeBundle bundleB,
-      T b,
-      String... exclude) {
-    diffColumnsExcluding(diffs, clazz, desc, bundleA, a, bundleB, b, Arrays.asList(exclude));
-  }
-
-  private static <T> void diffColumnsExcluding(
-      List<String> diffs,
-      Class<T> clazz,
-      String desc,
-      ChangeBundle bundleA,
-      T a,
-      ChangeBundle bundleB,
-      T b,
-      Iterable<String> exclude) {
-    Set<String> toExclude = Sets.newLinkedHashSet(exclude);
-    for (Field f : clazz.getDeclaredFields()) {
-      Column col = f.getAnnotation(Column.class);
-      if (col == null) {
-        continue;
-      } else if (toExclude.remove(f.getName())) {
-        continue;
-      }
-      f.setAccessible(true);
-      try {
-        if (Timestamp.class.isAssignableFrom(f.getType())) {
-          diffTimestamps(diffs, desc, bundleA, a, bundleB, b, f.getName());
-        } else {
-          diffValues(diffs, desc, f.get(a), f.get(b), f.getName());
-        }
-      } catch (IllegalAccessException e) {
-        throw new IllegalArgumentException(e);
-      }
-    }
-    checkArgument(
-        toExclude.isEmpty(),
-        "requested columns to exclude not present in %s: %s",
-        clazz.getSimpleName(),
-        toExclude);
-  }
-
-  private static void diffTimestamps(
-      List<String> diffs,
-      String desc,
-      ChangeBundle bundleA,
-      Object a,
-      ChangeBundle bundleB,
-      Object b,
-      String field) {
-    checkArgument(a.getClass() == b.getClass());
-    Class<?> clazz = a.getClass();
-
-    Timestamp ta;
-    Timestamp tb;
-    try {
-      Field f = clazz.getDeclaredField(field);
-      checkArgument(f.getAnnotation(Column.class) != null);
-      f.setAccessible(true);
-      ta = (Timestamp) f.get(a);
-      tb = (Timestamp) f.get(b);
-    } catch (IllegalAccessException | NoSuchFieldException | SecurityException e) {
-      throw new IllegalArgumentException(e);
-    }
-    diffTimestamps(diffs, desc, bundleA, ta, bundleB, tb, field);
-  }
-
-  private static void diffTimestamps(
-      List<String> diffs,
-      String desc,
-      ChangeBundle bundleA,
-      Timestamp ta,
-      ChangeBundle bundleB,
-      Timestamp tb,
-      String fieldDesc) {
-    if (bundleA.source == bundleB.source || ta == null || tb == null) {
-      diffValues(diffs, desc, ta, tb, fieldDesc);
-    } else if (bundleA.source == NOTE_DB) {
-      diffTimestamps(diffs, desc, bundleA.getChange(), ta, bundleB.getChange(), tb, fieldDesc);
-    } else {
-      diffTimestamps(diffs, desc, bundleB.getChange(), tb, bundleA.getChange(), ta, fieldDesc);
-    }
-  }
-
-  private static boolean timestampsDiffer(
-      ChangeBundle bundleA, Timestamp ta, ChangeBundle bundleB, Timestamp tb) {
-    List<String> tempDiffs = new ArrayList<>(1);
-    diffTimestamps(tempDiffs, "temp", bundleA, ta, bundleB, tb, "temp");
-    return !tempDiffs.isEmpty();
-  }
-
-  private static void diffTimestamps(
-      List<String> diffs,
-      String desc,
-      Change changeFromNoteDb,
-      Timestamp tsFromNoteDb,
-      Change changeFromReviewDb,
-      Timestamp tsFromReviewDb,
-      String field) {
-    // Because ChangeRebuilder may batch events together that are several
-    // seconds apart, the timestamp in NoteDb may actually be several seconds
-    // *earlier* than the timestamp in ReviewDb that it was converted from.
-    checkArgument(
-        tsFromNoteDb.equals(truncateToSecond(tsFromNoteDb)),
-        "%s from NoteDb has non-rounded %s timestamp: %s",
-        desc,
-        field,
-        tsFromNoteDb);
-
-    if (tsFromReviewDb.before(changeFromReviewDb.getCreatedOn())
-        && tsFromNoteDb.equals(changeFromNoteDb.getCreatedOn())) {
-      // Timestamp predates change creation. These are truncated to change
-      // creation time during NoteDb conversion, so allow this if the timestamp
-      // in NoteDb matches the createdOn time in NoteDb.
-      return;
-    }
-
-    long delta = tsFromReviewDb.getTime() - tsFromNoteDb.getTime();
-    long max = ChangeRebuilderImpl.MAX_WINDOW_MS;
-    if (delta < 0 || delta > max) {
-      diffs.add(
-          field
-              + " differs for "
-              + desc
-              + " in NoteDb vs. ReviewDb:"
-              + " {"
-              + tsFromNoteDb
-              + "} != {"
-              + tsFromReviewDb
-              + "}");
-    }
-  }
-
-  private static void diffValues(
-      List<String> diffs, String desc, Object va, Object vb, String name) {
-    if (!Objects.equals(va, vb)) {
-      diffs.add(name + " differs for " + desc + ": {" + va + "} != {" + vb + "}");
-    }
-  }
-
-  private static String describe(Object key) {
-    return keyClass(key) + " " + key;
-  }
-
-  private static String keyClass(Object obj) {
-    Class<?> clazz = obj.getClass();
-    String name = clazz.getSimpleName();
-    checkArgument(name.endsWith("Key") || name.endsWith("Id"), "not an Id/Key class: %s", name);
-    if (name.equals("Key") || name.equals("Id")) {
-      return clazz.getEnclosingClass().getSimpleName() + "." + name;
-    } else if (name.startsWith("AutoValue_")) {
-      return name.substring(name.lastIndexOf('_') + 1);
-    }
-    return name;
-  }
-
-  @Override
-  public String toString() {
-    return getClass().getSimpleName()
-        + "{id="
-        + change.getId()
-        + ", ChangeMessage["
-        + changeMessages.size()
-        + "]"
-        + ", PatchSet["
-        + patchSets.size()
-        + "]"
-        + ", PatchSetApproval["
-        + patchSetApprovals.size()
-        + "]"
-        + ", PatchLineComment["
-        + patchLineComments.size()
-        + "]"
-        + "}";
-  }
-}
diff --git a/java/com/google/gerrit/server/notedb/ChangeBundleReader.java b/java/com/google/gerrit/server/notedb/ChangeBundleReader.java
deleted file mode 100644
index 3207c3b..0000000
--- a/java/com/google/gerrit/server/notedb/ChangeBundleReader.java
+++ /dev/null
@@ -1,25 +0,0 @@
-// Copyright (C) 2016 The Android Open Source Project
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-// http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-
-package com.google.gerrit.server.notedb;
-
-import com.google.gerrit.common.Nullable;
-import com.google.gerrit.reviewdb.client.Change;
-import com.google.gerrit.reviewdb.server.ReviewDb;
-import com.google.gwtorm.server.OrmException;
-
-public interface ChangeBundleReader {
-  @Nullable
-  ChangeBundle fromReviewDb(ReviewDb db, Change.Id id) throws OrmException;
-}
diff --git a/java/com/google/gerrit/server/notedb/GwtormChangeBundleReader.java b/java/com/google/gerrit/server/notedb/GwtormChangeBundleReader.java
deleted file mode 100644
index 347ba48..0000000
--- a/java/com/google/gerrit/server/notedb/GwtormChangeBundleReader.java
+++ /dev/null
@@ -1,52 +0,0 @@
-// Copyright (C) 2016 The Android Open Source Project
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-// http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-
-package com.google.gerrit.server.notedb;
-
-import com.google.gerrit.common.Nullable;
-import com.google.gerrit.reviewdb.client.Change;
-import com.google.gerrit.reviewdb.client.PatchSetApproval;
-import com.google.gerrit.reviewdb.server.ReviewDb;
-import com.google.gerrit.server.ReviewerSet;
-import com.google.gerrit.server.notedb.ChangeBundle.Source;
-import com.google.gwtorm.server.OrmException;
-import com.google.inject.Inject;
-import com.google.inject.Singleton;
-import java.util.List;
-
-@Singleton
-public class GwtormChangeBundleReader implements ChangeBundleReader {
-  @Inject
-  GwtormChangeBundleReader() {}
-
-  @Override
-  @Nullable
-  public ChangeBundle fromReviewDb(ReviewDb db, Change.Id id) throws OrmException {
-    Change reviewDbChange = db.changes().get(id);
-    if (reviewDbChange == null) {
-      return null;
-    }
-
-    // TODO(dborowitz): Figure out how to do this more consistently, e.g. hand-written inner joins.
-    List<PatchSetApproval> approvals = db.patchSetApprovals().byChange(id).toList();
-    return new ChangeBundle(
-        reviewDbChange,
-        db.changeMessages().byChange(id),
-        db.patchSets().byChange(id),
-        approvals,
-        db.patchComments().byChange(id),
-        ReviewerSet.fromApprovals(approvals),
-        Source.REVIEW_DB);
-  }
-}
diff --git a/java/com/google/gerrit/server/notedb/NoteDbModule.java b/java/com/google/gerrit/server/notedb/NoteDbModule.java
index c17fafd..cf12d84 100644
--- a/java/com/google/gerrit/server/notedb/NoteDbModule.java
+++ b/java/com/google/gerrit/server/notedb/NoteDbModule.java
@@ -17,31 +17,21 @@
 import com.google.common.cache.Cache;
 import com.google.common.cache.CacheBuilder;
 import com.google.gerrit.extensions.config.FactoryModule;
-import com.google.gerrit.reviewdb.client.Change;
-import com.google.gerrit.reviewdb.client.Change.Id;
-import com.google.gerrit.reviewdb.client.Project;
-import com.google.gerrit.reviewdb.server.ReviewDb;
-import com.google.gerrit.server.notedb.NoteDbUpdateManager.Result;
-import com.google.gerrit.server.notedb.rebuild.ChangeRebuilder;
-import com.google.gerrit.server.notedb.rebuild.ChangeRebuilderImpl;
 import com.google.inject.TypeLiteral;
 import com.google.inject.name.Names;
-import org.eclipse.jgit.lib.Config;
 
 public class NoteDbModule extends FactoryModule {
-  private final Config cfg;
   private final boolean useTestBindings;
 
-  static NoteDbModule forTest(Config cfg) {
-    return new NoteDbModule(cfg, true);
+  static NoteDbModule forTest() {
+    return new NoteDbModule(true);
   }
 
-  public NoteDbModule(Config cfg) {
-    this(cfg, false);
+  public NoteDbModule() {
+    this(false);
   }
 
-  private NoteDbModule(Config cfg, boolean useTestBindings) {
-    this.cfg = cfg;
+  private NoteDbModule(boolean useTestBindings) {
     this.useTestBindings = useTestBindings;
   }
 
@@ -57,53 +47,7 @@
 
     if (!useTestBindings) {
       install(ChangeNotesCache.module());
-      if (cfg.getBoolean("noteDb", null, "testRebuilderWrapper", false)) {
-        // Yes, another variety of test bindings with a different way of
-        // configuring it.
-        bind(ChangeRebuilder.class).to(TestChangeRebuilderWrapper.class);
-      } else {
-        bind(ChangeRebuilder.class).to(ChangeRebuilderImpl.class);
-      }
     } else {
-      bind(ChangeRebuilder.class)
-          .toInstance(
-              new ChangeRebuilder(null) {
-                @Override
-                public Result rebuild(ReviewDb db, Change.Id changeId) {
-                  return null;
-                }
-
-                @Override
-                public Result rebuildEvenIfReadOnly(ReviewDb db, Id changeId) {
-                  return null;
-                }
-
-                @Override
-                public Result rebuild(NoteDbUpdateManager manager, ChangeBundle bundle) {
-                  return null;
-                }
-
-                @Override
-                public NoteDbUpdateManager stage(ReviewDb db, Change.Id changeId) {
-                  return null;
-                }
-
-                @Override
-                public Result execute(
-                    ReviewDb db, Change.Id changeId, NoteDbUpdateManager manager) {
-                  return null;
-                }
-
-                @Override
-                public void buildUpdates(NoteDbUpdateManager manager, ChangeBundle bundle) {
-                  // Do nothing.
-                }
-
-                @Override
-                public void rebuildReviewDb(ReviewDb db, Project.NameKey project, Id changeId) {
-                  // Do nothing.
-                }
-              });
       bind(new TypeLiteral<Cache<ChangeNotesCache.Key, ChangeNotesState>>() {})
           .annotatedWith(Names.named(ChangeNotesCache.CACHE_NAME))
           .toInstance(CacheBuilder.newBuilder().<ChangeNotesCache.Key, ChangeNotesState>build());
diff --git a/java/com/google/gerrit/server/notedb/TestChangeRebuilderWrapper.java b/java/com/google/gerrit/server/notedb/TestChangeRebuilderWrapper.java
deleted file mode 100644
index 11fef24..0000000
--- a/java/com/google/gerrit/server/notedb/TestChangeRebuilderWrapper.java
+++ /dev/null
@@ -1,125 +0,0 @@
-// Copyright (C) 2016 The Android Open Source Project
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-// http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-
-package com.google.gerrit.server.notedb;
-
-import com.google.common.annotations.VisibleForTesting;
-import com.google.gerrit.reviewdb.client.Change;
-import com.google.gerrit.reviewdb.client.Change.Id;
-import com.google.gerrit.reviewdb.client.Project;
-import com.google.gerrit.reviewdb.server.ReviewDb;
-import com.google.gerrit.server.notedb.NoteDbUpdateManager.Result;
-import com.google.gerrit.server.notedb.rebuild.ChangeRebuilder;
-import com.google.gerrit.server.notedb.rebuild.ChangeRebuilderImpl;
-import com.google.gwtorm.server.OrmException;
-import com.google.gwtorm.server.SchemaFactory;
-import com.google.inject.Inject;
-import com.google.inject.Singleton;
-import java.io.IOException;
-import java.util.concurrent.atomic.AtomicBoolean;
-
-@VisibleForTesting
-@Singleton
-public class TestChangeRebuilderWrapper extends ChangeRebuilder {
-  private final ChangeRebuilderImpl delegate;
-  private final AtomicBoolean failNextUpdate;
-  private final AtomicBoolean stealNextUpdate;
-
-  @Inject
-  TestChangeRebuilderWrapper(SchemaFactory<ReviewDb> schemaFactory, ChangeRebuilderImpl rebuilder) {
-    super(schemaFactory);
-    this.delegate = rebuilder;
-    this.failNextUpdate = new AtomicBoolean();
-    this.stealNextUpdate = new AtomicBoolean();
-  }
-
-  public void failNextUpdate() {
-    failNextUpdate.set(true);
-  }
-
-  public void stealNextUpdate() {
-    stealNextUpdate.set(true);
-  }
-
-  @Override
-  public Result rebuild(ReviewDb db, Change.Id changeId) throws IOException, OrmException {
-    return rebuild(db, changeId, true);
-  }
-
-  @Override
-  public Result rebuildEvenIfReadOnly(ReviewDb db, Change.Id changeId)
-      throws IOException, OrmException {
-    return rebuild(db, changeId, false);
-  }
-
-  private Result rebuild(ReviewDb db, Change.Id changeId, boolean checkReadOnly)
-      throws IOException, OrmException {
-    if (failNextUpdate.getAndSet(false)) {
-      throw new IOException("Update failed");
-    }
-    Result result =
-        checkReadOnly
-            ? delegate.rebuild(db, changeId)
-            : delegate.rebuildEvenIfReadOnly(db, changeId);
-    if (stealNextUpdate.getAndSet(false)) {
-      throw new IOException("Update stolen");
-    }
-    return result;
-  }
-
-  @Override
-  public Result rebuild(NoteDbUpdateManager manager, ChangeBundle bundle)
-      throws IOException, OrmException {
-    // stealNextUpdate doesn't really apply in this case because the IOException
-    // would normally come from the manager.execute() method, which isn't called
-    // here.
-    return delegate.rebuild(manager, bundle);
-  }
-
-  @Override
-  public NoteDbUpdateManager stage(ReviewDb db, Change.Id changeId)
-      throws IOException, OrmException {
-    // Don't inspect stealNextUpdate; that happens in execute() below.
-    return delegate.stage(db, changeId);
-  }
-
-  @Override
-  public Result execute(ReviewDb db, Change.Id changeId, NoteDbUpdateManager manager)
-      throws OrmException, IOException {
-    if (failNextUpdate.getAndSet(false)) {
-      throw new IOException("Update failed");
-    }
-    Result result = delegate.execute(db, changeId, manager);
-    if (stealNextUpdate.getAndSet(false)) {
-      throw new IOException("Update stolen");
-    }
-    return result;
-  }
-
-  @Override
-  public void buildUpdates(NoteDbUpdateManager manager, ChangeBundle bundle)
-      throws IOException, OrmException {
-    // Don't check for manual failure; that happens in execute().
-    delegate.buildUpdates(manager, bundle);
-  }
-
-  @Override
-  public void rebuildReviewDb(ReviewDb db, Project.NameKey project, Id changeId)
-      throws OrmException {
-    if (failNextUpdate.getAndSet(false)) {
-      throw new OrmException("Update failed");
-    }
-    delegate.rebuildReviewDb(db, project, changeId);
-  }
-}
diff --git a/java/com/google/gerrit/server/notedb/rebuild/AbortUpdateException.java b/java/com/google/gerrit/server/notedb/rebuild/AbortUpdateException.java
deleted file mode 100644
index 0e6d3e9..0000000
--- a/java/com/google/gerrit/server/notedb/rebuild/AbortUpdateException.java
+++ /dev/null
@@ -1,25 +0,0 @@
-// Copyright (C) 2016 The Android Open Source Project
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-// http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-
-package com.google.gerrit.server.notedb.rebuild;
-
-import com.google.gwtorm.server.OrmRuntimeException;
-
-class AbortUpdateException extends OrmRuntimeException {
-  private static final long serialVersionUID = 1L;
-
-  AbortUpdateException() {
-    super("aborted");
-  }
-}
diff --git a/java/com/google/gerrit/server/notedb/rebuild/ApprovalEvent.java b/java/com/google/gerrit/server/notedb/rebuild/ApprovalEvent.java
deleted file mode 100644
index 9ecf476..0000000
--- a/java/com/google/gerrit/server/notedb/rebuild/ApprovalEvent.java
+++ /dev/null
@@ -1,64 +0,0 @@
-// Copyright (C) 2016 The Android Open Source Project
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-// http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-
-package com.google.gerrit.server.notedb.rebuild;
-
-import com.google.common.base.MoreObjects.ToStringHelper;
-import com.google.gerrit.reviewdb.client.PatchSetApproval;
-import com.google.gerrit.server.notedb.ChangeUpdate;
-import java.sql.Timestamp;
-
-class ApprovalEvent extends Event {
-  private PatchSetApproval psa;
-
-  ApprovalEvent(PatchSetApproval psa, Timestamp changeCreatedOn) {
-    super(
-        psa.getPatchSetId(),
-        psa.getAccountId(),
-        psa.getRealAccountId(),
-        psa.getGranted(),
-        changeCreatedOn,
-        psa.getTag());
-    this.psa = psa;
-  }
-
-  @Override
-  boolean uniquePerUpdate() {
-    return false;
-  }
-
-  @Override
-  protected boolean canHaveTag() {
-    // Legacy SUBM approvals don't have a tag field set, but the corresponding
-    // ChangeMessage for merging the change does. We need to let these be in the
-    // same meta commit so the SUBM approval isn't counted as post-submit.
-    return !psa.isLegacySubmit();
-  }
-
-  @Override
-  void apply(ChangeUpdate update) {
-    checkUpdate(update);
-    update.putApproval(psa.getLabel(), psa.getValue());
-  }
-
-  @Override
-  protected boolean isPostSubmitApproval() {
-    return psa.isPostSubmit();
-  }
-
-  @Override
-  protected void addToString(ToStringHelper helper) {
-    helper.add("approval", psa);
-  }
-}
diff --git a/java/com/google/gerrit/server/notedb/rebuild/ChangeMessageEvent.java b/java/com/google/gerrit/server/notedb/rebuild/ChangeMessageEvent.java
deleted file mode 100644
index 53c9dc4..0000000
--- a/java/com/google/gerrit/server/notedb/rebuild/ChangeMessageEvent.java
+++ /dev/null
@@ -1,185 +0,0 @@
-// Copyright (C) 2016 The Android Open Source Project
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-// http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-
-package com.google.gerrit.server.notedb.rebuild;
-
-import com.google.common.base.MoreObjects.ToStringHelper;
-import com.google.common.base.Strings;
-import com.google.common.collect.ImmutableMap;
-import com.google.gerrit.reviewdb.client.Change;
-import com.google.gerrit.reviewdb.client.ChangeMessage;
-import com.google.gerrit.server.ChangeMessagesUtil;
-import com.google.gerrit.server.notedb.ChangeUpdate;
-import com.google.gwtorm.server.OrmException;
-import java.sql.Timestamp;
-import java.util.Map;
-import java.util.Optional;
-import java.util.regex.Matcher;
-import java.util.regex.Pattern;
-
-class ChangeMessageEvent extends Event {
-  private static final ImmutableMap<Change.Status, Pattern> STATUS_PATTERNS =
-      ImmutableMap.of(
-          Change.Status.ABANDONED, Pattern.compile("^Abandoned(\n.*)*$"),
-          Change.Status.MERGED,
-              Pattern.compile(
-                  "^Change has been successfully (merged|cherry-picked|rebased|pushed).*$"),
-          Change.Status.NEW, Pattern.compile("^Restored(\n.*)*$"));
-
-  private static final Pattern PRIVATE_SET_REGEXP = Pattern.compile("^Set private$");
-  private static final Pattern PRIVATE_UNSET_REGEXP = Pattern.compile("^Unset private$");
-
-  private static final Pattern TOPIC_SET_REGEXP = Pattern.compile("^Topic set to (.+)$");
-  private static final Pattern TOPIC_CHANGED_REGEXP =
-      Pattern.compile("^Topic changed from (.+) to (.+)$");
-  private static final Pattern TOPIC_REMOVED_REGEXP = Pattern.compile("^Topic (.+) removed$");
-
-  private static final Pattern WIP_SET_REGEXP = Pattern.compile("^Set Work In Progress$");
-  private static final Pattern WIP_UNSET_REGEXP = Pattern.compile("^Set Ready For Review$");
-
-  private final Change change;
-  private final Change noteDbChange;
-  private final Optional<Change.Status> status;
-  private final ChangeMessage message;
-
-  ChangeMessageEvent(
-      Change change, Change noteDbChange, ChangeMessage message, Timestamp changeCreatedOn) {
-    super(
-        message.getPatchSetId(),
-        message.getAuthor(),
-        message.getRealAuthor(),
-        message.getWrittenOn(),
-        changeCreatedOn,
-        message.getTag());
-    this.change = change;
-    this.noteDbChange = noteDbChange;
-    this.message = message;
-    this.status = parseStatus(message);
-  }
-
-  @Override
-  boolean uniquePerUpdate() {
-    return true;
-  }
-
-  @Override
-  protected boolean isSubmit() {
-    return status.isPresent() && status.get() == Change.Status.MERGED;
-  }
-
-  @Override
-  protected boolean canHaveTag() {
-    return true;
-  }
-
-  @SuppressWarnings("deprecation")
-  @Override
-  void apply(ChangeUpdate update) throws OrmException {
-    checkUpdate(update);
-    update.setChangeMessage(message.getMessage());
-    setPrivate(update);
-    setTopic(update);
-    setWorkInProgress(update);
-
-    if (status.isPresent()) {
-      Change.Status s = status.get();
-      update.fixStatus(s);
-      noteDbChange.setStatus(s);
-      if (s == Change.Status.MERGED) {
-        update.setSubmissionId(change.getSubmissionId());
-        noteDbChange.setSubmissionId(change.getSubmissionId());
-      }
-    }
-  }
-
-  private static Optional<Change.Status> parseStatus(ChangeMessage message) {
-    String msg = message.getMessage();
-    if (msg == null) {
-      return Optional.empty();
-    }
-    for (Map.Entry<Change.Status, Pattern> e : STATUS_PATTERNS.entrySet()) {
-      if (e.getValue().matcher(msg).matches()) {
-        return Optional.of(e.getKey());
-      }
-    }
-    return Optional.empty();
-  }
-
-  private void setPrivate(ChangeUpdate update) {
-    String msg = message.getMessage();
-    if (msg == null) {
-      return;
-    }
-    Matcher m = PRIVATE_SET_REGEXP.matcher(msg);
-    if (m.matches()) {
-      update.setPrivate(true);
-      noteDbChange.setPrivate(true);
-      return;
-    }
-
-    m = PRIVATE_UNSET_REGEXP.matcher(msg);
-    if (m.matches()) {
-      update.setPrivate(false);
-      noteDbChange.setPrivate(false);
-    }
-  }
-
-  private void setTopic(ChangeUpdate update) {
-    String msg = message.getMessage();
-    if (msg == null) {
-      return;
-    }
-    Matcher m = TOPIC_SET_REGEXP.matcher(msg);
-    if (m.matches()) {
-      String topic = m.group(1);
-      update.setTopic(topic);
-      noteDbChange.setTopic(topic);
-      return;
-    }
-
-    m = TOPIC_CHANGED_REGEXP.matcher(msg);
-    if (m.matches()) {
-      String topic = m.group(2);
-      update.setTopic(topic);
-      noteDbChange.setTopic(topic);
-      return;
-    }
-
-    if (TOPIC_REMOVED_REGEXP.matcher(msg).matches()) {
-      update.setTopic(null);
-      noteDbChange.setTopic(null);
-    }
-  }
-
-  private void setWorkInProgress(ChangeUpdate update) {
-    String msg = Strings.nullToEmpty(message.getMessage());
-    String tag = message.getTag();
-    if (ChangeMessagesUtil.TAG_SET_WIP.equals(tag)
-        || ChangeMessagesUtil.TAG_UPLOADED_WIP_PATCH_SET.equals(tag)
-        || WIP_SET_REGEXP.matcher(msg).matches()) {
-      update.setWorkInProgress(true);
-      noteDbChange.setWorkInProgress(true);
-    } else if (ChangeMessagesUtil.TAG_SET_READY.equals(tag)
-        || ChangeMessagesUtil.TAG_UPLOADED_PATCH_SET.equals(tag)
-        || WIP_UNSET_REGEXP.matcher(msg).matches()) {
-      update.setWorkInProgress(false);
-      noteDbChange.setWorkInProgress(false);
-    }
-  }
-
-  @Override
-  protected void addToString(ToStringHelper helper) {
-    helper.add("message", message);
-  }
-}
diff --git a/java/com/google/gerrit/server/notedb/rebuild/ChangeRebuilder.java b/java/com/google/gerrit/server/notedb/rebuild/ChangeRebuilder.java
deleted file mode 100644
index 8ce9987..0000000
--- a/java/com/google/gerrit/server/notedb/rebuild/ChangeRebuilder.java
+++ /dev/null
@@ -1,81 +0,0 @@
-// Copyright (C) 2016 The Android Open Source Project
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-// http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-
-package com.google.gerrit.server.notedb.rebuild;
-
-import com.google.common.util.concurrent.ListenableFuture;
-import com.google.common.util.concurrent.ListeningExecutorService;
-import com.google.gerrit.reviewdb.client.Change;
-import com.google.gerrit.reviewdb.client.Project;
-import com.google.gerrit.reviewdb.server.ReviewDb;
-import com.google.gerrit.server.notedb.ChangeBundle;
-import com.google.gerrit.server.notedb.NoteDbUpdateManager;
-import com.google.gerrit.server.notedb.NoteDbUpdateManager.Result;
-import com.google.gwtorm.server.OrmException;
-import com.google.gwtorm.server.SchemaFactory;
-import java.io.IOException;
-
-public abstract class ChangeRebuilder {
-  public static class NoPatchSetsException extends OrmException {
-    private static final long serialVersionUID = 1L;
-
-    NoPatchSetsException(Change.Id changeId) {
-      super("Change " + changeId + " cannot be rebuilt because it has no patch sets");
-    }
-  }
-
-  private final SchemaFactory<ReviewDb> schemaFactory;
-
-  protected ChangeRebuilder(SchemaFactory<ReviewDb> schemaFactory) {
-    this.schemaFactory = schemaFactory;
-  }
-
-  public final ListenableFuture<Result> rebuildAsync(
-      Change.Id id, ListeningExecutorService executor) {
-    return executor.submit(
-        () -> {
-          try (ReviewDb db = schemaFactory.open()) {
-            return rebuild(db, id);
-          }
-        });
-  }
-
-  /**
-   * Rebuild ReviewDb contents by copying from NoteDb.
-   *
-   * <p>Requires NoteDb to be the primary storage for the change.
-   */
-  public abstract void rebuildReviewDb(ReviewDb db, Project.NameKey project, Change.Id changeId)
-      throws OrmException;
-
-  // In the following methods "rebuilding" always refers to copying the state
-  // from ReviewDb to NoteDb, i.e. assuming ReviewDb is the primary storage.
-
-  public abstract Result rebuild(ReviewDb db, Change.Id changeId) throws IOException, OrmException;
-
-  public abstract Result rebuildEvenIfReadOnly(ReviewDb db, Change.Id changeId)
-      throws IOException, OrmException;
-
-  public abstract Result rebuild(NoteDbUpdateManager manager, ChangeBundle bundle)
-      throws IOException, OrmException;
-
-  public abstract void buildUpdates(NoteDbUpdateManager manager, ChangeBundle bundle)
-      throws IOException, OrmException;
-
-  public abstract NoteDbUpdateManager stage(ReviewDb db, Change.Id changeId)
-      throws IOException, OrmException;
-
-  public abstract Result execute(ReviewDb db, Change.Id changeId, NoteDbUpdateManager manager)
-      throws OrmException, IOException;
-}
diff --git a/java/com/google/gerrit/server/notedb/rebuild/ChangeRebuilderImpl.java b/java/com/google/gerrit/server/notedb/rebuild/ChangeRebuilderImpl.java
deleted file mode 100644
index 8740710..0000000
--- a/java/com/google/gerrit/server/notedb/rebuild/ChangeRebuilderImpl.java
+++ /dev/null
@@ -1,687 +0,0 @@
-// Copyright (C) 2014 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.notedb.rebuild;
-
-import static com.google.common.base.MoreObjects.firstNonNull;
-import static com.google.common.base.Preconditions.checkState;
-import static com.google.gerrit.reviewdb.client.RefNames.changeMetaRef;
-import static com.google.gerrit.server.notedb.ChangeNoteUtil.FOOTER_HASHTAGS;
-import static com.google.gerrit.server.notedb.ChangeNoteUtil.FOOTER_PATCH_SET;
-import static java.util.Objects.requireNonNull;
-import static java.util.concurrent.TimeUnit.SECONDS;
-import static java.util.stream.Collectors.toList;
-
-import com.google.common.base.Splitter;
-import com.google.common.collect.FluentIterable;
-import com.google.common.collect.ImmutableCollection;
-import com.google.common.collect.ImmutableSet;
-import com.google.common.collect.ListMultimap;
-import com.google.common.collect.Lists;
-import com.google.common.collect.MultimapBuilder;
-import com.google.common.collect.Ordering;
-import com.google.common.collect.Sets;
-import com.google.common.collect.Table;
-import com.google.common.primitives.Ints;
-import com.google.gerrit.common.Nullable;
-import com.google.gerrit.reviewdb.client.Account;
-import com.google.gerrit.reviewdb.client.Change;
-import com.google.gerrit.reviewdb.client.ChangeMessage;
-import com.google.gerrit.reviewdb.client.Comment;
-import com.google.gerrit.reviewdb.client.PatchLineComment;
-import com.google.gerrit.reviewdb.client.PatchLineComment.Status;
-import com.google.gerrit.reviewdb.client.PatchSet;
-import com.google.gerrit.reviewdb.client.PatchSetApproval;
-import com.google.gerrit.reviewdb.client.Project;
-import com.google.gerrit.reviewdb.client.RefNames;
-import com.google.gerrit.reviewdb.server.ReviewDb;
-import com.google.gerrit.reviewdb.server.ReviewDbUtil;
-import com.google.gerrit.server.CommentsUtil;
-import com.google.gerrit.server.GerritPersonIdent;
-import com.google.gerrit.server.config.GerritServerConfig;
-import com.google.gerrit.server.config.GerritServerId;
-import com.google.gerrit.server.notedb.ChangeBundle;
-import com.google.gerrit.server.notedb.ChangeBundleReader;
-import com.google.gerrit.server.notedb.ChangeDraftUpdate;
-import com.google.gerrit.server.notedb.ChangeNoteUtil;
-import com.google.gerrit.server.notedb.ChangeNotes;
-import com.google.gerrit.server.notedb.ChangeUpdate;
-import com.google.gerrit.server.notedb.NoteDbChangeState;
-import com.google.gerrit.server.notedb.NoteDbChangeState.PrimaryStorage;
-import com.google.gerrit.server.notedb.NoteDbUpdateManager;
-import com.google.gerrit.server.notedb.NoteDbUpdateManager.OpenRepo;
-import com.google.gerrit.server.notedb.NoteDbUpdateManager.Result;
-import com.google.gerrit.server.notedb.NotesMigration;
-import com.google.gerrit.server.notedb.ReviewerStateInternal;
-import com.google.gerrit.server.patch.PatchListCache;
-import com.google.gerrit.server.project.NoSuchChangeException;
-import com.google.gerrit.server.project.ProjectCache;
-import com.google.gerrit.server.update.ChainedReceiveCommands;
-import com.google.gwtorm.client.Key;
-import com.google.gwtorm.server.Access;
-import com.google.gwtorm.server.AtomicUpdate;
-import com.google.gwtorm.server.OrmException;
-import com.google.gwtorm.server.SchemaFactory;
-import com.google.inject.Inject;
-import java.io.IOException;
-import java.sql.Timestamp;
-import java.util.ArrayList;
-import java.util.Collection;
-import java.util.Collections;
-import java.util.Comparator;
-import java.util.Iterator;
-import java.util.List;
-import java.util.Objects;
-import java.util.Optional;
-import java.util.Set;
-import java.util.TreeMap;
-import org.eclipse.jgit.errors.ConfigInvalidException;
-import org.eclipse.jgit.lib.Config;
-import org.eclipse.jgit.lib.ObjectId;
-import org.eclipse.jgit.lib.PersonIdent;
-import org.eclipse.jgit.lib.Ref;
-import org.eclipse.jgit.revwalk.RevCommit;
-import org.eclipse.jgit.revwalk.RevWalk;
-import org.eclipse.jgit.transport.ReceiveCommand;
-
-public class ChangeRebuilderImpl extends ChangeRebuilder {
-  /**
-   * The maximum amount of time between the ReviewDb timestamp of the first and last events batched
-   * together into a single NoteDb update.
-   *
-   * <p>Used to account for the fact that different records with their own timestamps (e.g. {@link
-   * PatchSetApproval} and {@link ChangeMessage}) historically didn't necessarily use the same
-   * timestamp, and tended to call {@code System.currentTimeMillis()} independently.
-   */
-  public static final long MAX_WINDOW_MS = SECONDS.toMillis(3);
-
-  /**
-   * The maximum amount of time between two consecutive events to consider them to be in the same
-   * batch.
-   */
-  static final long MAX_DELTA_MS = SECONDS.toMillis(1);
-
-  private final ChangeBundleReader bundleReader;
-  private final ChangeDraftUpdate.Factory draftUpdateFactory;
-  private final ChangeNoteUtil changeNoteUtil;
-  private final ChangeNotes.Factory notesFactory;
-  private final ChangeUpdate.Factory updateFactory;
-  private final CommentsUtil commentsUtil;
-  private final NoteDbUpdateManager.Factory updateManagerFactory;
-  private final NotesMigration migration;
-  private final PatchListCache patchListCache;
-  private final PersonIdent serverIdent;
-  private final ProjectCache projectCache;
-  private final String serverId;
-  private final long skewMs;
-
-  @Inject
-  ChangeRebuilderImpl(
-      @GerritServerConfig Config cfg,
-      SchemaFactory<ReviewDb> schemaFactory,
-      ChangeBundleReader bundleReader,
-      ChangeDraftUpdate.Factory draftUpdateFactory,
-      ChangeNoteUtil changeNoteUtil,
-      ChangeNotes.Factory notesFactory,
-      ChangeUpdate.Factory updateFactory,
-      CommentsUtil commentsUtil,
-      NoteDbUpdateManager.Factory updateManagerFactory,
-      NotesMigration migration,
-      PatchListCache patchListCache,
-      @GerritPersonIdent PersonIdent serverIdent,
-      @Nullable ProjectCache projectCache,
-      @GerritServerId String serverId) {
-    super(schemaFactory);
-    this.bundleReader = bundleReader;
-    this.draftUpdateFactory = draftUpdateFactory;
-    this.changeNoteUtil = changeNoteUtil;
-    this.notesFactory = notesFactory;
-    this.updateFactory = updateFactory;
-    this.commentsUtil = commentsUtil;
-    this.updateManagerFactory = updateManagerFactory;
-    this.migration = migration;
-    this.patchListCache = patchListCache;
-    this.serverIdent = serverIdent;
-    this.projectCache = projectCache;
-    this.serverId = serverId;
-    this.skewMs = NoteDbChangeState.getReadOnlySkew(cfg);
-  }
-
-  @Override
-  public Result rebuild(ReviewDb db, Change.Id changeId) throws IOException, OrmException {
-    return rebuild(db, changeId, true);
-  }
-
-  @Override
-  public Result rebuildEvenIfReadOnly(ReviewDb db, Change.Id changeId)
-      throws IOException, OrmException {
-    return rebuild(db, changeId, false);
-  }
-
-  private Result rebuild(ReviewDb db, Change.Id changeId, boolean checkReadOnly)
-      throws IOException, OrmException {
-    db = ReviewDbUtil.unwrapDb(db);
-    // Read change just to get project; this instance is then discarded so we can read a consistent
-    // ChangeBundle inside a transaction.
-    Change change = db.changes().get(changeId);
-    if (change == null) {
-      throw new NoSuchChangeException(changeId);
-    }
-    try (NoteDbUpdateManager manager = updateManagerFactory.create(change.getProject())) {
-      buildUpdates(manager, bundleReader.fromReviewDb(db, changeId));
-      return execute(db, changeId, manager, checkReadOnly, true);
-    }
-  }
-
-  @Override
-  public Result rebuild(NoteDbUpdateManager manager, ChangeBundle bundle)
-      throws NoSuchChangeException, IOException, OrmException {
-    Change change = new Change(bundle.getChange());
-    buildUpdates(manager, bundle);
-    return manager.stageAndApplyDelta(change);
-  }
-
-  @Override
-  public NoteDbUpdateManager stage(ReviewDb db, Change.Id changeId)
-      throws IOException, OrmException {
-    db = ReviewDbUtil.unwrapDb(db);
-    Change change = checkNoteDbState(ChangeNotes.readOneReviewDbChange(db, changeId));
-    if (change == null) {
-      throw new NoSuchChangeException(changeId);
-    }
-    NoteDbUpdateManager manager = updateManagerFactory.create(change.getProject());
-    buildUpdates(manager, bundleReader.fromReviewDb(db, changeId));
-    manager.stage();
-    return manager;
-  }
-
-  @Override
-  public Result execute(ReviewDb db, Change.Id changeId, NoteDbUpdateManager manager)
-      throws OrmException, IOException {
-    return execute(db, changeId, manager, true, true);
-  }
-
-  public Result execute(
-      ReviewDb db,
-      Change.Id changeId,
-      NoteDbUpdateManager manager,
-      boolean checkReadOnly,
-      boolean executeManager)
-      throws OrmException, IOException {
-    db = ReviewDbUtil.unwrapDb(db);
-    Change change = checkNoteDbState(ChangeNotes.readOneReviewDbChange(db, changeId));
-    if (change == null) {
-      throw new NoSuchChangeException(changeId);
-    }
-
-    String oldNoteDbStateStr = change.getNoteDbState();
-    Result r = manager.stageAndApplyDelta(change);
-    String newNoteDbStateStr = change.getNoteDbState();
-    if (newNoteDbStateStr == null) {
-      throw new OrmException(
-          String.format(
-              "Rebuilding change %s produced no writes to NoteDb: %s",
-              changeId, bundleReader.fromReviewDb(db, changeId)));
-    }
-    NoteDbChangeState newNoteDbState =
-        requireNonNull(NoteDbChangeState.parse(changeId, newNoteDbStateStr));
-    try {
-      db.changes()
-          .atomicUpdate(
-              changeId,
-              new AtomicUpdate<Change>() {
-                @Override
-                public Change update(Change change) {
-                  if (checkReadOnly) {
-                    NoteDbChangeState.checkNotReadOnly(change, skewMs);
-                  }
-                  String currNoteDbStateStr = change.getNoteDbState();
-                  if (Objects.equals(currNoteDbStateStr, newNoteDbStateStr)) {
-                    // Another thread completed the same rebuild we were about to.
-                    throw new AbortUpdateException();
-                  } else if (!Objects.equals(oldNoteDbStateStr, currNoteDbStateStr)) {
-                    // Another thread updated the state to something else.
-                    throw new ConflictingUpdateRuntimeException(change, oldNoteDbStateStr);
-                  }
-                  change.setNoteDbState(newNoteDbStateStr);
-                  return change;
-                }
-              });
-    } catch (ConflictingUpdateRuntimeException e) {
-      // Rethrow as an OrmException so the caller knows to use staged results. Strictly speaking
-      // they are not completely up to date, but result we send to the caller is the same as if this
-      // rebuild had executed before the other thread.
-      throw new ConflictingUpdateException(e);
-    } catch (AbortUpdateException e) {
-      if (newNoteDbState.isUpToDate(
-          manager.getChangeRepo().cmds.getRepoRefCache(),
-          manager.getAllUsersRepo().cmds.getRepoRefCache())) {
-        // If the state in ReviewDb matches NoteDb at this point, it means another thread
-        // successfully completed this rebuild. It's ok to not execute the update in this case,
-        // since the object referenced in the Result was flushed to the repo by whatever thread won
-        // the race.
-        return r;
-      }
-      // If the state doesn't match, that means another thread attempted this rebuild, but
-      // failed. Fall through and try to update the ref again.
-    }
-    if (migration.failChangeWrites()) {
-      // Don't even attempt to execute if read-only, it would fail anyway. But do throw an exception
-      // to the caller so they know to use the staged results instead of reading from the repo.
-      throw new OrmException(NoteDbUpdateManager.CHANGES_READ_ONLY);
-    }
-    if (executeManager) {
-      manager.execute();
-    }
-    return r;
-  }
-
-  static Change checkNoteDbState(Change c) throws OrmException {
-    // Can only rebuild a change if its primary storage is ReviewDb.
-    NoteDbChangeState s = NoteDbChangeState.parse(c);
-    if (s != null && s.getPrimaryStorage() != PrimaryStorage.REVIEW_DB) {
-      throw new OrmException(String.format("cannot rebuild change %s with state %s", c.getId(), s));
-    }
-    return c;
-  }
-
-  @Override
-  public void buildUpdates(NoteDbUpdateManager manager, ChangeBundle bundle)
-      throws IOException, OrmException {
-    manager.setCheckExpectedState(false).setRefLogMessage("Rebuilding change");
-    Change change = new Change(bundle.getChange());
-    if (bundle.getPatchSets().isEmpty()) {
-      throw new NoPatchSetsException(change.getId());
-    }
-    if (change.getLastUpdatedOn().compareTo(change.getCreatedOn()) < 0) {
-      // A bug in data migration might set created_on to the time of the migration. The
-      // correct timestamps were lost, but we can at least set it so created_on is not after
-      // last_updated_on.
-      // See https://bugs.chromium.org/p/gerrit/issues/detail?id=7397
-      change.setCreatedOn(change.getLastUpdatedOn());
-    }
-
-    // We will rebuild all events, except for draft comments, in buckets based on author and
-    // timestamp.
-    List<Event> events = new ArrayList<>();
-    ListMultimap<Account.Id, DraftCommentEvent> draftCommentEvents =
-        MultimapBuilder.hashKeys().arrayListValues().build();
-
-    events.addAll(getHashtagsEvents(change, manager));
-
-    // Delete ref only after hashtags have been read.
-    deleteChangeMetaRef(change, manager.getChangeRepo().cmds);
-    deleteDraftRefs(change, manager.getAllUsersRepo());
-
-    Integer minPsNum = getMinPatchSetNum(bundle);
-    TreeMap<PatchSet.Id, PatchSetEvent> patchSetEvents =
-        new TreeMap<>(ReviewDbUtil.intKeyOrdering());
-
-    for (PatchSet ps : bundle.getPatchSets()) {
-      PatchSetEvent pse = new PatchSetEvent(change, ps, manager.getChangeRepo().rw);
-      patchSetEvents.put(ps.getId(), pse);
-      events.add(pse);
-      for (Comment c : getComments(bundle, serverId, Status.PUBLISHED, ps)) {
-        CommentEvent e = new CommentEvent(c, change, ps, patchListCache);
-        events.add(e.addDep(pse));
-      }
-      for (Comment c : getComments(bundle, serverId, Status.DRAFT, ps)) {
-        DraftCommentEvent e = new DraftCommentEvent(c, change, ps, patchListCache);
-        draftCommentEvents.put(c.author.getId(), e);
-      }
-    }
-    ensurePatchSetOrder(patchSetEvents);
-
-    for (PatchSetApproval psa : bundle.getPatchSetApprovals()) {
-      PatchSetEvent pse = patchSetEvents.get(psa.getPatchSetId());
-      if (pse != null) {
-        events.add(new ApprovalEvent(psa, change.getCreatedOn()).addDep(pse));
-      }
-    }
-
-    for (Table.Cell<ReviewerStateInternal, Account.Id, Timestamp> r :
-        bundle.getReviewers().asTable().cellSet()) {
-      events.add(new ReviewerEvent(r, change.getCreatedOn()));
-    }
-
-    Change noteDbChange = new Change(null, null, null, null, null);
-    for (ChangeMessage msg : bundle.getChangeMessages()) {
-      Event msgEvent = new ChangeMessageEvent(change, noteDbChange, msg, change.getCreatedOn());
-      if (msg.getPatchSetId() != null) {
-        PatchSetEvent pse = patchSetEvents.get(msg.getPatchSetId());
-        if (pse == null) {
-          continue; // Ignore events for missing patch sets.
-        }
-        msgEvent.addDep(pse);
-      }
-      events.add(msgEvent);
-    }
-
-    sortAndFillEvents(change, noteDbChange, bundle.getPatchSets(), events, minPsNum);
-
-    EventList<Event> el = new EventList<>();
-    for (Event e : events) {
-      if (!el.canAdd(e)) {
-        flushEventsToUpdate(manager, el, change);
-        checkState(el.canAdd(e));
-      }
-      el.add(e);
-    }
-    flushEventsToUpdate(manager, el, change);
-
-    EventList<DraftCommentEvent> plcel = new EventList<>();
-    for (Account.Id author : draftCommentEvents.keys()) {
-      for (DraftCommentEvent e : Ordering.natural().sortedCopy(draftCommentEvents.get(author))) {
-        if (!plcel.canAdd(e)) {
-          flushEventsToDraftUpdate(manager, plcel, change);
-          checkState(plcel.canAdd(e));
-        }
-        plcel.add(e);
-      }
-      flushEventsToDraftUpdate(manager, plcel, change);
-    }
-  }
-
-  private static Integer getMinPatchSetNum(ChangeBundle bundle) {
-    Integer minPsNum = null;
-    for (PatchSet ps : bundle.getPatchSets()) {
-      int n = ps.getId().get();
-      if (minPsNum == null || n < minPsNum) {
-        minPsNum = n;
-      }
-    }
-    return minPsNum;
-  }
-
-  private static void ensurePatchSetOrder(TreeMap<PatchSet.Id, PatchSetEvent> events) {
-    if (events.isEmpty()) {
-      return;
-    }
-    Iterator<PatchSetEvent> it = events.values().iterator();
-    PatchSetEvent curr = it.next();
-    while (it.hasNext()) {
-      PatchSetEvent next = it.next();
-      next.addDep(curr);
-      curr = next;
-    }
-  }
-
-  private static List<Comment> getComments(
-      ChangeBundle bundle, String serverId, PatchLineComment.Status status, PatchSet ps) {
-    return bundle
-        .getPatchLineComments()
-        .stream()
-        .filter(c -> c.getPatchSetId().equals(ps.getId()) && c.getStatus() == status)
-        .map(plc -> plc.asComment(serverId))
-        .sorted(CommentsUtil.COMMENT_ORDER)
-        .collect(toList());
-  }
-
-  private void sortAndFillEvents(
-      Change change,
-      Change noteDbChange,
-      ImmutableCollection<PatchSet> patchSets,
-      List<Event> events,
-      Integer minPsNum) {
-    Event finalUpdates = new FinalUpdatesEvent(change, noteDbChange, patchSets);
-    events.add(finalUpdates);
-    setPostSubmitDeps(events);
-    new EventSorter(events).sort();
-
-    // Ensure the first event in the list creates the change, setting the author and any required
-    // footers. Also force the creation time of the first patch set to match the creation time of
-    // the change.
-    Event first = events.get(0);
-    if (first instanceof PatchSetEvent && change.getOwner().equals(first.user)) {
-      first.when = change.getCreatedOn();
-      ((PatchSetEvent) first).createChange = true;
-    } else {
-      events.add(0, new CreateChangeEvent(change, minPsNum));
-    }
-
-    // Final pass to correct some inconsistencies.
-    //
-    // First, fill in any missing patch set IDs using the latest patch set of the change at the time
-    // of the event, because NoteDb can't represent actions with no associated patch set ID. This
-    // workaround is as if a user added a ChangeMessage on the change by replying from the latest
-    // patch set.
-    //
-    // Start with the first patch set that actually exists. If there are no patch sets at all,
-    // minPsNum will be null, so just bail and use 1 as the patch set ID.
-    //
-    // Second, ensure timestamps are nondecreasing, by copying the previous timestamp if this
-    // happens. This assumes that the only way this can happen is due to dependency constraints, and
-    // it is ok to give an event the same timestamp as one of its dependencies.
-    int ps = firstNonNull(minPsNum, 1);
-    for (int i = 0; i < events.size(); i++) {
-      Event e = events.get(i);
-      if (e.psId == null) {
-        e.psId = new PatchSet.Id(change.getId(), ps);
-      } else {
-        ps = Math.max(ps, e.psId.get());
-      }
-
-      if (i > 0) {
-        Event p = events.get(i - 1);
-        if (e.when.before(p.when)) {
-          e.when = p.when;
-        }
-      }
-    }
-  }
-
-  private void setPostSubmitDeps(List<Event> events) {
-    Optional<Event> submitEvent =
-        Lists.reverse(events).stream().filter(Event::isSubmit).findFirst();
-    if (submitEvent.isPresent()) {
-      events.stream().filter(Event::isPostSubmitApproval).forEach(e -> e.addDep(submitEvent.get()));
-    }
-  }
-
-  private void flushEventsToUpdate(
-      NoteDbUpdateManager manager, EventList<Event> events, Change change)
-      throws OrmException, IOException {
-    if (events.isEmpty()) {
-      return;
-    }
-    Comparator<String> labelNameComparator;
-    if (projectCache != null) {
-      labelNameComparator = projectCache.get(change.getProject()).getLabelTypes().nameComparator();
-    } else {
-      // No project cache available, bail and use natural ordering; there's no semantic difference
-      // anyway difference.
-      labelNameComparator = Ordering.natural();
-    }
-    ChangeUpdate update =
-        updateFactory.create(
-            change,
-            events.getAccountId(),
-            events.getRealAccountId(),
-            newAuthorIdent(events),
-            events.getWhen(),
-            labelNameComparator);
-    update.setAllowWriteToNewRef(true);
-    update.setPatchSetId(events.getPatchSetId());
-    update.setTag(events.getTag());
-    for (Event e : events) {
-      e.apply(update);
-    }
-    manager.add(update);
-    events.clear();
-  }
-
-  private void flushEventsToDraftUpdate(
-      NoteDbUpdateManager manager, EventList<DraftCommentEvent> events, Change change) {
-    if (events.isEmpty()) {
-      return;
-    }
-    ChangeDraftUpdate update =
-        draftUpdateFactory.create(
-            change,
-            events.getAccountId(),
-            events.getRealAccountId(),
-            newAuthorIdent(events),
-            events.getWhen());
-    update.setPatchSetId(events.getPatchSetId());
-    for (DraftCommentEvent e : events) {
-      e.applyDraft(update);
-    }
-    manager.add(update);
-    events.clear();
-  }
-
-  private PersonIdent newAuthorIdent(EventList<?> events) {
-    Account.Id id = events.getAccountId();
-    if (id == null) {
-      return new PersonIdent(serverIdent, events.getWhen());
-    }
-    return changeNoteUtil.newIdent(id, events.getWhen(), serverIdent);
-  }
-
-  private List<HashtagsEvent> getHashtagsEvents(Change change, NoteDbUpdateManager manager)
-      throws IOException {
-    String refName = changeMetaRef(change.getId());
-    Optional<ObjectId> old = manager.getChangeRepo().getObjectId(refName);
-    if (!old.isPresent()) {
-      return Collections.emptyList();
-    }
-
-    RevWalk rw = manager.getChangeRepo().rw;
-    List<HashtagsEvent> events = new ArrayList<>();
-    rw.reset();
-    rw.markStart(rw.parseCommit(old.get()));
-    for (RevCommit commit : rw) {
-      Account.Id authorId;
-      try {
-        authorId =
-            changeNoteUtil
-                .getLegacyChangeNoteRead()
-                .parseIdent(commit.getAuthorIdent(), change.getId());
-      } catch (ConfigInvalidException e) {
-        continue; // Corrupt data, no valid hashtags in this commit.
-      }
-      PatchSet.Id psId = parsePatchSetId(change, commit);
-      Set<String> hashtags = parseHashtags(commit);
-      if (authorId == null || psId == null || hashtags == null) {
-        continue;
-      }
-
-      Timestamp commitTime = new Timestamp(commit.getCommitterIdent().getWhen().getTime());
-      events.add(new HashtagsEvent(psId, authorId, commitTime, hashtags, change.getCreatedOn()));
-    }
-    return events;
-  }
-
-  private Set<String> parseHashtags(RevCommit commit) {
-    List<String> hashtagsLines = commit.getFooterLines(FOOTER_HASHTAGS);
-    if (hashtagsLines.isEmpty() || hashtagsLines.size() > 1) {
-      return null;
-    }
-
-    if (hashtagsLines.get(0).isEmpty()) {
-      return ImmutableSet.of();
-    }
-    return Sets.newHashSet(Splitter.on(',').split(hashtagsLines.get(0)));
-  }
-
-  private PatchSet.Id parsePatchSetId(Change change, RevCommit commit) {
-    List<String> psIdLines = commit.getFooterLines(FOOTER_PATCH_SET);
-    if (psIdLines.size() != 1) {
-      return null;
-    }
-    Integer psId = Ints.tryParse(psIdLines.get(0));
-    if (psId == null) {
-      return null;
-    }
-    return new PatchSet.Id(change.getId(), psId);
-  }
-
-  private void deleteChangeMetaRef(Change change, ChainedReceiveCommands cmds) throws IOException {
-    String refName = changeMetaRef(change.getId());
-    Optional<ObjectId> old = cmds.get(refName);
-    if (old.isPresent()) {
-      cmds.add(new ReceiveCommand(old.get(), ObjectId.zeroId(), refName));
-    }
-  }
-
-  private void deleteDraftRefs(Change change, OpenRepo allUsersRepo) throws IOException {
-    for (Ref r :
-        allUsersRepo
-            .repo
-            .getRefDatabase()
-            .getRefsByPrefix(RefNames.refsDraftCommentsPrefix(change.getId()))) {
-      allUsersRepo.cmds.add(new ReceiveCommand(r.getObjectId(), ObjectId.zeroId(), r.getName()));
-    }
-  }
-
-  static void createChange(ChangeUpdate update, Change change) {
-    update.setSubjectForCommit("Create change");
-    update.setChangeId(change.getKey().get());
-    update.setBranch(change.getDest().get());
-    update.setSubject(change.getOriginalSubject());
-    if (change.getRevertOf() != null) {
-      update.setRevertOf(change.getRevertOf().get());
-    }
-  }
-
-  @Override
-  public void rebuildReviewDb(ReviewDb db, Project.NameKey project, Change.Id changeId)
-      throws OrmException {
-    // TODO(dborowitz): Fail fast if changes tables are disabled in ReviewDb.
-    ChangeNotes notes = notesFactory.create(db, project, changeId);
-    ChangeBundle bundle = ChangeBundle.fromNotes(commentsUtil, notes);
-
-    db = ReviewDbUtil.unwrapDb(db);
-    db.changes().beginTransaction(changeId);
-    try {
-      Change c = db.changes().get(changeId);
-      if (c != null) {
-        PrimaryStorage ps = PrimaryStorage.of(c);
-        switch (ps) {
-          case REVIEW_DB:
-            return; // Nothing to do.
-          case NOTE_DB:
-            break; // Continue and rebuild.
-          default:
-            throw new OrmException("primary storage of " + changeId + " is " + ps);
-        }
-      } else {
-        c = notes.getChange();
-      }
-      db.changes().upsert(Collections.singleton(c));
-      putExactlyEntities(
-          db.changeMessages(), db.changeMessages().byChange(c.getId()), bundle.getChangeMessages());
-      putExactlyEntities(db.patchSets(), db.patchSets().byChange(c.getId()), bundle.getPatchSets());
-      putExactlyEntities(
-          db.patchSetApprovals(),
-          db.patchSetApprovals().byChange(c.getId()),
-          bundle.getPatchSetApprovals());
-      putExactlyEntities(
-          db.patchComments(),
-          db.patchComments().byChange(c.getId()),
-          bundle.getPatchLineComments());
-      db.commit();
-    } finally {
-      db.rollback();
-    }
-  }
-
-  private static <T, K extends Key<?>> void putExactlyEntities(
-      Access<T, K> access, Iterable<T> existing, Collection<T> ents) throws OrmException {
-    Set<K> toKeep = access.toMap(ents).keySet();
-    access.delete(
-        FluentIterable.from(existing).filter(e -> !toKeep.contains(access.primaryKey(e))));
-    access.upsert(ents);
-  }
-}
diff --git a/java/com/google/gerrit/server/notedb/rebuild/CommentEvent.java b/java/com/google/gerrit/server/notedb/rebuild/CommentEvent.java
deleted file mode 100644
index 8f7b387..0000000
--- a/java/com/google/gerrit/server/notedb/rebuild/CommentEvent.java
+++ /dev/null
@@ -1,82 +0,0 @@
-// Copyright (C) 2016 The Android Open Source Project
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-// http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-
-package com.google.gerrit.server.notedb.rebuild;
-
-import static com.google.gerrit.server.CommentsUtil.setCommentRevId;
-
-import com.google.common.base.MoreObjects.ToStringHelper;
-import com.google.common.flogger.FluentLogger;
-import com.google.gerrit.reviewdb.client.Change;
-import com.google.gerrit.reviewdb.client.Comment;
-import com.google.gerrit.reviewdb.client.PatchLineComment;
-import com.google.gerrit.reviewdb.client.PatchSet;
-import com.google.gerrit.server.CommentsUtil;
-import com.google.gerrit.server.notedb.ChangeUpdate;
-import com.google.gerrit.server.patch.PatchListCache;
-import com.google.gerrit.server.patch.PatchListNotAvailableException;
-
-class CommentEvent extends Event {
-  private static final FluentLogger logger = FluentLogger.forEnclosingClass();
-
-  public final Comment c;
-  private final Change change;
-  private final PatchSet ps;
-  private final PatchListCache cache;
-
-  CommentEvent(Comment c, Change change, PatchSet ps, PatchListCache cache) {
-    super(
-        CommentsUtil.getCommentPsId(change.getId(), c),
-        c.author.getId(),
-        c.getRealAuthor().getId(),
-        c.writtenOn,
-        change.getCreatedOn(),
-        c.tag);
-    this.c = c;
-    this.change = change;
-    this.ps = ps;
-    this.cache = cache;
-  }
-
-  @Override
-  boolean uniquePerUpdate() {
-    return false;
-  }
-
-  @Override
-  protected boolean canHaveTag() {
-    return true;
-  }
-
-  @Override
-  void apply(ChangeUpdate update) {
-    checkUpdate(update);
-    if (c.revId == null) {
-      try {
-        setCommentRevId(c, cache, change, ps);
-      } catch (PatchListNotAvailableException e) {
-        logger.atWarning().log(
-            "Unable to determine parent commit of patch set %s (%s); omitting inline comment %s",
-            ps.getId(), ps.getRevision(), c);
-        return;
-      }
-    }
-    update.putComment(PatchLineComment.Status.PUBLISHED, c);
-  }
-
-  @Override
-  protected void addToString(ToStringHelper helper) {
-    helper.add("message", c.message);
-  }
-}
diff --git a/java/com/google/gerrit/server/notedb/rebuild/ConflictingUpdateException.java b/java/com/google/gerrit/server/notedb/rebuild/ConflictingUpdateException.java
deleted file mode 100644
index d8e7480..0000000
--- a/java/com/google/gerrit/server/notedb/rebuild/ConflictingUpdateException.java
+++ /dev/null
@@ -1,32 +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.notedb.rebuild;
-
-import com.google.gwtorm.server.OrmException;
-
-/**
- * {@link com.google.gwtorm.server.OrmException} thrown by {@link ChangeRebuilder} when rebuilding a
- * change failed because another operation modified its {@link
- * com.google.gerrit.server.notedb.NoteDbChangeState}.
- */
-public class ConflictingUpdateException extends OrmException {
-  private static final long serialVersionUID = 1L;
-
-  // Always created from a ConflictingUpdateRuntimeException because it originates from an
-  // AtomicUpdate, which cannot throw checked exceptions.
-  ConflictingUpdateException(ConflictingUpdateRuntimeException cause) {
-    super(cause.getMessage(), cause);
-  }
-}
diff --git a/java/com/google/gerrit/server/notedb/rebuild/ConflictingUpdateRuntimeException.java b/java/com/google/gerrit/server/notedb/rebuild/ConflictingUpdateRuntimeException.java
deleted file mode 100644
index abfafa2..0000000
--- a/java/com/google/gerrit/server/notedb/rebuild/ConflictingUpdateRuntimeException.java
+++ /dev/null
@@ -1,29 +0,0 @@
-// Copyright (C) 2016 The Android Open Source Project
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-// http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-
-package com.google.gerrit.server.notedb.rebuild;
-
-import com.google.gerrit.reviewdb.client.Change;
-import com.google.gwtorm.server.OrmRuntimeException;
-
-class ConflictingUpdateRuntimeException extends OrmRuntimeException {
-  private static final long serialVersionUID = 1L;
-
-  ConflictingUpdateRuntimeException(Change change, String expectedNoteDbState) {
-    super(
-        String.format(
-            "Expected change %s to have noteDbState %s but was %s",
-            change.getId(), expectedNoteDbState, change.getNoteDbState()));
-  }
-}
diff --git a/java/com/google/gerrit/server/notedb/rebuild/CreateChangeEvent.java b/java/com/google/gerrit/server/notedb/rebuild/CreateChangeEvent.java
deleted file mode 100644
index d01071b..0000000
--- a/java/com/google/gerrit/server/notedb/rebuild/CreateChangeEvent.java
+++ /dev/null
@@ -1,59 +0,0 @@
-// Copyright (C) 2016 The Android Open Source Project
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-// http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-
-package com.google.gerrit.server.notedb.rebuild;
-
-import com.google.gerrit.reviewdb.client.Change;
-import com.google.gerrit.reviewdb.client.PatchSet;
-import com.google.gerrit.server.notedb.ChangeUpdate;
-import com.google.gwtorm.server.OrmException;
-import java.io.IOException;
-
-class CreateChangeEvent extends Event {
-  private final Change change;
-
-  private static PatchSet.Id psId(Change change, Integer minPsNum) {
-    int n;
-    if (minPsNum == null) {
-      // There were no patch sets for the change at all, so something is very
-      // wrong. Bail and use 1 as the patch set.
-      n = 1;
-    } else {
-      n = minPsNum;
-    }
-    return new PatchSet.Id(change.getId(), n);
-  }
-
-  CreateChangeEvent(Change change, Integer minPsNum) {
-    super(
-        psId(change, minPsNum),
-        change.getOwner(),
-        change.getOwner(),
-        change.getCreatedOn(),
-        change.getCreatedOn(),
-        null);
-    this.change = change;
-  }
-
-  @Override
-  boolean uniquePerUpdate() {
-    return true;
-  }
-
-  @Override
-  void apply(ChangeUpdate update) throws IOException, OrmException {
-    checkUpdate(update);
-    ChangeRebuilderImpl.createChange(update, change);
-  }
-}
diff --git a/java/com/google/gerrit/server/notedb/rebuild/DraftCommentEvent.java b/java/com/google/gerrit/server/notedb/rebuild/DraftCommentEvent.java
deleted file mode 100644
index 2a2795d..0000000
--- a/java/com/google/gerrit/server/notedb/rebuild/DraftCommentEvent.java
+++ /dev/null
@@ -1,81 +0,0 @@
-// Copyright (C) 2016 The Android Open Source Project
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-// http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-
-package com.google.gerrit.server.notedb.rebuild;
-
-import static com.google.gerrit.server.CommentsUtil.setCommentRevId;
-
-import com.google.common.base.MoreObjects.ToStringHelper;
-import com.google.common.flogger.FluentLogger;
-import com.google.gerrit.reviewdb.client.Change;
-import com.google.gerrit.reviewdb.client.Comment;
-import com.google.gerrit.reviewdb.client.PatchSet;
-import com.google.gerrit.server.CommentsUtil;
-import com.google.gerrit.server.notedb.ChangeDraftUpdate;
-import com.google.gerrit.server.notedb.ChangeUpdate;
-import com.google.gerrit.server.patch.PatchListCache;
-import com.google.gerrit.server.patch.PatchListNotAvailableException;
-
-class DraftCommentEvent extends Event {
-  private static final FluentLogger logger = FluentLogger.forEnclosingClass();
-
-  public final Comment c;
-  private final Change change;
-  private final PatchSet ps;
-  private final PatchListCache cache;
-
-  DraftCommentEvent(Comment c, Change change, PatchSet ps, PatchListCache cache) {
-    super(
-        CommentsUtil.getCommentPsId(change.getId(), c),
-        c.author.getId(),
-        c.getRealAuthor().getId(),
-        c.writtenOn,
-        change.getCreatedOn(),
-        c.tag);
-    this.c = c;
-    this.change = change;
-    this.ps = ps;
-    this.cache = cache;
-  }
-
-  @Override
-  boolean uniquePerUpdate() {
-    return false;
-  }
-
-  @Override
-  void apply(ChangeUpdate update) {
-    throw new UnsupportedOperationException();
-  }
-
-  void applyDraft(ChangeDraftUpdate draftUpdate) {
-    if (c.revId == null) {
-      try {
-        setCommentRevId(c, cache, change, ps);
-      } catch (PatchListNotAvailableException e) {
-        logger.atWarning().log(
-            "Unable to determine parent commit of patch set %s (%s);"
-                + " omitting draft inline comment %s",
-            ps.getId(), ps.getRevision(), c);
-        return;
-      }
-    }
-    draftUpdate.putComment(c);
-  }
-
-  @Override
-  protected void addToString(ToStringHelper helper) {
-    helper.add("message", c.message);
-  }
-}
diff --git a/java/com/google/gerrit/server/notedb/rebuild/Event.java b/java/com/google/gerrit/server/notedb/rebuild/Event.java
deleted file mode 100644
index 3957c5c..0000000
--- a/java/com/google/gerrit/server/notedb/rebuild/Event.java
+++ /dev/null
@@ -1,146 +0,0 @@
-// Copyright (C) 2016 The Android Open Source Project
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-// http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-
-package com.google.gerrit.server.notedb.rebuild;
-
-import static com.google.common.base.Preconditions.checkState;
-import static com.google.gerrit.server.notedb.rebuild.ChangeRebuilderImpl.MAX_WINDOW_MS;
-
-import com.google.common.base.MoreObjects;
-import com.google.common.base.MoreObjects.ToStringHelper;
-import com.google.common.collect.ComparisonChain;
-import com.google.gerrit.reviewdb.client.Account;
-import com.google.gerrit.reviewdb.client.PatchSet;
-import com.google.gerrit.reviewdb.server.ReviewDbUtil;
-import com.google.gerrit.server.notedb.AbstractChangeUpdate;
-import com.google.gerrit.server.notedb.ChangeUpdate;
-import com.google.gwtorm.server.OrmException;
-import java.io.IOException;
-import java.sql.Timestamp;
-import java.util.ArrayList;
-import java.util.List;
-import java.util.Objects;
-
-abstract class Event implements Comparable<Event> {
-  // NOTE: EventList only supports direct subclasses, not an arbitrary
-  // hierarchy.
-
-  final Account.Id user;
-  final Account.Id realUser;
-  final String tag;
-  final boolean predatesChange;
-
-  /** Dependencies of this event; other events that must happen before this one. */
-  final List<Event> deps;
-
-  Timestamp when;
-  PatchSet.Id psId;
-
-  protected Event(
-      PatchSet.Id psId,
-      Account.Id effectiveUser,
-      Account.Id realUser,
-      Timestamp when,
-      Timestamp changeCreatedOn,
-      String tag) {
-    this.psId = psId;
-    this.user = effectiveUser;
-    this.realUser = realUser != null ? realUser : effectiveUser;
-    this.tag = tag;
-    // Truncate timestamps at the change's createdOn timestamp.
-    predatesChange = when.before(changeCreatedOn);
-    this.when = predatesChange ? changeCreatedOn : when;
-    deps = new ArrayList<>();
-  }
-
-  protected void checkUpdate(AbstractChangeUpdate update) {
-    checkState(
-        Objects.equals(update.getPatchSetId(), psId),
-        "cannot apply event for %s to update for %s",
-        update.getPatchSetId(),
-        psId);
-    checkState(
-        when.getTime() - update.getWhen().getTime() <= MAX_WINDOW_MS,
-        "event at %s outside update window starting at %s",
-        when,
-        update.getWhen());
-    checkState(
-        Objects.equals(update.getNullableAccountId(), user),
-        "cannot apply event by %s to update by %s",
-        user,
-        update.getNullableAccountId());
-  }
-
-  Event addDep(Event e) {
-    deps.add(e);
-    return this;
-  }
-
-  /**
-   * @return whether this event type must be unique per {@link ChangeUpdate}, i.e. there may be at
-   *     most one of this type.
-   */
-  abstract boolean uniquePerUpdate();
-
-  abstract void apply(ChangeUpdate update) throws OrmException, IOException;
-
-  protected boolean isPostSubmitApproval() {
-    return false;
-  }
-
-  protected boolean isSubmit() {
-    return false;
-  }
-
-  protected boolean canHaveTag() {
-    return false;
-  }
-
-  @Override
-  public String toString() {
-    ToStringHelper helper =
-        MoreObjects.toStringHelper(this)
-            .add("psId", psId)
-            .add("effectiveUser", user)
-            .add("realUser", realUser)
-            .add("when", when)
-            .add("tag", tag);
-    addToString(helper);
-    return helper.toString();
-  }
-
-  /** @param helper toString helper to add fields to */
-  protected void addToString(ToStringHelper helper) {}
-
-  @Override
-  public int compareTo(Event other) {
-    return ComparisonChain.start()
-        .compareFalseFirst(this.isFinalUpdates(), other.isFinalUpdates())
-        .compare(this.when, other.when)
-        .compareTrueFirst(isPatchSet(), isPatchSet())
-        .compareTrueFirst(this.predatesChange, other.predatesChange)
-        .compare(this.user, other.user, ReviewDbUtil.intKeyOrdering())
-        .compare(this.realUser, other.realUser, ReviewDbUtil.intKeyOrdering())
-        .compare(this.psId, other.psId, ReviewDbUtil.intKeyOrdering().nullsLast())
-        .result();
-  }
-
-  private boolean isPatchSet() {
-    return this instanceof PatchSetEvent;
-  }
-
-  private boolean isFinalUpdates() {
-    return this instanceof FinalUpdatesEvent;
-  }
-}
diff --git a/java/com/google/gerrit/server/notedb/rebuild/EventList.java b/java/com/google/gerrit/server/notedb/rebuild/EventList.java
deleted file mode 100644
index e83814d..0000000
--- a/java/com/google/gerrit/server/notedb/rebuild/EventList.java
+++ /dev/null
@@ -1,170 +0,0 @@
-// Copyright (C) 2016 The Android Open Source Project
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-// http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-
-package com.google.gerrit.server.notedb.rebuild;
-
-import static com.google.common.base.Preconditions.checkArgument;
-import static com.google.common.base.Preconditions.checkState;
-import static java.util.Objects.requireNonNull;
-
-import com.google.common.collect.Lists;
-import com.google.gerrit.reviewdb.client.Account;
-import com.google.gerrit.reviewdb.client.PatchSet;
-import java.sql.Timestamp;
-import java.util.ArrayList;
-import java.util.Iterator;
-import java.util.Objects;
-
-class EventList<E extends Event> implements Iterable<E> {
-  private final ArrayList<E> list = new ArrayList<>();
-  private boolean isSubmit;
-
-  @Override
-  public Iterator<E> iterator() {
-    return list.iterator();
-  }
-
-  void add(E e) {
-    list.add(e);
-    if (e.isSubmit()) {
-      isSubmit = true;
-    }
-  }
-
-  void clear() {
-    list.clear();
-    isSubmit = false;
-  }
-
-  boolean isEmpty() {
-    return list.isEmpty();
-  }
-
-  boolean canAdd(E e) {
-    if (isEmpty()) {
-      return true;
-    }
-    if (e instanceof FinalUpdatesEvent) {
-      return false; // FinalUpdatesEvent always gets its own update.
-    }
-
-    Event last = getLast();
-    if (!Objects.equals(e.user, last.user)
-        || !Objects.equals(e.realUser, last.realUser)
-        || !e.psId.equals(last.psId)) {
-      return false; // Different patch set or author.
-    }
-    if (e.canHaveTag() && canHaveTag() && !Objects.equals(e.tag, getTag())) {
-      // We should trust the tag field, and it doesn't match.
-      return false;
-    }
-    if (e.isPostSubmitApproval() && isSubmit) {
-      // Post-submit approvals must come after the update that submits.
-      return false;
-    }
-
-    long t = e.when.getTime();
-    long tFirst = getFirstTime();
-    long tLast = getLastTime();
-    checkArgument(t >= tLast, "event %s is before previous event in list %s", e, last);
-    if (t - tLast > ChangeRebuilderImpl.MAX_DELTA_MS
-        || t - tFirst > ChangeRebuilderImpl.MAX_WINDOW_MS) {
-      return false; // Too much time elapsed.
-    }
-
-    if (!e.uniquePerUpdate()) {
-      return true;
-    }
-    for (Event o : this) {
-      if (e.getClass() == o.getClass()) {
-        return false; // Only one event of this type allowed per update.
-      }
-    }
-
-    // TODO(dborowitz): Additional heuristics, like keeping events separate if
-    // they affect overlapping fields within a single entity.
-
-    return true;
-  }
-
-  Timestamp getWhen() {
-    return get(0).when;
-  }
-
-  PatchSet.Id getPatchSetId() {
-    PatchSet.Id id = requireNonNull(get(0).psId);
-    for (int i = 1; i < size(); i++) {
-      checkState(
-          get(i).psId.equals(id), "mismatched patch sets in EventList: %s != %s", id, get(i).psId);
-    }
-    return id;
-  }
-
-  Account.Id getAccountId() {
-    Account.Id id = get(0).user;
-    for (int i = 1; i < size(); i++) {
-      checkState(
-          Objects.equals(id, get(i).user),
-          "mismatched users in EventList: %s != %s",
-          id,
-          get(i).user);
-    }
-    return id;
-  }
-
-  Account.Id getRealAccountId() {
-    Account.Id id = get(0).realUser;
-    for (int i = 1; i < size(); i++) {
-      checkState(
-          Objects.equals(id, get(i).realUser),
-          "mismatched real users in EventList: %s != %s",
-          id,
-          get(i).realUser);
-    }
-    return id;
-  }
-
-  String getTag() {
-    for (E e : Lists.reverse(list)) {
-      if (e.tag != null) {
-        return e.tag;
-      }
-    }
-    return null;
-  }
-
-  private boolean canHaveTag() {
-    return list.stream().anyMatch(Event::canHaveTag);
-  }
-
-  private E get(int i) {
-    return list.get(i);
-  }
-
-  private int size() {
-    return list.size();
-  }
-
-  private E getLast() {
-    return list.get(list.size() - 1);
-  }
-
-  private long getLastTime() {
-    return getLast().when.getTime();
-  }
-
-  private long getFirstTime() {
-    return list.get(0).when.getTime();
-  }
-}
diff --git a/java/com/google/gerrit/server/notedb/rebuild/EventSorter.java b/java/com/google/gerrit/server/notedb/rebuild/EventSorter.java
deleted file mode 100644
index 077a027..0000000
--- a/java/com/google/gerrit/server/notedb/rebuild/EventSorter.java
+++ /dev/null
@@ -1,112 +0,0 @@
-// Copyright (C) 2016 The Android Open Source Project
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-// http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-
-package com.google.gerrit.server.notedb.rebuild;
-
-import static com.google.common.base.Preconditions.checkArgument;
-import static com.google.common.base.Preconditions.checkState;
-
-import com.google.common.collect.ListMultimap;
-import com.google.common.collect.MultimapBuilder;
-import com.google.common.collect.SetMultimap;
-import java.util.Collections;
-import java.util.LinkedHashSet;
-import java.util.List;
-import java.util.PriorityQueue;
-
-/**
- * Helper to sort a list of events.
- *
- * <p>Events are sorted in two passes:
- *
- * <ol>
- *   <li>Sort by natural order (timestamp, patch set, author, etc.)
- *   <li>Postpone any events with dependencies to occur only after all of their dependencies, where
- *       this violates natural order.
- * </ol>
- *
- * {@link #sort()} modifies the event list in place (similar to {@link Collections#sort(List)}), but
- * does not modify any event. In particular, events might end up out of order with respect to
- * timestamp; callers are responsible for adjusting timestamps later if they prefer monotonicity.
- */
-class EventSorter {
-  private final List<Event> out;
-  private final LinkedHashSet<Event> sorted;
-  private ListMultimap<Event, Event> waiting;
-  private SetMultimap<Event, Event> deps;
-
-  EventSorter(List<Event> events) {
-    LinkedHashSet<Event> all = new LinkedHashSet<>(events);
-    out = events;
-
-    for (Event e : events) {
-      for (Event d : e.deps) {
-        checkArgument(all.contains(d), "dep %s of %s not in input list", d, e);
-      }
-    }
-
-    all.clear();
-    sorted = all; // Presized.
-  }
-
-  void sort() {
-    // First pass: sort by natural order.
-    PriorityQueue<Event> todo = new PriorityQueue<>(out);
-
-    // Populate waiting map after initial sort to preserve natural order.
-    waiting = MultimapBuilder.hashKeys().arrayListValues().build();
-    deps = MultimapBuilder.hashKeys().hashSetValues().build();
-    for (Event e : todo) {
-      for (Event d : e.deps) {
-        deps.put(e, d);
-        waiting.put(d, e);
-      }
-    }
-
-    // Second pass: enforce dependencies.
-    int size = out.size();
-    while (!todo.isEmpty()) {
-      process(todo.remove(), todo);
-    }
-    checkState(
-        sorted.size() == size, "event sort expected %s elements, got %s", size, sorted.size());
-
-    // Modify out in-place a la Collections#sort.
-    out.clear();
-    out.addAll(sorted);
-  }
-
-  void process(Event e, PriorityQueue<Event> todo) {
-    if (sorted.contains(e)) {
-      return; // Already emitted.
-    }
-    if (!deps.get(e).isEmpty()) {
-      // Not all events that e depends on have been emitted yet. Ignore e for
-      // now; it will get added back to the queue in the block below once its
-      // last dependency is processed.
-      return;
-    }
-
-    // All events that e depends on have been emitted, so e can be emitted.
-    sorted.add(e);
-
-    // Remove e from the dependency set of all events waiting on e, and add
-    // those events back to the queue in the original priority order for
-    // reconsideration.
-    for (Event w : waiting.get(e)) {
-      deps.get(w).remove(e);
-      todo.add(w);
-    }
-  }
-}
diff --git a/java/com/google/gerrit/server/notedb/rebuild/FinalUpdatesEvent.java b/java/com/google/gerrit/server/notedb/rebuild/FinalUpdatesEvent.java
deleted file mode 100644
index 55d5a31..0000000
--- a/java/com/google/gerrit/server/notedb/rebuild/FinalUpdatesEvent.java
+++ /dev/null
@@ -1,101 +0,0 @@
-// Copyright (C) 2016 The Android Open Source Project
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-// http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-
-package com.google.gerrit.server.notedb.rebuild;
-
-import static com.google.gerrit.reviewdb.server.ReviewDbUtil.intKeyOrdering;
-
-import com.google.common.base.MoreObjects.ToStringHelper;
-import com.google.common.collect.ImmutableCollection;
-import com.google.gerrit.reviewdb.client.Change;
-import com.google.gerrit.reviewdb.client.PatchSet;
-import com.google.gerrit.server.notedb.ChangeUpdate;
-import com.google.gwtorm.server.OrmException;
-import java.util.Objects;
-
-class FinalUpdatesEvent extends Event {
-  private final Change change;
-  private final Change noteDbChange;
-  private final ImmutableCollection<PatchSet> patchSets;
-
-  FinalUpdatesEvent(Change change, Change noteDbChange, ImmutableCollection<PatchSet> patchSets) {
-    super(
-        change.currentPatchSetId(),
-        change.getOwner(),
-        change.getOwner(),
-        change.getLastUpdatedOn(),
-        change.getCreatedOn(),
-        null);
-    this.change = change;
-    this.noteDbChange = noteDbChange;
-    this.patchSets = patchSets;
-  }
-
-  @Override
-  boolean uniquePerUpdate() {
-    return true;
-  }
-
-  @SuppressWarnings("deprecation")
-  @Override
-  void apply(ChangeUpdate update) throws OrmException {
-    if (!Objects.equals(change.getTopic(), noteDbChange.getTopic())) {
-      update.setTopic(change.getTopic());
-    }
-    if (!statusMatches()) {
-      // TODO(dborowitz): Stamp approximate approvals at this time.
-      update.fixStatus(change.getStatus());
-    }
-    if (change.isPrivate() != noteDbChange.isPrivate()) {
-      update.setPrivate(change.isPrivate());
-    }
-    if (change.isWorkInProgress() != noteDbChange.isWorkInProgress()) {
-      update.setWorkInProgress(change.isWorkInProgress());
-    }
-    if (change.getSubmissionId() != null && noteDbChange.getSubmissionId() == null) {
-      update.setSubmissionId(change.getSubmissionId());
-    }
-    if (!Objects.equals(change.getAssignee(), noteDbChange.getAssignee())) {
-      // TODO(dborowitz): Parse intermediate values out from messages.
-      update.setAssignee(change.getAssignee());
-    }
-    if (!patchSets.isEmpty() && !highestNumberedPatchSetIsCurrent()) {
-      update.setCurrentPatchSet();
-    }
-    if (!update.isEmpty()) {
-      update.setSubjectForCommit("Final NoteDb migration updates");
-    }
-  }
-
-  private boolean statusMatches() {
-    return Objects.equals(change.getStatus(), noteDbChange.getStatus());
-  }
-
-  private boolean highestNumberedPatchSetIsCurrent() {
-    PatchSet.Id max = patchSets.stream().map(PatchSet::getId).max(intKeyOrdering()).get();
-    return max.equals(change.currentPatchSetId());
-  }
-
-  @Override
-  protected boolean isSubmit() {
-    return change.getStatus() == Change.Status.MERGED;
-  }
-
-  @Override
-  protected void addToString(ToStringHelper helper) {
-    if (!statusMatches()) {
-      helper.add("status", change.getStatus());
-    }
-  }
-}
diff --git a/java/com/google/gerrit/server/notedb/rebuild/GcAllUsers.java b/java/com/google/gerrit/server/notedb/rebuild/GcAllUsers.java
deleted file mode 100644
index f2a5cc6..0000000
--- a/java/com/google/gerrit/server/notedb/rebuild/GcAllUsers.java
+++ /dev/null
@@ -1,121 +0,0 @@
-// 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.
-
-package com.google.gerrit.server.notedb.rebuild;
-
-import static java.util.Objects.requireNonNull;
-import static org.eclipse.jgit.lib.ConfigConstants.CONFIG_GC_SECTION;
-import static org.eclipse.jgit.lib.ConfigConstants.CONFIG_KEY_AUTO;
-
-import com.google.common.base.Throwables;
-import com.google.common.collect.ImmutableList;
-import com.google.common.flogger.FluentLogger;
-import com.google.gerrit.common.Nullable;
-import com.google.gerrit.common.data.GarbageCollectionResult;
-import com.google.gerrit.server.config.AllUsersName;
-import com.google.gerrit.server.git.GarbageCollection;
-import com.google.gerrit.server.git.GitRepositoryManager;
-import com.google.gerrit.server.git.LocalDiskRepositoryManager;
-import com.google.inject.Inject;
-import com.google.inject.Singleton;
-import java.io.IOException;
-import java.io.PrintWriter;
-import java.util.function.Consumer;
-import org.eclipse.jgit.lib.Repository;
-
-@Singleton
-public class GcAllUsers {
-  private static final FluentLogger logger = FluentLogger.forEnclosingClass();
-
-  private final AllUsersName allUsers;
-  private final GarbageCollection.Factory gcFactory;
-  private final GitRepositoryManager repoManager;
-
-  @Inject
-  GcAllUsers(
-      AllUsersName allUsers,
-      GarbageCollection.Factory gcFactory,
-      GitRepositoryManager repoManager) {
-    this.allUsers = allUsers;
-    this.gcFactory = gcFactory;
-    this.repoManager = repoManager;
-  }
-
-  public void runWithLogger() {
-    // Print log messages using logger, and skip progress.
-    run(s -> logger.atInfo().log(s), null);
-  }
-
-  public void run(PrintWriter writer) {
-    // Print both log messages and progress to given writer.
-    run(requireNonNull(writer)::println, writer);
-  }
-
-  private void run(Consumer<String> logOneLine, @Nullable PrintWriter progressWriter) {
-    if (!(repoManager instanceof LocalDiskRepositoryManager)) {
-      logOneLine.accept("Skipping GC of " + allUsers + "; not a local disk repo");
-      return;
-    }
-    if (!enableAutoGc(logOneLine)) {
-      logOneLine.accept(
-          "Skipping GC of "
-              + allUsers
-              + " due to disabling "
-              + CONFIG_GC_SECTION
-              + "."
-              + CONFIG_KEY_AUTO);
-      logOneLine.accept(
-          "If loading accounts is slow after the NoteDb migration, run `git gc` on "
-              + allUsers
-              + " manually");
-      return;
-    }
-
-    if (progressWriter == null) {
-      // Mimic log line from GarbageCollection.
-      logOneLine.accept("collecting garbage for \"" + allUsers + "\":\n");
-    }
-    GarbageCollectionResult result =
-        gcFactory.create().run(ImmutableList.of(allUsers), progressWriter);
-    if (!result.hasErrors()) {
-      return;
-    }
-    for (GarbageCollectionResult.Error e : result.getErrors()) {
-      switch (e.getType()) {
-        case GC_ALREADY_SCHEDULED:
-          logOneLine.accept("GC already scheduled for " + e.getProjectName());
-          break;
-        case GC_FAILED:
-          logOneLine.accept("GC failed for " + e.getProjectName());
-          break;
-        case REPOSITORY_NOT_FOUND:
-          logOneLine.accept(e.getProjectName() + " repo not found");
-          break;
-        default:
-          logOneLine.accept("GC failed for " + e.getProjectName() + ": " + e.getType());
-          break;
-      }
-    }
-  }
-
-  private boolean enableAutoGc(Consumer<String> logOneLine) {
-    try (Repository repo = repoManager.openRepository(allUsers)) {
-      return repo.getConfig().getInt(CONFIG_GC_SECTION, CONFIG_KEY_AUTO, -1) != 0;
-    } catch (IOException e) {
-      logOneLine.accept(
-          "Error reading config for " + allUsers + ":\n" + Throwables.getStackTraceAsString(e));
-      return false;
-    }
-  }
-}
diff --git a/java/com/google/gerrit/server/notedb/rebuild/HashtagsEvent.java b/java/com/google/gerrit/server/notedb/rebuild/HashtagsEvent.java
deleted file mode 100644
index 4f6f6ad..0000000
--- a/java/com/google/gerrit/server/notedb/rebuild/HashtagsEvent.java
+++ /dev/null
@@ -1,62 +0,0 @@
-// Copyright (C) 2016 The Android Open Source Project
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-// http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-
-package com.google.gerrit.server.notedb.rebuild;
-
-import com.google.common.base.MoreObjects.ToStringHelper;
-import com.google.gerrit.reviewdb.client.Account;
-import com.google.gerrit.reviewdb.client.PatchSet;
-import com.google.gerrit.server.notedb.ChangeUpdate;
-import com.google.gwtorm.server.OrmException;
-import java.sql.Timestamp;
-import java.util.Set;
-
-class HashtagsEvent extends Event {
-  private final Set<String> hashtags;
-
-  HashtagsEvent(
-      PatchSet.Id psId,
-      Account.Id who,
-      Timestamp when,
-      Set<String> hashtags,
-      Timestamp changeCreatdOn) {
-    super(
-        psId,
-        who,
-        who,
-        when,
-        changeCreatdOn,
-        // Somewhat confusingly, hashtags do not use the setTag method on
-        // AbstractChangeUpdate, so pass null as the tag.
-        null);
-    this.hashtags = hashtags;
-  }
-
-  @Override
-  boolean uniquePerUpdate() {
-    // Since these are produced from existing commits in the old NoteDb graph,
-    // we know that there must be one per commit in the rebuilt graph.
-    return true;
-  }
-
-  @Override
-  void apply(ChangeUpdate update) throws OrmException {
-    update.setHashtags(hashtags);
-  }
-
-  @Override
-  protected void addToString(ToStringHelper helper) {
-    helper.add("hashtags", hashtags);
-  }
-}
diff --git a/java/com/google/gerrit/server/notedb/rebuild/PatchSetEvent.java b/java/com/google/gerrit/server/notedb/rebuild/PatchSetEvent.java
deleted file mode 100644
index acb80c0..0000000
--- a/java/com/google/gerrit/server/notedb/rebuild/PatchSetEvent.java
+++ /dev/null
@@ -1,86 +0,0 @@
-// Copyright (C) 2016 The Android Open Source Project
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-// http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-
-package com.google.gerrit.server.notedb.rebuild;
-
-import com.google.gerrit.reviewdb.client.Change;
-import com.google.gerrit.reviewdb.client.PatchSet;
-import com.google.gerrit.server.notedb.ChangeUpdate;
-import com.google.gwtorm.server.OrmException;
-import java.io.IOException;
-import java.util.List;
-import org.eclipse.jgit.errors.InvalidObjectIdException;
-import org.eclipse.jgit.errors.MissingObjectException;
-import org.eclipse.jgit.lib.ObjectId;
-import org.eclipse.jgit.revwalk.RevWalk;
-
-class PatchSetEvent extends Event {
-  private final Change change;
-  private final PatchSet ps;
-  private final RevWalk rw;
-  boolean createChange;
-
-  PatchSetEvent(Change change, PatchSet ps, RevWalk rw) {
-    super(
-        ps.getId(),
-        ps.getUploader(),
-        ps.getUploader(),
-        ps.getCreatedOn(),
-        change.getCreatedOn(),
-        null);
-    this.change = change;
-    this.ps = ps;
-    this.rw = rw;
-  }
-
-  @Override
-  boolean uniquePerUpdate() {
-    return true;
-  }
-
-  @Override
-  void apply(ChangeUpdate update) throws IOException, OrmException {
-    checkUpdate(update);
-    if (createChange) {
-      ChangeRebuilderImpl.createChange(update, change);
-    } else {
-      update.setSubject(change.getSubject());
-      update.setSubjectForCommit("Create patch set " + ps.getPatchSetId());
-    }
-    setRevision(update, ps);
-    update.setPsDescription(ps.getDescription());
-    List<String> groups = ps.getGroups();
-    if (!groups.isEmpty()) {
-      update.setGroups(ps.getGroups());
-    }
-  }
-
-  private void setRevision(ChangeUpdate update, PatchSet ps) throws IOException {
-    String rev = ps.getRevision().get();
-    String cert = ps.getPushCertificate();
-    ObjectId id;
-    try {
-      id = ObjectId.fromString(rev);
-    } catch (InvalidObjectIdException e) {
-      update.setRevisionForMissingCommit(rev, cert);
-      return;
-    }
-    try {
-      update.setCommit(rw, id, cert);
-    } catch (MissingObjectException e) {
-      update.setRevisionForMissingCommit(rev, cert);
-      return;
-    }
-  }
-}
diff --git a/java/com/google/gerrit/server/notedb/rebuild/ReviewerEvent.java b/java/com/google/gerrit/server/notedb/rebuild/ReviewerEvent.java
deleted file mode 100644
index 2ecf969..0000000
--- a/java/com/google/gerrit/server/notedb/rebuild/ReviewerEvent.java
+++ /dev/null
@@ -1,63 +0,0 @@
-// Copyright (C) 2016 The Android Open Source Project
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-// http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-
-package com.google.gerrit.server.notedb.rebuild;
-
-import com.google.common.base.MoreObjects.ToStringHelper;
-import com.google.common.collect.Table;
-import com.google.gerrit.reviewdb.client.Account;
-import com.google.gerrit.server.notedb.ChangeUpdate;
-import com.google.gerrit.server.notedb.ReviewerStateInternal;
-import com.google.gwtorm.server.OrmException;
-import java.io.IOException;
-import java.sql.Timestamp;
-
-class ReviewerEvent extends Event {
-  private Table.Cell<ReviewerStateInternal, Account.Id, Timestamp> reviewer;
-
-  ReviewerEvent(
-      Table.Cell<ReviewerStateInternal, Account.Id, Timestamp> reviewer,
-      Timestamp changeCreatedOn) {
-    super(
-        // Reviewers aren't generally associated with a particular patch set
-        // (although as an implementation detail they were in ReviewDb). Just
-        // use the latest patch set at the time of the event.
-        null,
-        reviewer.getColumnKey(),
-        // TODO(dborowitz): Real account ID shouldn't really matter for
-        // reviewers, but we might have to deal with this to avoid ChangeBundle
-        // diffs when run against real data.
-        reviewer.getColumnKey(),
-        reviewer.getValue(),
-        changeCreatedOn,
-        null);
-    this.reviewer = reviewer;
-  }
-
-  @Override
-  boolean uniquePerUpdate() {
-    return false;
-  }
-
-  @Override
-  void apply(ChangeUpdate update) throws IOException, OrmException {
-    checkUpdate(update);
-    update.putReviewer(reviewer.getColumnKey(), reviewer.getRowKey());
-  }
-
-  @Override
-  protected void addToString(ToStringHelper helper) {
-    helper.add("account", reviewer.getColumnKey()).add("state", reviewer.getRowKey());
-  }
-}
diff --git a/java/com/google/gerrit/server/schema/DatabaseModule.java b/java/com/google/gerrit/server/schema/DatabaseModule.java
index 9c64bf2..c65b20e 100644
--- a/java/com/google/gerrit/server/schema/DatabaseModule.java
+++ b/java/com/google/gerrit/server/schema/DatabaseModule.java
@@ -16,8 +16,6 @@
 
 import com.google.gerrit.extensions.config.FactoryModule;
 import com.google.gerrit.reviewdb.server.ReviewDb;
-import com.google.gerrit.server.notedb.ChangeBundleReader;
-import com.google.gerrit.server.notedb.GwtormChangeBundleReader;
 import com.google.gwtorm.server.OrmException;
 import com.google.gwtorm.server.SchemaFactory;
 import com.google.inject.Key;
@@ -35,6 +33,5 @@
             () -> {
               throw new OrmException("ReviewDb no longer exists");
             });
-    bind(ChangeBundleReader.class).to(GwtormChangeBundleReader.class);
   }
 }
diff --git a/java/com/google/gerrit/testing/InMemoryModule.java b/java/com/google/gerrit/testing/InMemoryModule.java
index 911f5a2..682e8c2 100644
--- a/java/com/google/gerrit/testing/InMemoryModule.java
+++ b/java/com/google/gerrit/testing/InMemoryModule.java
@@ -73,8 +73,6 @@
 import com.google.gerrit.server.index.group.GroupIndexCollection;
 import com.google.gerrit.server.index.group.GroupSchemaDefinitions;
 import com.google.gerrit.server.mail.SignedTokenEmailTokenVerifier;
-import com.google.gerrit.server.notedb.ChangeBundleReader;
-import com.google.gerrit.server.notedb.GwtormChangeBundleReader;
 import com.google.gerrit.server.notedb.MutableNotesMigration;
 import com.google.gerrit.server.notedb.NotesMigration;
 import com.google.gerrit.server.patch.DiffExecutor;
@@ -198,7 +196,6 @@
     bind(ListeningExecutorService.class)
         .annotatedWith(ChangeUpdateExecutor.class)
         .toInstance(MoreExecutors.newDirectExecutorService());
-    bind(ChangeBundleReader.class).to(GwtormChangeBundleReader.class);
     bind(SecureStore.class).to(DefaultSecureStore.class);
 
     TypeLiteral<SchemaFactory<ReviewDb>> schemaFactory =
diff --git a/java/com/google/gerrit/testing/NoteDbChecker.java b/java/com/google/gerrit/testing/NoteDbChecker.java
deleted file mode 100644
index 1dc8ee2..0000000
--- a/java/com/google/gerrit/testing/NoteDbChecker.java
+++ /dev/null
@@ -1,225 +0,0 @@
-// Copyright (C) 2016 The Android Open Source Project
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-// http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-
-package com.google.gerrit.testing;
-
-import static com.google.common.truth.Truth.assertThat;
-import static java.util.Comparator.comparing;
-import static java.util.stream.Collectors.toList;
-
-import com.google.common.base.Joiner;
-import com.google.common.collect.ImmutableListMultimap;
-import com.google.common.collect.ListMultimap;
-import com.google.common.flogger.FluentLogger;
-import com.google.gerrit.reviewdb.client.Change;
-import com.google.gerrit.reviewdb.client.Project;
-import com.google.gerrit.reviewdb.client.RefNames;
-import com.google.gerrit.reviewdb.server.ReviewDb;
-import com.google.gerrit.reviewdb.server.ReviewDbUtil;
-import com.google.gerrit.server.CommentsUtil;
-import com.google.gerrit.server.git.GitRepositoryManager;
-import com.google.gerrit.server.notedb.ChangeBundle;
-import com.google.gerrit.server.notedb.ChangeBundleReader;
-import com.google.gerrit.server.notedb.ChangeNotes;
-import com.google.gerrit.server.notedb.MutableNotesMigration;
-import com.google.gerrit.server.notedb.rebuild.ChangeRebuilder;
-import com.google.gwtorm.client.IntKey;
-import com.google.gwtorm.server.OrmException;
-import com.google.gwtorm.server.OrmRuntimeException;
-import com.google.inject.Inject;
-import com.google.inject.Provider;
-import com.google.inject.Singleton;
-import java.util.ArrayList;
-import java.util.Arrays;
-import java.util.List;
-import java.util.stream.Stream;
-import org.eclipse.jgit.errors.RepositoryNotFoundException;
-import org.eclipse.jgit.lib.Repository;
-import org.junit.runner.Description;
-
-@Singleton
-public class NoteDbChecker {
-  private static final FluentLogger logger = FluentLogger.forEnclosingClass();
-
-  private final Provider<ReviewDb> dbProvider;
-  private final GitRepositoryManager repoManager;
-  private final MutableNotesMigration notesMigration;
-  private final ChangeBundleReader bundleReader;
-  private final ChangeNotes.Factory notesFactory;
-  private final ChangeRebuilder changeRebuilder;
-  private final CommentsUtil commentsUtil;
-
-  @Inject
-  NoteDbChecker(
-      Provider<ReviewDb> dbProvider,
-      GitRepositoryManager repoManager,
-      MutableNotesMigration notesMigration,
-      ChangeBundleReader bundleReader,
-      ChangeNotes.Factory notesFactory,
-      ChangeRebuilder changeRebuilder,
-      CommentsUtil commentsUtil) {
-    this.dbProvider = dbProvider;
-    this.repoManager = repoManager;
-    this.bundleReader = bundleReader;
-    this.notesMigration = notesMigration;
-    this.notesFactory = notesFactory;
-    this.changeRebuilder = changeRebuilder;
-    this.commentsUtil = commentsUtil;
-  }
-
-  public void rebuildAndCheckAllChanges() throws Exception {
-    rebuildAndCheckChanges(
-        getUnwrappedDb().changes().all().toList().stream().map(Change::getId),
-        ImmutableListMultimap.of());
-  }
-
-  public void rebuildAndCheckChanges(Change.Id... changeIds) throws Exception {
-    rebuildAndCheckChanges(Arrays.stream(changeIds), ImmutableListMultimap.of());
-  }
-
-  private void rebuildAndCheckChanges(
-      Stream<Change.Id> changeIds, ListMultimap<Change.Id, String> expectedDiffs) throws Exception {
-    ReviewDb db = getUnwrappedDb();
-
-    List<ChangeBundle> allExpected = readExpected(changeIds);
-
-    boolean oldWrite = notesMigration.rawWriteChangesSetting();
-    boolean oldRead = notesMigration.readChanges();
-    try {
-      notesMigration.setWriteChanges(true);
-      notesMigration.setReadChanges(true);
-      List<String> msgs = new ArrayList<>();
-      for (ChangeBundle expected : allExpected) {
-        Change c = expected.getChange();
-        try {
-          changeRebuilder.rebuild(db, c.getId());
-        } catch (RepositoryNotFoundException e) {
-          msgs.add("Repository not found for change, cannot convert: " + c);
-        }
-      }
-
-      checkActual(allExpected, expectedDiffs, msgs);
-    } finally {
-      notesMigration.setReadChanges(oldRead);
-      notesMigration.setWriteChanges(oldWrite);
-    }
-  }
-
-  public void checkChanges(Change.Id... changeIds) throws Exception {
-    checkActual(
-        readExpected(Arrays.stream(changeIds)), ImmutableListMultimap.of(), new ArrayList<>());
-  }
-
-  public void rebuildAndCheckChange(Change.Id changeId, String... expectedDiff) throws Exception {
-    ImmutableListMultimap.Builder<Change.Id, String> b = ImmutableListMultimap.builder();
-    b.putAll(changeId, Arrays.asList(expectedDiff));
-    rebuildAndCheckChanges(Stream.of(changeId), b.build());
-  }
-
-  public void assertNoChangeRef(Project.NameKey project, Change.Id changeId) throws Exception {
-    try (Repository repo = repoManager.openRepository(project)) {
-      assertThat(repo.exactRef(RefNames.changeMetaRef(changeId))).isNull();
-    }
-  }
-
-  public void assertNoReviewDbChanges(Description desc) throws Exception {
-    ReviewDb db = getUnwrappedDb();
-    assertThat(db.changes().all().toList()).named("Changes in " + desc.getTestClass()).isEmpty();
-    assertThat(db.changeMessages().all().toList())
-        .named("ChangeMessages in " + desc.getTestClass())
-        .isEmpty();
-    assertThat(db.patchSets().all().toList())
-        .named("PatchSets in " + desc.getTestClass())
-        .isEmpty();
-    assertThat(db.patchSetApprovals().all().toList())
-        .named("PatchSetApprovals in " + desc.getTestClass())
-        .isEmpty();
-    assertThat(db.patchComments().all().toList())
-        .named("PatchLineComments in " + desc.getTestClass())
-        .isEmpty();
-  }
-
-  private List<ChangeBundle> readExpected(Stream<Change.Id> changeIds) throws Exception {
-    boolean old = notesMigration.readChanges();
-    try {
-      notesMigration.setReadChanges(false);
-      return changeIds
-          .sorted(comparing(IntKey::get))
-          .map(this::readBundleUnchecked)
-          .collect(toList());
-    } finally {
-      notesMigration.setReadChanges(old);
-    }
-  }
-
-  private ChangeBundle readBundleUnchecked(Change.Id id) {
-    try {
-      return bundleReader.fromReviewDb(getUnwrappedDb(), id);
-    } catch (OrmException e) {
-      throw new OrmRuntimeException(e);
-    }
-  }
-
-  private void checkActual(
-      List<ChangeBundle> allExpected,
-      ListMultimap<Change.Id, String> expectedDiffs,
-      List<String> msgs)
-      throws Exception {
-    ReviewDb db = getUnwrappedDb();
-    boolean oldRead = notesMigration.readChanges();
-    boolean oldWrite = notesMigration.rawWriteChangesSetting();
-    try {
-      notesMigration.setWriteChanges(true);
-      notesMigration.setReadChanges(true);
-      for (ChangeBundle expected : allExpected) {
-        Change c = expected.getChange();
-        ChangeBundle actual;
-        try {
-          actual =
-              ChangeBundle.fromNotes(
-                  commentsUtil, notesFactory.create(db, c.getProject(), c.getId()));
-        } catch (Throwable t) {
-          String msg = "Error converting change: " + c;
-          msgs.add(msg);
-          logger.atSevere().withCause(t).log(msg);
-          continue;
-        }
-        List<String> diff = expected.differencesFrom(actual);
-        List<String> expectedDiff = expectedDiffs.get(c.getId());
-        if (!diff.equals(expectedDiff)) {
-          msgs.add("Differences between ReviewDb and NoteDb for " + c + ":");
-          msgs.addAll(diff);
-          if (!expectedDiff.isEmpty()) {
-            msgs.add("Expected differences:");
-            msgs.addAll(expectedDiff);
-          }
-          msgs.add("");
-        } else {
-          System.err.println("NoteDb conversion of change " + c.getId() + " successful");
-        }
-      }
-    } finally {
-      notesMigration.setReadChanges(oldRead);
-      notesMigration.setWriteChanges(oldWrite);
-    }
-    if (!msgs.isEmpty()) {
-      throw new AssertionError(Joiner.on('\n').join(msgs));
-    }
-  }
-
-  private ReviewDb getUnwrappedDb() {
-    ReviewDb db = dbProvider.get();
-    return ReviewDbUtil.unwrapDb(db);
-  }
-}
diff --git a/javatests/com/google/gerrit/acceptance/api/accounts/AccountIT.java b/javatests/com/google/gerrit/acceptance/api/accounts/AccountIT.java
index 2980b78..cce7bca 100644
--- a/javatests/com/google/gerrit/acceptance/api/accounts/AccountIT.java
+++ b/javatests/com/google/gerrit/acceptance/api/accounts/AccountIT.java
@@ -123,7 +123,6 @@
 import com.google.gerrit.server.git.meta.MetaDataUpdate;
 import com.google.gerrit.server.index.account.AccountIndexer;
 import com.google.gerrit.server.index.account.StalenessChecker;
-import com.google.gerrit.server.notedb.rebuild.ChangeRebuilderImpl;
 import com.google.gerrit.server.project.ProjectConfig;
 import com.google.gerrit.server.project.RefPattern;
 import com.google.gerrit.server.query.account.InternalAccountQuery;
@@ -468,7 +467,7 @@
       RevCommit c = rw.parseCommit(ref.getObjectId());
       long timestampDiffMs =
           Math.abs(c.getCommitTime() * 1000L - getAccount(accountId).getRegisteredOn().getTime());
-      assertThat(timestampDiffMs).isAtMost(ChangeRebuilderImpl.MAX_WINDOW_MS);
+      assertThat(timestampDiffMs).isAtMost(SECONDS.toMillis(1));
 
       // Check the 'account.config' file.
       try (TreeWalk tw = TreeWalk.forPath(or, AccountProperties.ACCOUNT_CONFIG, c.getTree())) {
diff --git a/javatests/com/google/gerrit/server/notedb/AbstractChangeNotesTest.java b/javatests/com/google/gerrit/server/notedb/AbstractChangeNotesTest.java
index d00f96b..ed4aacb 100644
--- a/javatests/com/google/gerrit/server/notedb/AbstractChangeNotesTest.java
+++ b/javatests/com/google/gerrit/server/notedb/AbstractChangeNotesTest.java
@@ -137,7 +137,7 @@
                 install(new GitModule());
 
                 install(new DefaultUrlFormatter.Module());
-                install(NoteDbModule.forTest(testConfig));
+                install(NoteDbModule.forTest());
                 bind(AllUsersName.class).toProvider(AllUsersNameProvider.class);
                 bind(String.class).annotatedWith(GerritServerId.class).toInstance("gerrit");
                 bind(GitRepositoryManager.class).toInstance(repoManager);
@@ -172,11 +172,6 @@
                         () -> {
                           throw new UnsupportedOperationException();
                         });
-                bind(ChangeBundleReader.class)
-                    .toInstance(
-                        (db, id) -> {
-                          throw new UnsupportedOperationException();
-                        });
               }
             });
 
diff --git a/javatests/com/google/gerrit/server/notedb/ChangeBundleTest.java b/javatests/com/google/gerrit/server/notedb/ChangeBundleTest.java
deleted file mode 100644
index fc2a272..0000000
--- a/javatests/com/google/gerrit/server/notedb/ChangeBundleTest.java
+++ /dev/null
@@ -1,1976 +0,0 @@
-// Copyright (C) 2016 The Android Open Source Project
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-// http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-
-package com.google.gerrit.server.notedb;
-
-import static com.google.common.base.Preconditions.checkArgument;
-import static com.google.common.truth.Truth.assertThat;
-import static com.google.gerrit.server.notedb.ChangeBundle.Source.NOTE_DB;
-import static com.google.gerrit.server.notedb.ChangeBundle.Source.REVIEW_DB;
-import static com.google.gerrit.server.notedb.ReviewerStateInternal.CC;
-import static com.google.gerrit.server.notedb.ReviewerStateInternal.REVIEWER;
-import static com.google.gerrit.server.util.time.TimeUtil.truncateToSecond;
-import static java.util.concurrent.TimeUnit.MILLISECONDS;
-import static java.util.concurrent.TimeUnit.SECONDS;
-
-import com.google.common.collect.HashBasedTable;
-import com.google.common.collect.ImmutableList;
-import com.google.common.collect.Table;
-import com.google.gerrit.reviewdb.client.Account;
-import com.google.gerrit.reviewdb.client.Change;
-import com.google.gerrit.reviewdb.client.ChangeMessage;
-import com.google.gerrit.reviewdb.client.LabelId;
-import com.google.gerrit.reviewdb.client.Patch;
-import com.google.gerrit.reviewdb.client.PatchLineComment;
-import com.google.gerrit.reviewdb.client.PatchSet;
-import com.google.gerrit.reviewdb.client.PatchSetApproval;
-import com.google.gerrit.reviewdb.client.Project;
-import com.google.gerrit.reviewdb.client.RevId;
-import com.google.gerrit.server.ReviewerSet;
-import com.google.gerrit.server.notedb.rebuild.ChangeRebuilderImpl;
-import com.google.gerrit.server.util.time.TimeUtil;
-import com.google.gerrit.testing.GerritBaseTests;
-import com.google.gerrit.testing.TestChanges;
-import com.google.gerrit.testing.TestTimeUtil;
-import com.google.gwtorm.protobuf.CodecFactory;
-import com.google.gwtorm.protobuf.ProtobufCodec;
-import java.sql.Timestamp;
-import java.time.LocalDate;
-import java.time.Month;
-import java.time.ZoneId;
-import java.util.ArrayList;
-import java.util.Arrays;
-import java.util.Collections;
-import java.util.List;
-import java.util.TimeZone;
-import org.junit.After;
-import org.junit.Before;
-import org.junit.Test;
-
-public class ChangeBundleTest extends GerritBaseTests {
-  private static final ProtobufCodec<Change> CHANGE_CODEC = CodecFactory.encoder(Change.class);
-  private static final ProtobufCodec<ChangeMessage> CHANGE_MESSAGE_CODEC =
-      CodecFactory.encoder(ChangeMessage.class);
-  private static final ProtobufCodec<PatchSet> PATCH_SET_CODEC =
-      CodecFactory.encoder(PatchSet.class);
-  private static final ProtobufCodec<PatchSetApproval> PATCH_SET_APPROVAL_CODEC =
-      CodecFactory.encoder(PatchSetApproval.class);
-  private static final ProtobufCodec<PatchLineComment> PATCH_LINE_COMMENT_CODEC =
-      CodecFactory.encoder(PatchLineComment.class);
-  private static final String TIMEZONE_ID = "US/Eastern";
-
-  private String systemTimeZoneProperty;
-  private TimeZone systemTimeZone;
-
-  private Project.NameKey project;
-  private Account.Id accountId;
-
-  @Before
-  public void setUp() {
-    systemTimeZoneProperty = System.setProperty("user.timezone", TIMEZONE_ID);
-    systemTimeZone = TimeZone.getDefault();
-    TimeZone.setDefault(TimeZone.getTimeZone(TIMEZONE_ID));
-    long maxMs = ChangeRebuilderImpl.MAX_WINDOW_MS;
-    assertThat(maxMs).isGreaterThan(1000L);
-    TestTimeUtil.resetWithClockStep(maxMs * 2, MILLISECONDS);
-    project = new Project.NameKey("project");
-    accountId = new Account.Id(100);
-  }
-
-  @After
-  public void tearDown() {
-    TestTimeUtil.useSystemTime();
-    System.setProperty("user.timezone", systemTimeZoneProperty);
-    TimeZone.setDefault(systemTimeZone);
-  }
-
-  private void superWindowResolution() {
-    TestTimeUtil.setClockStep(ChangeRebuilderImpl.MAX_WINDOW_MS * 2, MILLISECONDS);
-    TimeUtil.nowTs();
-  }
-
-  private void subWindowResolution() {
-    TestTimeUtil.setClockStep(1, SECONDS);
-    TimeUtil.nowTs();
-  }
-
-  @Test
-  public void diffChangesDifferentIds() throws Exception {
-    Change c1 = TestChanges.newChange(project, accountId);
-    int id1 = c1.getId().get();
-    Change c2 = TestChanges.newChange(project, accountId);
-    int id2 = c2.getId().get();
-    ChangeBundle b1 =
-        new ChangeBundle(
-            c1, messages(), patchSets(), approvals(), comments(), reviewers(), REVIEW_DB);
-    ChangeBundle b2 =
-        new ChangeBundle(
-            c2, messages(), patchSets(), approvals(), comments(), reviewers(), REVIEW_DB);
-
-    assertDiffs(
-        b1,
-        b2,
-        "changeId differs for Changes: {" + id1 + "} != {" + id2 + "}",
-        "createdOn differs for Changes: {2009-09-30 17:00:00.0} != {2009-09-30 17:00:06.0}",
-        "effective last updated time differs for Changes:"
-            + " {2009-09-30 17:00:00.0} != {2009-09-30 17:00:06.0}");
-  }
-
-  @Test
-  public void diffChangesSameId() throws Exception {
-    Change c1 = TestChanges.newChange(new Project.NameKey("project"), new Account.Id(100));
-    Change c2 = clone(c1);
-    ChangeBundle b1 =
-        new ChangeBundle(
-            c1, messages(), patchSets(), approvals(), comments(), reviewers(), REVIEW_DB);
-    ChangeBundle b2 =
-        new ChangeBundle(
-            c2, messages(), patchSets(), approvals(), comments(), reviewers(), REVIEW_DB);
-
-    assertNoDiffs(b1, b2);
-
-    c2.setTopic("topic");
-    assertDiffs(b1, b2, "topic differs for Change.Id " + c1.getId() + ": {null} != {topic}");
-  }
-
-  @Test
-  public void diffChangesMixedSourcesAllowsSlop() throws Exception {
-    subWindowResolution();
-    Change c1 = TestChanges.newChange(new Project.NameKey("project"), new Account.Id(100));
-    Change c2 = clone(c1);
-    c2.setCreatedOn(TimeUtil.nowTs());
-    c2.setLastUpdatedOn(TimeUtil.nowTs());
-
-    // Both are ReviewDb, exact timestamp match is required.
-    ChangeBundle b1 =
-        new ChangeBundle(
-            c1, messages(), patchSets(), approvals(), comments(), reviewers(), REVIEW_DB);
-    ChangeBundle b2 =
-        new ChangeBundle(
-            c2, messages(), patchSets(), approvals(), comments(), reviewers(), REVIEW_DB);
-    assertDiffs(
-        b1,
-        b2,
-        "createdOn differs for Change.Id "
-            + c1.getId()
-            + ":"
-            + " {2009-09-30 17:00:01.0} != {2009-09-30 17:00:02.0}",
-        "effective last updated time differs for Change.Id "
-            + c1.getId()
-            + ":"
-            + " {2009-09-30 17:00:01.0} != {2009-09-30 17:00:03.0}");
-
-    // One NoteDb, slop is allowed.
-    b1 =
-        new ChangeBundle(
-            c1, messages(), patchSets(), approvals(), comments(), reviewers(), NOTE_DB);
-    b2 =
-        new ChangeBundle(
-            c2, messages(), patchSets(), approvals(), comments(), reviewers(), REVIEW_DB);
-    assertNoDiffs(b1, b2);
-    assertNoDiffs(b2, b1);
-
-    // But not too much slop.
-    superWindowResolution();
-    Change c3 = clone(c1);
-    c3.setLastUpdatedOn(TimeUtil.nowTs());
-    b1 =
-        new ChangeBundle(
-            c1, messages(), patchSets(), approvals(), comments(), reviewers(), NOTE_DB);
-    ChangeBundle b3 =
-        new ChangeBundle(
-            c3, messages(), patchSets(), approvals(), comments(), reviewers(), REVIEW_DB);
-    String msg =
-        "effective last updated time differs for Change.Id "
-            + c1.getId()
-            + " in NoteDb vs. ReviewDb:"
-            + " {2009-09-30 17:00:01.0} != {2009-09-30 17:00:10.0}";
-    assertDiffs(b1, b3, msg);
-    assertDiffs(b3, b1, msg);
-  }
-
-  @Test
-  public void diffChangesIgnoresOriginalSubjectInReviewDb() throws Exception {
-    Change c1 = TestChanges.newChange(new Project.NameKey("project"), new Account.Id(100));
-    c1.setCurrentPatchSet(c1.currentPatchSetId(), "Subject", "Original A");
-    Change c2 = clone(c1);
-    c2.setCurrentPatchSet(c2.currentPatchSetId(), c1.getSubject(), "Original B");
-
-    // Both ReviewDb, exact match required.
-    ChangeBundle b1 =
-        new ChangeBundle(
-            c1, messages(), patchSets(), approvals(), comments(), reviewers(), REVIEW_DB);
-    ChangeBundle b2 =
-        new ChangeBundle(
-            c2, messages(), patchSets(), approvals(), comments(), reviewers(), REVIEW_DB);
-    assertDiffs(
-        b1,
-        b2,
-        "originalSubject differs for Change.Id "
-            + c1.getId()
-            + ":"
-            + " {Original A} != {Original B}");
-
-    // Both NoteDb, exact match required.
-    b1 =
-        new ChangeBundle(
-            c1, messages(), patchSets(), approvals(), comments(), reviewers(), NOTE_DB);
-    b2 =
-        new ChangeBundle(
-            c2, messages(), patchSets(), approvals(), comments(), reviewers(), NOTE_DB);
-    assertDiffs(
-        b1,
-        b2,
-        "originalSubject differs for Change.Id "
-            + c1.getId()
-            + ":"
-            + " {Original A} != {Original B}");
-
-    // One ReviewDb, one NoteDb, original subject is ignored.
-    b1 =
-        new ChangeBundle(
-            c1, messages(), patchSets(), approvals(), comments(), reviewers(), REVIEW_DB);
-    b2 =
-        new ChangeBundle(
-            c2, messages(), patchSets(), approvals(), comments(), reviewers(), NOTE_DB);
-    assertNoDiffs(b1, b2);
-    assertNoDiffs(b2, b1);
-  }
-
-  @Test
-  public void diffChangesSanitizesSubjectsBeforeComparison() throws Exception {
-    Change c1 = TestChanges.newChange(new Project.NameKey("project"), new Account.Id(100));
-    c1.setCurrentPatchSet(c1.currentPatchSetId(), "Subject\r\rbody", "Original");
-    Change c2 = clone(c1);
-    c2.setCurrentPatchSet(c2.currentPatchSetId(), "Subject  body", "Original");
-
-    // Both ReviewDb, exact match required
-    ChangeBundle b1 =
-        new ChangeBundle(
-            c1, messages(), patchSets(), approvals(), comments(), reviewers(), REVIEW_DB);
-    ChangeBundle b2 =
-        new ChangeBundle(
-            c2, messages(), patchSets(), approvals(), comments(), reviewers(), REVIEW_DB);
-    assertDiffs(
-        b1,
-        b2,
-        "subject differs for Change.Id "
-            + c1.getId()
-            + ":"
-            + " {Subject\r\rbody} != {Subject  body}");
-
-    // Both NoteDb, exact match required (although it should be impossible to
-    // create a NoteDb change with '\r' in the subject).
-    b1 =
-        new ChangeBundle(
-            c1, messages(), patchSets(), approvals(), comments(), reviewers(), NOTE_DB);
-    b2 =
-        new ChangeBundle(
-            c2, messages(), patchSets(), approvals(), comments(), reviewers(), NOTE_DB);
-    assertDiffs(
-        b1,
-        b2,
-        "subject differs for Change.Id "
-            + c1.getId()
-            + ":"
-            + " {Subject\r\rbody} != {Subject  body}");
-
-    // One ReviewDb, one NoteDb, '\r' is normalized to ' '.
-    b1 =
-        new ChangeBundle(
-            c1, messages(), patchSets(), approvals(), comments(), reviewers(), REVIEW_DB);
-    b2 =
-        new ChangeBundle(
-            c2, messages(), patchSets(), approvals(), comments(), reviewers(), NOTE_DB);
-    assertNoDiffs(b1, b2);
-    assertNoDiffs(b2, b1);
-  }
-
-  @Test
-  public void diffChangesConsidersEmptyReviewDbTopicEquivalentToNullInNoteDb() throws Exception {
-    Change c1 = TestChanges.newChange(new Project.NameKey("project"), new Account.Id(100));
-    c1.setTopic("");
-    Change c2 = clone(c1);
-    c2.setTopic(null);
-
-    // Both ReviewDb, exact match required.
-    ChangeBundle b1 =
-        new ChangeBundle(
-            c1, messages(), patchSets(), approvals(), comments(), reviewers(), REVIEW_DB);
-    ChangeBundle b2 =
-        new ChangeBundle(
-            c2, messages(), patchSets(), approvals(), comments(), reviewers(), REVIEW_DB);
-    assertDiffs(b1, b2, "topic differs for Change.Id " + c1.getId() + ": {} != {null}");
-
-    // Topic ignored if ReviewDb is empty and NoteDb is null.
-    b1 =
-        new ChangeBundle(
-            c1, messages(), patchSets(), approvals(), comments(), reviewers(), REVIEW_DB);
-    b2 =
-        new ChangeBundle(
-            c2, messages(), patchSets(), approvals(), comments(), reviewers(), NOTE_DB);
-    assertNoDiffs(b1, b2);
-
-    // Exact match still required if NoteDb has empty value (not realistic).
-    b1 =
-        new ChangeBundle(
-            c1, messages(), patchSets(), approvals(), comments(), reviewers(), NOTE_DB);
-    b2 =
-        new ChangeBundle(
-            c2, messages(), patchSets(), approvals(), comments(), reviewers(), REVIEW_DB);
-    assertDiffs(b1, b2, "topic differs for Change.Id " + c1.getId() + ": {} != {null}");
-
-    // Null is not equal to a non-empty string.
-    Change c3 = clone(c1);
-    c3.setTopic("topic");
-    b1 =
-        new ChangeBundle(
-            c3, messages(), patchSets(), approvals(), comments(), reviewers(), REVIEW_DB);
-    b2 =
-        new ChangeBundle(
-            c2, messages(), patchSets(), approvals(), comments(), reviewers(), NOTE_DB);
-    assertDiffs(b1, b2, "topic differs for Change.Id " + c1.getId() + ": {topic} != {null}");
-
-    // Null is equal to a string that is all whitespace.
-    Change c4 = clone(c1);
-    c4.setTopic("  ");
-    b1 =
-        new ChangeBundle(
-            c4, messages(), patchSets(), approvals(), comments(), reviewers(), REVIEW_DB);
-    b2 =
-        new ChangeBundle(
-            c2, messages(), patchSets(), approvals(), comments(), reviewers(), NOTE_DB);
-    assertNoDiffs(b1, b2);
-    assertNoDiffs(b2, b1);
-  }
-
-  @Test
-  public void diffChangesIgnoresLeadingAndTrailingWhitespaceInReviewDbTopics() throws Exception {
-    Change c1 = TestChanges.newChange(new Project.NameKey("project"), new Account.Id(100));
-    c1.setTopic(" abc ");
-    Change c2 = clone(c1);
-    c2.setTopic("abc");
-
-    // Both ReviewDb, exact match required.
-    ChangeBundle b1 =
-        new ChangeBundle(
-            c1, messages(), patchSets(), approvals(), comments(), reviewers(), REVIEW_DB);
-    ChangeBundle b2 =
-        new ChangeBundle(
-            c2, messages(), patchSets(), approvals(), comments(), reviewers(), REVIEW_DB);
-    assertDiffs(b1, b2, "topic differs for Change.Id " + c1.getId() + ": { abc } != {abc}");
-
-    // Leading whitespace in ReviewDb topic is ignored.
-    b1 =
-        new ChangeBundle(
-            c1, messages(), patchSets(), approvals(), comments(), reviewers(), REVIEW_DB);
-    b2 =
-        new ChangeBundle(
-            c2, messages(), patchSets(), approvals(), comments(), reviewers(), NOTE_DB);
-    assertNoDiffs(b1, b2);
-    assertNoDiffs(b2, b1);
-
-    // Must match except for the leading/trailing whitespace.
-    Change c3 = clone(c1);
-    c3.setTopic("cba");
-    b1 =
-        new ChangeBundle(
-            c1, messages(), patchSets(), approvals(), comments(), reviewers(), REVIEW_DB);
-    b2 =
-        new ChangeBundle(
-            c3, messages(), patchSets(), approvals(), comments(), reviewers(), NOTE_DB);
-    assertDiffs(b1, b2, "topic differs for Change.Id " + c1.getId() + ": { abc } != {cba}");
-  }
-
-  @Test
-  public void diffChangesTakesMaxEntityTimestampFromReviewDb() throws Exception {
-    Change c1 = TestChanges.newChange(new Project.NameKey("project"), new Account.Id(100));
-    PatchSet ps = new PatchSet(c1.currentPatchSetId());
-    ps.setRevision(new RevId("deadbeefdeadbeefdeadbeefdeadbeefdeadbeef"));
-    ps.setUploader(accountId);
-    ps.setCreatedOn(TimeUtil.nowTs());
-    PatchSetApproval a =
-        new PatchSetApproval(
-            new PatchSetApproval.Key(c1.currentPatchSetId(), accountId, new LabelId("Code-Review")),
-            (short) 1,
-            TimeUtil.nowTs());
-
-    Change c2 = clone(c1);
-    c2.setLastUpdatedOn(a.getGranted());
-
-    // Both ReviewDb, exact match required.
-    ChangeBundle b1 =
-        new ChangeBundle(
-            c1, messages(), patchSets(ps), approvals(a), comments(), reviewers(), REVIEW_DB);
-    ChangeBundle b2 =
-        new ChangeBundle(
-            c2, messages(), patchSets(ps), approvals(a), comments(), reviewers(), REVIEW_DB);
-    assertDiffs(
-        b1,
-        b2,
-        "effective last updated time differs for Change.Id "
-            + c1.getId()
-            + ":"
-            + " {2009-09-30 17:00:00.0} != {2009-09-30 17:00:12.0}");
-
-    // NoteDb allows latest timestamp from all entities in bundle.
-    b2 =
-        new ChangeBundle(
-            c2, messages(), patchSets(ps), approvals(a), comments(), reviewers(), NOTE_DB);
-    assertNoDiffs(b1, b2);
-  }
-
-  @Test
-  public void diffChangesIgnoresChangeTimestampIfAnyOtherEntitiesExist() {
-    Change c1 = TestChanges.newChange(new Project.NameKey("project"), new Account.Id(100));
-    PatchSet ps = new PatchSet(c1.currentPatchSetId());
-    ps.setRevision(new RevId("deadbeefdeadbeefdeadbeefdeadbeefdeadbeef"));
-    ps.setUploader(accountId);
-    ps.setCreatedOn(TimeUtil.nowTs());
-    PatchSetApproval a =
-        new PatchSetApproval(
-            new PatchSetApproval.Key(c1.currentPatchSetId(), accountId, new LabelId("Code-Review")),
-            (short) 1,
-            TimeUtil.nowTs());
-    c1.setLastUpdatedOn(a.getGranted());
-
-    Change c2 = clone(c1);
-    c2.setLastUpdatedOn(TimeUtil.nowTs());
-
-    // ReviewDb has later lastUpdatedOn timestamp than NoteDb, allowed since
-    // NoteDb matches the latest timestamp of a non-Change entity.
-    ChangeBundle b1 =
-        new ChangeBundle(
-            c2, messages(), patchSets(ps), approvals(a), comments(), reviewers(), REVIEW_DB);
-    ChangeBundle b2 =
-        new ChangeBundle(
-            c1, messages(), patchSets(ps), approvals(a), comments(), reviewers(), NOTE_DB);
-    assertThat(b1.getChange().getLastUpdatedOn()).isGreaterThan(b2.getChange().getLastUpdatedOn());
-    assertNoDiffs(b1, b2);
-
-    // Timestamps must actually match if Change is the only entity.
-    b1 =
-        new ChangeBundle(
-            c2, messages(), patchSets(), approvals(), comments(), reviewers(), REVIEW_DB);
-    b2 =
-        new ChangeBundle(
-            c1, messages(), patchSets(), approvals(), comments(), reviewers(), NOTE_DB);
-    assertDiffs(
-        b1,
-        b2,
-        "effective last updated time differs for Change.Id "
-            + c1.getId()
-            + " in NoteDb vs. ReviewDb:"
-            + " {2009-09-30 17:00:12.0} != {2009-09-30 17:00:18.0}");
-  }
-
-  @Test
-  public void diffChangesAllowsReviewDbSubjectToBePrefixOfNoteDbSubject() throws Exception {
-    Change c1 = TestChanges.newChange(new Project.NameKey("project"), new Account.Id(100));
-    Change c2 = clone(c1);
-    c2.setCurrentPatchSet(
-        c1.currentPatchSetId(), c1.getSubject().substring(0, 10), c1.getOriginalSubject());
-    assertThat(c2.getSubject()).isNotEqualTo(c1.getSubject());
-
-    // Both ReviewDb, exact match required.
-    ChangeBundle b1 =
-        new ChangeBundle(
-            c1, messages(), patchSets(), approvals(), comments(), reviewers(), REVIEW_DB);
-    ChangeBundle b2 =
-        new ChangeBundle(
-            c2, messages(), patchSets(), approvals(), comments(), reviewers(), REVIEW_DB);
-    assertDiffs(
-        b1,
-        b2,
-        "subject differs for Change.Id " + c1.getId() + ": {Change subject} != {Change sub}");
-
-    // ReviewDb has shorter subject, allowed.
-    b1 =
-        new ChangeBundle(
-            c1, messages(), patchSets(), approvals(), comments(), reviewers(), NOTE_DB);
-    b2 =
-        new ChangeBundle(
-            c2, messages(), patchSets(), approvals(), comments(), reviewers(), REVIEW_DB);
-    assertNoDiffs(b1, b2);
-
-    // NoteDb has shorter subject, not allowed.
-    b1 =
-        new ChangeBundle(
-            c1, messages(), latest(c1), approvals(), comments(), reviewers(), REVIEW_DB);
-    b2 =
-        new ChangeBundle(c2, messages(), latest(c2), approvals(), comments(), reviewers(), NOTE_DB);
-    assertDiffs(
-        b1,
-        b2,
-        "subject differs for Change.Id " + c1.getId() + ": {Change subject} != {Change sub}");
-  }
-
-  @Test
-  public void diffChangesTrimsLeadingSpacesFromReviewDbComparingToNoteDb() throws Exception {
-    Change c1 = TestChanges.newChange(new Project.NameKey("project"), new Account.Id(100));
-    Change c2 = clone(c1);
-    c2.setCurrentPatchSet(c1.currentPatchSetId(), "   " + c1.getSubject(), c1.getOriginalSubject());
-
-    // Both ReviewDb, exact match required.
-    ChangeBundle b1 =
-        new ChangeBundle(
-            c1, messages(), patchSets(), approvals(), comments(), reviewers(), REVIEW_DB);
-    ChangeBundle b2 =
-        new ChangeBundle(
-            c2, messages(), patchSets(), approvals(), comments(), reviewers(), REVIEW_DB);
-    assertDiffs(
-        b1,
-        b2,
-        "subject differs for Change.Id "
-            + c1.getId()
-            + ":"
-            + " {Change subject} != {   Change subject}");
-
-    // ReviewDb is missing leading spaces, allowed.
-    b1 =
-        new ChangeBundle(
-            c1, messages(), patchSets(), approvals(), comments(), reviewers(), NOTE_DB);
-    b2 =
-        new ChangeBundle(
-            c2, messages(), patchSets(), approvals(), comments(), reviewers(), REVIEW_DB);
-    assertNoDiffs(b1, b2);
-    assertNoDiffs(b2, b1);
-  }
-
-  @Test
-  public void diffChangesDoesntTrimLeadingNonSpaceWhitespaceFromSubject() throws Exception {
-    Change c1 = TestChanges.newChange(new Project.NameKey("project"), new Account.Id(100));
-    Change c2 = clone(c1);
-    c2.setCurrentPatchSet(c1.currentPatchSetId(), "\t" + c1.getSubject(), c1.getOriginalSubject());
-
-    // Both ReviewDb.
-    ChangeBundle b1 =
-        new ChangeBundle(
-            c1, messages(), patchSets(), approvals(), comments(), reviewers(), REVIEW_DB);
-    ChangeBundle b2 =
-        new ChangeBundle(
-            c2, messages(), patchSets(), approvals(), comments(), reviewers(), REVIEW_DB);
-    assertDiffs(
-        b1,
-        b2,
-        "subject differs for Change.Id "
-            + c1.getId()
-            + ":"
-            + " {Change subject} != {\tChange subject}");
-
-    // One NoteDb.
-    b1 =
-        new ChangeBundle(c1, messages(), latest(c1), approvals(), comments(), reviewers(), NOTE_DB);
-    b2 =
-        new ChangeBundle(
-            c2, messages(), latest(c2), approvals(), comments(), reviewers(), REVIEW_DB);
-    assertDiffs(
-        b1,
-        b2,
-        "subject differs for Change.Id "
-            + c1.getId()
-            + ":"
-            + " {Change subject} != {\tChange subject}");
-    assertDiffs(
-        b2,
-        b1,
-        "subject differs for Change.Id "
-            + c1.getId()
-            + ":"
-            + " {\tChange subject} != {Change subject}");
-  }
-
-  @Test
-  public void diffChangesHandlesBuggyJGitSubjectExtraction() throws Exception {
-    Change c1 = TestChanges.newChange(project, accountId);
-    String buggySubject = "Subject\r \r Rest of message.";
-    c1.setCurrentPatchSet(c1.currentPatchSetId(), buggySubject, buggySubject);
-    Change c2 = clone(c1);
-    c2.setCurrentPatchSet(c2.currentPatchSetId(), "Subject", "Subject");
-
-    // Both ReviewDb.
-    ChangeBundle b1 =
-        new ChangeBundle(
-            c1, messages(), patchSets(), approvals(), comments(), reviewers(), REVIEW_DB);
-    ChangeBundle b2 =
-        new ChangeBundle(
-            c2, messages(), patchSets(), approvals(), comments(), reviewers(), REVIEW_DB);
-    assertDiffs(
-        b1,
-        b2,
-        "originalSubject differs for Change.Id "
-            + c1.getId()
-            + ":"
-            + " {Subject\r \r Rest of message.} != {Subject}",
-        "subject differs for Change.Id "
-            + c1.getId()
-            + ":"
-            + " {Subject\r \r Rest of message.} != {Subject}");
-
-    // NoteDb has correct subject without "\r ".
-    b1 =
-        new ChangeBundle(
-            c1, messages(), patchSets(), approvals(), comments(), reviewers(), REVIEW_DB);
-    b2 =
-        new ChangeBundle(
-            c2, messages(), patchSets(), approvals(), comments(), reviewers(), NOTE_DB);
-    assertNoDiffs(b1, b2);
-    assertNoDiffs(b2, b1);
-  }
-
-  @Test
-  public void diffChangesIgnoresInvalidCurrentPatchSetIdInReviewDb() throws Exception {
-    Change c1 = TestChanges.newChange(new Project.NameKey("project"), new Account.Id(100));
-    Change c2 = clone(c1);
-    c2.setCurrentPatchSet(
-        new PatchSet.Id(c2.getId(), 0), "Unrelated subject", c2.getOriginalSubject());
-
-    // Both ReviewDb.
-    ChangeBundle b1 =
-        new ChangeBundle(
-            c1, messages(), patchSets(), approvals(), comments(), reviewers(), REVIEW_DB);
-    ChangeBundle b2 =
-        new ChangeBundle(
-            c2, messages(), patchSets(), approvals(), comments(), reviewers(), REVIEW_DB);
-    assertDiffs(
-        b1,
-        b2,
-        "currentPatchSetId differs for Change.Id " + c1.getId() + ": {1} != {0}",
-        "subject differs for Change.Id "
-            + c1.getId()
-            + ":"
-            + " {Change subject} != {Unrelated subject}");
-
-    // One NoteDb.
-    //
-    // This is based on a real corrupt change where all patch sets were deleted
-    // but the Change entity stuck around, resulting in a currentPatchSetId of 0
-    // after converting to NoteDb.
-    b1 =
-        new ChangeBundle(
-            c1, messages(), patchSets(), approvals(), comments(), reviewers(), REVIEW_DB);
-    b2 =
-        new ChangeBundle(
-            c2, messages(), patchSets(), approvals(), comments(), reviewers(), NOTE_DB);
-    assertNoDiffs(b1, b2);
-    assertNoDiffs(b2, b1);
-  }
-
-  @Test
-  public void diffChangesAllowsCreatedToMatchLastUpdated() throws Exception {
-    Change c1 = TestChanges.newChange(new Project.NameKey("project"), new Account.Id(100));
-    c1.setCreatedOn(TimeUtil.nowTs());
-    assertThat(c1.getCreatedOn()).isGreaterThan(c1.getLastUpdatedOn());
-    Change c2 = clone(c1);
-    c2.setCreatedOn(c2.getLastUpdatedOn());
-
-    // Both ReviewDb.
-    ChangeBundle b1 =
-        new ChangeBundle(
-            c1, messages(), patchSets(), approvals(), comments(), reviewers(), REVIEW_DB);
-    ChangeBundle b2 =
-        new ChangeBundle(
-            c2, messages(), patchSets(), approvals(), comments(), reviewers(), REVIEW_DB);
-    assertDiffs(
-        b1,
-        b2,
-        "createdOn differs for Change.Id "
-            + c1.getId()
-            + ": {2009-09-30 17:00:06.0} != {2009-09-30 17:00:00.0}");
-
-    // One NoteDb.
-    b1 =
-        new ChangeBundle(
-            c1, messages(), patchSets(), approvals(), comments(), reviewers(), REVIEW_DB);
-    b2 =
-        new ChangeBundle(
-            c2, messages(), patchSets(), approvals(), comments(), reviewers(), NOTE_DB);
-    assertNoDiffs(b1, b2);
-    assertNoDiffs(b2, b1);
-  }
-
-  @Test
-  public void diffChangeMessageKeySets() throws Exception {
-    Change c = TestChanges.newChange(project, accountId);
-    int id = c.getId().get();
-    ChangeMessage cm1 =
-        new ChangeMessage(
-            new ChangeMessage.Key(c.getId(), "uuid1"),
-            accountId,
-            TimeUtil.nowTs(),
-            c.currentPatchSetId());
-    ChangeMessage cm2 =
-        new ChangeMessage(
-            new ChangeMessage.Key(c.getId(), "uuid2"),
-            accountId,
-            TimeUtil.nowTs(),
-            c.currentPatchSetId());
-    ChangeBundle b1 =
-        new ChangeBundle(
-            c, messages(cm1), latest(c), approvals(), comments(), reviewers(), REVIEW_DB);
-    ChangeBundle b2 =
-        new ChangeBundle(
-            c, messages(cm2), latest(c), approvals(), comments(), reviewers(), REVIEW_DB);
-
-    assertDiffs(
-        b1,
-        b2,
-        "ChangeMessage.Key sets differ:"
-            + " ["
-            + id
-            + ",uuid1] only in A; ["
-            + id
-            + ",uuid2] only in B");
-  }
-
-  @Test
-  public void diffChangeMessages() throws Exception {
-    Change c = TestChanges.newChange(project, accountId);
-    ChangeMessage cm1 =
-        new ChangeMessage(
-            new ChangeMessage.Key(c.getId(), "uuid"),
-            accountId,
-            TimeUtil.nowTs(),
-            c.currentPatchSetId());
-    cm1.setMessage("message 1");
-    ChangeMessage cm2 = clone(cm1);
-    ChangeBundle b1 =
-        new ChangeBundle(
-            c, messages(cm1), latest(c), approvals(), comments(), reviewers(), REVIEW_DB);
-    ChangeBundle b2 =
-        new ChangeBundle(
-            c, messages(cm2), latest(c), approvals(), comments(), reviewers(), REVIEW_DB);
-
-    assertNoDiffs(b1, b2);
-
-    cm2.setMessage("message 2");
-    assertDiffs(
-        b1,
-        b2,
-        "message differs for ChangeMessage.Key "
-            + c.getId()
-            + ",uuid:"
-            + " {message 1} != {message 2}");
-  }
-
-  @Test
-  public void diffChangeMessagesIgnoresUuids() throws Exception {
-    Change c = TestChanges.newChange(project, accountId);
-    int id = c.getId().get();
-    ChangeMessage cm1 =
-        new ChangeMessage(
-            new ChangeMessage.Key(c.getId(), "uuid1"),
-            accountId,
-            TimeUtil.nowTs(),
-            c.currentPatchSetId());
-    cm1.setMessage("message 1");
-    ChangeMessage cm2 = clone(cm1);
-    cm2.getKey().set("uuid2");
-
-    ChangeBundle b1 =
-        new ChangeBundle(
-            c, messages(cm1), latest(c), approvals(), comments(), reviewers(), REVIEW_DB);
-    ChangeBundle b2 =
-        new ChangeBundle(
-            c, messages(cm2), latest(c), approvals(), comments(), reviewers(), REVIEW_DB);
-    // Both are ReviewDb, exact UUID match is required.
-    assertDiffs(
-        b1,
-        b2,
-        "ChangeMessage.Key sets differ:"
-            + " ["
-            + id
-            + ",uuid1] only in A; ["
-            + id
-            + ",uuid2] only in B");
-
-    // One NoteDb, UUIDs are ignored.
-    b1 =
-        new ChangeBundle(
-            c, messages(cm1), latest(c), approvals(), comments(), reviewers(), REVIEW_DB);
-    b2 =
-        new ChangeBundle(
-            c, messages(cm2), latest(c), approvals(), comments(), reviewers(), NOTE_DB);
-    assertNoDiffs(b1, b2);
-  }
-
-  @Test
-  public void diffChangeMessagesWithDifferentCounts() throws Exception {
-    Change c = TestChanges.newChange(project, accountId);
-    int id = c.getId().get();
-    ChangeMessage cm1 =
-        new ChangeMessage(
-            new ChangeMessage.Key(c.getId(), "uuid1"),
-            accountId,
-            TimeUtil.nowTs(),
-            c.currentPatchSetId());
-    cm1.setMessage("message 1");
-    ChangeMessage cm2 =
-        new ChangeMessage(
-            new ChangeMessage.Key(c.getId(), "uuid2"),
-            accountId,
-            TimeUtil.nowTs(),
-            c.currentPatchSetId());
-    cm1.setMessage("message 2");
-
-    // Both ReviewDb: Uses same keySet diff as other types.
-    ChangeBundle b1 =
-        new ChangeBundle(
-            c, messages(cm1, cm2), latest(c), approvals(), comments(), reviewers(), REVIEW_DB);
-    ChangeBundle b2 =
-        new ChangeBundle(
-            c, messages(cm1), latest(c), approvals(), comments(), reviewers(), REVIEW_DB);
-    assertDiffs(
-        b1, b2, "ChangeMessage.Key sets differ: [" + id + ",uuid2] only in A; [] only in B");
-
-    // One NoteDb: UUIDs in keys can't be used for comparison, just diff counts.
-    b1 =
-        new ChangeBundle(
-            c, messages(cm1, cm2), latest(c), approvals(), comments(), reviewers(), REVIEW_DB);
-    b2 =
-        new ChangeBundle(
-            c, messages(cm1), latest(c), approvals(), comments(), reviewers(), NOTE_DB);
-    assertDiffs(b1, b2, "ChangeMessages differ for Change.Id " + id + "\nOnly in A:\n  " + cm2);
-    assertDiffs(b2, b1, "ChangeMessages differ for Change.Id " + id + "\nOnly in B:\n  " + cm2);
-  }
-
-  @Test
-  public void diffChangeMessagesMixedSourcesWithDifferences() throws Exception {
-    Change c = TestChanges.newChange(project, accountId);
-    int id = c.getId().get();
-    ChangeMessage cm1 =
-        new ChangeMessage(
-            new ChangeMessage.Key(c.getId(), "uuid1"),
-            accountId,
-            TimeUtil.nowTs(),
-            c.currentPatchSetId());
-    cm1.setMessage("message 1");
-    ChangeMessage cm2 = clone(cm1);
-    cm2.setMessage("message 2");
-    ChangeMessage cm3 = clone(cm1);
-    cm3.getKey().set("uuid2"); // Differs only in UUID.
-
-    ChangeBundle b1 =
-        new ChangeBundle(
-            c, messages(cm1, cm3), latest(c), approvals(), comments(), reviewers(), REVIEW_DB);
-    ChangeBundle b2 =
-        new ChangeBundle(
-            c, messages(cm2, cm3), latest(c), approvals(), comments(), reviewers(), NOTE_DB);
-    // Implementation happens to pair up cm1 in b1 with cm3 in b2 because it
-    // depends on iteration order and doesn't care about UUIDs. The important
-    // thing is that there's some diff.
-    assertDiffs(
-        b1,
-        b2,
-        "ChangeMessages differ for Change.Id "
-            + id
-            + "\n"
-            + "Only in A:\n  "
-            + cm3
-            + "\n"
-            + "Only in B:\n  "
-            + cm2);
-    assertDiffs(
-        b2,
-        b1,
-        "ChangeMessages differ for Change.Id "
-            + id
-            + "\n"
-            + "Only in A:\n  "
-            + cm2
-            + "\n"
-            + "Only in B:\n  "
-            + cm3);
-  }
-
-  @Test
-  public void diffChangeMessagesMixedSourcesAllowsSlop() throws Exception {
-    subWindowResolution();
-    Change c = TestChanges.newChange(project, accountId);
-    ChangeMessage cm1 =
-        new ChangeMessage(
-            new ChangeMessage.Key(c.getId(), "uuid1"),
-            accountId,
-            TimeUtil.nowTs(),
-            c.currentPatchSetId());
-    ChangeMessage cm2 = clone(cm1);
-    cm2.setWrittenOn(TimeUtil.nowTs());
-
-    // Both are ReviewDb, exact timestamp match is required.
-    ChangeBundle b1 =
-        new ChangeBundle(
-            c, messages(cm1), latest(c), approvals(), comments(), reviewers(), REVIEW_DB);
-    ChangeBundle b2 =
-        new ChangeBundle(
-            c, messages(cm2), latest(c), approvals(), comments(), reviewers(), REVIEW_DB);
-    assertDiffs(
-        b1,
-        b2,
-        "writtenOn differs for ChangeMessage.Key "
-            + c.getId()
-            + ",uuid1:"
-            + " {2009-09-30 17:00:02.0} != {2009-09-30 17:00:03.0}");
-
-    // One NoteDb, slop is allowed.
-    b1 =
-        new ChangeBundle(
-            c, messages(cm1), latest(c), approvals(), comments(), reviewers(), NOTE_DB);
-    b2 =
-        new ChangeBundle(
-            c, messages(cm2), latest(c), approvals(), comments(), reviewers(), REVIEW_DB);
-    assertNoDiffs(b1, b2);
-    assertNoDiffs(b2, b1);
-
-    // But not too much slop.
-    superWindowResolution();
-    ChangeMessage cm3 = clone(cm1);
-    cm3.setWrittenOn(TimeUtil.nowTs());
-    b1 =
-        new ChangeBundle(
-            c, messages(cm1), latest(c), approvals(), comments(), reviewers(), NOTE_DB);
-    ChangeBundle b3 =
-        new ChangeBundle(
-            c, messages(cm3), latest(c), approvals(), comments(), reviewers(), REVIEW_DB);
-    int id = c.getId().get();
-    assertDiffs(
-        b1,
-        b3,
-        "ChangeMessages differ for Change.Id "
-            + id
-            + "\n"
-            + "Only in A:\n  "
-            + cm1
-            + "\n"
-            + "Only in B:\n  "
-            + cm3);
-    assertDiffs(
-        b3,
-        b1,
-        "ChangeMessages differ for Change.Id "
-            + id
-            + "\n"
-            + "Only in A:\n  "
-            + cm3
-            + "\n"
-            + "Only in B:\n  "
-            + cm1);
-  }
-
-  @Test
-  public void diffChangeMessagesAllowsNullPatchSetIdFromReviewDb() throws Exception {
-    Change c = TestChanges.newChange(project, accountId);
-    int id = c.getId().get();
-    ChangeMessage cm1 =
-        new ChangeMessage(
-            new ChangeMessage.Key(c.getId(), "uuid"),
-            accountId,
-            TimeUtil.nowTs(),
-            c.currentPatchSetId());
-    cm1.setMessage("message 1");
-    ChangeMessage cm2 = clone(cm1);
-    cm2.setPatchSetId(null);
-
-    ChangeBundle b1 =
-        new ChangeBundle(
-            c, messages(cm1), latest(c), approvals(), comments(), reviewers(), REVIEW_DB);
-    ChangeBundle b2 =
-        new ChangeBundle(
-            c, messages(cm2), latest(c), approvals(), comments(), reviewers(), REVIEW_DB);
-
-    // Both are ReviewDb, exact patch set ID match is required.
-    assertDiffs(
-        b1,
-        b2,
-        "patchset differs for ChangeMessage.Key "
-            + c.getId()
-            + ",uuid:"
-            + " {"
-            + id
-            + ",1} != {null}");
-
-    // Null patch set ID on ReviewDb is ignored.
-    b1 =
-        new ChangeBundle(
-            c, messages(cm1), latest(c), approvals(), comments(), reviewers(), NOTE_DB);
-    b2 =
-        new ChangeBundle(
-            c, messages(cm2), latest(c), approvals(), comments(), reviewers(), REVIEW_DB);
-    assertNoDiffs(b1, b2);
-
-    // Null patch set ID on NoteDb is not ignored (but is not realistic).
-    b1 =
-        new ChangeBundle(
-            c, messages(cm1), latest(c), approvals(), comments(), reviewers(), REVIEW_DB);
-    b2 =
-        new ChangeBundle(
-            c, messages(cm2), latest(c), approvals(), comments(), reviewers(), NOTE_DB);
-    assertDiffs(
-        b1,
-        b2,
-        "ChangeMessages differ for Change.Id "
-            + id
-            + "\n"
-            + "Only in A:\n  "
-            + cm1
-            + "\n"
-            + "Only in B:\n  "
-            + cm2);
-    assertDiffs(
-        b2,
-        b1,
-        "ChangeMessages differ for Change.Id "
-            + id
-            + "\n"
-            + "Only in A:\n  "
-            + cm2
-            + "\n"
-            + "Only in B:\n  "
-            + cm1);
-  }
-
-  @Test
-  public void diffPatchSetIdSets() throws Exception {
-    Change c = TestChanges.newChange(project, accountId);
-    TestChanges.incrementPatchSet(c);
-
-    PatchSet ps1 = new PatchSet(new PatchSet.Id(c.getId(), 1));
-    ps1.setRevision(new RevId("deadbeefdeadbeefdeadbeefdeadbeefdeadbeef"));
-    ps1.setUploader(accountId);
-    ps1.setCreatedOn(TimeUtil.nowTs());
-    PatchSet ps2 = new PatchSet(new PatchSet.Id(c.getId(), 2));
-    ps2.setRevision(new RevId("badc0feebadc0feebadc0feebadc0feebadc0fee"));
-    ps2.setUploader(accountId);
-    ps2.setCreatedOn(TimeUtil.nowTs());
-
-    ChangeBundle b1 =
-        new ChangeBundle(
-            c, messages(), patchSets(ps2), approvals(), comments(), reviewers(), REVIEW_DB);
-    ChangeBundle b2 =
-        new ChangeBundle(
-            c, messages(), patchSets(ps1, ps2), approvals(), comments(), reviewers(), REVIEW_DB);
-
-    assertDiffs(b1, b2, "PatchSet.Id sets differ: [] only in A; [" + c.getId() + ",1] only in B");
-  }
-
-  @Test
-  public void diffPatchSets() throws Exception {
-    Change c = TestChanges.newChange(project, accountId);
-    PatchSet ps1 = new PatchSet(c.currentPatchSetId());
-    ps1.setRevision(new RevId("deadbeefdeadbeefdeadbeefdeadbeefdeadbeef"));
-    ps1.setUploader(accountId);
-    ps1.setCreatedOn(TimeUtil.nowTs());
-    PatchSet ps2 = clone(ps1);
-    ChangeBundle b1 =
-        new ChangeBundle(
-            c, messages(), patchSets(ps1), approvals(), comments(), reviewers(), REVIEW_DB);
-    ChangeBundle b2 =
-        new ChangeBundle(
-            c, messages(), patchSets(ps2), approvals(), comments(), reviewers(), REVIEW_DB);
-
-    assertNoDiffs(b1, b2);
-
-    ps2.setRevision(new RevId("badc0feebadc0feebadc0feebadc0feebadc0fee"));
-    assertDiffs(
-        b1,
-        b2,
-        "revision differs for PatchSet.Id "
-            + c.getId()
-            + ",1:"
-            + " {RevId{deadbeefdeadbeefdeadbeefdeadbeefdeadbeef}}"
-            + " != {RevId{badc0feebadc0feebadc0feebadc0feebadc0fee}}");
-  }
-
-  @Test
-  public void diffPatchSetsMixedSourcesAllowsSlop() throws Exception {
-    subWindowResolution();
-    Change c = TestChanges.newChange(project, accountId);
-    PatchSet ps1 = new PatchSet(c.currentPatchSetId());
-    ps1.setRevision(new RevId("deadbeefdeadbeefdeadbeefdeadbeefdeadbeef"));
-    ps1.setUploader(accountId);
-    ps1.setCreatedOn(truncateToSecond(TimeUtil.nowTs()));
-    PatchSet ps2 = clone(ps1);
-    ps2.setCreatedOn(TimeUtil.nowTs());
-
-    // Both are ReviewDb, exact timestamp match is required.
-    ChangeBundle b1 =
-        new ChangeBundle(
-            c, messages(), patchSets(ps1), approvals(), comments(), reviewers(), REVIEW_DB);
-    ChangeBundle b2 =
-        new ChangeBundle(
-            c, messages(), patchSets(ps2), approvals(), comments(), reviewers(), REVIEW_DB);
-    assertDiffs(
-        b1,
-        b2,
-        "createdOn differs for PatchSet.Id "
-            + c.getId()
-            + ",1:"
-            + " {2009-09-30 17:00:02.0} != {2009-09-30 17:00:03.0}");
-
-    // One NoteDb, slop is allowed.
-    b1 =
-        new ChangeBundle(
-            c, messages(), patchSets(ps1), approvals(), comments(), reviewers(), NOTE_DB);
-    b2 =
-        new ChangeBundle(
-            c, messages(), patchSets(ps2), approvals(), comments(), reviewers(), REVIEW_DB);
-    assertNoDiffs(b1, b2);
-
-    // But not too much slop.
-    superWindowResolution();
-    PatchSet ps3 = clone(ps1);
-    ps3.setCreatedOn(TimeUtil.nowTs());
-    b1 =
-        new ChangeBundle(
-            c, messages(), patchSets(ps1), approvals(), comments(), reviewers(), NOTE_DB);
-    ChangeBundle b3 =
-        new ChangeBundle(
-            c, messages(), patchSets(ps3), approvals(), comments(), reviewers(), REVIEW_DB);
-    String msg =
-        "createdOn differs for PatchSet.Id "
-            + c.getId()
-            + ",1 in NoteDb vs. ReviewDb:"
-            + " {2009-09-30 17:00:02.0} != {2009-09-30 17:00:10.0}";
-    assertDiffs(b1, b3, msg);
-    assertDiffs(b3, b1, msg);
-  }
-
-  @Test
-  public void diffPatchSetsIgnoresTrailingNewlinesInPushCertificate() throws Exception {
-    subWindowResolution();
-    Change c = TestChanges.newChange(project, accountId);
-    PatchSet ps1 = new PatchSet(c.currentPatchSetId());
-    ps1.setRevision(new RevId("deadbeefdeadbeefdeadbeefdeadbeefdeadbeef"));
-    ps1.setUploader(accountId);
-    ps1.setCreatedOn(truncateToSecond(TimeUtil.nowTs()));
-    ps1.setPushCertificate("some cert");
-    PatchSet ps2 = clone(ps1);
-    ps2.setPushCertificate(ps2.getPushCertificate() + "\n\n");
-
-    ChangeBundle b1 =
-        new ChangeBundle(
-            c, messages(), patchSets(ps1), approvals(), comments(), reviewers(), NOTE_DB);
-    ChangeBundle b2 =
-        new ChangeBundle(
-            c, messages(), patchSets(ps2), approvals(), comments(), reviewers(), REVIEW_DB);
-    assertNoDiffs(b1, b2);
-    assertNoDiffs(b2, b1);
-
-    b1 =
-        new ChangeBundle(
-            c, messages(), patchSets(ps1), approvals(), comments(), reviewers(), REVIEW_DB);
-    b2 =
-        new ChangeBundle(
-            c, messages(), patchSets(ps2), approvals(), comments(), reviewers(), NOTE_DB);
-    assertNoDiffs(b1, b2);
-    assertNoDiffs(b2, b1);
-  }
-
-  @Test
-  public void diffPatchSetsGreaterThanCurrent() throws Exception {
-    Change c = TestChanges.newChange(project, accountId);
-
-    PatchSet ps1 = new PatchSet(new PatchSet.Id(c.getId(), 1));
-    ps1.setRevision(new RevId("deadbeefdeadbeefdeadbeefdeadbeefdeadbeef"));
-    ps1.setUploader(accountId);
-    ps1.setCreatedOn(TimeUtil.nowTs());
-    PatchSet ps2 = new PatchSet(new PatchSet.Id(c.getId(), 2));
-    ps2.setRevision(new RevId("badc0feebadc0feebadc0feebadc0feebadc0fee"));
-    ps2.setUploader(accountId);
-    ps2.setCreatedOn(TimeUtil.nowTs());
-    assertThat(ps2.getId().get()).isGreaterThan(c.currentPatchSetId().get());
-
-    ChangeMessage cm1 =
-        new ChangeMessage(
-            new ChangeMessage.Key(c.getId(), "uuid1"),
-            accountId,
-            TimeUtil.nowTs(),
-            c.currentPatchSetId());
-    ChangeMessage cm2 =
-        new ChangeMessage(
-            new ChangeMessage.Key(c.getId(), "uuid2"),
-            accountId,
-            TimeUtil.nowTs(),
-            c.currentPatchSetId());
-
-    PatchSetApproval a1 =
-        new PatchSetApproval(
-            new PatchSetApproval.Key(ps1.getId(), accountId, new LabelId("Code-Review")),
-            (short) 1,
-            TimeUtil.nowTs());
-    PatchSetApproval a2 =
-        new PatchSetApproval(
-            new PatchSetApproval.Key(ps2.getId(), accountId, new LabelId("Code-Review")),
-            (short) 1,
-            TimeUtil.nowTs());
-
-    // Both ReviewDb.
-    ChangeBundle b1 =
-        new ChangeBundle(
-            c, messages(cm1), patchSets(ps1), approvals(a1), comments(), reviewers(), REVIEW_DB);
-    ChangeBundle b2 =
-        new ChangeBundle(
-            c,
-            messages(cm1, cm2),
-            patchSets(ps1, ps2),
-            approvals(a1, a2),
-            comments(),
-            reviewers(),
-            REVIEW_DB);
-    assertDiffs(
-        b1,
-        b2,
-        "ChangeMessage.Key sets differ: [] only in A; [" + cm2.getKey() + "] only in B",
-        "PatchSet.Id sets differ: [] only in A; [" + ps2.getId() + "] only in B",
-        "PatchSetApproval.Key sets differ: [] only in A; [" + a2.getKey() + "] only in B");
-
-    // One NoteDb.
-    b1 =
-        new ChangeBundle(
-            c, messages(cm1), patchSets(ps1), approvals(a1), comments(), reviewers(), NOTE_DB);
-    b2 =
-        new ChangeBundle(
-            c,
-            messages(cm1, cm2),
-            patchSets(ps1, ps2),
-            approvals(a1, a2),
-            comments(),
-            reviewers(),
-            REVIEW_DB);
-    assertDiffs(
-        b1,
-        b2,
-        "ChangeMessages differ for Change.Id " + c.getId() + "\nOnly in B:\n  " + cm2,
-        "PatchSet.Id sets differ: [] only in A; [" + ps2.getId() + "] only in B",
-        "PatchSetApproval.Key sets differ: [] only in A; [" + a2.getKey() + "] only in B");
-
-    // Both NoteDb.
-    b1 =
-        new ChangeBundle(
-            c, messages(cm1), patchSets(ps1), approvals(a1), comments(), reviewers(), NOTE_DB);
-    b2 =
-        new ChangeBundle(
-            c,
-            messages(cm1, cm2),
-            patchSets(ps1, ps2),
-            approvals(a1, a2),
-            comments(),
-            reviewers(),
-            NOTE_DB);
-    assertDiffs(
-        b1,
-        b2,
-        "ChangeMessages differ for Change.Id " + c.getId() + "\nOnly in B:\n  " + cm2,
-        "PatchSet.Id sets differ: [] only in A; [" + ps2.getId() + "] only in B",
-        "PatchSetApproval.Key sets differ: [] only in A; [" + a2.getKey() + "] only in B");
-  }
-
-  @Test
-  public void diffPatchSetsIgnoresLeadingAndTrailingWhitespaceInReviewDbDescriptions()
-      throws Exception {
-    Change c = TestChanges.newChange(project, accountId);
-
-    PatchSet ps1 = new PatchSet(new PatchSet.Id(c.getId(), 1));
-    ps1.setRevision(new RevId("deadbeefdeadbeefdeadbeefdeadbeefdeadbeef"));
-    ps1.setUploader(accountId);
-    ps1.setCreatedOn(TimeUtil.nowTs());
-    ps1.setDescription(" abc ");
-    PatchSet ps2 = clone(ps1);
-    ps2.setDescription("abc");
-
-    // Both ReviewDb, exact match required.
-    ChangeBundle b1 =
-        new ChangeBundle(
-            c, messages(), patchSets(ps1), approvals(), comments(), reviewers(), REVIEW_DB);
-    ChangeBundle b2 =
-        new ChangeBundle(
-            c, messages(), patchSets(ps2), approvals(), comments(), reviewers(), REVIEW_DB);
-    assertDiffs(
-        b1, b2, "description differs for PatchSet.Id " + ps1.getId() + ": { abc } != {abc}");
-
-    // Whitespace in ReviewDb description is ignored.
-    b1 =
-        new ChangeBundle(
-            c, messages(), patchSets(ps1), approvals(), comments(), reviewers(), REVIEW_DB);
-    b2 =
-        new ChangeBundle(
-            c, messages(), patchSets(ps2), approvals(), comments(), reviewers(), NOTE_DB);
-    assertNoDiffs(b1, b2);
-    assertNoDiffs(b2, b1);
-
-    // Must match except for the leading/trailing whitespace.
-    PatchSet ps3 = clone(ps1);
-    ps3.setDescription("cba");
-    b1 =
-        new ChangeBundle(
-            c, messages(), patchSets(ps1), approvals(), comments(), reviewers(), REVIEW_DB);
-    b2 =
-        new ChangeBundle(
-            c, messages(), patchSets(ps3), approvals(), comments(), reviewers(), NOTE_DB);
-    assertDiffs(
-        b1, b2, "description differs for PatchSet.Id " + ps1.getId() + ": { abc } != {cba}");
-  }
-
-  @Test
-  public void diffPatchSetsIgnoresCreatedOnWhenReviewDbIsNonMonotonic() throws Exception {
-    Change c = TestChanges.newChange(project, accountId);
-
-    Timestamp beforePs1 = TimeUtil.nowTs();
-
-    PatchSet goodPs1 = new PatchSet(new PatchSet.Id(c.getId(), 1));
-    goodPs1.setRevision(new RevId("deadbeefdeadbeefdeadbeefdeadbeefdeadbeef"));
-    goodPs1.setUploader(accountId);
-    goodPs1.setCreatedOn(TimeUtil.nowTs());
-    PatchSet goodPs2 = new PatchSet(new PatchSet.Id(c.getId(), 2));
-    goodPs2.setRevision(new RevId("deadbeefdeadbeefdeadbeefdeadbeefdeadbeef"));
-    goodPs2.setUploader(accountId);
-    goodPs2.setCreatedOn(TimeUtil.nowTs());
-    assertThat(goodPs2.getCreatedOn()).isGreaterThan(goodPs1.getCreatedOn());
-
-    PatchSet badPs2 = clone(goodPs2);
-    badPs2.setCreatedOn(beforePs1);
-    assertThat(badPs2.getCreatedOn()).isLessThan(goodPs1.getCreatedOn());
-
-    // Both ReviewDb, exact match required.
-    ChangeBundle b1 =
-        new ChangeBundle(
-            c,
-            messages(),
-            patchSets(goodPs1, goodPs2),
-            approvals(),
-            comments(),
-            reviewers(),
-            REVIEW_DB);
-    ChangeBundle b2 =
-        new ChangeBundle(
-            c,
-            messages(),
-            patchSets(goodPs1, badPs2),
-            approvals(),
-            comments(),
-            reviewers(),
-            REVIEW_DB);
-    assertDiffs(
-        b1,
-        b2,
-        "createdOn differs for PatchSet.Id "
-            + badPs2.getId()
-            + ":"
-            + " {2009-09-30 17:00:18.0} != {2009-09-30 17:00:06.0}");
-
-    // Non-monotonic in ReviewDb but monotonic in NoteDb, timestamps are
-    // ignored, including for ps1.
-    PatchSet badPs1 = clone(goodPs1);
-    badPs1.setCreatedOn(TimeUtil.nowTs());
-    b1 =
-        new ChangeBundle(
-            c,
-            messages(),
-            patchSets(badPs1, badPs2),
-            approvals(),
-            comments(),
-            reviewers(),
-            REVIEW_DB);
-    b2 =
-        new ChangeBundle(
-            c,
-            messages(),
-            patchSets(goodPs1, goodPs2),
-            approvals(),
-            comments(),
-            reviewers(),
-            NOTE_DB);
-    assertNoDiffs(b1, b2);
-    assertNoDiffs(b2, b1);
-
-    // Non-monotonic in NoteDb but monotonic in ReviewDb, timestamps are not
-    // ignored.
-    b1 =
-        new ChangeBundle(
-            c,
-            messages(),
-            patchSets(goodPs1, goodPs2),
-            approvals(),
-            comments(),
-            reviewers(),
-            REVIEW_DB);
-    b2 =
-        new ChangeBundle(
-            c,
-            messages(),
-            patchSets(badPs1, badPs2),
-            approvals(),
-            comments(),
-            reviewers(),
-            NOTE_DB);
-    assertDiffs(
-        b1,
-        b2,
-        "createdOn differs for PatchSet.Id "
-            + badPs1.getId()
-            + " in NoteDb vs. ReviewDb:"
-            + " {2009-09-30 17:00:24.0} != {2009-09-30 17:00:12.0}",
-        "createdOn differs for PatchSet.Id "
-            + badPs2.getId()
-            + " in NoteDb vs. ReviewDb:"
-            + " {2009-09-30 17:00:06.0} != {2009-09-30 17:00:18.0}");
-  }
-
-  @Test
-  public void diffPatchSetsAllowsFirstPatchSetCreatedOnToMatchChangeCreatedOn() {
-    Change c = TestChanges.newChange(project, accountId);
-    c.setLastUpdatedOn(TimeUtil.nowTs());
-
-    PatchSet goodPs1 = new PatchSet(new PatchSet.Id(c.getId(), 1));
-    goodPs1.setRevision(new RevId("deadbeefdeadbeefdeadbeefdeadbeefdeadbeef"));
-    goodPs1.setUploader(accountId);
-    goodPs1.setCreatedOn(TimeUtil.nowTs());
-    assertThat(goodPs1.getCreatedOn()).isGreaterThan(c.getCreatedOn());
-
-    PatchSet ps1AtCreatedOn = clone(goodPs1);
-    ps1AtCreatedOn.setCreatedOn(c.getCreatedOn());
-
-    PatchSet goodPs2 = new PatchSet(new PatchSet.Id(c.getId(), 2));
-    goodPs2.setRevision(new RevId("deadbeefdeadbeefdeadbeefdeadbeefdeadbeef"));
-    goodPs2.setUploader(accountId);
-    goodPs2.setCreatedOn(TimeUtil.nowTs());
-
-    PatchSet ps2AtCreatedOn = clone(goodPs2);
-    ps2AtCreatedOn.setCreatedOn(c.getCreatedOn());
-
-    // Both ReviewDb, exact match required.
-    ChangeBundle b1 =
-        new ChangeBundle(
-            c,
-            messages(),
-            patchSets(goodPs1, goodPs2),
-            approvals(),
-            comments(),
-            reviewers(),
-            REVIEW_DB);
-    ChangeBundle b2 =
-        new ChangeBundle(
-            c,
-            messages(),
-            patchSets(ps1AtCreatedOn, ps2AtCreatedOn),
-            approvals(),
-            comments(),
-            reviewers(),
-            REVIEW_DB);
-    assertDiffs(
-        b1,
-        b2,
-        "createdOn differs for PatchSet.Id "
-            + c.getId()
-            + ",1: {2009-09-30 17:00:12.0} != {2009-09-30 17:00:00.0}",
-        "createdOn differs for PatchSet.Id "
-            + c.getId()
-            + ",2: {2009-09-30 17:00:18.0} != {2009-09-30 17:00:00.0}");
-
-    // One ReviewDb, PS1 is allowed to match change createdOn, but PS2 isn't.
-    b1 =
-        new ChangeBundle(
-            c,
-            messages(),
-            patchSets(goodPs1, goodPs2),
-            approvals(),
-            comments(),
-            reviewers(),
-            REVIEW_DB);
-    b2 =
-        new ChangeBundle(
-            c,
-            messages(),
-            patchSets(ps1AtCreatedOn, ps2AtCreatedOn),
-            approvals(),
-            comments(),
-            reviewers(),
-            NOTE_DB);
-    assertDiffs(
-        b1,
-        b2,
-        "createdOn differs for PatchSet.Id "
-            + c.getId()
-            + ",2 in NoteDb vs. ReviewDb: {2009-09-30 17:00:00.0} != {2009-09-30 17:00:18.0}");
-    assertDiffs(
-        b2,
-        b1,
-        "createdOn differs for PatchSet.Id "
-            + c.getId()
-            + ",2 in NoteDb vs. ReviewDb: {2009-09-30 17:00:00.0} != {2009-09-30 17:00:18.0}");
-  }
-
-  @Test
-  public void diffPatchSetApprovalKeySets() throws Exception {
-    Change c = TestChanges.newChange(project, accountId);
-    int id = c.getId().get();
-    PatchSetApproval a1 =
-        new PatchSetApproval(
-            new PatchSetApproval.Key(c.currentPatchSetId(), accountId, new LabelId("Code-Review")),
-            (short) 1,
-            TimeUtil.nowTs());
-    PatchSetApproval a2 =
-        new PatchSetApproval(
-            new PatchSetApproval.Key(c.currentPatchSetId(), accountId, new LabelId("Verified")),
-            (short) 1,
-            TimeUtil.nowTs());
-
-    ChangeBundle b1 =
-        new ChangeBundle(
-            c, messages(), latest(c), approvals(a1), comments(), reviewers(), REVIEW_DB);
-    ChangeBundle b2 =
-        new ChangeBundle(
-            c, messages(), latest(c), approvals(a2), comments(), reviewers(), REVIEW_DB);
-
-    assertDiffs(
-        b1,
-        b2,
-        "PatchSetApproval.Key sets differ:"
-            + " ["
-            + id
-            + "%2C1,100,Code-Review] only in A;"
-            + " ["
-            + id
-            + "%2C1,100,Verified] only in B");
-  }
-
-  @Test
-  public void diffPatchSetApprovals() throws Exception {
-    Change c = TestChanges.newChange(project, accountId);
-    PatchSetApproval a1 =
-        new PatchSetApproval(
-            new PatchSetApproval.Key(c.currentPatchSetId(), accountId, new LabelId("Code-Review")),
-            (short) 1,
-            TimeUtil.nowTs());
-    PatchSetApproval a2 = clone(a1);
-    ChangeBundle b1 =
-        new ChangeBundle(
-            c, messages(), latest(c), approvals(a1), comments(), reviewers(), REVIEW_DB);
-    ChangeBundle b2 =
-        new ChangeBundle(
-            c, messages(), latest(c), approvals(a2), comments(), reviewers(), REVIEW_DB);
-
-    assertNoDiffs(b1, b2);
-
-    a2.setValue((short) -1);
-    assertDiffs(
-        b1,
-        b2,
-        "value differs for PatchSetApproval.Key "
-            + c.getId()
-            + "%2C1,100,Code-Review: {1} != {-1}");
-  }
-
-  @Test
-  public void diffPatchSetApprovalsMixedSourcesAllowsSlop() throws Exception {
-    Change c = TestChanges.newChange(project, accountId);
-    subWindowResolution();
-    PatchSetApproval a1 =
-        new PatchSetApproval(
-            new PatchSetApproval.Key(c.currentPatchSetId(), accountId, new LabelId("Code-Review")),
-            (short) 1,
-            truncateToSecond(TimeUtil.nowTs()));
-    PatchSetApproval a2 = clone(a1);
-    a2.setGranted(TimeUtil.nowTs());
-
-    // Both are ReviewDb, exact timestamp match is required.
-    ChangeBundle b1 =
-        new ChangeBundle(
-            c, messages(), latest(c), approvals(a1), comments(), reviewers(), REVIEW_DB);
-    ChangeBundle b2 =
-        new ChangeBundle(
-            c, messages(), latest(c), approvals(a2), comments(), reviewers(), REVIEW_DB);
-    assertDiffs(
-        b1,
-        b2,
-        "granted differs for PatchSetApproval.Key "
-            + c.getId()
-            + "%2C1,100,Code-Review:"
-            + " {2009-09-30 17:00:07.0} != {2009-09-30 17:00:08.0}");
-
-    // One NoteDb, slop is allowed.
-    b1 =
-        new ChangeBundle(c, messages(), latest(c), approvals(a1), comments(), reviewers(), NOTE_DB);
-    b2 =
-        new ChangeBundle(
-            c, messages(), latest(c), approvals(a2), comments(), reviewers(), REVIEW_DB);
-    assertNoDiffs(b1, b2);
-
-    // But not too much slop.
-    superWindowResolution();
-    PatchSetApproval a3 = clone(a1);
-    a3.setGranted(TimeUtil.nowTs());
-    b1 =
-        new ChangeBundle(c, messages(), latest(c), approvals(a1), comments(), reviewers(), NOTE_DB);
-    ChangeBundle b3 =
-        new ChangeBundle(
-            c, messages(), latest(c), approvals(a3), comments(), reviewers(), REVIEW_DB);
-    String msg =
-        "granted differs for PatchSetApproval.Key "
-            + c.getId()
-            + "%2C1,100,Code-Review in NoteDb vs. ReviewDb:"
-            + " {2009-09-30 17:00:07.0} != {2009-09-30 17:00:15.0}";
-    assertDiffs(b1, b3, msg);
-    assertDiffs(b3, b1, msg);
-  }
-
-  @Test
-  public void diffPatchSetApprovalsAllowsTruncatedTimestampInNoteDb() throws Exception {
-    Change c = TestChanges.newChange(project, accountId);
-    PatchSetApproval a1 =
-        new PatchSetApproval(
-            new PatchSetApproval.Key(c.currentPatchSetId(), accountId, new LabelId("Code-Review")),
-            (short) 1,
-            c.getCreatedOn());
-    PatchSetApproval a2 = clone(a1);
-    a2.setGranted(
-        new Timestamp(
-            LocalDate.of(1900, Month.JANUARY, 1)
-                .atStartOfDay()
-                .atZone(ZoneId.of(TIMEZONE_ID))
-                .toInstant()
-                .toEpochMilli()));
-
-    // Both are ReviewDb, exact match is required.
-    ChangeBundle b1 =
-        new ChangeBundle(
-            c, messages(), latest(c), approvals(a1), comments(), reviewers(), REVIEW_DB);
-    ChangeBundle b2 =
-        new ChangeBundle(
-            c, messages(), latest(c), approvals(a2), comments(), reviewers(), REVIEW_DB);
-    assertDiffs(
-        b1,
-        b2,
-        "granted differs for PatchSetApproval.Key "
-            + c.getId()
-            + "%2C1,100,Code-Review:"
-            + " {2009-09-30 17:00:00.0} != {1900-01-01 00:00:00.0}");
-
-    // Truncating NoteDb timestamp is allowed.
-    b1 =
-        new ChangeBundle(c, messages(), latest(c), approvals(a1), comments(), reviewers(), NOTE_DB);
-    b2 =
-        new ChangeBundle(
-            c, messages(), latest(c), approvals(a2), comments(), reviewers(), REVIEW_DB);
-    assertNoDiffs(b1, b2);
-    assertNoDiffs(b2, b1);
-  }
-
-  @Test
-  public void diffPatchSetApprovalsIgnoresPostSubmitBitOnZeroVote() throws Exception {
-    Change c = TestChanges.newChange(project, accountId);
-    c.setStatus(Change.Status.MERGED);
-    PatchSetApproval a1 =
-        new PatchSetApproval(
-            new PatchSetApproval.Key(c.currentPatchSetId(), accountId, new LabelId("Code-Review")),
-            (short) 0,
-            TimeUtil.nowTs());
-    a1.setPostSubmit(false);
-    PatchSetApproval a2 = clone(a1);
-    a2.setPostSubmit(true);
-
-    // Both are ReviewDb, exact match is required.
-    ChangeBundle b1 =
-        new ChangeBundle(
-            c, messages(), latest(c), approvals(a1), comments(), reviewers(), REVIEW_DB);
-    ChangeBundle b2 =
-        new ChangeBundle(
-            c, messages(), latest(c), approvals(a2), comments(), reviewers(), REVIEW_DB);
-    assertDiffs(
-        b1,
-        b2,
-        "postSubmit differs for PatchSetApproval.Key "
-            + c.getId()
-            + "%2C1,100,Code-Review:"
-            + " {false} != {true}");
-
-    // One NoteDb, postSubmit is ignored.
-    b1 =
-        new ChangeBundle(
-            c, messages(), latest(c), approvals(a1), comments(), reviewers(), REVIEW_DB);
-    b2 =
-        new ChangeBundle(c, messages(), latest(c), approvals(a2), comments(), reviewers(), NOTE_DB);
-    assertNoDiffs(b1, b2);
-    assertNoDiffs(b2, b1);
-
-    // postSubmit is not ignored if vote isn't 0.
-    a1.setValue((short) 1);
-    a2.setValue((short) 1);
-    assertDiffs(
-        b1,
-        b2,
-        "postSubmit differs for PatchSetApproval.Key "
-            + c.getId()
-            + "%2C1,100,Code-Review:"
-            + " {false} != {true}");
-    assertDiffs(
-        b2,
-        b1,
-        "postSubmit differs for PatchSetApproval.Key "
-            + c.getId()
-            + "%2C1,100,Code-Review:"
-            + " {true} != {false}");
-  }
-
-  @Test
-  public void diffReviewers() throws Exception {
-    Change c = TestChanges.newChange(project, accountId);
-    Timestamp now = TimeUtil.nowTs();
-    ReviewerSet r1 = reviewers(REVIEWER, new Account.Id(1), now);
-    ReviewerSet r2 = reviewers(REVIEWER, new Account.Id(2), now);
-
-    ChangeBundle b1 =
-        new ChangeBundle(c, messages(), latest(c), approvals(), comments(), r1, REVIEW_DB);
-    ChangeBundle b2 =
-        new ChangeBundle(c, messages(), latest(c), approvals(), comments(), r2, REVIEW_DB);
-    assertNoDiffs(b1, b1);
-    assertNoDiffs(b2, b2);
-    assertDiffs(b1, b2, "reviewer sets differ: [1] only in A; [2] only in B");
-  }
-
-  @Test
-  public void diffReviewersIgnoresStateAndTimestamp() throws Exception {
-    Change c = TestChanges.newChange(project, accountId);
-    ReviewerSet r1 = reviewers(REVIEWER, new Account.Id(1), TimeUtil.nowTs());
-    ReviewerSet r2 = reviewers(CC, new Account.Id(1), TimeUtil.nowTs());
-
-    ChangeBundle b1 =
-        new ChangeBundle(c, messages(), latest(c), approvals(), comments(), r1, REVIEW_DB);
-    ChangeBundle b2 =
-        new ChangeBundle(c, messages(), latest(c), approvals(), comments(), r2, REVIEW_DB);
-    assertNoDiffs(b1, b1);
-    assertNoDiffs(b2, b2);
-  }
-
-  @Test
-  public void diffPatchLineCommentKeySets() throws Exception {
-    Change c = TestChanges.newChange(project, accountId);
-    int id = c.getId().get();
-    PatchLineComment c1 =
-        new PatchLineComment(
-            new PatchLineComment.Key(new Patch.Key(c.currentPatchSetId(), "filename1"), "uuid1"),
-            5,
-            accountId,
-            null,
-            TimeUtil.nowTs());
-    PatchLineComment c2 =
-        new PatchLineComment(
-            new PatchLineComment.Key(new Patch.Key(c.currentPatchSetId(), "filename2"), "uuid2"),
-            5,
-            accountId,
-            null,
-            TimeUtil.nowTs());
-
-    ChangeBundle b1 =
-        new ChangeBundle(
-            c, messages(), latest(c), approvals(), comments(c1), reviewers(), REVIEW_DB);
-    ChangeBundle b2 =
-        new ChangeBundle(
-            c, messages(), latest(c), approvals(), comments(c2), reviewers(), REVIEW_DB);
-
-    assertDiffs(
-        b1,
-        b2,
-        "PatchLineComment.Key sets differ:"
-            + " ["
-            + id
-            + ",1,filename1,uuid1] only in A;"
-            + " ["
-            + id
-            + ",1,filename2,uuid2] only in B");
-  }
-
-  @Test
-  public void diffPatchLineComments() throws Exception {
-    Change c = TestChanges.newChange(project, accountId);
-    PatchLineComment c1 =
-        new PatchLineComment(
-            new PatchLineComment.Key(new Patch.Key(c.currentPatchSetId(), "filename"), "uuid"),
-            5,
-            accountId,
-            null,
-            TimeUtil.nowTs());
-    PatchLineComment c2 = clone(c1);
-    ChangeBundle b1 =
-        new ChangeBundle(
-            c, messages(), latest(c), approvals(), comments(c1), reviewers(), REVIEW_DB);
-    ChangeBundle b2 =
-        new ChangeBundle(
-            c, messages(), latest(c), approvals(), comments(c2), reviewers(), REVIEW_DB);
-
-    assertNoDiffs(b1, b2);
-
-    c2.setStatus(PatchLineComment.Status.PUBLISHED);
-    assertDiffs(
-        b1,
-        b2,
-        "status differs for PatchLineComment.Key " + c.getId() + ",1,filename,uuid: {d} != {P}");
-  }
-
-  @Test
-  public void diffPatchLineCommentsMixedSourcesAllowsSlop() throws Exception {
-    subWindowResolution();
-    Change c = TestChanges.newChange(project, accountId);
-    PatchLineComment c1 =
-        new PatchLineComment(
-            new PatchLineComment.Key(new Patch.Key(c.currentPatchSetId(), "filename"), "uuid"),
-            5,
-            accountId,
-            null,
-            truncateToSecond(TimeUtil.nowTs()));
-    PatchLineComment c2 = clone(c1);
-    c2.setWrittenOn(TimeUtil.nowTs());
-
-    // Both are ReviewDb, exact timestamp match is required.
-    ChangeBundle b1 =
-        new ChangeBundle(
-            c, messages(), latest(c), approvals(), comments(c1), reviewers(), REVIEW_DB);
-    ChangeBundle b2 =
-        new ChangeBundle(
-            c, messages(), latest(c), approvals(), comments(c2), reviewers(), REVIEW_DB);
-    assertDiffs(
-        b1,
-        b2,
-        "writtenOn differs for PatchLineComment.Key "
-            + c.getId()
-            + ",1,filename,uuid:"
-            + " {2009-09-30 17:00:02.0} != {2009-09-30 17:00:03.0}");
-
-    // One NoteDb, slop is allowed.
-    b1 =
-        new ChangeBundle(c, messages(), latest(c), approvals(), comments(c1), reviewers(), NOTE_DB);
-    b2 =
-        new ChangeBundle(
-            c, messages(), latest(c), approvals(), comments(c2), reviewers(), REVIEW_DB);
-    assertNoDiffs(b1, b2);
-
-    // But not too much slop.
-    superWindowResolution();
-    PatchLineComment c3 = clone(c1);
-    c3.setWrittenOn(TimeUtil.nowTs());
-    b1 =
-        new ChangeBundle(c, messages(), latest(c), approvals(), comments(c1), reviewers(), NOTE_DB);
-    ChangeBundle b3 =
-        new ChangeBundle(
-            c, messages(), latest(c), approvals(), comments(c3), reviewers(), REVIEW_DB);
-    String msg =
-        "writtenOn differs for PatchLineComment.Key "
-            + c.getId()
-            + ",1,filename,uuid in NoteDb vs. ReviewDb:"
-            + " {2009-09-30 17:00:02.0} != {2009-09-30 17:00:10.0}";
-    assertDiffs(b1, b3, msg);
-    assertDiffs(b3, b1, msg);
-  }
-
-  @Test
-  public void diffPatchLineCommentsIgnoresCommentsOnInvalidPatchSet() throws Exception {
-    Change c = TestChanges.newChange(project, accountId);
-    PatchLineComment c1 =
-        new PatchLineComment(
-            new PatchLineComment.Key(new Patch.Key(c.currentPatchSetId(), "filename1"), "uuid1"),
-            5,
-            accountId,
-            null,
-            TimeUtil.nowTs());
-    PatchLineComment c2 =
-        new PatchLineComment(
-            new PatchLineComment.Key(
-                new Patch.Key(new PatchSet.Id(c.getId(), 0), "filename2"), "uuid2"),
-            5,
-            accountId,
-            null,
-            TimeUtil.nowTs());
-
-    ChangeBundle b1 =
-        new ChangeBundle(
-            c, messages(), latest(c), approvals(), comments(c1, c2), reviewers(), REVIEW_DB);
-    ChangeBundle b2 =
-        new ChangeBundle(
-            c, messages(), latest(c), approvals(), comments(c1), reviewers(), REVIEW_DB);
-    assertNoDiffs(b1, b2);
-  }
-
-  private static void assertNoDiffs(ChangeBundle a, ChangeBundle b) {
-    assertThat(a.differencesFrom(b)).isEmpty();
-    assertThat(b.differencesFrom(a)).isEmpty();
-  }
-
-  private static void assertDiffs(ChangeBundle a, ChangeBundle b, String first, String... rest) {
-    List<String> actual = a.differencesFrom(b);
-    if (actual.size() == 1 && rest.length == 0) {
-      // This error message is much easier to read.
-      assertThat(actual.get(0)).isEqualTo(first);
-    } else {
-      List<String> expected = new ArrayList<>(1 + rest.length);
-      expected.add(first);
-      Collections.addAll(expected, rest);
-      assertThat(actual).containsExactlyElementsIn(expected).inOrder();
-    }
-    assertThat(a).isNotEqualTo(b);
-  }
-
-  private static List<ChangeMessage> messages(ChangeMessage... ents) {
-    return Arrays.asList(ents);
-  }
-
-  private static List<PatchSet> patchSets(PatchSet... ents) {
-    return Arrays.asList(ents);
-  }
-
-  private static List<PatchSet> latest(Change c) {
-    PatchSet ps = new PatchSet(c.currentPatchSetId());
-    ps.setCreatedOn(c.getLastUpdatedOn());
-    return ImmutableList.of(ps);
-  }
-
-  private static List<PatchSetApproval> approvals(PatchSetApproval... ents) {
-    return Arrays.asList(ents);
-  }
-
-  private static ReviewerSet reviewers(Object... ents) {
-    checkArgument(ents.length % 3 == 0);
-    Table<ReviewerStateInternal, Account.Id, Timestamp> t = HashBasedTable.create();
-    for (int i = 0; i < ents.length; i += 3) {
-      t.put((ReviewerStateInternal) ents[i], (Account.Id) ents[i + 1], (Timestamp) ents[i + 2]);
-    }
-    return ReviewerSet.fromTable(t);
-  }
-
-  private static List<PatchLineComment> comments(PatchLineComment... ents) {
-    return Arrays.asList(ents);
-  }
-
-  private static Change clone(Change ent) {
-    return clone(CHANGE_CODEC, ent);
-  }
-
-  private static ChangeMessage clone(ChangeMessage ent) {
-    return clone(CHANGE_MESSAGE_CODEC, ent);
-  }
-
-  private static PatchSet clone(PatchSet ent) {
-    return clone(PATCH_SET_CODEC, ent);
-  }
-
-  private static PatchSetApproval clone(PatchSetApproval ent) {
-    return clone(PATCH_SET_APPROVAL_CODEC, ent);
-  }
-
-  private static PatchLineComment clone(PatchLineComment ent) {
-    return clone(PATCH_LINE_COMMENT_CODEC, ent);
-  }
-
-  private static <T> T clone(ProtobufCodec<T> codec, T obj) {
-    return codec.decode(codec.encodeToByteArray(obj));
-  }
-}
diff --git a/javatests/com/google/gerrit/server/notedb/rebuild/EventSorterTest.java b/javatests/com/google/gerrit/server/notedb/rebuild/EventSorterTest.java
deleted file mode 100644
index 7fb9d82..0000000
--- a/javatests/com/google/gerrit/server/notedb/rebuild/EventSorterTest.java
+++ /dev/null
@@ -1,232 +0,0 @@
-// Copyright (C) 2016 The Android Open Source Project
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-// http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-
-package com.google.gerrit.server.notedb.rebuild;
-
-import static com.google.common.truth.Truth.assertThat;
-import static java.util.stream.Collectors.toList;
-import static org.junit.Assert.fail;
-
-import com.google.common.collect.Collections2;
-import com.google.common.collect.Lists;
-import com.google.gerrit.reviewdb.client.Account;
-import com.google.gerrit.reviewdb.client.Change;
-import com.google.gerrit.reviewdb.client.PatchSet;
-import com.google.gerrit.server.notedb.ChangeUpdate;
-import com.google.gerrit.server.util.time.TimeUtil;
-import com.google.gerrit.testing.GerritBaseTests;
-import com.google.gerrit.testing.TestTimeUtil;
-import java.sql.Timestamp;
-import java.util.ArrayList;
-import java.util.List;
-import java.util.concurrent.TimeUnit;
-import java.util.stream.Stream;
-import org.junit.Before;
-import org.junit.Test;
-
-public class EventSorterTest extends GerritBaseTests {
-  private class TestEvent extends Event {
-    protected TestEvent(Timestamp when) {
-      super(
-          new PatchSet.Id(new Change.Id(1), 1),
-          new Account.Id(1000),
-          new Account.Id(1000),
-          when,
-          changeCreatedOn,
-          null);
-    }
-
-    @Override
-    boolean uniquePerUpdate() {
-      return false;
-    }
-
-    @Override
-    void apply(ChangeUpdate update) {
-      throw new UnsupportedOperationException();
-    }
-
-    @SuppressWarnings("deprecation")
-    @Override
-    public String toString() {
-      return "E{" + when.getSeconds() + '}';
-    }
-  }
-
-  private Timestamp changeCreatedOn;
-
-  @Before
-  public void setUp() {
-    TestTimeUtil.resetWithClockStep(10, TimeUnit.SECONDS);
-    changeCreatedOn = TimeUtil.nowTs();
-  }
-
-  @Test
-  public void naturalSort() {
-    Event e1 = new TestEvent(TimeUtil.nowTs());
-    Event e2 = new TestEvent(TimeUtil.nowTs());
-    Event e3 = new TestEvent(TimeUtil.nowTs());
-
-    for (List<Event> events : Collections2.permutations(events(e1, e2, e3))) {
-      assertSorted(events, events(e1, e2, e3));
-    }
-  }
-
-  @Test
-  public void topoSortOneDep() {
-    List<Event> es;
-
-    // Input list is 0,1,2
-
-    // 0 depends on 1 => 1,0,2
-    es = threeEventsOneDep(0, 1);
-    assertSorted(es, events(es, 1, 0, 2));
-
-    // 1 depends on 0 => 0,1,2
-    es = threeEventsOneDep(1, 0);
-    assertSorted(es, events(es, 0, 1, 2));
-
-    // 0 depends on 2 => 1,2,0
-    es = threeEventsOneDep(0, 2);
-    assertSorted(es, events(es, 1, 2, 0));
-
-    // 2 depends on 0 => 0,1,2
-    es = threeEventsOneDep(2, 0);
-    assertSorted(es, events(es, 0, 1, 2));
-
-    // 1 depends on 2 => 0,2,1
-    es = threeEventsOneDep(1, 2);
-    assertSorted(es, events(es, 0, 2, 1));
-
-    // 2 depends on 1 => 0,1,2
-    es = threeEventsOneDep(2, 1);
-    assertSorted(es, events(es, 0, 1, 2));
-  }
-
-  private List<Event> threeEventsOneDep(int depFromIdx, int depOnIdx) {
-    List<Event> events =
-        Lists.newArrayList(
-            new TestEvent(TimeUtil.nowTs()),
-            new TestEvent(TimeUtil.nowTs()),
-            new TestEvent(TimeUtil.nowTs()));
-    events.get(depFromIdx).addDep(events.get(depOnIdx));
-    return events;
-  }
-
-  @Test
-  public void lastEventDependsOnFirstEvent() {
-    List<Event> events = new ArrayList<>();
-    for (int i = 0; i < 20; i++) {
-      events.add(new TestEvent(TimeUtil.nowTs()));
-    }
-    events.get(events.size() - 1).addDep(events.get(0));
-    assertSorted(events, events);
-  }
-
-  @Test
-  public void firstEventDependsOnLastEvent() {
-    List<Event> events = new ArrayList<>();
-    for (int i = 0; i < 20; i++) {
-      events.add(new TestEvent(TimeUtil.nowTs()));
-    }
-    events.get(0).addDep(events.get(events.size() - 1));
-
-    List<Event> expected = new ArrayList<>();
-    expected.addAll(events.subList(1, events.size()));
-    expected.add(events.get(0));
-    assertSorted(events, expected);
-  }
-
-  @Test
-  public void topoSortChainOfDeps() {
-    Event e1 = new TestEvent(TimeUtil.nowTs());
-    Event e2 = new TestEvent(TimeUtil.nowTs());
-    Event e3 = new TestEvent(TimeUtil.nowTs());
-    Event e4 = new TestEvent(TimeUtil.nowTs());
-    e1.addDep(e2);
-    e2.addDep(e3);
-    e3.addDep(e4);
-
-    assertSorted(events(e1, e2, e3, e4), events(e4, e3, e2, e1));
-  }
-
-  @Test
-  public void topoSortMultipleDeps() {
-    Event e1 = new TestEvent(TimeUtil.nowTs());
-    Event e2 = new TestEvent(TimeUtil.nowTs());
-    Event e3 = new TestEvent(TimeUtil.nowTs());
-    Event e4 = new TestEvent(TimeUtil.nowTs());
-    e1.addDep(e2);
-    e1.addDep(e4);
-    e2.addDep(e3);
-
-    // Processing 3 pops 2, processing 4 pops 1.
-    assertSorted(events(e2, e3, e1, e4), events(e3, e2, e4, e1));
-  }
-
-  @Test
-  public void topoSortMultipleDepsPreservesNaturalOrder() {
-    Event e1 = new TestEvent(TimeUtil.nowTs());
-    Event e2 = new TestEvent(TimeUtil.nowTs());
-    Event e3 = new TestEvent(TimeUtil.nowTs());
-    Event e4 = new TestEvent(TimeUtil.nowTs());
-    e1.addDep(e4);
-    e2.addDep(e4);
-    e3.addDep(e4);
-
-    // Processing 4 pops 1, 2, 3 in natural order.
-    assertSorted(events(e4, e3, e2, e1), events(e4, e1, e2, e3));
-  }
-
-  @Test
-  public void topoSortCycle() {
-    Event e1 = new TestEvent(TimeUtil.nowTs());
-    Event e2 = new TestEvent(TimeUtil.nowTs());
-
-    // Implementation is not really defined, but infinite looping would be bad.
-    // According to current implementation details, 2 pops 1, 1 pops 2 which was
-    // already seen.
-    assertSorted(events(e2, e1), events(e1, e2));
-  }
-
-  @Test
-  public void topoSortDepNotInInputList() {
-    Event e1 = new TestEvent(TimeUtil.nowTs());
-    Event e2 = new TestEvent(TimeUtil.nowTs());
-    Event e3 = new TestEvent(TimeUtil.nowTs());
-    e1.addDep(e3);
-
-    List<Event> events = events(e2, e1);
-    try {
-      new EventSorter(events).sort();
-      fail("expected IllegalArgumentException");
-    } catch (IllegalArgumentException e) {
-      // Expected.
-    }
-  }
-
-  private static List<Event> events(Event... es) {
-    return Lists.newArrayList(es);
-  }
-
-  private static List<Event> events(List<Event> in, Integer... indexes) {
-    return Stream.of(indexes).map(in::get).collect(toList());
-  }
-
-  private static void assertSorted(List<Event> unsorted, List<Event> expected) {
-    List<Event> actual = new ArrayList<>(unsorted);
-    new EventSorter(actual).sort();
-    assertThat(actual).named("sorted" + unsorted).isEqualTo(expected);
-  }
-}