Add revertOf to ChangeInfo and populate it when /revert is called

Change-Id: I10c16c667e4bbb61d35a6c7b6be917fc595ab3ec

Documentation/rest-api-changes.txt

@@ -5729,6 +5729,8 @@ When present, change is marked as private.
 When present, change is marked as Work In Progress.
 |`has_review_started` |optional, not set if `false`|
 When present, change has been marked Ready at some point in time.
+|`revert_of`          |optional|
+The numeric Change-Id of the change that this change reverts.
 |==================================
 
 [[change-input]]

gerrit-acceptance-tests/src/test/java/com/google/gerrit/acceptance/api/change/ChangeIT.java

@@ -617,6 +617,7 @@ public class ChangeIT extends AbstractDaemonTest {
 
     assertThat(revertChange.messages).hasSize(1);
     assertThat(revertChange.messages.iterator().next().message).isEqualTo("Uploaded patch set 1.");
+    assertThat(revertChange.revertOf).isEqualTo(gApi.changes().id(r.getChangeId()).get()._number);
   }
 
   @Test

gerrit-extension-api/src/main/java/com/google/gerrit/extensions/common/ChangeInfo.java

@@ -48,6 +48,7 @@ public class ChangeInfo {
   public Boolean isPrivate;
   public Boolean workInProgress;
   public Boolean hasReviewStarted;
+  public Integer revertOf;
 
   public int _number;
 

gerrit-server/src/main/java/com/google/gerrit/server/change/ChangeInserter.java

@@ -129,6 +129,7 @@ public class ChangeInserter implements InsertChangeOp {
   private boolean fireRevisionCreated;
   private boolean sendMail;
   private boolean updateRef;
+  private Change.Id revertOf;
 
   // Fields set during the insertion process.
   private ReceiveCommand cmd;
@@ -198,6 +199,7 @@ public class ChangeInserter implements InsertChangeOp {
     change.setPrivate(isPrivate);
     change.setWorkInProgress(workInProgress);
     change.setReviewStarted(!workInProgress);
+    change.setRevertOf(revertOf);
     return change;
   }
 
@@ -319,6 +321,11 @@ public class ChangeInserter implements InsertChangeOp {
     return this;
   }
 
+  public ChangeInserter setRevertOf(Change.Id revertOf) {
+    this.revertOf = revertOf;
+    return this;
+  }
+
   public void setPushCertificate(String cert) {
     pushCert = cert;
   }
@@ -390,6 +397,9 @@ public class ChangeInserter implements InsertChangeOp {
     update.setPsDescription(patchSetDescription);
     update.setPrivate(isPrivate);
     update.setWorkInProgress(workInProgress);
+    if (revertOf != null) {
+      update.setRevertOf(revertOf.get());
+    }
 
     boolean draft = status == Change.Status.DRAFT;
     List<String> newGroups = groups;

gerrit-server/src/main/java/com/google/gerrit/server/change/ChangeJson.java

@@ -542,6 +542,7 @@ public class ChangeJson {
     out.submitted = getSubmittedOn(cd);
     out.plugins =
         pluginDefinedAttributesFactory != null ? pluginDefinedAttributesFactory.create(cd) : null;
+    out.revertOf = cd.change().getRevertOf() != null ? cd.change().getRevertOf().get() : null;
 
     if (out.labels != null && has(DETAILED_LABELS)) {
       // If limited to specific patch sets but not the current patch set, don't

gerrit-server/src/main/java/com/google/gerrit/server/change/Revert.java

@@ -218,6 +218,7 @@ public class Revert extends RetryingRestModifyView<ChangeResource, RevertInput,
       Set<Account.Id> ccs = new HashSet<>(reviewerSet.byState(ReviewerStateInternal.CC));
       ccs.remove(user.getAccountId());
       ins.setExtraCC(ccs);
+      ins.setRevertOf(changeIdToRevert);
 
       try (BatchUpdate bu = updateFactory.create(db.get(), project, user, now)) {
         bu.setRepository(git, revWalk, oi);

gerrit-server/src/main/java/com/google/gerrit/server/notedb/rebuild/ChangeRebuilderImpl.java

@@ -618,6 +618,9 @@ public class ChangeRebuilderImpl extends ChangeRebuilder {
     update.setChangeId(change.getKey().get());
     update.setBranch(change.getDest().get());
     update.setSubject(change.getOriginalSubject());
+    if (change.getRevertOf() != null) {
+      update.setRevertOf(change.getRevertOf().get());
+    }
   }
 
   @Override