Add topic to CherryPickInput

Currently, when creating a cherry-pick, the topic of the created
change will be {source_change_topic}-{destination_branch} if
there is a source change topic, otherwise, it will not be set.

This change adds the ability to also set a topic when creating
a cherry-pick.

This is useful especially when implementing Cherry-pick topic,
since when cherry-picking a topic we want to set a specific and
unique topic for all created changes.

Change-Id: I9eabf0b3526875711bd21da0c1f31d434dcc4059

Documentation/rest-api-changes.txt

@@ -6177,6 +6177,12 @@ Callers can find out if there were conflicts by checking the
 `contains_git_conflicts` field in the link:#change-info[ChangeInfo]. If
 there are conflicts the cherry-pick change is marked as
 work-in-progress.
+|`topic`            |optional|
+The topic of the created cherry-picked change. If not set, the default depends
+on the source. If the source is a change with a topic, the resulting topic
+of the cherry-picked change will be {source_change_topic}-{destination_branch}.
+Otherwise, if the source change has no topic, or the source is a commit,
+the created change will have no topic.
 |===========================
 
 [[comment-info]]

java/com/google/gerrit/extensions/api/changes/CherryPickInput.java

@@ -29,4 +29,5 @@ public class CherryPickInput {
 
   public boolean keepReviewers;
   public boolean allowConflicts;
+  public String topic;
 }

java/com/google/gerrit/server/restapi/change/CherryPickChange.java

@@ -175,7 +175,6 @@ public class CherryPickChange {
         null,
         null,
         null,
-        null,
         null);
   }
 
@@ -217,7 +216,6 @@ public class CherryPickChange {
         null,
         null,
         null,
-        null,
         null);
   }
 
@@ -235,7 +233,6 @@ public class CherryPickChange {
    * @param ignoreIdenticalTree When false, we throw an error when trying to cherry-pick creates an
    *     empty commit. When true, we allow creation of an empty commit.
    * @param timestamp the current timestamp.
-   * @param topic Topic name for the change created.
    * @param revertedChange The id of the change that is reverted. This is used for the "revertOf"
    *     field to mark the created cherry pick change as "revertOf" the original change that was
    *     reverted.
@@ -263,7 +260,6 @@ public class CherryPickChange {
       BranchNameKey dest,
       boolean ignoreIdenticalTree,
       Timestamp timestamp,
-      @Nullable String topic,
       @Nullable Change.Id revertedChange,
       @Nullable ObjectId changeIdForNewChange,
       @Nullable Change.Id idForNewChange,
@@ -381,8 +377,11 @@ public class CherryPickChange {
           } else {
             // Change key not found on destination branch. We can create a new
             // change.
-            String newTopic = topic;
-            if (topic == null
+            String newTopic = null;
+            if (input.topic != null) {
+              newTopic = Strings.emptyToNull(input.topic.trim());
+            }
+            if (newTopic == null
                 && sourceChange != null
                 && !Strings.isNullOrEmpty(sourceChange.getTopic())) {
               newTopic = sourceChange.getTopic() + "-" + newDest.shortName();

java/com/google/gerrit/server/restapi/change/RevertSubmission.java

@@ -20,6 +20,7 @@ import static com.google.gerrit.server.permissions.RefPermission.CREATE_CHANGE;
 import static com.google.gerrit.server.project.ProjectCache.illegalState;
 import static java.util.Objects.requireNonNull;
 
+import com.google.common.base.Strings;
 import com.google.common.collect.ArrayListMultimap;
 import com.google.common.collect.Multimap;
 import com.google.common.flogger.FluentLogger;
@@ -195,6 +196,9 @@ public class RevertSubmission
   }
 
   private String createTopic(String topic, String submissionId) {
+    if (topic != null) {
+      topic = Strings.emptyToNull(topic.trim());
+    }
     if (topic == null) {
       return String.format(
           "revert-%s-%s", submissionId, RandomStringUtils.randomAlphabetic(10).toUpperCase());
@@ -321,12 +325,7 @@ public class RevertSubmission
       bu.addOp(
           changeNotes.getChange().getId(),
           new CreateCherryPickOp(
-              revCommitId,
-              revertInput.topic,
-              generatedChangeId,
-              cherryPickRevertChangeId,
-              groupName,
-              timestamp));
+              revCommitId, generatedChangeId, cherryPickRevertChangeId, groupName, timestamp));
       bu.addOp(changeNotes.getChange().getId(), new PostRevertedMessageOp(generatedChangeId));
       bu.addOp(
           cherryPickRevertChangeId,
@@ -356,6 +355,7 @@ public class RevertSubmission
     cherryPickInput.notifyDetails = revertInput.notifyDetails;
     cherryPickInput.parent = 1;
     cherryPickInput.keepReviewers = true;
+    cherryPickInput.topic = revertInput.topic;
     return cherryPickInput;
   }
 
@@ -570,7 +570,6 @@ public class RevertSubmission
 
   private class CreateCherryPickOp implements BatchUpdateOp {
     private final ObjectId revCommitId;
-    private final String topic;
     private final ObjectId computedChangeId;
     private final Change.Id cherryPickRevertChangeId;
     private final String groupName;
@@ -578,13 +577,11 @@ public class RevertSubmission
 
     CreateCherryPickOp(
         ObjectId revCommitId,
-        String topic,
         ObjectId computedChangeId,
         Change.Id cherryPickRevertChangeId,
         String groupName,
         Timestamp timestamp) {
       this.revCommitId = revCommitId;
-      this.topic = topic;
       this.computedChangeId = computedChangeId;
       this.cherryPickRevertChangeId = cherryPickRevertChangeId;
       this.groupName = groupName;
@@ -604,7 +601,6 @@ public class RevertSubmission
                   change.getProject(), RefNames.fullName(cherryPickInput.destination)),
               true,
               timestamp,
-              topic,
               change.getId(),
               computedChangeId,
               cherryPickRevertChangeId,

javatests/com/google/gerrit/acceptance/api/project/CommitIT.java

@@ -169,6 +169,21 @@ public class CommitIT extends AbstractDaemonTest {
     assertThat(revInfo.commit.message).isEqualTo(input.message + "\n");
   }
 
+  @Test
+  public void cherryPickCommitWithSetTopic() throws Exception {
+    String branch = "foo";
+    RevCommit revCommit = createChange().getCommit();
+    gApi.projects().name(project.get()).branch(branch).create(new BranchInput());
+    CherryPickInput input = new CherryPickInput();
+    input.destination = branch;
+    input.topic = "topic";
+    String changeId =
+        gApi.projects().name(project.get()).commit(revCommit.name()).cherryPick(input).get().id;
+
+    ChangeInfo changeInfo = gApi.changes().id(changeId).get();
+    assertThat(changeInfo.topic).isEqualTo(input.topic);
+  }
+
   private IncludedInInfo getIncludedIn(ObjectId id) throws Exception {
     return gApi.projects().name(project.get()).commit(id.name()).includedIn();
   }

javatests/com/google/gerrit/acceptance/api/revision/RevisionIT.java

@@ -408,6 +408,19 @@ public class RevisionIT extends AbstractDaemonTest {
     cherry.current().submit();
   }
 
+  @Test
+  public void cherryPickWithSetTopic() throws Exception {
+    PushOneCommit.Result r = pushTo("refs/for/master");
+    CherryPickInput in = new CherryPickInput();
+    in.destination = "foo";
+    in.topic = "topic";
+    gApi.projects().name(project.get()).branch(in.destination).create(new BranchInput());
+    ChangeApi orig = gApi.changes().id(project.get() + "~master~" + r.getChangeId());
+
+    ChangeApi cherry = orig.revision(r.getCommit().name()).cherryPick(in);
+    assertThat(cherry.get().topic).isEqualTo("topic");
+  }
+
   @Test
   public void cherryPickWorkInProgressChange() throws Exception {
     PushOneCommit.Result r = pushTo("refs/for/master%wip");