Refactor adding message to source change in cherry pick

When a change is cherry picked from one branch to another resulting in
a new change, a message is added to the source change:

 "This patch set was cherry picked to branch <name> as commit <sha1>"

Confusingly, this message is being added to the source change through
the ChangeInserter that is set up to insert the destination change. It
is being correctly added on the source change because the ChangeMessage
object stores the ID of the change to which the message belongs.

Refactor it so that the message is explicitly added to the source change,
rather than through the ChangeInserter for the destination change.

This is less efficient, as we now need instances of the change messages
utility and change update factory in the cherry pick, but it is rather
less confusing than before.

Change-Id: I49bd269969da61fb0a75fe9cbbdcd59016cb8a63

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

@@ -22,6 +22,7 @@ import com.google.gerrit.reviewdb.client.ChangeMessage;
 import com.google.gerrit.reviewdb.client.PatchSet;
 import com.google.gerrit.reviewdb.client.Project;
 import com.google.gerrit.reviewdb.server.ReviewDb;
+import com.google.gerrit.server.ChangeMessagesUtil;
 import com.google.gerrit.server.ChangeUtil;
 import com.google.gerrit.server.CurrentUser;
 import com.google.gerrit.server.GerritPersonIdent;
@@ -34,6 +35,7 @@ import com.google.gerrit.server.git.MergeIdenticalTreeException;
 import com.google.gerrit.server.git.MergeUtil;
 import com.google.gerrit.server.git.validators.CommitValidationException;
 import com.google.gerrit.server.git.validators.CommitValidators;
+import com.google.gerrit.server.notedb.ChangeUpdate;
 import com.google.gerrit.server.project.ChangeControl;
 import com.google.gerrit.server.project.InvalidChangeOperationException;
 import com.google.gerrit.server.project.NoSuchChangeException;
@@ -76,7 +78,9 @@ public class CherryPickChange {
   private final CommitValidators.Factory commitValidatorsFactory;
   private final ChangeInserter.Factory changeInserterFactory;
   private final PatchSetInserter.Factory patchSetInserterFactory;
-  final MergeUtil.Factory mergeUtilFactory;
+  private final MergeUtil.Factory mergeUtilFactory;
+  private final ChangeMessagesUtil changeMessagesUtil;
+  private final ChangeUpdate.Factory updateFactory;
 
   @Inject
   CherryPickChange(Provider<ReviewDb> db,
@@ -87,7 +91,9 @@ public class CherryPickChange {
       CommitValidators.Factory commitValidatorsFactory,
       ChangeInserter.Factory changeInserterFactory,
       PatchSetInserter.Factory patchSetInserterFactory,
-      MergeUtil.Factory mergeUtilFactory) {
+      MergeUtil.Factory mergeUtilFactory,
+      ChangeMessagesUtil changeMessagesUtil,
+      ChangeUpdate.Factory updateFactory) {
     this.db = db;
     this.queryProvider = queryProvider;
     this.gitManager = gitManager;
@@ -97,6 +103,8 @@ public class CherryPickChange {
     this.changeInserterFactory = changeInserterFactory;
     this.patchSetInserterFactory = patchSetInserterFactory;
     this.mergeUtilFactory = mergeUtilFactory;
+    this.changeMessagesUtil = changeMessagesUtil;
+    this.updateFactory = updateFactory;
   }
 
   public Change.Id cherryPick(Change change, PatchSet patch,
@@ -185,9 +193,14 @@ public class CherryPickChange {
         } else {
           // Change key not found on destination branch. We can create a new
           // change.
-          return createNewChange(git, revWalk, changeKey, project,
-              patch.getId(), destRef, cherryPickCommit, refControl,
+          Change.Id newChange = createNewChange(git, revWalk, changeKey, project,
+              destRef, cherryPickCommit, refControl,
               identifiedUser, change.getTopic());
+
+          addMessageToSourceChange(change, patch.getId(), destinationBranch,
+              cherryPickCommit, identifiedUser, refControl);
+
+          return newChange;
         }
       } finally {
         revWalk.release();
@@ -217,7 +230,7 @@ public class CherryPickChange {
   }
 
   private Change.Id createNewChange(Repository git, RevWalk revWalk,
-      Change.Key changeKey, Project.NameKey project, PatchSet.Id patchSetId,
+      Change.Key changeKey, Project.NameKey project,
       Ref destRef, RevCommit cherryPickCommit, RefControl refControl,
       IdentifiedUser identifiedUser, String topic)
       throws OrmException, InvalidChangeOperationException, IOException {
@@ -254,31 +267,30 @@ public class CherryPickChange {
           change.getDest().getParentKey().get(), ru.getResult()));
     }
 
-    ins.setMessage(buildChangeMessage(patchSetId, change, cherryPickCommit,
-        identifiedUser))
-        .insert();
+    ins.insert();
 
     return change.getId();
   }
 
-  private ChangeMessage buildChangeMessage(PatchSet.Id patchSetId, Change dest,
-      RevCommit cherryPickCommit, IdentifiedUser identifiedUser)
-      throws OrmException {
-    ChangeMessage cmsg = new ChangeMessage(
+  private void addMessageToSourceChange(Change change, PatchSet.Id patchSetId,
+      String destinationBranch, RevCommit cherryPickCommit,
+      IdentifiedUser identifiedUser, RefControl refControl) throws OrmException {
+    ChangeMessage changeMessage = new ChangeMessage(
         new ChangeMessage.Key(
             patchSetId.getParentKey(), ChangeUtil.messageUUID(db.get())),
             identifiedUser.getAccountId(), TimeUtil.nowTs(), patchSetId);
-    String destBranchName = dest.getDest().get();
-    StringBuilder msgBuf = new StringBuilder("Patch Set ")
+    StringBuilder sb = new StringBuilder("Patch Set ")
         .append(patchSetId.get())
         .append(": Cherry Picked")
         .append("\n\n")
         .append("This patchset was cherry picked to branch ")
-        .append(destBranchName.substring(
-            destBranchName.indexOf("refs/heads/") + "refs/heads/".length()))
+        .append(destinationBranch)
         .append(" as commit ")
         .append(cherryPickCommit.getId().getName());
-    cmsg.setMessage(msgBuf.toString());
-    return cmsg;
+    changeMessage.setMessage(sb.toString());
+
+    ChangeControl ctl = refControl.getProjectControl().controlFor(change);
+    ChangeUpdate update = updateFactory.create(ctl, change.getCreatedOn());
+    changeMessagesUtil.addChangeMessage(db.get(), update, changeMessage);
   }
 }