InlineEdit: Add support for changing commit message

Change-Id: I27fe806d699e2980f2e7eab07617df17edcb4b13

gerrit-acceptance-tests/src/test/java/com/google/gerrit/acceptance/edit/ChangeEditIT.java

@@ -30,7 +30,9 @@ import com.google.gerrit.acceptance.AbstractDaemonTest;
 import com.google.gerrit.acceptance.PushOneCommit;
 import com.google.gerrit.acceptance.RestResponse;
 import com.google.gerrit.acceptance.RestSession;
+import com.google.gerrit.extensions.common.ChangeInfo;
 import com.google.gerrit.extensions.common.EditInfo;
+import com.google.gerrit.extensions.common.ListChangesOption;
 import com.google.gerrit.extensions.restapi.BinaryResult;
 import com.google.gerrit.extensions.restapi.ResourceNotFoundException;
 import com.google.gerrit.reviewdb.client.Change;
@@ -234,6 +236,38 @@ public class ChangeEditIT extends AbstractDaemonTest {
     assertThat(edit.isPresent()).isFalse();
   }
 
+  @Test
+  public void updateMessage() throws Exception {
+    assertThat(modifier.createEdit(change, getCurrentPatchSet(changeId)))
+        .isEqualTo(RefUpdate.Result.NEW);
+    Optional<ChangeEdit> edit = editUtil.byChange(change);
+
+    try {
+      modifier.modifyMessage(
+          edit.get(),
+          edit.get().getEditCommit().getFullMessage());
+      fail("InvalidChangeOperationException expected");
+    } catch (InvalidChangeOperationException ex) {
+      assertThat(ex.getMessage()).isEqualTo(
+          "New commit message cannot be same as existing commit message");
+    }
+
+    String msg = String.format("New commit message\n\nChange-Id: %s",
+        change.getKey());
+    assertThat(modifier.modifyMessage(edit.get(), msg)).isEqualTo(
+        RefUpdate.Result.FORCED);
+    edit = editUtil.byChange(change);
+    assertThat(edit.get().getEditCommit().getFullMessage()).isEqualTo(msg);
+
+    editUtil.publish(edit.get());
+    assertThat(editUtil.byChange(change).isPresent()).isFalse();
+
+    ChangeInfo info = get(changeId, ListChangesOption.CURRENT_COMMIT,
+        ListChangesOption.CURRENT_REVISION);
+    assertThat(info.revisions.get(info.currentRevision).commit.message)
+        .isEqualTo(msg);
+  }
+
   @Test
   public void retrieveEdit() throws Exception {
     RestResponse r = adminSession.get(urlEdit());

gerrit-server/src/main/java/com/google/gerrit/server/edit/ChangeEditModifier.java

@@ -15,10 +15,12 @@
 package com.google.gerrit.server.edit;
 
 import static com.google.common.base.Preconditions.checkNotNull;
+import static com.google.common.base.Preconditions.checkState;
 import static com.google.gerrit.server.edit.ChangeEditUtil.editRefName;
 import static com.google.gerrit.server.edit.ChangeEditUtil.editRefPrefix;
 import static org.eclipse.jgit.lib.Constants.OBJ_BLOB;
 
+import com.google.common.base.Strings;
 import com.google.common.io.ByteStreams;
 import com.google.gerrit.common.Nullable;
 import com.google.gerrit.common.TimeUtil;
@@ -216,6 +218,55 @@ public class ChangeEditModifier {
     }
   }
 
+  /**
+   * Modify commit message in existing change edit.
+   *
+   * @param edit change edit
+   * @param msg new commit message
+   * @return result
+   * @throws AuthException
+   * @throws InvalidChangeOperationException
+   * @throws IOException
+   */
+  public RefUpdate.Result modifyMessage(ChangeEdit edit, String msg)
+      throws AuthException, InvalidChangeOperationException, IOException {
+    checkState(!Strings.isNullOrEmpty(msg), "message cannot be null");
+    if (!currentUser.get().isIdentifiedUser()) {
+      throw new AuthException("Authentication required");
+    }
+    RevCommit prevEdit = edit.getEditCommit();
+    if (prevEdit.getParentCount() == 0) {
+      throw new InvalidChangeOperationException(
+          "Modify edit against root commit not supported");
+    }
+
+    if (prevEdit.getFullMessage().equals(msg)) {
+      throw new InvalidChangeOperationException(
+          "New commit message cannot be same as existing commit message");
+    }
+
+    IdentifiedUser me = (IdentifiedUser) currentUser.get();
+    Repository repo = gitManager.openRepository(edit.getChange().getProject());
+    try {
+      RevWalk rw = new RevWalk(repo);
+      ObjectInserter inserter = repo.newObjectInserter();
+      try {
+        String refName = edit.getRefName();
+        ObjectId commit = createCommit(me, inserter, prevEdit,
+            rw.parseCommit(prevEdit.getParent(0)),
+            prevEdit.getTree(),
+            msg);
+        inserter.flush();
+        return update(repo, me, refName, rw, prevEdit, commit);
+      } finally {
+        rw.release();
+        inserter.release();
+      }
+    } finally {
+      repo.close();
+    }
+  }
+
   /**
    * Modify file in existing change edit from its base commit.
    *
@@ -322,12 +373,19 @@ public class ChangeEditModifier {
 
   private ObjectId createCommit(IdentifiedUser me, ObjectInserter inserter,
       RevCommit prevEdit, RevCommit base, ObjectId tree) throws IOException {
+    return createCommit(me, inserter, prevEdit, base, tree,
+        prevEdit.getFullMessage());
+  }
+
+  private ObjectId createCommit(IdentifiedUser me, ObjectInserter inserter,
+      RevCommit prevEdit, RevCommit base, ObjectId tree, String msg)
+      throws IOException {
     CommitBuilder builder = new CommitBuilder();
     builder.setTreeId(tree);
     builder.setParentIds(base);
     builder.setAuthor(prevEdit.getAuthorIdent());
     builder.setCommitter(getCommitterIdent(me));
-    builder.setMessage(prevEdit.getFullMessage());
+    builder.setMessage(msg);
     return inserter.insert(builder);
   }
 

gerrit-server/src/main/java/com/google/gerrit/server/edit/ChangeEditUtil.java

@@ -224,8 +224,9 @@ public class ChangeEditUtil {
       throws IOException, ResourceConflictException {
     RevCommit parent = rw.parseCommit(ObjectId.fromString(
         basePatchSet.getRevision().get()));
-    if (parent.getTree().equals(edit.getTree())) {
-      throw new ResourceConflictException("identical tree");
+    if (parent.getTree().equals(edit.getTree())
+        && edit.getFullMessage().equals(parent.getFullMessage())) {
+      throw new ResourceConflictException("identical tree and message");
     }
     return writeSquashedCommit(rw, inserter, parent, edit);
   }
@@ -278,7 +279,7 @@ public class ChangeEditUtil {
       mergeCommit.addParentId(parent.getParent(i));
     }
     mergeCommit.setAuthor(parent.getAuthorIdent());
-    mergeCommit.setMessage(parent.getFullMessage());
+    mergeCommit.setMessage(edit.getFullMessage());
     mergeCommit.setCommitter(edit.getCommitterIdent());
     mergeCommit.setTreeId(edit.getTree());