in java/com/google/gerrit/server/notedb/ChangeUpdate.java [1071:1098]
public boolean isEmpty() {
return commitSubject == null
&& approvals.isEmpty()
&& copiedApprovals.isEmpty()
&& changeMessage == null
&& comments.isEmpty()
&& reviewers.isEmpty()
&& reviewersByEmail.isEmpty()
&& changeId == null
&& branch == null
&& status == null
&& submissionId == null
&& submitRecords == null
&& plannedAttentionSetUpdates == null
&& assignee == null
&& hashtags == null
&& topic == null
&& commit == null
&& psState == null
&& groups == null
&& tag == null
&& psDescription == null
&& !currentPatchSet
&& isPrivate == null
&& workInProgress == null
&& revertOf == null
&& cherryPickOf == null;
}