Deduplicate conditions on current change in Submit

Before this commit, the change was part of the change set on which the
permissions and submit records were checked. As such, these checks were
done twice, using potentially invalid cached submit records (stale).

Instead, we want to ignore the change and only consider the parent (and
the topic) changes.

Change-Id: I28c302db7f8f153903493d999eb587527681d895

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

@@ -236,6 +236,11 @@ public class Submit
   }
 
   /**
+   * Returns a message describing what prevents the current change from being submitted - or null.
+   * This method only considers parent changes, and changes in the same topic. The caller is
+   * responsible for making sure the current change to be submitted can indeed be submitted
+   * (permissions, submit rules, is not a WIP...)
+   *
    * @param cd the change the user is currently looking at
    * @param cs set of changes to be submitted at once
    * @param user the user who is checking to submit
@@ -247,6 +252,11 @@ public class Submit
         return BLOCKED_HIDDEN_SUBMIT_TOOLTIP;
       }
       for (ChangeData c : cs.changes()) {
+        if (cd.getId().equals(c.getId())) {
+          // We ignore the change about to be submitted, as these checks are already done in the
+          // #apply and #getDescription methods.
+          continue;
+        }
         Set<ChangePermission> can =
             permissionBackend
                 .user(user)
@@ -293,6 +303,7 @@ public class Submit
   public UiAction.Description getDescription(RevisionResource resource) {
     Change change = resource.getChange();
     if (!change.getStatus().isOpen()
+        || change.isWorkInProgress()
         || !resource.isCurrent()
         || !resource.permissions().testOrFalse(ChangePermission.SUBMIT)) {
       return null; // submit not visible