A few updates to gr-diff-comment-thread-group

- getPatchNum should check patch_set rather than patchNum. This fixes a
   previous bug due to checking the wrong attribute that is surfaced
   when threads in a unified view's thread group come from both the
   patch and base patch num.
 - Adds logic for sorting drafts, which should always be at the end,
   regardless of date
 - Use the draftID as rootId if it's the first (only) comment in a thread

Change-Id: I93c92dc77e158e245697e2f0ae01cde0af3a7ae1

polygerrit-ui/app/elements/diff/gr-diff-comment-thread-group/gr-diff-comment-thread-group.js

@@ -138,12 +138,15 @@
      * there are unsaved drafts.
      */
     _getPatchNum(comment) {
-      return comment.patchNum || this.patchForNewThreads;
+      return comment.patch_set || this.patchForNewThreads;
     },
 
     _getThreads(comments) {
-      const sortedComments = comments.slice(0).sort((a, b) =>
+      const sortedComments = comments.slice(0).sort((a, b) => {
-          util.parseDate(a.updated) - util.parseDate(b.updated));
+        if (b.__draft && !a.__draft ) { return 0; }
+        if (a.__draft && !b.__draft ) { return 1; }
+        return util.parseDate(a.updated) - util.parseDate(b.updated);
+      });
 
       const threads = [];
       for (const comment of sortedComments) {
@@ -164,7 +167,7 @@
           comments: [comment],
           commentSide: comment.__commentSide,
           patchNum: this._getPatchNum(comment),
-          rootId: comment.id,
+          rootId: comment.id || comment.__draftID,
         };
         if (comment.range) {
           newThread.range = Object.assign({}, comment.range);

polygerrit-ui/app/elements/diff/gr-diff-comment-thread-group/gr-diff-comment-thread-group_test.html

@@ -65,6 +65,13 @@ limitations under the License.
           __commentSide: 'left',
           in_reply_to: 'sallys_confession',
         },
+        {
+          __draftID: 'new_draft',
+          message: 'i do not like either of you',
+          __commentSide: 'left',
+          __draft: true,
+          updated: '2015-12-20 15:01:20.396000000',
+        },
       ];
 
       let expectedThreadGroups = [
@@ -86,6 +93,21 @@ limitations under the License.
           rootId: 'sallys_confession',
           patchNum: 3,
         },
+        {
+          start_datetime: '2015-12-20 15:01:20.396000000',
+          commentSide: 'left',
+          comments: [
+            {
+              __draftID: 'new_draft',
+              message: 'i do not like either of you',
+              __commentSide: 'left',
+              __draft: true,
+              updated: '2015-12-20 15:01:20.396000000',
+            },
+          ],
+          rootId: 'new_draft',
+          patchNum: 3,
+        },
       ];
 
       assert.deepEqual(element._getThreads(comments), expectedThreadGroups);
@@ -147,6 +169,21 @@ limitations under the License.
             end_character: 2,
           },
         },
+        {
+          start_datetime: '2015-12-20 15:01:20.396000000',
+          commentSide: 'left',
+          comments: [
+            {
+              __draftID: 'new_draft',
+              message: 'i do not like either of you',
+              __commentSide: 'left',
+              __draft: true,
+              updated: '2015-12-20 15:01:20.396000000',
+            },
+          ],
+          rootId: 'new_draft',
+          patchNum: 3,
+        },
       ];
 
       assert.deepEqual(element._getThreads(comments), expectedThreadGroups);
@@ -266,7 +303,7 @@ limitations under the License.
         updated: '2015-12-23 15:00:20.396000000',
       };
       assert.equal(element._getPatchNum(comment), 3);
-      comment.patchNum = 4;
+      comment.patch_set = 4;
       assert.equal(element._getPatchNum(comment), 4);
     });