Only file bugs if grouper previously looked at the testcase. (#2535)

* Only file bugs if grouper previous looked at the testcase.

Part of #2533.

* lint

src/appengine/handlers/cron/grouper.py

@@ -203,8 +203,7 @@ def _key_func(testcase):
     else:
       group_id_with_testcases_map[testcase.group_id].append(testcase)
 
-  for group_id in group_id_with_testcases_map:
-    testcases_in_group = group_id_with_testcases_map[group_id]
+  for testcases_in_group in group_id_with_testcases_map.values():
     if len(testcases_in_group) <= GROUP_MAX_TESTCASE_LIMIT:
       continue
 
@@ -347,8 +346,9 @@ def group_testcases():
         (testcase.group_bug_information != updated_group_bug_information) or
         (testcase.is_leader != updated_is_leader))
 
+    testcase.set_metadata('ran_grouper', True, update_testcase=False)
     if not is_changed:
-      # If nothing is changed, no more work to do. It's faster this way.
+      testcase.put()
       continue
 
     testcase.group_bug_information = updated_group_bug_information

src/appengine/handlers/cron/triage.py

@@ -276,7 +276,9 @@ class Handler(base_handler.Handler):
   def get(self):
     """Handle a get request."""
     try:
+      logs.log('Grouping testcases.')
       grouper.group_testcases()
+      logs.log('Grouping done.')
     except:
       logs.log_error('Error occurred while grouping test cases.')
       return
@@ -332,10 +334,16 @@ def get(self):
       # to account for that.
       # FIXME: In future, grouping might be dependent on regression range, so we
       # would have to add an additional wait time.
+      # TODO(ochang): Remove this after verifying that the `ran_grouper`
+      # metadata works well.
       if not testcase.group_id and not dates.time_has_expired(
           testcase.timestamp, hours=data_types.MIN_ELAPSED_TIME_SINCE_REPORT):
         continue
 
+      if not testcase.get_metadata('ran_grouper'):
+        # Testcase should be considered by the grouper first before filing.
+        continue
+
       # If this project does not have an associated issue tracker, we cannot
       # file this crash anywhere.
       issue_tracker = issue_tracker_utils.get_issue_tracker_for_testcase(