Redis: Fixes problem with nested chords where parent chord overwrites chord message field. Closes #2922

celery/canvas.py

@@ -717,11 +717,12 @@ class group(Signature):
                 yield task, task.freeze(group_id=group_id, root_id=root_id)
 
     def _apply_tasks(self, tasks, producer=None, app=None,
-                     add_to_parent=None, **options):
+                     add_to_parent=None, chord=None, **options):
         app = app or self.app
         with app.producer_or_acquire(producer) as producer:
             for sig, res in tasks:
                 sig.apply_async(producer=producer, add_to_parent=False,
+                                chord=sig.options.get('chord') or chord,
                                 **options)
                 yield res  # <-- r.parent, etc set in the frozen result.
 
@@ -868,9 +869,11 @@ class chord(Signature):
                root_id=None, parent_id=None):
         if not isinstance(self.tasks, group):
             self.tasks = group(self.tasks)
-        self.tasks.freeze(parent_id=parent_id, root_id=root_id)
+        bodyres = self.body.freeze(_id, parent_id=self.id, root_id=root_id)
+        self.tasks.freeze(parent_id=parent_id, root_id=root_id, chord=self.body)
         self.id = self.tasks.id
-        return self.body.freeze(_id, parent_id=self.id, root_id=root_id)
+        self.body.set_parent_id(self.id)
+        return bodyres
 
     def set_parent_id(self, parent_id):
         tasks = self.tasks