Fix chords with chained groups (#5947)

celery · Mar 2, 2020 · 01dd66c · 01dd66c
1 parent 6892beb
commit 01dd66c
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diff --git a/celery/canvas.py b/celery/canvas.py
@@ -1366,6 +1366,8 @@ def _traverse_tasks(self, tasks, value=None):
             task = stack.popleft()
             if isinstance(task, group):
                 stack.extend(task.tasks)
+            elif isinstance(task, _chain) and isinstance(task.tasks[-1], group):
+                stack.extend(task.tasks[-1].tasks)
             else:
                 yield task if value is None else value
 

diff --git a/t/unit/tasks/test_canvas.py b/t/unit/tasks/test_canvas.py
@@ -742,6 +742,13 @@ def test_app_fallback_to_current(self):
         x = chord([t1], body=t1)
         assert x.app is current_app
 
+    def test_chord_size_with_groups(self):
+        x = chord([
+            self.add.s(2, 2) | group([self.add.si(2, 2), self.add.si(2, 2)]),
+            self.add.s(2, 2) | group([self.add.si(2, 2), self.add.si(2, 2)]),
+        ], body=self.add.si(2, 2))
+        assert x.__length_hint__() == 4
+
     def test_set_immutable(self):
         x = chord([Mock(name='t1'), Mock(name='t2')], app=self.app)
         x.set_immutable(True)