fix: Ensure group tasks are deeply deserialised

Fixes #6341

celery/canvas.py

@@ -1047,8 +1047,16 @@ class group(Signature):
 
     @classmethod
     def from_dict(cls, d, app=None):
+        # We need to mutate the `kwargs` element in place to avoid confusing
+        # `freeze()` implementations which end up here and expect to be able to
+        # access elements from that dictionary later and refer to objects
+        # canonicalized here
+        orig_tasks = d["kwargs"]["tasks"]
+        d["kwargs"]["tasks"] = rebuilt_tasks = type(orig_tasks)((
+            maybe_signature(task, app=app) for task in orig_tasks
+        ))
         return _upgrade(
-            d, group(d['kwargs']['tasks'], app=app, **d['options']),
+            d, group(rebuilt_tasks, app=app, **d['options']),
         )
 
     def __init__(self, *tasks, **options):

t/integration/test_canvas.py

@@ -1133,23 +1133,20 @@ def test_rebuild_nested_chain_chord(self, manager):
         )
         sig.delay().get(timeout=TIMEOUT)
 
-    @pytest.mark.xfail(reason="#6341")
     def test_rebuild_nested_group_chain(self, manager):
         sig = chain(
             tasks.return_nested_signature_group_chain.s(),
             tasks.rebuild_signature.s()
         )
         sig.delay().get(timeout=TIMEOUT)
 
-    @pytest.mark.xfail(reason="#6341")
     def test_rebuild_nested_group_group(self, manager):
         sig = chain(
             tasks.return_nested_signature_group_group.s(),
             tasks.rebuild_signature.s()
         )
         sig.delay().get(timeout=TIMEOUT)
 
-    @pytest.mark.xfail(reason="#6341")
     def test_rebuild_nested_group_chord(self, manager):
         try:
             manager.app.backend.ensure_chords_allowed()

t/unit/tasks/test_canvas.py

@@ -694,7 +694,6 @@ def test_from_dict(self):
         x['args'] = None
         assert group.from_dict(dict(x))
 
-    @pytest.mark.xfail(reason="#6341")
     def test_from_dict_deep_deserialize(self):
         original_group = group([self.add.s(1, 2)] * 42)
         serialized_group = json.loads(json.dumps(original_group))
@@ -704,7 +703,6 @@ def test_from_dict_deep_deserialize(self):
             for child_task in deserialized_group.tasks
         )
 
-    @pytest.mark.xfail(reason="#6341")
     def test_from_dict_deeper_deserialize(self):
         inner_group = group([self.add.s(1, 2)] * 42)
         outer_group = group([inner_group] * 42)
@@ -1112,7 +1110,6 @@ def test_from_dict_deep_deserialize(self, subtests):
         with subtests.test(msg="Verify chord body is deserialized"):
             assert isinstance(deserialized_chord.body, Signature)
 
-    @pytest.mark.xfail(reason="#6341")
     def test_from_dict_deep_deserialize_group(self, subtests):
         header = body = group([self.add.s(1, 2)] * 42)
         original_chord = chord(header=header, body=body)
@@ -1139,7 +1136,6 @@ def test_from_dict_deep_deserialize_group(self, subtests):
                 for body_child_task in deserialized_chord.body.tasks
             )
 
-    @pytest.mark.xfail(reason="#6341")
     def test_from_dict_deeper_deserialize_group(self, subtests):
         inner_group = group([self.add.s(1, 2)] * 42)
         header = body = group([inner_group] * 42)