Fixing scene serialisation error that was crashing jobs after restoration from a checkpoint.

Root cause: _make_json_serializable() silently drops SceneSpec dataclass objects from the checkpoint, so the 'scene' key vanishes.

Fix: Made get_state()/set_state() no-ops — _round_idx_to_scene is derived from the constructor's scenes arg, which is re-supplied when the prefab rebuilds on restore. No dynamic state needs persisting.
PiperOrigin-RevId: 878400465
Change-Id: I976ecddfcced1dbf84d37a00003c43252cb280fd

Author: vezhnick

concordia/components/game_master/scene_tracker.py

@@ -267,12 +267,8 @@ def pre_act(
 
   def get_state(self) -> entity_component.ComponentState:
     """Returns the state of the component."""
-    return {
-        'round_idx_to_scene': self._round_idx_to_scene,
-        'max_rounds': self._max_rounds,
-    }
+    return {}
 
   def set_state(self, state: entity_component.ComponentState) -> None:
     """Sets the state of the component."""
-    self._round_idx_to_scene = state['round_idx_to_scene']
-    self._max_rounds = state['max_rounds']
+    pass

concordia/components/game_master/scene_tracker_test.py

@@ -140,6 +140,22 @@ def test_premises_not_queued_twice_for_same_scene(self):
     # Verify no premises were queued (marker exists) - no add_to_queue calls
     self.assertEqual(self.mock_observation.add_to_queue.call_count, 0)
 
+  def test_state_round_trip_preserves_scene_data(self):
+    tracker = self._create_tracker_with_mocks(existing_markers=[])
+    state = tracker.get_state()
+    tracker2 = self._create_tracker_with_mocks(existing_markers=[])
+    tracker2.set_state(state)
+    self.assertEqual(tracker2._max_rounds, tracker._max_rounds)
+    for idx in range(tracker._max_rounds):
+      self.assertEqual(
+          tracker2._round_idx_to_scene[idx]["step_within_scene"],
+          tracker._round_idx_to_scene[idx]["step_within_scene"],
+      )
+      self.assertEqual(
+          tracker2._round_idx_to_scene[idx]["scene"],
+          tracker._round_idx_to_scene[idx]["scene"],
+      )
+
 
 if __name__ == "__main__":
   absltest.main()