Defer cfg-class imports in cartpole shims to avoid AppLauncher import-state leak

Importing the historical per-variant cfg classes at the top of each
cartpole task ``__init__.py`` (so ``cfg_factory=lambda: SomeClass()``
could close over them) pulled ``isaaclab.envs``, ``isaaclab.scene``, and
their downstream modules into ``sys.modules`` *during*
``isaaclab_tasks.direct.cartpole``'s package import. That happens before
``AppLauncher._create_app`` runs, and AppLauncher's mod-cache cycle
``del sys.modules[key]`` + ``sys.modules[key] = value`` only restores
the ``sys.modules`` entries -- it never re-binds the submodules as
attributes on the parent ``isaaclab`` package. After the cycle,
``isaaclab.scene`` lives in ``sys.modules`` but ``isaaclab.scene``
``getattr`` on the ``isaaclab`` module raises ``AttributeError``, which
breaks any unrelated test that walks a dotted string path like
``monkeypatch.setattr("isaaclab.scene.interactive_scene.cloner.X", Y)``.

Concretely on this PR, both ``test_clone_environments_executes_*`` cases
in ``source/isaaclab/test/scene/test_interactive_scene.py`` started
failing once the eager imports landed. The same tests pass on develop
because there the cfg classes are only referenced via lazy
``"module:Class"`` strings in the gym entry points, so nothing imports
them before ``AppLauncher`` runs.

Fix: introduce a tiny ``_lazy_cfg(class_name, module=...)`` helper in
each of the four cartpole ``__init__.py`` files. The helper returns a
zero-arg callable that imports the cfg class via ``importlib`` only
when invoked. ``deprecated_task_alias`` still calls ``cfg_factory()``
exactly once per ``gym.make()``, so the deferred import path runs at
the same moment the eager-import path would have triggered (the
shim's factory body), just without the side effect of pre-loading the
cfg module before ``AppLauncher``.

Local verification:
* ``test_clone_environments_executes_env_root_plan_with_positions``: PASS
* ``test_clone_environments_executes_asset_level_plan_without_usd_positions``: PASS
* 73 cartpole-deprecation tests + 5 preset-kit-decision tests: all pass.

Author: hujc7

source/isaaclab_tasks/isaaclab_tasks/direct/cartpole/__init__.py

@@ -12,15 +12,27 @@
 from isaaclab_tasks.utils import deprecated_task_alias
 
 from . import agents
-from .cartpole_camera_env_cfg import (
-    CartpoleAlbedoCameraEnvCfg,
-    CartpoleDepthCameraEnvCfg,
-    CartpoleRGBCameraEnvCfg,
-    CartpoleSimpleShadingConstantCameraEnvCfg,
-    CartpoleSimpleShadingDiffuseCameraEnvCfg,
-    CartpoleSimpleShadingFullCameraEnvCfg,
-)
-from .cartpole_camera_presets_env_cfg import CartpoleCameraPresetsEnvCfg
+
+
+def _lazy_cfg(class_name: str, module: str = "cartpole_camera_env_cfg"):
+    """Return a zero-arg callable that lazily imports the named cfg class.
+
+    Deferring the cfg-class import to ``gym.make()`` time keeps the
+    eager-import surface of this ``__init__.py`` minimal. Importing the cfg
+    classes at module top pulls ``isaaclab.scene`` and friends into
+    ``sys.modules`` *before* an ``AppLauncher`` cycle clears and restores
+    them, which leaves ``isaaclab.scene`` in ``sys.modules`` but no longer
+    bound as an attribute of the ``isaaclab`` package -- breaking string
+    ``monkeypatch.setattr("isaaclab.scene...")`` calls in unrelated tests.
+    """
+
+    def factory():
+        from importlib import import_module
+
+        return getattr(import_module(f"{__name__}.{module}"), class_name)()
+
+    return factory
+
 
 ##
 # Register Gym environments.
@@ -68,7 +80,7 @@
         "env_cfg_entry_point": deprecated_task_alias(
             old_task_id="Isaac-Cartpole-RGB-Camera-Direct-v0",
             new_command=["--task=Isaac-Cartpole-Camera-Direct-v0", "presets=rgb"],
-            cfg_factory=lambda: CartpoleRGBCameraEnvCfg(),
+            cfg_factory=_lazy_cfg("CartpoleRGBCameraEnvCfg"),
         ),
         "rl_games_cfg_entry_point": f"{agents.__name__}:rl_games_camera_ppo_cfg.yaml",
         "skrl_cfg_entry_point": f"{agents.__name__}:skrl_camera_ppo_cfg.yaml",
@@ -83,7 +95,7 @@
         "env_cfg_entry_point": deprecated_task_alias(
             old_task_id="Isaac-Cartpole-Albedo-Camera-Direct-v0",
             new_command=["--task=Isaac-Cartpole-Camera-Direct-v0", "presets=albedo"],
-            cfg_factory=lambda: CartpoleAlbedoCameraEnvCfg(),
+            cfg_factory=_lazy_cfg("CartpoleAlbedoCameraEnvCfg"),
         ),
         "rl_games_cfg_entry_point": f"{agents.__name__}:rl_games_camera_ppo_cfg.yaml",
         "skrl_cfg_entry_point": f"{agents.__name__}:skrl_camera_ppo_cfg.yaml",
@@ -98,7 +110,7 @@
         "env_cfg_entry_point": deprecated_task_alias(
             old_task_id="Isaac-Cartpole-SimpleShading-Constant-Camera-Direct-v0",
             new_command=["--task=Isaac-Cartpole-Camera-Direct-v0", "presets=simple_shading_constant_diffuse"],
-            cfg_factory=lambda: CartpoleSimpleShadingConstantCameraEnvCfg(),
+            cfg_factory=_lazy_cfg("CartpoleSimpleShadingConstantCameraEnvCfg"),
         ),
         "rl_games_cfg_entry_point": f"{agents.__name__}:rl_games_camera_ppo_cfg.yaml",
         "skrl_cfg_entry_point": f"{agents.__name__}:skrl_camera_ppo_cfg.yaml",
@@ -113,7 +125,7 @@
         "env_cfg_entry_point": deprecated_task_alias(
             old_task_id="Isaac-Cartpole-SimpleShading-Diffuse-Camera-Direct-v0",
             new_command=["--task=Isaac-Cartpole-Camera-Direct-v0", "presets=simple_shading_diffuse_mdl"],
-            cfg_factory=lambda: CartpoleSimpleShadingDiffuseCameraEnvCfg(),
+            cfg_factory=_lazy_cfg("CartpoleSimpleShadingDiffuseCameraEnvCfg"),
         ),
         "rl_games_cfg_entry_point": f"{agents.__name__}:rl_games_camera_ppo_cfg.yaml",
         "skrl_cfg_entry_point": f"{agents.__name__}:skrl_camera_ppo_cfg.yaml",
@@ -128,7 +140,7 @@
         "env_cfg_entry_point": deprecated_task_alias(
             old_task_id="Isaac-Cartpole-SimpleShading-Full-Camera-Direct-v0",
             new_command=["--task=Isaac-Cartpole-Camera-Direct-v0", "presets=simple_shading_full_mdl"],
-            cfg_factory=lambda: CartpoleSimpleShadingFullCameraEnvCfg(),
+            cfg_factory=_lazy_cfg("CartpoleSimpleShadingFullCameraEnvCfg"),
         ),
         "rl_games_cfg_entry_point": f"{agents.__name__}:rl_games_camera_ppo_cfg.yaml",
         "skrl_cfg_entry_point": f"{agents.__name__}:skrl_camera_ppo_cfg.yaml",
@@ -143,7 +155,7 @@
         "env_cfg_entry_point": deprecated_task_alias(
             old_task_id="Isaac-Cartpole-Depth-Camera-Direct-v0",
             new_command=["--task=Isaac-Cartpole-Camera-Direct-v0", "presets=depth"],
-            cfg_factory=lambda: CartpoleDepthCameraEnvCfg(),
+            cfg_factory=_lazy_cfg("CartpoleDepthCameraEnvCfg"),
         ),
         "rl_games_cfg_entry_point": f"{agents.__name__}:rl_games_camera_ppo_cfg.yaml",
         "skrl_cfg_entry_point": f"{agents.__name__}:skrl_camera_ppo_cfg.yaml",
@@ -161,7 +173,7 @@
         "env_cfg_entry_point": deprecated_task_alias(
             old_task_id="Isaac-Cartpole-Camera-Presets-Direct-v0",
             new_command=["--task=Isaac-Cartpole-Camera-Direct-v0"],
-            cfg_factory=lambda: CartpoleCameraPresetsEnvCfg(),
+            cfg_factory=_lazy_cfg("CartpoleCameraPresetsEnvCfg", module="cartpole_camera_presets_env_cfg"),
         ),
         "rl_games_cfg_entry_point": f"{agents.__name__}:rl_games_camera_ppo_cfg.yaml",
         "skrl_cfg_entry_point": f"{agents.__name__}:skrl_camera_ppo_cfg.yaml",

source/isaaclab_tasks/isaaclab_tasks/direct/cartpole_showcase/cartpole/__init__.py

@@ -12,23 +12,25 @@
 from isaaclab_tasks.utils import deprecated_task_alias
 
 from . import agents
-from .cartpole_env_cfg import (
-    BoxBoxEnvCfg,
-    BoxDiscreteEnvCfg,
-    BoxMultiDiscreteEnvCfg,
-    DictBoxEnvCfg,
-    DictDiscreteEnvCfg,
-    DictMultiDiscreteEnvCfg,
-    DiscreteBoxEnvCfg,
-    DiscreteDiscreteEnvCfg,
-    DiscreteMultiDiscreteEnvCfg,
-    MultiDiscreteBoxEnvCfg,
-    MultiDiscreteDiscreteEnvCfg,
-    MultiDiscreteMultiDiscreteEnvCfg,
-    TupleBoxEnvCfg,
-    TupleDiscreteEnvCfg,
-    TupleMultiDiscreteEnvCfg,
-)
+
+
+def _lazy_cfg(class_name: str, module: str = "cartpole_env_cfg"):
+    """Return a zero-arg callable that lazily imports the named cfg class.
+
+    Deferring the cfg-class import to ``gym.make()`` time avoids pulling
+    ``isaaclab.scene`` (and other heavy modules) into ``sys.modules`` *before*
+    an ``AppLauncher`` cycle clears and restores them, which would leave
+    ``isaaclab.scene`` in ``sys.modules`` but no longer bound as an attribute
+    of the ``isaaclab`` package -- breaking string
+    ``monkeypatch.setattr("isaaclab.scene...")`` calls in unrelated tests.
+    """
+
+    def factory():
+        from importlib import import_module
+
+        return getattr(import_module(f"{__name__}.{module}"), class_name)()
+
+    return factory
 
 ###########################
 # Register Gym environments
@@ -80,7 +82,7 @@
         "env_cfg_entry_point": deprecated_task_alias(
             old_task_id="Isaac-Cartpole-Showcase-Box-Box-Direct-v0",
             new_command=["--task=Isaac-Cartpole-Showcase-Direct-v0", "presets=box_box"],
-            cfg_factory=lambda: BoxBoxEnvCfg(),
+            cfg_factory=_lazy_cfg("BoxBoxEnvCfg"),
         ),
         "skrl_cfg_entry_point": f"{agents.__name__}:skrl_box_box_ppo_cfg.yaml",
     },
@@ -98,7 +100,7 @@
                 "--agent=skrl_box_discrete_cfg_entry_point",
                 "presets=box_discrete",
             ],
-            cfg_factory=lambda: BoxDiscreteEnvCfg(),
+            cfg_factory=_lazy_cfg("BoxDiscreteEnvCfg"),
         ),
         "skrl_cfg_entry_point": f"{agents.__name__}:skrl_box_discrete_ppo_cfg.yaml",
     },
@@ -116,7 +118,7 @@
                 "--agent=skrl_box_multidiscrete_cfg_entry_point",
                 "presets=box_multidiscrete",
             ],
-            cfg_factory=lambda: BoxMultiDiscreteEnvCfg(),
+            cfg_factory=_lazy_cfg("BoxMultiDiscreteEnvCfg"),
         ),
         "skrl_cfg_entry_point": f"{agents.__name__}:skrl_box_multidiscrete_ppo_cfg.yaml",
     },
@@ -138,7 +140,7 @@
                 "--agent=skrl_discrete_box_cfg_entry_point",
                 "presets=discrete_box",
             ],
-            cfg_factory=lambda: DiscreteBoxEnvCfg(),
+            cfg_factory=_lazy_cfg("DiscreteBoxEnvCfg"),
         ),
         "skrl_cfg_entry_point": f"{agents.__name__}:skrl_discrete_box_ppo_cfg.yaml",
     },
@@ -156,7 +158,7 @@
                 "--agent=skrl_discrete_discrete_cfg_entry_point",
                 "presets=discrete_discrete",
             ],
-            cfg_factory=lambda: DiscreteDiscreteEnvCfg(),
+            cfg_factory=_lazy_cfg("DiscreteDiscreteEnvCfg"),
         ),
         "skrl_cfg_entry_point": f"{agents.__name__}:skrl_discrete_discrete_ppo_cfg.yaml",
     },
@@ -174,7 +176,7 @@
                 "--agent=skrl_discrete_multidiscrete_cfg_entry_point",
                 "presets=discrete_multidiscrete",
             ],
-            cfg_factory=lambda: DiscreteMultiDiscreteEnvCfg(),
+            cfg_factory=_lazy_cfg("DiscreteMultiDiscreteEnvCfg"),
         ),
         "skrl_cfg_entry_point": f"{agents.__name__}:skrl_discrete_multidiscrete_ppo_cfg.yaml",
     },
@@ -196,7 +198,7 @@
                 "--agent=skrl_multidiscrete_box_cfg_entry_point",
                 "presets=multidiscrete_box",
             ],
-            cfg_factory=lambda: MultiDiscreteBoxEnvCfg(),
+            cfg_factory=_lazy_cfg("MultiDiscreteBoxEnvCfg"),
         ),
         "skrl_cfg_entry_point": f"{agents.__name__}:skrl_multidiscrete_box_ppo_cfg.yaml",
     },
@@ -214,7 +216,7 @@
                 "--agent=skrl_multidiscrete_discrete_cfg_entry_point",
                 "presets=multidiscrete_discrete",
             ],
-            cfg_factory=lambda: MultiDiscreteDiscreteEnvCfg(),
+            cfg_factory=_lazy_cfg("MultiDiscreteDiscreteEnvCfg"),
         ),
         "skrl_cfg_entry_point": f"{agents.__name__}:skrl_multidiscrete_discrete_ppo_cfg.yaml",
     },
@@ -232,7 +234,7 @@
                 "--agent=skrl_multidiscrete_multidiscrete_cfg_entry_point",
                 "presets=multidiscrete_multidiscrete",
             ],
-            cfg_factory=lambda: MultiDiscreteMultiDiscreteEnvCfg(),
+            cfg_factory=_lazy_cfg("MultiDiscreteMultiDiscreteEnvCfg"),
         ),
         "skrl_cfg_entry_point": f"{agents.__name__}:skrl_multidiscrete_multidiscrete_ppo_cfg.yaml",
     },
@@ -254,7 +256,7 @@
                 "--agent=skrl_dict_box_cfg_entry_point",
                 "presets=dict_box",
             ],
-            cfg_factory=lambda: DictBoxEnvCfg(),
+            cfg_factory=_lazy_cfg("DictBoxEnvCfg"),
         ),
         "skrl_cfg_entry_point": f"{agents.__name__}:skrl_dict_box_ppo_cfg.yaml",
     },
@@ -272,7 +274,7 @@
                 "--agent=skrl_dict_discrete_cfg_entry_point",
                 "presets=dict_discrete",
             ],
-            cfg_factory=lambda: DictDiscreteEnvCfg(),
+            cfg_factory=_lazy_cfg("DictDiscreteEnvCfg"),
         ),
         "skrl_cfg_entry_point": f"{agents.__name__}:skrl_dict_discrete_ppo_cfg.yaml",
     },
@@ -290,7 +292,7 @@
                 "--agent=skrl_dict_multidiscrete_cfg_entry_point",
                 "presets=dict_multidiscrete",
             ],
-            cfg_factory=lambda: DictMultiDiscreteEnvCfg(),
+            cfg_factory=_lazy_cfg("DictMultiDiscreteEnvCfg"),
         ),
         "skrl_cfg_entry_point": f"{agents.__name__}:skrl_dict_multidiscrete_ppo_cfg.yaml",
     },
@@ -312,7 +314,7 @@
                 "--agent=skrl_tuple_box_cfg_entry_point",
                 "presets=tuple_box",
             ],
-            cfg_factory=lambda: TupleBoxEnvCfg(),
+            cfg_factory=_lazy_cfg("TupleBoxEnvCfg"),
         ),
         "skrl_cfg_entry_point": f"{agents.__name__}:skrl_tuple_box_ppo_cfg.yaml",
     },
@@ -330,7 +332,7 @@
                 "--agent=skrl_tuple_discrete_cfg_entry_point",
                 "presets=tuple_discrete",
             ],
-            cfg_factory=lambda: TupleDiscreteEnvCfg(),
+            cfg_factory=_lazy_cfg("TupleDiscreteEnvCfg"),
         ),
         "skrl_cfg_entry_point": f"{agents.__name__}:skrl_tuple_discrete_ppo_cfg.yaml",
     },
@@ -348,7 +350,7 @@
                 "--agent=skrl_tuple_multidiscrete_cfg_entry_point",
                 "presets=tuple_multidiscrete",
             ],
-            cfg_factory=lambda: TupleMultiDiscreteEnvCfg(),
+            cfg_factory=_lazy_cfg("TupleMultiDiscreteEnvCfg"),
         ),
         "skrl_cfg_entry_point": f"{agents.__name__}:skrl_tuple_multidiscrete_ppo_cfg.yaml",
     },

source/isaaclab_tasks/isaaclab_tasks/direct/cartpole_showcase/cartpole_camera/__init__.py

@@ -12,17 +12,25 @@
 from isaaclab_tasks.utils import deprecated_task_alias
 
 from . import agents
-from .cartpole_camera_env_cfg import (
-    BoxBoxEnvCfg,
-    BoxDiscreteEnvCfg,
-    BoxMultiDiscreteEnvCfg,
-    DictBoxEnvCfg,
-    DictDiscreteEnvCfg,
-    DictMultiDiscreteEnvCfg,
-    TupleBoxEnvCfg,
-    TupleDiscreteEnvCfg,
-    TupleMultiDiscreteEnvCfg,
-)
+
+
+def _lazy_cfg(class_name: str, module: str = "cartpole_camera_env_cfg"):
+    """Return a zero-arg callable that lazily imports the named cfg class.
+
+    Deferring the cfg-class import to ``gym.make()`` time avoids pulling
+    ``isaaclab.scene`` (and other heavy modules) into ``sys.modules`` *before*
+    an ``AppLauncher`` cycle clears and restores them, which would leave
+    ``isaaclab.scene`` in ``sys.modules`` but no longer bound as an attribute
+    of the ``isaaclab`` package -- breaking string
+    ``monkeypatch.setattr("isaaclab.scene...")`` calls in unrelated tests.
+    """
+
+    def factory():
+        from importlib import import_module
+
+        return getattr(import_module(f"{__name__}.{module}"), class_name)()
+
+    return factory
 
 ###########################
 # Register Gym environments
@@ -68,7 +76,7 @@
         "env_cfg_entry_point": deprecated_task_alias(
             old_task_id="Isaac-Cartpole-Camera-Showcase-Box-Box-Direct-v0",
             new_command=["--task=Isaac-Cartpole-Camera-Showcase-Direct-v0", "presets=box_box"],
-            cfg_factory=lambda: BoxBoxEnvCfg(),
+            cfg_factory=_lazy_cfg("BoxBoxEnvCfg"),
         ),
         "skrl_cfg_entry_point": f"{agents.__name__}:skrl_box_box_ppo_cfg.yaml",
     },
@@ -86,7 +94,7 @@
                 "--agent=skrl_box_discrete_cfg_entry_point",
                 "presets=box_discrete",
             ],
-            cfg_factory=lambda: BoxDiscreteEnvCfg(),
+            cfg_factory=_lazy_cfg("BoxDiscreteEnvCfg"),
         ),
         "skrl_cfg_entry_point": f"{agents.__name__}:skrl_box_discrete_ppo_cfg.yaml",
     },
@@ -104,7 +112,7 @@
                 "--agent=skrl_box_multidiscrete_cfg_entry_point",
                 "presets=box_multidiscrete",
             ],
-            cfg_factory=lambda: BoxMultiDiscreteEnvCfg(),
+            cfg_factory=_lazy_cfg("BoxMultiDiscreteEnvCfg"),
         ),
         "skrl_cfg_entry_point": f"{agents.__name__}:skrl_box_multidiscrete_ppo_cfg.yaml",
     },
@@ -126,7 +134,7 @@
                 "--agent=skrl_dict_box_cfg_entry_point",
                 "presets=dict_box",
             ],
-            cfg_factory=lambda: DictBoxEnvCfg(),
+            cfg_factory=_lazy_cfg("DictBoxEnvCfg"),
         ),
         "skrl_cfg_entry_point": f"{agents.__name__}:skrl_dict_box_ppo_cfg.yaml",
     },
@@ -144,7 +152,7 @@
                 "--agent=skrl_dict_discrete_cfg_entry_point",
                 "presets=dict_discrete",
             ],
-            cfg_factory=lambda: DictDiscreteEnvCfg(),
+            cfg_factory=_lazy_cfg("DictDiscreteEnvCfg"),
         ),
         "skrl_cfg_entry_point": f"{agents.__name__}:skrl_dict_discrete_ppo_cfg.yaml",
     },
@@ -162,7 +170,7 @@
                 "--agent=skrl_dict_multidiscrete_cfg_entry_point",
                 "presets=dict_multidiscrete",
             ],
-            cfg_factory=lambda: DictMultiDiscreteEnvCfg(),
+            cfg_factory=_lazy_cfg("DictMultiDiscreteEnvCfg"),
         ),
         "skrl_cfg_entry_point": f"{agents.__name__}:skrl_dict_multidiscrete_ppo_cfg.yaml",
     },
@@ -184,7 +192,7 @@
                 "--agent=skrl_tuple_box_cfg_entry_point",
                 "presets=tuple_box",
             ],
-            cfg_factory=lambda: TupleBoxEnvCfg(),
+            cfg_factory=_lazy_cfg("TupleBoxEnvCfg"),
         ),
         "skrl_cfg_entry_point": f"{agents.__name__}:skrl_tuple_box_ppo_cfg.yaml",
     },
@@ -202,7 +210,7 @@
                 "--agent=skrl_tuple_discrete_cfg_entry_point",
                 "presets=tuple_discrete",
             ],
-            cfg_factory=lambda: TupleDiscreteEnvCfg(),
+            cfg_factory=_lazy_cfg("TupleDiscreteEnvCfg"),
         ),
         "skrl_cfg_entry_point": f"{agents.__name__}:skrl_tuple_discrete_ppo_cfg.yaml",
     },
@@ -220,7 +228,7 @@
                 "--agent=skrl_tuple_multidiscrete_cfg_entry_point",
                 "presets=tuple_multidiscrete",
             ],
-            cfg_factory=lambda: TupleMultiDiscreteEnvCfg(),
+            cfg_factory=_lazy_cfg("TupleMultiDiscreteEnvCfg"),
         ),
         "skrl_cfg_entry_point": f"{agents.__name__}:skrl_tuple_multidiscrete_ppo_cfg.yaml",
     },