Lazily import locomotion envs to prevent ModuleNotFoundError when lab…

…maze is not installed (#125)

shimmy/registration.py

@@ -1,4 +1,5 @@
 """Registers environments within gymnasium for optional modules."""
+
 from __future__ import annotations
 
 from functools import partial
@@ -68,6 +69,41 @@ def _make_dm_control_generic_env(env, **render_kwargs):
     # Register all suite environments
     import dm_control.suite
 
+    def _register_locomotion_envs():
+        try:
+            from dm_control import composer
+            from dm_control.locomotion.examples import basic_cmu_2019, basic_rodent_2020
+        except ImportError:
+            print(
+                "Warning, registration of `dm_control` locomotion envs has failed due to an ImportError"
+            )
+            return
+
+        def _make_dm_control_example_locomotion_env(
+            env_fn: Callable[[np.random.RandomState | None], composer.Environment],
+            random_state: np.random.RandomState | None = None,
+            **render_kwargs,
+        ):
+            return DmControlCompatibilityV0(env_fn(random_state), **render_kwargs)
+
+        for locomotion_env, nondeterministic in (
+            (basic_cmu_2019.cmu_humanoid_run_walls, False),
+            (basic_cmu_2019.cmu_humanoid_run_gaps, False),
+            (basic_cmu_2019.cmu_humanoid_go_to_target, False),
+            (basic_cmu_2019.cmu_humanoid_maze_forage, True),
+            (basic_cmu_2019.cmu_humanoid_heterogeneous_forage, True),
+            (basic_rodent_2020.rodent_escape_bowl, False),
+            (basic_rodent_2020.rodent_run_gaps, False),
+            (basic_rodent_2020.rodent_maze_forage, True),
+            (basic_rodent_2020.rodent_two_touch, True),
+            # (cmu_2020_tracking.cmu_humanoid_tracking, False),
+        ):
+            register(
+                f"dm_control/{locomotion_env.__name__.title().replace('_', '')}-v0",
+                partial(_make_dm_control_example_locomotion_env, env_fn=locomotion_env),
+                nondeterministic=nondeterministic,
+            )
+
     def _make_dm_control_suite_env(
         domain_name: str,
         task_name: str,
@@ -98,33 +134,7 @@ def _make_dm_control_suite_env(
 
     # Register all example locomotion environments
     # Listed in https://github.com/deepmind/dm_control/blob/main/dm_control/locomotion/examples/examples_test.py
-    from dm_control import composer
-    from dm_control.locomotion.examples import basic_cmu_2019, basic_rodent_2020
-
-    def _make_dm_control_example_locomotion_env(
-        env_fn: Callable[[np.random.RandomState | None], composer.Environment],
-        random_state: np.random.RandomState | None = None,
-        **render_kwargs,
-    ):
-        return DmControlCompatibilityV0(env_fn(random_state), **render_kwargs)
-
-    for locomotion_env, nondeterministic in (
-        (basic_cmu_2019.cmu_humanoid_run_walls, False),
-        (basic_cmu_2019.cmu_humanoid_run_gaps, False),
-        (basic_cmu_2019.cmu_humanoid_go_to_target, False),
-        (basic_cmu_2019.cmu_humanoid_maze_forage, True),
-        (basic_cmu_2019.cmu_humanoid_heterogeneous_forage, True),
-        (basic_rodent_2020.rodent_escape_bowl, False),
-        (basic_rodent_2020.rodent_run_gaps, False),
-        (basic_rodent_2020.rodent_maze_forage, True),
-        (basic_rodent_2020.rodent_two_touch, True),
-        # (cmu_2020_tracking.cmu_humanoid_tracking, False),
-    ):
-        register(
-            f"dm_control/{locomotion_env.__name__.title().replace('_', '')}-v0",
-            partial(_make_dm_control_example_locomotion_env, env_fn=locomotion_env),
-            nondeterministic=nondeterministic,
-        )
+    _register_locomotion_envs()
 
     # Register all manipulation environments
     import dm_control.manipulation