Fixes failing CI test for mock interfaces

[AntoineRichard]

Description

Fixes failing CI test for mock interfaces. This was caused by some pointers being deleted by the garbage collector.

Type of change

• Bug fix (non-breaking change which fixes an issue)

Checklist

• I have read and understood the contribution guidelines
• I have run the pre-commit checks with ./isaaclab.sh --format
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• I have updated the changelog and the corresponding version in the extension's config/extension.toml file
• I have added my name to the CONTRIBUTORS.md or my name already exists there

[greptile-apps]

Greptile Summary

This PR fixes flaky CI tests (test_mock_data_properties) caused by use-after-free bugs in mock asset data properties. The root cause was that several warp @property methods returned .view() aliases of locally-scoped temporary arrays. When CPython's reference counter freed these temporaries before the view was consumed (particularly by downstream zero-copy pointer arithmetic properties like root_com_lin_vel_w), reads would produce garbage data.

The fix caches the default arrays in instance attributes (self._root_link_vel_w, self._root_com_vel_w, etc.) so the backing memory stays alive for the object's lifetime. This is applied consistently across MockArticulationData, MockRigidObjectData, and MockRigidObjectCollectionData.

• 18 properties fixed across 3 mock data classes by changing return wp.zeros(...).view(...) / return wp.clone(...) to self._field = ...; return self._field
• Version bumped to 4.5.23 with a detailed changelog entry
• A few other properties with the same .view() pattern (default_root_vel, default_body_pose, default_body_vel, joint_pos_limits, body_incoming_joint_wrench_b) were not updated — these may not currently trigger issues but are inconsistent with the fix

Confidence Score: 4/5

• This PR is safe to merge — it fixes a real use-after-free bug in test mock classes with a correct caching approach.
• The fix correctly addresses the use-after-free pattern for the properties that were causing CI flakiness. The change is mechanical and low-risk (caching default values in instance attributes). Score is 4 instead of 5 because a few other properties with the same .view() pattern were left unfixed, which represents a minor inconsistency rather than a blocking issue.
• The three mock data files (mock_articulation.py, mock_rigid_object.py, mock_rigid_object_collection.py) still have a handful of properties with the same uncached .view() pattern that could cause similar issues in the future.

Important Files Changed

Filename	Overview
source/isaaclab/isaaclab/test/mock_interfaces/assets/mock_articulation.py	Correctly fixes 8 use-after-free properties by caching warp arrays, but several other properties with the same .view() pattern remain unfixed (e.g., default_root_vel, joint_pos_limits, body_incoming_joint_wrench_b).
source/isaaclab/isaaclab/test/mock_interfaces/assets/mock_rigid_object.py	Correctly fixes 6 use-after-free properties by caching warp arrays, but default_root_vel still has the same uncached .view() pattern.
source/isaaclab/isaaclab/test/mock_interfaces/assets/mock_rigid_object_collection.py	Correctly fixes 4 use-after-free properties by caching warp arrays, but default_body_pose and default_body_vel still have the same uncached .view() pattern.
source/isaaclab/config/extension.toml	Patch version bump from 4.5.22 to 4.5.23, appropriate for a bug fix.
source/isaaclab/docs/CHANGELOG.rst	Well-written changelog entry explaining the root cause (use-after-free from warp view pointer aliases) and the fix (caching default arrays).

Flowchart

%%{init: {'theme': 'neutral'}}%%
flowchart TD
    A["Property accessed<br/>(e.g., root_com_lin_vel_w)"] --> B["Calls parent property<br/>(e.g., root_com_vel_w)"]
    B --> C{"self._field<br/>is None?"}
    C -->|"Yes (before fix)"| D["return wp.zeros(...).view()<br/>Temporary created"]
    D --> E["Temporary may be GC'd"]
    E --> F["wp.array(ptr=v.ptr, ...)<br/>Dangling pointer!"]
    F --> G["❌ Use-after-free:<br/>garbage data"]
    C -->|"Yes (after fix)"| H["self._field = wp.zeros(...).view()<br/>Cached on instance"]
    H --> I["wp.array(ptr=v.ptr, ...)<br/>Pointer stays valid"]
    I --> J["✅ Correct data returned"]
    C -->|No| K["Return cached self._field"]
    K --> I

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Comments Outside Diff (1)

1. source/isaaclab/isaaclab/test/mock_interfaces/assets/mock_articulation.py, line 170-174 (link)

   Same use-after-free pattern remains unfixed

   default_root_vel still returns a .view() of a temporary without caching to self._default_root_vel, matching the exact bug pattern fixed elsewhere in this PR. While current consumers (default_root_state) call wp.to_torch() which may keep the array alive, this is fragile and inconsistent with the fix applied to the other properties.

   The same unfixed pattern also appears in:

   • mock_articulation.py:282 — joint_pos_limits returns wp.array(...).view(wp.vec2f) without caching
   • mock_articulation.py:629 — body_incoming_joint_wrench_b returns wp.zeros(...).view(wp.spatial_vectorf) without caching
   • mock_rigid_object.py:107 — default_root_vel returns wp.zeros(...).view(wp.spatial_vectorf) without caching
   • mock_rigid_object_collection.py:99 — default_body_pose returns wp.array(...).view(wp.transformf) without caching
   • mock_rigid_object_collection.py:106 — default_body_vel returns wp.zeros(...).view(wp.spatial_vectorf) without caching

   Consider applying the same caching fix to all .view() and wp.clone() return paths for consistency and to prevent future regressions.

_{Last reviewed commit: ee15789}

[pascal-roth]

LGTM