fix(sim): report joint_pos_target in sorted order on isaacgym and pybullet - #34
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…ullet joint_pos/joint_vel/joint_effort_target are emitted in alphabetically-sorted joint order (isaacgym via _get_joint_ids_reindex, pybullet via joint_reindex), but both backends assembled the reported joint_pos_target by iterating their native URDF joint order instead — isaacgym from _joint_info[...]["names"] in _joint_pos_target_from_cache, pybullet from object_joint_order in _get_states. Whenever a robot's native joint order is not already alphabetical (e.g. numeric names joint_2/joint_10, or A,C,B), joint_pos_target[i] then referred to a different joint than joint_pos[i] — a silent index misalignment for downstream consumers that assume the fields share an ordering. Iterate _get_joint_names(..., sort=True) in both materializers instead. Values are name-keyed, so only the output ordering changes; the control path (isaacgym _set_dof_targets / _get_action_array_all and pybullet _apply_action, which legitimately drive the articulation in native order) is untouched. Completes the fix started in 92755f6 for sapien2/genesis, bringing isaacgym and pybullet into parity with sapien3/mujoco/mjx. Adds a general (no-GPU) AST regression guard pinning that both materializers build joint_pos_target from the sorted joint-name list and no longer reference the native-order list. Verified by inspection and the AST guard; the isaacgym and pybullet backends are not runnable in this environment (isaacgym needs a GPU and special import order), so the live end-to-end path could not be executed here.
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joint_pos/joint_vel/joint_effort_target are emitted in alphabetically-sorted
joint order (isaacgym via _get_joint_ids_reindex, pybullet via joint_reindex),
but both backends assembled the reported joint_pos_target by iterating their
native URDF joint order instead — isaacgym from _joint_info[...]["names"] in
_joint_pos_target_from_cache, pybullet from object_joint_order in _get_states.
Whenever a robot's native joint order is not already alphabetical (e.g. numeric
names joint_2/joint_10, or A,C,B), joint_pos_target[i] then referred to a
different joint than joint_pos[i] — a silent index misalignment for downstream
consumers that assume the fields share an ordering.
Iterate _get_joint_names(..., sort=True) in both materializers instead. Values
are name-keyed, so only the output ordering changes; the control path (isaacgym
_set_dof_targets / _get_action_array_all and pybullet _apply_action, which
legitimately drive the articulation in native order) is untouched.
Completes the fix started in 92755f6 for sapien2/genesis, bringing isaacgym and
pybullet into parity with sapien3/mujoco/mjx. Adds a general (no-GPU) AST
regression guard pinning that both materializers build joint_pos_target from
the sorted joint-name list and no longer reference the native-order list.
Verified by inspection and the AST guard; the isaacgym and pybullet backends
are not runnable in this environment (isaacgym needs a GPU and special import
order), so the live end-to-end path could not be executed here.
Review: independently reviewed against current main (verdict MERGE AS-IS); rebased, re-verified: 489 passed, 5 skipped, 577 deselected, 2 xfailed in 7.39s
🤖 Generated with Claude Code
https://claude.ai/code/session_017i6VtKoovBNed815mWFqxw