Add support for python-env.sh for dev workflows

[pbarejko]

Description

Local Isaac Sim builds (6.1+) ship setup_python_env.sh instead of setup_conda_env.sh. Isaac Lab only sourced the latter, breaking the developer workflow when _isaac_sim points at a source build. This PR falls back to setup_python_env.sh, sets the required Kit env vars, and prepends the active environment's site-packages to avoid Kit prebundle shadowing.

Fixes # (issue)

Type of change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (existing functionality will not work without user modification)
• Documentation update

Screenshots

Please attach before and after screenshots of the change if applicable.

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 extends isaaclab.sh to fall back to setup_python_env.sh when setup_conda_env.sh is absent, enabling the developer workflow with local Isaac Sim 6.1+ source builds. It also exports the required Kit environment variables (ISAAC_PATH, CARB_APP_PATH, EXP_PATH) and, for activated venv/conda environments, prepends the environment's site-packages to PYTHONPATH to prevent Kit's prebundle directories from shadowing user-installed packages.

• Env-script fallback: When _isaac_sim/setup_conda_env.sh is missing, the script now sources setup_python_env.sh and manually exports the three Kit vars that setup_conda_env.sh would have set automatically.
• PYTHONPATH ordering fix: After sourcing, the active environment's site-packages path (obtained via site.getsitepackages()[0]) is prepended so that user packages win over Kit's vendored copies; this fix applies only when VIRTUAL_ENV or CONDA_PREFIX is set, leaving the auto-discovered env_isaaclab venv uncovered.
• Updated warning message: The warning text now names both missing scripts for clarity.

Confidence Score: 4/5

Safe to merge for the primary dev workflow (activated venv/conda + local Isaac Sim source build); the env_isaaclab auto-discovered venv won't get the PYTHONPATH fix but is a secondary use case.

The new sourcing path and env-var exports are straightforward and consistent with the existing setup_conda_env.sh pattern. The site-packages prepend logic is correctly guarded and degrades silently on older Python. The one gap is that the env_isaaclab auto-discovered venv is excluded from the PYTHONPATH fix even though python_exe resolves to it in that scenario, leaving Kit prebundle shadowing possible for users relying on that path.

Only isaaclab.sh changed; the env_isaaclab handling on lines 52-56 warrants a second look.

Important Files Changed

Filename	Overview
isaaclab.sh	Adds fallback to setup_python_env.sh for local Isaac Sim 6.1+ source builds, exports required Kit env vars, and prepends the active venv/conda site-packages to PYTHONPATH; the auto-discovered env_isaaclab venv case is not covered by the site-packages fix.

Flowchart

%%{init: {'theme': 'neutral'}}%%
flowchart TD
    A[isaaclab.sh starts] --> B[Resolve python_exe\nVIRTUAL_ENV / CONDA_PREFIX /\nenv_isaaclab / python.sh / python3]
    B --> C[Prepend source/isaaclab to PYTHONPATH]
    C --> D{_isaac_sim dir present?}
    D -- No --> Z[exec python_exe]
    D -- Yes --> E{setup_conda_env.sh\nexists?}
    E -- Yes --> F[Source setup_conda_env.sh]
    F --> Z
    E -- No --> G{setup_python_env.sh\nexists?}
    G -- No --> H[Print WARNING]
    H --> Z
    G -- Yes --> I[Export ISAAC_PATH\nCARB_APP_PATH\nEXP_PATH]
    I --> J[Source setup_python_env.sh\nKit prebundle dirs prepended to PYTHONPATH]
    J --> K{VIRTUAL_ENV or\nCONDA_PREFIX set?}
    K -- No --> Z
    K -- Yes --> L[Get env site-packages\nvia python_exe]
    L --> M{site-packages\npath found?}
    M -- No --> Z
    M -- Yes --> N[Prepend env site-packages\nto PYTHONPATH\nenv pkgs win over Kit bundle]
    N --> Z[exec python_exe]

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%%{init: {'theme': 'base', 'themeVariables': {"darkMode": true, "background": "#0d1117", "primaryColor": "#21262d", "primaryTextColor": "#e6edf3", "primaryBorderColor": "#8b949e", "lineColor": "#8b949e", "textColor": "#e6edf3", "edgeLabelBackground": "#161b22", "actorBkg": "#21262d", "actorBorder": "#8b949e", "actorTextColor": "#e6edf3", "actorLineColor": "#8b949e", "signalColor": "#8b949e", "signalTextColor": "#e6edf3", "noteBkgColor": "#373320", "noteBorderColor": "#d4a72c", "noteTextColor": "#f0e6c0", "labelBoxBkgColor": "#21262d", "labelBoxBorderColor": "#8b949e", "labelTextColor": "#e6edf3", "loopTextColor": "#e6edf3", "activationBkgColor": "#30363d", "activationBorderColor": "#8b949e"}}}%%
flowchart TD
    A[isaaclab.sh starts] --> B[Resolve python_exe\nVIRTUAL_ENV / CONDA_PREFIX /\nenv_isaaclab / python.sh / python3]
    B --> C[Prepend source/isaaclab to PYTHONPATH]
    C --> D{_isaac_sim dir present?}
    D -- No --> Z[exec python_exe]
    D -- Yes --> E{setup_conda_env.sh\nexists?}
    E -- Yes --> F[Source setup_conda_env.sh]
    F --> Z
    E -- No --> G{setup_python_env.sh\nexists?}
    G -- No --> H[Print WARNING]
    H --> Z
    G -- Yes --> I[Export ISAAC_PATH\nCARB_APP_PATH\nEXP_PATH]
    I --> J[Source setup_python_env.sh\nKit prebundle dirs prepended to PYTHONPATH]
    J --> K{VIRTUAL_ENV or\nCONDA_PREFIX set?}
    K -- No --> Z
    K -- Yes --> L[Get env site-packages\nvia python_exe]
    L --> M{site-packages\npath found?}
    M -- No --> Z
    M -- Yes --> N[Prepend env site-packages\nto PYTHONPATH\nenv pkgs win over Kit bundle]
    N --> Z[exec python_exe]

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_{Reviews (1): Last reviewed commit: "Add support for python-env.sh for dev wo..." | Re-trigger Greptile}

[greptile-apps]

env_isaaclab venv not covered by site-packages fix

The guard [ -n "$VIRTUAL_ENV" ] || [ -n "$CONDA_PREFIX" ] excludes the third resolution path for python_exe (line 19): the auto-discovered env_isaaclab venv. When a user has env_isaaclab present but no explicitly activated venv/conda, python_exe already points at env_isaaclab/bin/python, yet the site-packages prepend is never performed. After setup_python_env.sh injects Kit's prebundle directories into PYTHONPATH, those vendored copies will still shadow env_isaaclab's packages — the exact problem this block is meant to prevent.