Fixes OmniHub startup in Docker tests

[AntoineRichard]

Description

This PR is based on and includes the changes from #5620, then adds one CI fix on top: it unsets HUB__ARGS__DETECT_ONLY inside the Docker test container before running Isaac Lab commands. Some base images set this flag, which prevents OmniHub from starting and makes cold Nucleus asset retrieval fall back to slow repeated retries.

This was reproduced from the failing Actions job:
https://github.com/isaac-sim/IsaacLab/actions/runs/25904143763/job/76158743634

The affected test_rsl_rl_export_flow.py Dexsuite Kuka-Allegro export timed out at 600 s with the flag set, then completed in about 73 s with the flag unset after clearing the local KukaAllegro mirror.

Fixes # N/A

Type of change

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

Screenshots

N/A - CI-only change.

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 (N/A - CI-only change)
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works (validated with the affected Docker export test)
• I have added a changelog fragment under source/<pkg>/changelog.d/ for every touched package (N/A for the CI-only commit; Prevents early numpy imports to avoid Kit crash #5620 carries its own changelog fragments)
• I have added my name to the CONTRIBUTORS.md or my name already exists there

Test Plan

• ./isaaclab.sh -f
• Docker reproduction with HUB__ARGS__DETECT_ONLY=true: test_export_flow[Isaac-Dexsuite-Kuka-Allegro-Reorient-v0] timed out after 600 s.
• Docker reproduction with HUB__ARGS__DETECT_ONLY unset after clearing the KukaAllegro mirror: test_export_flow[Isaac-Dexsuite-Kuka-Allegro-Reorient-v0] passed in 72.75 s.

[isaaclab-review-bot]

Code Review Summary

This PR addresses a CI timeout issue caused by the HUB__ARGS__DETECT_ONLY environment variable preventing OmniHub from starting in Docker test containers.

✅ Strengths

1. Root cause correctly identified: The author traced the timeout in test_rsl_rl_export_flow.py to OmniHub's detect-only mode blocking asset downloads.

2. Minimal, surgical fix: The change adds just 4 lines (including helpful comments) in the right location - the test container setup phase.

3. Well-documented PR: Clear explanation of the problem, reproduction steps, and empirical timing data (600s timeout → 73s success).

4. Safe operation: unset HUB__ARGS__DETECT_ONLY is a no-op if the variable was never set, so this won't break environments where the flag isn't present.

5. No production impact: This change only affects CI test containers.

📋 Minor Observations

• Placement is good: The unset is positioned early in the test setup, before any Isaac Lab commands run, ensuring OmniHub can start properly for asset downloads.

• Comment is helpful: The inline explanation will help future maintainers understand why this workaround exists.

🤔 Question (Non-blocking)

Is this environment variable set intentionally in some base images for resource/network reasons? If so, it might be worth documenting which images set it and why, so future image updates don't reintroduce the issue.

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Overall: Clean fix with solid testing evidence. The change is correctly scoped and well-explained.

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Update (ccb6d49): Reviewed the additional changes from #5620 that are now included:

✅ AppLauncher CUDA device deferral — Good fix for fork-crash issue by deferring torch.cuda.set_device() until after SimulationApp starts. Well-documented in changelog.

✅ LEAPP export timing instrumentation — Clean _timed_phase context manager for debugging CI timeouts.

✅ Import optimizations — Lazy-loading configclass avoids eager imports.

✅ Test cleanups — Removing unnecessary AppLauncher from pure-Python tests and improving RTX renderer test fixtures.

✅ Better test diagnostics — Improved timeout messages with timing info.

No new issues found. All changes are well-structured and improve code quality.

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Update (7497d24): New commit adds export script hang detection improvements:

✅ Faulthandler integration — Adds traceback dumps if simulation_app.close() hangs for >120s. Good debugging aid for CI timeouts.

✅ _emit_timing() helper — Routes timing diagnostics to sys.__stderr__, ensuring output survives stream redirects.

✅ wait_for_replicator=False — Skips waiting for Replicator workflows during close, reducing potential hangs.

No issues found. Clean improvements to export script reliability.

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Update (6ef2fbf): New commit batches RSL-RL export flow tests:

✅ Export script refactoring — Made export.py importable by deferring runtime dependencies to _load_runtime_dependencies(), extracting parse_export_args(), and refactoring main() into export_rsl_rl_agent() with explicit parameters. Clean separation of CLI parsing from export logic.

✅ Robust cleanup handling — Added try/finally with leapp_started and env_closed flags to ensure proper cleanup on exceptions. Good defensive coding.

✅ Test batching — Groups ~8 tasks per Kit process via _task_batches() and subprocess isolation. Reduces Kit startup churn while keeping processes short enough to avoid GPU memory accumulation.

✅ Module loading — Clean _load_export_module() using importlib.util to import export.py dynamically.

✅ Changelog skip file — Appropriate for CI-only changes.

No new issues found. Well-structured performance optimization for CI.

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Update (63037a9): Timing instrumentation removed from export script and tests.

✅ Cleanup of diagnostic code — Removed _timed_phase(), _emit_timing(), _close_simulation_app(), and faulthandler integration. The export flow is now cleaner without the debugging scaffolding.

✅ Simplified test output — Removed timing extraction and timing-related log statements from tests.

✅ Reverted to standard close — simulation_app.close() without wait_for_replicator=False. Presumed safe now that root cause (OmniHub detect-only) is addressed.

No new issues. This is straightforward cleanup of temporary diagnostic code.

[greptile-apps]

Greptile Summary

This PR fixes a Docker test regression where the HUB__ARGS__DETECT_ONLY environment variable (set by some Isaac Sim base images) prevented OmniHub from starting inside the test container, causing cold Nucleus asset downloads to time out after 600 s instead of completing in ~73 s.

• Adds a single unset HUB__ARGS__DETECT_ONLY statement inside the container's entrypoint bash string, placed after the symlink setup and before pip installs, so the flag is cleared for all subsequent test processes.
• The fix is narrowly scoped to .github/actions/run-tests/action.yml and has no effect outside the Docker container entrypoint.

Confidence Score: 5/5

Safe to merge — single-line unset in the container entrypoint with no side effects outside the test container.

The change removes one environment variable inside the container's bash entrypoint. unset is a no-op when the variable is absent and has no impact on the host or other jobs. The fix is validated with timing data (600 s timeout → 73 s pass) and the code path is straightforward.

No files require special attention.

Important Files Changed

Filename	Overview
.github/actions/run-tests/action.yml	Adds unset HUB__ARGS__DETECT_ONLY to the container entrypoint to clear a base-image flag that blocks OmniHub startup; change is correct, minimal, and well-scoped.

Sequence Diagram

sequenceDiagram
    participant GHA as GitHub Actions
    participant Docker as Docker Container
    participant OmniHub as OmniHub
    participant Nucleus as Nucleus (asset server)

    GHA->>Docker: "docker run (base image may set HUB__ARGS__DETECT_ONLY=true)"
    Docker->>Docker: ln -s /isaac-sim _isaac_sim
    Note over Docker: NEW: unset HUB__ARGS__DETECT_ONLY
    Docker->>Docker: pip install extra packages (optional)
    Docker->>OmniHub: isaaclab.sh pytest (OmniHub starts normally)
    OmniHub->>Nucleus: Fetch cold assets
    Nucleus-->>OmniHub: Assets downloaded (~73 s)
    OmniHub-->>Docker: Ready
    Docker-->>GHA: Tests pass

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_{Reviews (1): Last reviewed commit: "Fix OmniHub startup in Docker tests" | Re-trigger Greptile}