Fix pretrained checkpoint matrix

[maxkra15]

Description

Fix the checkpoint workflow so unsupported preset-only tasks do not abort construction of the supported core matrix, and restore the Newton MJWarp checkpoint job for Isaac-Reach-Franka-OSC.

The OSC task previously required an exclusion because implicit feed-forward efforts were not limited by MJWarp. That controller issue was fixed by #7033 using a zero-gain explicit actuator that enforces the Franka asset effort limits before simulation. The checkpoint exclusion remained after that fix and is now stale.

Validation

• Focused Ruff hooks passed during uv run isaaclab -f
• uv run --frozen --extra test python -m pytest scripts/tools/test/test_train_and_publish_checkpoints.py -q — 8 passed
• Newton MJWarp OSC training: 1,000 PPO iterations, 4,096 environments, 98,304,000 steps, 92.92% final training success, no NaNs
• The trained checkpoint loaded successfully and its staged download matched the local SHA-256

The full local pre-commit run reaches unrelated changelog-fragment failures already present on the current develop checkout; this PR changes only the checkpoint utility, its tests, and an isaaclab_rl skip fragment.

Staged checkpoints

• omniverse://isaac-dev.ov.nvidia.com/Isaac/IsaacLab/PretrainedCheckpoints/rsl_rl/Isaac-Open-Drawer-Franka_newtonmjwarp_none_rsl_rl.pt
• omniverse://isaac-dev.ov.nvidia.com/Isaac/IsaacLab/PretrainedCheckpoints/rsl_rl/Isaac-Reach-Franka-OSC_newtonmjwarp_none_rsl_rl.pt

Public Isaac 6.1 asset-pack promotion is handled separately from this code change.

Type of change

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

Release backport

• Backport this pull request to the active release branch after it merges into develop

Screenshots

Not applicable.

Checklist

• I have read and understood the contribution guidelines
• I ran the applicable pre-commit and focused validation checks
• Documentation/changelog requirements are satisfied with a skip fragment because only tooling is changed
• My changes generate no new warnings
• I have added tests that prove the fix
• My name already exists in CONTRIBUTORS.md

[isaaclab-review-bot]

Isaac Lab Review Bot

The change correctly avoids default-backend normalization for preset-driven tasks, allowing unsupported preset-only tasks to be skipped, and restores the Newton MJWarp job for Isaac-Reach-Franka-OSC. The added tests cover both regressions.

• Design and architecture: The reordered lookup matches _select_physics_variants: preset-driven tasks select only recognized variants, while preset-less tasks still use their normalized default backend. The retained private task_name argument is unused after removing the exclusion, but this is optional cleanup rather than a material design defect.
• API: No public API, CLI option, or documented compatibility surface changes. Widening the private helper's default_backend parameter to str | None matches its new internal call path, and the skip fragment is appropriate for this tooling-only change.
• Implementation: The job-construction paths preserve existing behavior for supported preset and preset-less tasks. The regression tests directly exercise unsupported preset handling and restored OSC/Newton MJWarp selection; no concrete implementation failure is evidenced.

No blocking issues. No inline issue met the actionable-evidence threshold; the assessment above records the review feedback.

Automated review; human maintainers own approval decisions.

[greptile-apps]

Greptile Summary

The PR fixes checkpoint matrix construction so preset-only tasks with unsupported physics variants do not require default-backend normalization, and it restores Newton MJWarp checkpoint generation for the Franka OSC reach task.

• Defers default physics-backend normalization when explicit physics presets are available.
• Removes the stale Newton MJWarp exclusion for Isaac-Reach-Franka-OSC.
• Adds focused regression tests for unsupported presets and OSC backend selection.
• Adds the tooling-only changelog skip fragment.

Confidence Score: 5/5

The PR appears safe to merge, with no concrete blocking or independently actionable non-blocking issue identified.

The changed matrix logic avoids unsupported default-backend normalization while retaining concrete preset selection, and the restored Franka OSC Newton MJWarp path is covered by focused tests.

Important Files Changed

Filename	Overview
scripts/tools/train_and_publish_checkpoints.py	Reorders preset discovery and conditionally normalizes the default backend while removing the stale Franka OSC Newton MJWarp exclusion; no concrete defect was established.
scripts/tools/test/test_train_and_publish_checkpoints.py	Adds focused regression coverage for unsupported preset-only tasks and restored Franka OSC Newton MJWarp selection.
source/isaaclab_rl/changelog.d/maximiliank-skip-unsupported-checkpoint-presets.skip	Adds the expected empty changelog skip fragment for the tooling-only change.

Flowchart

%%{init: {'theme': 'neutral'}}%%
flowchart TD
    A[Registered core task] --> B[Enumerate task presets]
    B --> C[Parse environment configuration]
    C --> D[Select learning workflow]
    D --> E{Named physics presets exist?}
    E -->|No| F[Normalize default physics backend]
    E -->|Yes| G[Match requested concrete selectors]
    F --> H[Build checkpoint jobs]
    G --> H
    G --> I[Include Franka OSC Newton MJWarp]

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_{Reviews (1): Last reviewed commit: "Enable Franka Reach OSC MJWarp checkpoin..." | Re-trigger Greptile}

[maxkra15]

run-ci

[isaaclab-bot]

Backported to release/3.0.0 as 2d42577.