[https://nvbugs/6272598][fix] Replace the positive isinstance(..., MpiPoolSession) check with a negative…

[trtllm-agent]

Summary

• Root cause: isinstance(self.mpi_session, MpiPoolSession) raises TypeError because tests/test_common/session_reuse.py monkey-patches MpiPoolSession in tensorrt_llm.executor.proxy to a factory function (not a class).
• Fix: Replace the positive isinstance(..., MpiPoolSession) check with a negative check against (MpiCommSession, RemoteMpiCommSessionClient), mirroring the existing pattern in the same function.
• Automated fix generated by repair-bot

Test plan

• Verify fix on the same GPU type as the original failure
• Check for regressions in related tests

Links

• Bug: https://nvbugs/6272598

Summary by CodeRabbit

• Bug Fixes
  • Improved worker startup monitoring across supported MPI session modes.
  • Ensured worker process identities are registered consistently, except for remote and standard MPI communication sessions.

[coderabbitai]

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ℹ️ Recent review info

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📥 Commits

Reviewing files that changed from the base of the PR and between 95f9f92 and 58844a0.

📒 Files selected for processing (1)

• tensorrt_llm/executor/proxy.py

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📝 Walkthrough

Walkthrough

The worker initialization logic changes its MPI session type guard so worker_process_identities registration applies to additional session modes while excluding MpiCommSession and RemoteMpiSessionClient.

Changes

MPI startup registration

Layer / File(s)	Summary
Session type registration guard tensorrt_llm/executor/proxy.py	The len(status) == 3 startup path registers worker process identities for MPI session types other than MpiCommSession and RemoteMpiSessionClient, replacing the previous MpiPoolSession-only check.

Estimated code review effort: 1 (Trivial) | ~5 minutes

Possibly related PRs

• NVIDIA/TensorRT-LLM#16338: Updates the same worker initialization parsing and MPI session registration conditions.

Suggested reviewers: cascade812, lori-ren

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title matches the bug fix and ticket, and it clearly describes the main code change.
Description check	✅ Passed	The description explains the root cause, fix, test plan, and bug link, though it doesn't follow the template headings exactly.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests

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[cascade812]

This fix is already merged by PR #16444