[https://nvbugs/5979673][fix] Unwaive test_agent_multi_backends.py::test_run_with_different_env

[Shixiaowei02]

Summary by CodeRabbit

• Improvements
  • Enhanced CUDA version detection for disaggregated inference operations to support multiple CUDA versions.
• Tests
  • Resolved a known issue in disaggregated agent multi-backend testing, removing the associated test waiver.

Description

Test Coverage

PR Checklist

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[Shixiaowei02]

/bot skip --comment "CI had already passed in /LLM/main/L0_MergeRequest_PR pipeline #40891 before handling the waive file conflicts."

[coderabbitai]

📝 Walkthrough

Walkthrough

This PR updates the NIXL module dependency import logic to support CUDA-specific package variants with automatic fallback, and removes a corresponding test waiver that is no longer needed following the import fix.

Changes

NIXL Dependency Import and Test Waiver

Layer / File(s)	Summary
NIXL dynamic CUDA-aware import fallback tensorrt_llm/_torch/disaggregation/nixl/_agent_py.py	Module imports attempt nixl_cu13, then nixl_cu12, then nixl in sequence, with explicit ImportError if none are found. The symbols nixl_agent, nixl_agent_config, and nixl_xfer_handle are bound from the successfully imported package.
Test waiver removal tests/integration/test_lists/waives.txt	Waiver entry for unittest/disaggregated/test_agent_multi_backends.py::test_run_with_different_env[1] is removed, indicating the test now passes with the updated import logic.

Estimated code review effort

🎯 2 (Simple) | ⏱️ ~8 minutes

Possibly related PRs

• NVIDIA/TensorRT-LLM#14854: Modifies tests/integration/test_lists/waives.txt with additional waived test changes.
• NVIDIA/TensorRT-LLM#14545: Directly related waiver removal for the same unittest/disaggregated/test_agent_multi_backends.py::test_run_with_different_env[1] test case.
• NVIDIA/TensorRT-LLM#14896: Related test waiver list modifications in tests/integration/test_lists/waives.txt.

Suggested reviewers

• tburt-nv
• dpitman-nvda
• yuanjingx87

🚥 Pre-merge checks | ✅ 4 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Description check	⚠️ Warning	The PR description is mostly empty, containing only the template structure without filling in the required Description and Test Coverage sections.	Fill in the Description section explaining the NIXL import fix and test unwaival, and list the relevant tests (test_agent_multi_backends.py::test_run_with_different_env[1]) in Test Coverage.

✅ Passed checks (4 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title clearly and specifically identifies the main change: unwaiving a previously skipped test by addressing the underlying NIXL import issue.
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.

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✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests

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[coderabbitai]

Actionable comments posted: 1

🤖 Prompt for all review comments with AI agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

Inline comments:
In `@tensorrt_llm/_torch/disaggregation/nixl/_agent_py.py`:
- Around line 17-21: The loop that probes NIXL candidates uses
importlib.import_module(_candidate) and currently catches ImportError broadly,
which may hide failures inside a module; change the except clause to catch
ModuleNotFoundError as e, inspect e.name (or e.args[0]) and only continue when
the missing module equals the candidate string (_candidate); for any other
ModuleNotFoundError or any other ImportError/exception raised by
importlib.import_module, re-raise it so real import-time errors inside the
candidate are not swallowed; ensure this logic references _candidate and
_nixl_mod in the same block.

🪄 Autofix (Beta)

Fix all unresolved CodeRabbit comments on this PR:

• Push a commit to this branch (recommended)
• Create a new PR with the fixes

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ℹ️ Review info

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Configuration used: Path: .coderabbit.yaml

Review profile: CHILL

Plan: Enterprise

Run ID: 5b508712-758f-48fc-9d99-846e9df16b48

📥 Commits

Reviewing files that changed from the base of the PR and between b7ca2a6 and a1625b1.

📒 Files selected for processing (2)

• tensorrt_llm/_torch/disaggregation/nixl/_agent_py.py
• tests/integration/test_lists/waives.txt

💤 Files with no reviewable changes (1)

• tests/integration/test_lists/waives.txt

[tensorrt-cicd]

PR_Github #51980 [ skip ] triggered by Bot. Commit: a1625b1 Link to invocation

[tensorrt-cicd]

PR_Github #51980 [ skip ] completed with state SUCCESS. Commit: a1625b1
Skipping testing for commit a1625b1

Link to invocation