[None][fix] Set in_mtp_draft_loop on the synthetic DSA metadata stub

[brnguyen2]

Summary

test_on_update_kv_lens_rebuilds_stale_map (added in #16925) builds its DSAtrtllmAttentionMetadata with object.__new__, bypassing __init__ — the only place in_mtp_draft_loop is initialized. The same PR made on_update_kv_lens() read that flag, so the test fails deterministically with

AttributeError: 'DSAtrtllmAttentionMetadata' object has no attribute 'in_mtp_draft_loop'

on every pre-merge CI run since it merged (seen on H100, B200, and B300 pre-merge stages across unrelated PRs).

Fix

Set the __init__ default (False) on the synthetic stub, matching how the test already stubs its other collaborators.

Validation

Full tests/unittest/_torch/attention/sparse/dsa/test_req_idx_per_token.py run on a Blackwell node: 11/11 pass.

Dev Engineer Review

• Initialized md.in_mtp_draft_loop to False in the synthetic metadata fixture.
• This fixes the deterministic AttributeError caused by bypassing DSAtrtllmAttentionMetadata.__init__.
• The change matches the default initialization and has no API, performance, configuration, or regression impact.
• No public entities or test-list files changed.

QA Engineer Review

• Modified test_on_update_kv_lens_rebuilds_stale_map.
• The full test file passed with 11/11 tests on a Blackwell node.
• Coverage in tests/integration/test_lists/ was not provided.
• Verdict: needs follow-up.

[brnguyen2]

/bot run

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📥 Commits

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• tests/unittest/_torch/attention/sparse/dsa/test_req_idx_per_token.py

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Walkthrough

The test fixture now initializes in_mtp_draft_loop to False so on_update_kv_lens() can access the attribute during stale request-index map rebuilding tests.

Changes

DSA test fixture

Layer / File(s)	Summary
Initialize metadata fixture state tests/unittest/_torch/attention/sparse/dsa/test_req_idx_per_token.py	The fixture sets in_mtp_draft_loop to False after bypassing DSAtrtllmAttentionMetadata.__init__.

Estimated code review effort: 1 (Trivial) | ~2 minutes

Possibly related PRs

• NVIDIA/TensorRT-LLM#16925: Updates the tested on_update_kv_lens() behavior and its fixture context.

Suggested reviewers: bowenfu

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title clearly and concisely identifies the fix to initialize in_mtp_draft_loop on the synthetic DSA metadata stub.
Description check	✅ Passed	The description explains the failure, the fix, and test validation, although it does not include the full checklist template.
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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[tensorrt-cicd]

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[tensorrt-cicd]

PR_Github #64587 [ run ] completed with state SUCCESS. Commit: 614378b
/LLM/main/L0_MergeRequest_PR pipeline #52450 completed with status: 'SUCCESS'

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