python: fix -Werror unused-parameter build break in init_gnn_submodule (pre-9.26 headers)

[brandonfzhang]

init_gnn_submodule(py::module_ &m) guards its whole body with #if CUDNN_VERSION >= 92600 && !defined(_WIN32) — against pre-9.26 cuDNN headers (or on Windows) the body compiles away, m is unused, and the build's -Werror=unused-parameter makes every pip install . of current develop fail:

python/gnn.cpp:71:33: error: unused parameter 'm' [-Werror=unused-parameter]
ERROR: Failed building wheel for nvidia-cudnn-frontend

Seen wherever the source build runs inside a container shipping older cuDNN headers (e.g. recent NGC PyTorch images), while environments with 9.26+ headers build fine. Fix: [[maybe_unused]] on the parameter.

🤖 Generated with Claude Code

Summary by CodeRabbit

• Bug Fixes
  • Improved build compatibility for Windows and environments using older cuDNN headers.
  • Prevented unused-parameter warnings from being treated as build errors.
  • Preserved existing runtime behavior when GNN bindings are enabled.

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Reviewing files that changed from the base of the PR and between 139b154 and 333adcd.

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• python/gnn.cpp

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📝 Walkthrough

Walkthrough

The GNN submodule initializer marks its module parameter as [[maybe_unused]]. This prevents unused-parameter warnings when guarded GNN registration is excluded. Runtime behavior remains unchanged when GNN bindings are compiled.

Changes

GNN warning handling

Layer / File(s)	Summary
Initializer warning guard python/gnn.cpp	init_gnn_submodule marks its module parameter as [[maybe_unused]] and documents why the parameter can be unused on some builds.

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

Merge Risk: ⚪ Minimal · up to 333ad

This narrowly scoped build fix prevents an unused-parameter warning from failing builds with older cuDNN headers or on Windows; no actionable merge-blocking risk remains after normal checks and review.

Suggested reviewers: tingyu66

🚥 Pre-merge checks | ✅ 4 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Description check	⚠️ Warning	The description clearly explains the build failure, affected configurations, error, and fix. However, it omits the required template sections for affected area, API and compatibility impact, testing, …	Rewrite the description using the repository template. Add the affected area, API and compatibility impact, exact testing commands and results, related issue information or an explicit statement that none applies, and complete the license, …

✅ Passed checks (4 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title clearly identifies the Python binding, the unused-parameter build failure, and the affected pre-9.26 header configuration.
Docstring Coverage	✅ Passed	Docstring coverage is 100.00% which is sufficient. The required threshold is 80.00%. Docstring coverage is scoped to functions touched by this diff. Analyzed 1 functions across 1 files.
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.

Full details: Description check

Explanation

The description clearly explains the build failure, affected configurations, error, and fix. However, it omits the required template sections for affected area, API and compatibility impact, testing, related issues, and submission checklist items.

Resolution

Rewrite the description using the repository template. Add the affected area, API and compatibility impact, exact testing commands and results, related issue information or an explicit statement that none applies, and complete the license, pre-commit, and label checklist items.

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🧪 Generate unit tests (beta)

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