Audit pylibcudf for `noexcept`/`nogil` and remove "Exception check … requires the GIL" warnings · rapidsai/cudf#19720

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Pythonbuggood first issue

説明

Describe the bug When building pylibcudf, our CI logs show many performance warnings like:

performance hint: /__w/cudf/cudf/python/pylibcudf/pylibcudf/labeling.pyx:56:22:
Exception check after calling 'view' will always require the GIL to be acquired.
Declare 'view' as 'noexcept' if you control the definition and you're sure you
don't want the function to raise exceptions.

Example

https://github.com/rapidsai/cudf/actions/runs/17040978623/job/48305629162?pr=19446#step:12:330

Steps/Code to reproduce bug build pylibcudf with warnings

We should check pylibcudf for places where we’ve declared except * or except + but the C++ is non-throwing.

Expected behavior No perf warnings

Additional context Was recently fixed in RMM. See https://github.com/rapidsai/rmm/pull/2020

コントリビューターガイド

技術スタック: cpppython
領域: dataperformance
Issue 種別: bug
難度: 4
推定時間: 1-2 days
活動状況: fresh
明確さ: clear
前提条件: C++ exception handlingCython syntaxBuilding pylibcudf with warnings
初心者向け度: 45
調査方針: Start by building pylibcudf with warnings enabled to reproduce the issue (see CI logs linked). Examine the Cython .pyx files in pylibcudf for functions that have 'except *' or 'except +' declarations but call C++ functions that are marked noexcept. Compare with the approach in the RMM PR (rapidsai/rmm/pull/2020) which added noexcept to non throwing C++ functions. The goal is to add noexcept to all such C++ functions in cuDF called from Cython, and remove unnecessary except clauses in .pyx files.