Prevent object file collisions in parallel extension builds #393
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Parallel builds of extensions that share source files may write to the same object file paths under a common build directory, resulting in race conditions and non-deterministic build outputs. Use a per-extension build directory to isolate object files and ensure deterministic, parallel-safe builds. Bug: pypa/setuptools#3942
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Parallel builds of extensions that share source files may write to the same object file paths under a common build directory, resulting in race conditions and non-deterministic build outputs.
Use a per-extension build directory to isolate object files and ensure deterministic, parallel-safe builds.
Bug: pypa/setuptools#3942
Tests
I tested this change downstream at Gentoo after encountering https://bugs.gentoo.org/967476 and https://bugs.gentoo.org/945376 (packages https://pypi.org/project/librt and https://pypi.org/project/pymongo/). Since the build failures are encountered non-determinstically, i compiled both librt and pymongo as often as needed, capping the compilation attempts to 100.