[3.14] gh-144503: Pass sys.argv to forkserver as real argv elements (GH-148194)#148195
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gpshead merged 1 commit intopython:3.14from Apr 7, 2026
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[3.14] gh-144503: Pass sys.argv to forkserver as real argv elements (GH-148194)#148195gpshead merged 1 commit intopython:3.14from
gpshead merged 1 commit intopython:3.14from
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…ents (pythonGH-148194) Avoid embedding the parent's sys.argv into the forkserver -c command string via repr(). When sys.argv is large (e.g. thousands of file paths from a pre-commit hook), the resulting single argument could exceed the OS per-argument length limit (MAX_ARG_STRLEN on Linux, typically 128 KiB), causing posix_spawn to fail and the parent to observe a BrokenPipeError. Instead, append the argv entries as separate command-line arguments after -c; the forkserver child reads them back as sys.argv[1:]. This cannot exceed any limit the parent itself did not already satisfy. Regression introduced by pythongh-143706 / 298d544. (cherry picked from commit 5e9d90b) Co-authored-by: Gregory P. Smith <68491+gpshead@users.noreply.github.com>
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Avoid embedding the parent's sys.argv into the forkserver -c command string via repr(). When sys.argv is large (e.g. thousands of file paths from a pre-commit hook), the resulting single argument could exceed the OS per-argument length limit (MAX_ARG_STRLEN on Linux, typically 128 KiB), causing posix_spawn to fail and the parent to observe a BrokenPipeError.
Instead, append the argv entries as separate command-line arguments after -c; the forkserver child reads them back as sys.argv[1:]. This cannot exceed any limit the parent itself did not already satisfy.
Regression introduced by gh-143706 / 298d544. present in 3.14.3
(cherry picked from commit 5e9d90b)
multiprocessing.Poolfails if command has a long list of arguments (regression in 3.14.3, 3.13.12) #144503