gh-122941: Fix test_launcher sporadic failures via py.ini isolation#145090
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zooba merged 2 commits intopython:mainfrom Mar 4, 2026
Merged
gh-122941: Fix test_launcher sporadic failures via py.ini isolation#145090zooba merged 2 commits intopython:mainfrom
zooba merged 2 commits intopython:mainfrom
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The launcher reads py.ini from %LOCALAPPDATA% via SHGetFolderPathW, which is shared across all processes for a given user. When multiple test processes run concurrently on the same machine, one process's py.ini writes (e.g. python3=PythonTestSuite/3.100-arm64) leak into another process's launcher invocations, causing assertions like "PythonCore != PythonTestSuite" to fail. Add a PYLAUNCHER_INIDIR environment variable to the launcher that, when set, redirects py.ini lookup to the specified directory and skips the default locations. Update test_launcher.py to create an isolated temp directory per test class and pass it via PYLAUNCHER_INIDIR.
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!buildbot AMD64 Windows Server 2022 NoGIL |
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🤖 New build scheduled with the buildbot fleet by @itamaro for commit a8427d8 🤖 Results will be shown at: https://buildbot.python.org/all/#/grid?branch=refs%2Fpull%2F145090%2Fmerge The command will test the builders whose names match following regular expression: The builders matched are:
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chris-eibl
approved these changes
Feb 21, 2026
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LGTM! |
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@zooba any concerns with this change? |
zooba
reviewed
Mar 2, 2026
itamaro
added
needs backport to 3.13
miss-islington
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to miss-islington/cpython
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Mar 5, 2026
…tion (pythonGH-145090) Adds _PYLAUNCHER_INIDIR as a private variable since the launcher is deprecated and not getting new features. (cherry picked from commit 6cdbd7b) Co-authored-by: Itamar Oren <itamarost@gmail.com>
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GH-145572 is a backport of this pull request to the 3.13 branch. |
miss-islington
pushed a commit
to miss-islington/cpython
that referenced
this pull request
Mar 5, 2026
…tion (pythonGH-145090) Adds _PYLAUNCHER_INIDIR as a private variable since the launcher is deprecated and not getting new features. (cherry picked from commit 6cdbd7b) Co-authored-by: Itamar Oren <itamarost@gmail.com>
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GH-145573 is a backport of this pull request to the 3.14 branch. |
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Note: this PR was authored with assistance from Claude Code Opus 4.6
The launcher reads py.ini from
%LOCALAPPDATA%viaSHGetFolderPathW, which is shared across all processes for a given user. When multiple test processes run concurrently on the same machine, one process'spy.iniwrites leak into another process's launcher invocations, causing assertions like"PythonCore != PythonTestSuite"to fail.Add a
PYLAUNCHER_INIDIRenvironment variable to the launcher that, when set, redirectspy.inilookup to the specified directory and skips the default locations. Updatetest_launcher.pyto create an isolated temp directory per test class and pass it viaPYLAUNCHER_INIDIR.I verified this fix on my Windows buildbot worker that's currently failing due to this issue.
with this PR, all tests pass:
without it, 2 tests fail: