ci: test the free-threaded Python 3.14 build - #361
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Free threading is officially supported since Python 3.14 (PEP 779), but the free-threaded build was not exercised anywhere. Under xdist this plugin runs a socket server in the master to coordinate reruns across workers, spawning a thread per worker connection and sharing StatusDB behind a lock, so it is worth running the suite without the GIL. Add a py314t tox environment and a matching CI job. The job asserts that the GIL is still disabled after importing the test dependencies, since importing an extension that does not declare free-threading support re-enables it and would leave the job silently testing nothing. Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
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CI here needs maintainer approval since this is my first PR to this repo. In the meantime I ran the same workflow on my fork, on the same commit as this PR: https://github.com/pavlosambur/pytest-rerunfailures/actions/runs/33974552487 All 30 jobs pass, including the new |
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Free threading is officially supported as of Python 3.14 (PEP 779), but the
free-threaded build is not exercised anywhere in CI right now.
This matters more here than for a typical pure-Python package. Under xdist the
master runs a
ServerStatusDBthat workers connect to over a socket(
src/pytest_rerunfailures.pyL597-605); the server itself runs in a backgroundthread (L785-786) and spawns a thread per worker connection (L795-797), with
shared state guarded by
_suite_lock(L686). That is real concurrency, and ithas never been run without the GIL.
Changes:
py314t-pytest91-xdisttox environmentfree-threading:py-3.14t:pytest-9.1CI job, structured as a copy of theexisting
xdistjob — that one also installs dependencies with pip ratherthan going through tox, so this mirrors the existing convention
sys._is_gil_enabled()is false after importing pytest,xdist and the plugin, so it fails loudly instead of silently testing an
interpreter that quietly re-enabled the GIL
Verified locally on a real GIL-disabled interpreter (
Py_GIL_DISABLED=1,sys._is_gil_enabled()returns False):tox -e py314t-pytest91-xdistgives201 passed.
tox -e lintingis green.Deliberately left out: the
Free Threadingtrove classifier. Advertisingsupport in the same PR that starts testing it felt premature — happy to send
that separately once this job has been green for a while.
Unrelated, noticed while working on this:
allow-prereleases: truein theexisting 3.14 jobs is now a no-op, since 3.14 is marked stable in
actions/python-versions. Happy to clean that up in a follow-up if useful.
Worked on this with Claude as an assistant; the reasoning above is mine
and I ran everything locally.