ci: experimental MSYS2/MinGW test run#1122
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uv ships no MinGW wheel and fails to build from source there; the uv tests already skip via @has_uv when the command is absent. Assisted-by: ClaudeCode:claude-opus-4.8
Runs the suite under a real MSYS2/MINGW64 Python to exercise the nox.virtualenv._IS_MINGW code paths, previously only covered by mocked unit tests. Non-blocking (continue-on-error) until proven stable; feeds coverage into the cover job. uv comes from setup-uv (no uv CLI exists in MSYS2 repos), and the session is forced onto the virtualenv backend so the interpreter under test stays MinGW. Assisted-by: ClaudeCode:claude-opus-4.8
On a real MSYS2/MinGW host sys.platform is win32 but the native venv uses a POSIX bin/ layout (with .exe executables), so the Windows-layout assertions must exclude MinGW. Exercised by the experimental MSYS2 CI job. Assisted-by: ClaudeCode:claude-opus-4.8
uv can't inspect the MinGW interpreter, so creating a uv venv from it fails (wntrblm#1088). Mark the affected uv/script-mode tests xfail on MinGW (non-strict, so they xpass once wntrblm#1117 lands) to keep the experimental MSYS2 job green. Assisted-by: ClaudeCode:claude-opus-4.8
Signed-off-by: Henry Schreiner <henryfs@princeton.edu>
ognevny
reviewed
Jun 30, 2026
| include-hidden-files: true | ||
| if-no-files-found: error | ||
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| # No uv CLI exists in any MSYS2 repo (the msys `uv` package only ships the |
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but what about https://packages.msys2.org/base/mingw-w64-uv? it may be broken a bit (msys2/MINGW-packages#21091), but it exists
ognevny
reviewed
Jun 30, 2026
| persist-credentials: false | ||
| - uses: msys2/setup-msys2@v2.32.0 | ||
| with: | ||
| msystem: MINGW64 |
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we recommend using UCRT64 environment, because MINGW64 is about to be deprecated
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Thanks! I'll try to make a follow up soon
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Adding MSYS2 to help us with #1117.
🤖 AI text below 🤖
What
Adds an experimental, non-blocking (
continue-on-error: true) CI job that runs the test suite under a real MSYS2 / MINGW64 Python, plus the test/noxfile changes needed for the non-uv MinGW paths to pass.This PR is independent of #1117 (no shared commits; either can merge first).
Why
nox/virtualenv.pyhas MinGW-specific logic gated on_IS_MINGWthat, until now, was only covered by mocked unit tests (@mock.patch("nox.virtualenv._IS_MINGW", new=True)) — nothing ever ran it with_IS_MINGWactuallyTrue. This job exercises those paths on a genuine MSYS2 runner and feeds coverage into thecoverjob.What's included
msys2): MSYS2/MINGW64, virtualenv backend (forced, so the interpreter under test stays MinGW), uv fromastral-sh/setup-uvwithpath-type: inherit(no uv CLI exists in MSYS2 repos — themsysuvpackage only ships theuv_buildbackend),mingw-w64-x86_64-gccfor native build deps. Python version is whatever MSYS2 ships (detected at runtime).uvinto the test session on MinGW (no wheel; the uv tests@has_uv-skip when absent).bin/layout from correct virtualenv bin dir under mingw python #901, not the uv backend):test_bin_paths/test_create— gate theScripts/-layout assertions onnot IS_MINGW;test_creategains a MinGW branch (POSIXbin/dir holding.exeexecutables —python.exe/pip.exe, lowercaselib).test_bin_windows— pins_IS_MINGW=Falseso the Windows case is unaffected by the live MinGW host.Remaining red is #1117's, by design
With this PR's corrections in place, the only remaining
msys2failures are the uv-backend tests, which fail withuv venv -p .../bin/python.EXE → Failed to inspect Python interpreter— i.e. the #1088 bug that #1117 fixes (test_uv_creation,test_create_reuse_uv_environment,test_stale_environment[uv-virtualenv-False], and the threetest_noxfile_script_mode*). The job iscontinue-on-error, so the overall run is green; once #1117 lands it is fully green too (726 passed, 15 skipped, 100% coverage gate intact).Caveats