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hooks: last-resort python3 probe launches the Microsoft Store redirector on Windows (visible console flash, exit 9009) #4563
Description
Where: graphify/hooks.py, _PYTHON_DETECT, the "Last resort" block — python3 -c "$_GFY_PROBE" is tried before python -c … (0.9.92: L131–135; same order back to 0.8.36 L64–68).
What happens on Windows: with the Microsoft Store app-execution alias enabled (the Windows 10/11 default) and no Store Python installed, command -v python3 in Git Bash resolves to /c/Users/<me>/AppData/Local/Microsoft/WindowsApps/python3 — the AppInstallerPythonRedirector.exe stub. Running it opens a visible console window for ~1.1 s, then exits 9009. So on any machine where the pinned interpreter, .graphify_python, the launcher shebang and the uv-tools scan all miss (removed venv, graphify moved to another env, GUI git client with a minimal PATH), every commit flashes a terminal window before the hook falls through to python.
Environment: Windows 11 Home 23H2 (build 22631), Git for Windows, Windows Terminal 1.24 as default terminal, CPython 3.11.9 (per-user install under %LOCALAPPDATA%\Programs\Python, not the Store build), graphifyy 0.8.36 (probe block unchanged in 0.9.92).
Repro (Git Bash, alias on, no Store Python):
command -v python3 # -> /c/Users/<me>/AppData/Local/Microsoft/WindowsApps/python3
time python3 --version # console window appears for ~1.1 s; exit code 9009Measured three times from a hidden launcher: ~1.1 s each, one AppInstallerPythonRedirector.exe + OpenConsole.exe per call.
Caveat: on my machine the hook never reached this branch (the pinned interpreter has graphify), so this is measured on the alias directly, not through a hook run.
Suggested fix (either):
- on Windows (
uname -s= MINGW*/MSYS*/CYGWIN*) probepythonbeforepython3; or - skip a
python3whose resolved path contains/WindowsApps/(case "$(command -v python3)" in */WindowsApps/*) ;; esac).
Related: #287 noted the WindowsApps stub's exit code for the AGENTS.md command; #1416 touches the python3 fallback in skill-claw.md. Neither covers the hook probe or the window flash. The console-window burst from DETACHED_PROCESS is #2253 (fixed in 0.9.29) and is a different mechanism.
Activity
github-actions commentedon Oct 19, 2026
Thanks for opening this issue, @leonjeng. A maintainer will take a look soon.
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Deepjyoti-Sarmah commentedon Oct 19, 2026
Thanks for the precise report. I checked it against v8 (86c57be). The last-resort block in _PYTHON_DETECT (hooks.py:131) tries python3 before python on every platform, so on a machine with the Store alias and python.org's CPython, the hook runs the stub first every time probes 1 to 4 miss.
I don't have a Windows machine, so I reproduced the probe order on Linux instead. I put a fake WindowsApps/python3 at the front of PATH that logs its call, sleeps 1 s and exits 9009, with a real python behind it. Then I ran the v8 probe block. The stub was called first and python was chosen after it, 1.07 s in total.
I have a fix on a branch. It follows your first suggestion: when WINDIR or MSYSTEM is set, the last resort tries python before python3. That's the same Windows check hooks.py already uses for its pipe-handle handling. Everywhere else the order stays python3, then python. Probes 1 to 4, the probe itself, and the "could not locate a Python" message are unchanged. I didn't take the /WindowsApps/ skip, because a real Store Python also lives in WindowsApps, and skipping it there would leave those users with no fallback.
Tests, with sh-script fakes and only the fake interpreters on PATH:
I also ran the block under dash and BusyBox ash, and both behave the same.
Limits:
fix: hooks try python before python3 under Git for Windows (Graphify-…
test: hooks try python before python3 under Git for Windows (Graphify…