validate-family.py: git-not-runnable takes any OSError around the whole member check, so a holder whose members/<P> this user cannot enter is told to put git on PATH, and the two pinned validators count a missing git by two rules #928

Goal: the two pinned validators share one rule for "git could not be started", and a member directory this user cannot enter is never reported as a missing git.

Filed by lane openRepoShape-3, from its triage of #459 at the v1.1.1 release commit 5017830. It is #459's line U018 (lane 4's line on the two git-not-runnable wrappers), one pull request's worth. #430 covers the .exists() guard itself; this issue is the wrapper's rule.

Two git-not-runnable rules (U018)

State. _git_runs in templates/family-root/scripts/validate-family.py:289-292 turns any OSError into git-not-runnable ("put git on PATH and run this again"). It wraps all of _check_member_tree (:1075-1078), whose first line is (member / ".git").exists() (:946). templates/assembly-root/scripts/validate-pins.py:570-616 counts only an OSError whose filename is git, or a nameless FileNotFoundError or PermissionError, around the git calls alone. #575 (#539) did not unify them, and scripts/repo_shape.py holds no shared rule.

What happens. On Python 3.12 and 3.13, exists() raises PermissionError for a members/<P> this user cannot enter, so with git on PATH the holder is refused git-not-runnable and told to put git on PATH. Windows' nameless [WinError 193] (a git that cannot be executed) is counted by one rule and not the other; that is read from CPython, not run on Windows.

Evidence. The lines above at 5017830.

Direction. Move validate-pins.py's filename rule into scripts/repo_shape.py, have both validators use it, and wrap only the git calls in validate-family.py. All three are pinned copies, so it rides with the next re-pin.

Size: S (M if the rule moves into repo_shape.py).

Lane: openreposhape-3 (openRepoShape-3)