CI run 36189416163 failed after "git: unpacking": executing the cached
fetch-<sha> PortableGit PE in place left it handle-held (Defender
on-execute scan / the stub's RunProgram child chain) past pm's ~2 s
_remove_entry retry, so download cleanup raised WinError 32. Review
(teknium1, 5 threads) adds the rest:
- Git.unpack now copies the artifact into a .sfx-* dir beside the
staging tree and executes the copy; pm's .staging-* teardown
(ignore_errors) owns that path, so any hold lands on a disposable
path and the cache dir only ever holds read handles
- refuse off-Windows with the cross-host trade-off stated instead of a
raw PermissionError; documented in package-management.md and the PR
- the extractor is a GUI-subsystem stub that is silent under -y: error
messages now carry the exit code and the usual causes (disk full,
path length, antivirus) instead of promising captured output; the
docstring no longer claims "no GUI" and records that the stub shows
an Extracting window and runs the vendor post-install
- install.ps1: WaitForExit(600000) + Kill() mirrors pm's timeout=600,
Fail reports the exit code and the silence
- tests: the OS-refused-exec assertion and the not-in-text change
detectors are replaced by subprocess-argv invariants (scratch copy
location, exit-code message, off-Windows guard before any execution)
Related to #122512
(cherry picked from commit adaf76a286bebe30c89aee4174df27f1945b60c9)