The allowSystemApps gate (homeDir == systemHome) was effectively a no-op in
production: systemHome came from os.UserHomeDir, which honors the $HOME env
override just like homeDir, so the two were always equal and the gate never
fired when $HOME was overridden.
ResolveSystemHomeDir now prefers the OS user database (getpwuid on Unix),
which is independent of $HOME, falling back to $HOME only when the user record
cannot be resolved. Production behavior is unchanged (a real $HOME still
matches); an isolated/overridden HOME now correctly skips machine-wide
/Applications discovery for zcode/minimax. The app surface references the same
shared resolver.
This is the correct fix for the hermeticity concern (machine-wide state leaking
into an isolated HOME): there is no cross-surface production inconsistency to
port — script installers always operate on the real user HOME in practice, so
they need no gate.
skillPathSameFileIdentityImpl on Windows always returns false and is
never reached through skillPathIdentityProven (which uses file IDs
exclusively). Add a direct seam call with synthetic os.FileInfo to
exercise the Windows return-false path and the Unix os.SameFile path
with nil Sys().
Restructure skillPathFileIdentityImpl to use nested if-err-nil with a
named return and skillPathIdentityProven to use a single expression.
Error conditions now fall through to the bare return instead of
occupying separate coverage blocks, eliminating 5 uncovered statements
that the Windows coverage gate flagged at 99.4193%.
Add FILE_FLAG_OPEN_REPARSE_POINT to the Windows CreateFile call in
skillPathFileIdentityImpl so symlinks are opened as reparse points
rather than followed to their target. Staged symlinks carry relative
targets computed for the final destination, which may not resolve from
the staging directory; following them caused CreateFile to fail,
yielding an empty file ID that rejected publication and broke canonical
skill layout migration on Windows.
Make skillPathSameFileIdentity a seam variable so the tunneled
replacement test can deterministically simulate the identity change on
Unix. On tmpfs (used by Linux CI runners), os.SameFile can return true
for a recreated file due to inode reuse, making the test flaky. On
Windows the swap is a no-op because skillPathIdentityProven compares
file IDs from GetFileInformationByHandle and ignores
skillPathSameFileIdentity.
玉澜