From Copilot's tenth pass of #1962. The suite covered only pure helpers, so a
regression in source enumeration, install discovery, lockfile loading, the
sibling-guard vouch, or the nonzero exit on real skew would have left it
green — and the negative cases had only ever been run by hand, once per review
round.
Five end-to-end cases build a throwaway repo and run the guard as a
subprocess: aligned installs exit 0; a skewed one exits 1 naming the package
and every holder while leaving the agreeing package unreported; a package
imported only by `test-servers/src` still fails (so dropping the second shared
tree can't pass); a shared source matching no tracked file fails; and a
`validate` chain that stopped running `verify:format-coverage` fails the vouch
even when the versions are fine.
The fixture must be realpath'd. On macOS `tmpdir()` is `/var/…`, a symlink to
`/private/var/…`, and the guard runs `main()` only when `import.meta.url` (the
resolved path) matches `process.argv[1]` — so launching it via the unresolved
path loads the module and does nothing, exiting 0 silently. That is how all
five first "passed" as no-ops, and the comment records it.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01HDdo1rNRVQnVRRdsqSrvG3
32c827f089