A clone pinned to a commit or tag ran a second `git rev-parse HEAD`
through exec and compared it with the pin. The pre-driver clone could
land on the branch head when a pin was unavailable, and the check
existed for that case. The driver's clone fetches the pin directly and
attaches the branch with `checkout -B <branch> <pin>`, which fails when
the pin is absent, so a successful clone already has the pin checked
out; the driver's conformance suite verifies that on every provider.
`PinnedRevision` keeps only what the clone decision still uses: which
kind of pin was asked for, for the error messages.
Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>