$ git clone -n https://src.fedoraproject.org/rpms/rust-synstructure0.12.git /var/lib/mock/f45-build-45325-822/root/chroot_tmpdir/scmroot/rust-synstructure0.12
Cloning into '/var/lib/mock/f45-build-45325-822/root/chroot_tmpdir/scmroot/rust-synstructure0.12'...
$ git fetch origin 66de4b1ea90a16c4383c7bbf68d6488d392edf8d:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rust-synstructure0.12
 * [new ref]         66de4b1ea90a16c4383c7bbf68d6488d392edf8d -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 66de4b1 Rebuilt for https://fedoraproject.org/wiki/Fedora_45_Mass_Rebuild