$ git clone -n https://src.fedoraproject.org/rpms/rust-gdk0.17.git /var/lib/mock/f41-build-side-1-3124901-39482/root/chroot_tmpdir/scmroot/rust-gdk0.17
Cloning into '/var/lib/mock/f41-build-side-1-3124901-39482/root/chroot_tmpdir/scmroot/rust-gdk0.17'...
$ git fetch origin b045c646fa87e00395f247b12db906df927ebf9d:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rust-gdk0.17
 * [new ref]         b045c646fa87e00395f247b12db906df927ebf9d -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at b045c64 compat package no longer needed