$ git clone -n https://src.fedoraproject.org/rpms/java-1.8.0-openjdk.git /var/lib/mock/f39-build-1674346-40884/root/chroot_tmpdir/scmroot/java-1.8.0-openjdk
Cloning into '/var/lib/mock/f39-build-1674346-40884/root/chroot_tmpdir/scmroot/java-1.8.0-openjdk'...
$ git fetch origin b6bb344d6051b08868b564e0ea515198b4bd5087:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/java-1.8.0-openjdk
 * [new ref]         b6bb344d6051b08868b564e0ea515198b4bd5087 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at b6bb344 Fixed date