$ git clone -n https://src.fedoraproject.org/rpms/ghc-nanospec.git /var/lib/mock/f39-build-1507174-35227/root/chroot_tmpdir/scmroot/ghc-nanospec
Cloning into '/var/lib/mock/f39-build-1507174-35227/root/chroot_tmpdir/scmroot/ghc-nanospec'...
$ git fetch origin 2f7d8187fecdf17506755c2b99e4e549e08caa84:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/ghc-nanospec
 * [new ref]         2f7d8187fecdf17506755c2b99e4e549e08caa84 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 2f7d818 bump release