$ git clone -n https://src.fedoraproject.org/rpms/rubygem-mysql2.git /var/lib/mock/f42-build-3490762-45854/root/chroot_tmpdir/scmroot/rubygem-mysql2
Cloning into '/var/lib/mock/f42-build-3490762-45854/root/chroot_tmpdir/scmroot/rubygem-mysql2'...
$ git fetch origin 12ee15b8737699caf7abc02fe949718b9b7f8da7:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rubygem-mysql2
 * [new ref]         12ee15b8737699caf7abc02fe949718b9b7f8da7 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 12ee15b Re-enable test cases the FTBFS due to mariadb-connector-c-3.4.1-1.fc42 was fixed in mariadb-connector-c-3.4.3-10