$ git clone -n https://src.fedoraproject.org/rpms/ruby.git /var/lib/mock/f31-build-46882-26742/root/thebuilddir/tmp/scmroot/ruby
Cloning into '/var/lib/mock/f31-build-46882-26742/root/thebuilddir/tmp/scmroot/ruby'...
$ git reset --hard 13a1b3e907bdf6fd5a0b3d61f40f0f8bc21008d6
HEAD is now at 13a1b3e Properly support %prerelease in %gemspec_ macros.