$ git clone -n https://src.fedoraproject.org/rpms/rust-diesel.git /var/lib/mock/f39-build-1656737-40550/root/chroot_tmpdir/scmroot/rust-diesel
Cloning into '/var/lib/mock/f39-build-1656737-40550/root/chroot_tmpdir/scmroot/rust-diesel'...
$ git fetch origin 12cfd60c587183bcb408d145624eb1a835d04cac:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rust-diesel
 * [new ref]         12cfd60c587183bcb408d145624eb1a835d04cac -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 12cfd60 Update to version 2.1.3; Fixes RHBZ#2240658