[INFO] cloning repository https://github.com/obraunsdorf/cargo-downgrade
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/obraunsdorf/cargo-downgrade" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fobraunsdorf%2Fcargo-downgrade", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fobraunsdorf%2Fcargo-downgrade'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] da286ff50e9945153cbdce56a9dfa3b91cc56c8f
[INFO] checking obraunsdorf/cargo-downgrade against master#a26e97be8826d408309fffbd8168362365719f50 for pr-136776
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fobraunsdorf%2Fcargo-downgrade" "/workspace/builds/worker-4-tc1/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-4-tc1/source'...
[INFO] [stderr] error: failed to write new configuration file /workspace/builds/worker-4-tc1/source/.git/config.lock
[INFO] [stderr] fatal: could not set 'core.repositoryformatversion' to '0'


failed to checkout https://github.com/obraunsdorf/cargo-downgrade

Caused by:
    command failed: exit status: 128