[INFO] cloning repository https://github.com/whfuyn/rgb-coloring
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/whfuyn/rgb-coloring" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fwhfuyn%2Frgb-coloring", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fwhfuyn%2Frgb-coloring'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] 02ceb41011f997eeb6aa132cb321959155ad05e5
[INFO] checking whfuyn/rgb-coloring against master#8f21a5c92ea55c348c275a1bc4fedbdf181e0d64 for pr-143011
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fwhfuyn%2Frgb-coloring" "/workspace/builds/worker-2-tc1/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-2-tc1/source'...
[INFO] [stderr] done.
[INFO] [stderr] fatal: update_ref failed for ref 'HEAD': cannot update ref 'refs/heads/master': couldn't write '/workspace/builds/worker-2-tc1/source/.git/refs/heads/master.lock'


failed to checkout https://github.com/whfuyn/rgb-coloring

Caused by:
    command failed: exit status: 128