[INFO] cloning repository https://github.com/kisChang/rust-pico
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/kisChang/rust-pico" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2FkisChang%2Frust-pico", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2FkisChang%2Frust-pico'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] c9320a9259240500566a5c3e11035b6dcf48813d
[INFO] checking kisChang/rust-pico against master#b2728d5426bab1d8c39709768c7e22b7f66dde5d for pr-135852
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2FkisChang%2Frust-pico" "/workspace/builds/worker-1-tc1/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-1-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-1-tc1/source/.git/refs/heads/master.lock'


failed to checkout https://github.com/kisChang/rust-pico

Caused by:
    command failed: exit status: 128