[INFO] cloning repository https://github.com/hsiangawang/Principles-of-Blockchain-2020Spring
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/hsiangawang/Principles-of-Blockchain-2020Spring" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fhsiangawang%2FPrinciples-of-Blockchain-2020Spring", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fhsiangawang%2FPrinciples-of-Blockchain-2020Spring'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] 9952c4d0a9db21fd7b9da34694cc2230e097dedd
[ERROR] this task or one of its parent failed!
[ERROR] command failed: exit status: 1
[ERROR] note: run with `RUST_BACKTRACE=1` to display a backtrace.