[INFO] updating cached repository arden/rust-api
[INFO] running `"git" "fetch" "--all"`
[INFO] [stdout] Fetching origin
[INFO] [stderr] From git://github.com/arden/rust-api
[INFO] [stderr]  * branch            HEAD       -> FETCH_HEAD
[INFO] running `"git" "clone" "work/cache/sources/gh/arden/rust-api" "work/ex/beta-1.38-1/sources/1.37.0/gh/arden/rust-api"`
[INFO] [stderr] Cloning into 'work/ex/beta-1.38-1/sources/1.37.0/gh/arden/rust-api'...
[INFO] [stderr] done.
[INFO] running `"git" "clone" "work/cache/sources/gh/arden/rust-api" "work/ex/beta-1.38-1/sources/beta-2019-08-13/gh/arden/rust-api"`
[INFO] [stderr] Cloning into 'work/ex/beta-1.38-1/sources/beta-2019-08-13/gh/arden/rust-api'...
[INFO] [stderr] done.
[INFO] running `"git" "rev-parse" "HEAD"`
[INFO] [stdout] 09e521fd41b104c80a1d22a7f44e98d70e648eb7
[INFO] sha for GitHub repo arden/rust-api: 09e521fd41b104c80a1d22a7f44e98d70e648eb7
[INFO] validating manifest of arden/rust-api on toolchain 1.37.0
[INFO] running `"/mnt/big/crater/work/local/cargo-home/bin/cargo" "+1.37.0" "read-manifest" "--manifest-path" "Cargo.toml"`
[INFO] validating manifest of arden/rust-api on toolchain beta-2019-08-13
[INFO] running `"/mnt/big/crater/work/local/cargo-home/bin/cargo" "+beta-2019-08-13" "read-manifest" "--manifest-path" "Cargo.toml"`
[INFO] started frobbing arden/rust-api
[INFO] finished frobbing arden/rust-api
[INFO] frobbed toml for arden/rust-api written to work/ex/beta-1.38-1/sources/1.37.0/gh/arden/rust-api/Cargo.toml
[INFO] started frobbing arden/rust-api
[INFO] finished frobbing arden/rust-api
[INFO] frobbed toml for arden/rust-api written to work/ex/beta-1.38-1/sources/beta-2019-08-13/gh/arden/rust-api/Cargo.toml
[INFO] crate arden/rust-api already has a lockfile, it will not be regenerated
[INFO] running `"/mnt/big/crater/work/local/cargo-home/bin/cargo" "+1.37.0" "fetch" "--locked" "--manifest-path" "Cargo.toml"`
[INFO] [stderr]     Updating git repository `https://github.com/arden/nickel.rs`
[INFO] [stderr] error: failed to load source for a dependency on `nickel`
[INFO] [stderr] 
[INFO] [stderr] Caused by:
[INFO] [stderr]   Unable to update https://github.com/arden/nickel.rs
[INFO] [stderr] 
[INFO] [stderr] Caused by:
[INFO] [stderr]   failed to fetch into /mnt/big/crater/work/local/cargo-home/git/db/nickel.rs-19f8b5d73536d15d
[INFO] [stderr] 
[INFO] [stderr] Caused by:
[INFO] [stderr]   failed to authenticate when downloading repository
[INFO] [stderr] attempted to find username/password via git's `credential.helper` support, but failed
[INFO] [stderr] 
[INFO] [stderr] Caused by:
[INFO] [stderr]   failed to acquire username/password from local configuration
[ERROR] this task or one of its parent failed!
[ERROR] command `"/mnt/big/crater/work/local/cargo-home/bin/cargo" "+1.37.0" "fetch" "--locked" "--manifest-path" "Cargo.toml"` failed