[INFO] updating cached repository prewk/img_diff
[INFO] running `"git" "fetch" "--all"`
[INFO] [stdout] Fetching origin
[INFO] [stderr] From git://github.com/prewk/img_diff
[INFO] [stderr]  * branch            HEAD       -> FETCH_HEAD
[INFO] running `"git" "clone" "work/cache/sources/gh/prewk/img_diff" "work/ex/pr-56896/sources/master#adbfec229ce07ff4b2a7bf2d6dec2d13cb224980/gh/prewk/img_diff"`
[INFO] [stderr] Cloning into 'work/ex/pr-56896/sources/master#adbfec229ce07ff4b2a7bf2d6dec2d13cb224980/gh/prewk/img_diff'...
[INFO] [stderr] done.
[INFO] running `"git" "clone" "work/cache/sources/gh/prewk/img_diff" "work/ex/pr-56896/sources/try#bad365140e1e8233b42b21af70a407f14ce5fec5/gh/prewk/img_diff"`
[INFO] [stderr] Cloning into 'work/ex/pr-56896/sources/try#bad365140e1e8233b42b21af70a407f14ce5fec5/gh/prewk/img_diff'...
[INFO] [stderr] done.
[INFO] running `"git" "rev-parse" "HEAD"`
[INFO] [stdout] a97fe31a8d313dca2961a9a1d48496d6248262db
[INFO] sha for GitHub repo prewk/img_diff: a97fe31a8d313dca2961a9a1d48496d6248262db
[INFO] validating manifest of prewk/img_diff on toolchain master#adbfec229ce07ff4b2a7bf2d6dec2d13cb224980
[INFO] running `"/mnt/big/crater/work/local/cargo-home/bin/cargo" "+adbfec229ce07ff4b2a7bf2d6dec2d13cb224980-alt" "read-manifest" "--manifest-path" "Cargo.toml"`
[INFO] validating manifest of prewk/img_diff on toolchain try#bad365140e1e8233b42b21af70a407f14ce5fec5
[INFO] running `"/mnt/big/crater/work/local/cargo-home/bin/cargo" "+bad365140e1e8233b42b21af70a407f14ce5fec5-alt" "read-manifest" "--manifest-path" "Cargo.toml"`
[INFO] started frobbing prewk/img_diff
[INFO] finished frobbing prewk/img_diff
[INFO] frobbed toml for prewk/img_diff written to work/ex/pr-56896/sources/master#adbfec229ce07ff4b2a7bf2d6dec2d13cb224980/gh/prewk/img_diff/Cargo.toml
[INFO] started frobbing prewk/img_diff
[INFO] finished frobbing prewk/img_diff
[INFO] frobbed toml for prewk/img_diff written to work/ex/pr-56896/sources/try#bad365140e1e8233b42b21af70a407f14ce5fec5/gh/prewk/img_diff/Cargo.toml
[INFO] crate prewk/img_diff has a lockfile. skipping
[INFO] running `"/mnt/big/crater/work/local/cargo-home/bin/cargo" "+adbfec229ce07ff4b2a7bf2d6dec2d13cb224980-alt" "fetch" "--locked" "--manifest-path" "Cargo.toml"`
[INFO] [stderr] error: the lock file /mnt/big/crater/work/ex/pr-56896/sources/master#adbfec229ce07ff4b2a7bf2d6dec2d13cb224980/gh/prewk/img_diff/Cargo.lock needs to be updated but --locked was passed to prevent this
[ERROR] this task or one of its parent failed!
[ERROR] command `"/mnt/big/crater/work/local/cargo-home/bin/cargo" "+adbfec229ce07ff4b2a7bf2d6dec2d13cb224980-alt" "fetch" "--locked" "--manifest-path" "Cargo.toml"` failed