[INFO] cloning repository https://github.com/alexclear/rust-koans-answers
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/alexclear/rust-koans-answers" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Falexclear%2Frust-koans-answers", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Falexclear%2Frust-koans-answers'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] 89e124c056c315e10c6d5ab8548902c0cfc64be5
[INFO] testing alexclear/rust-koans-answers against try#ce59db7a1b1b012fb2793c4641c1bdecad7a128b for pr-85530
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Falexclear%2Frust-koans-answers" "/workspace/builds/worker-12/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-12/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/alexclear/rust-koans-answers on toolchain ce59db7a1b1b012fb2793c4641c1bdecad7a128b
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+ce59db7a1b1b012fb2793c4641c1bdecad7a128b" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] started tweaking git repo https://github.com/alexclear/rust-koans-answers
[INFO] finished tweaking git repo https://github.com/alexclear/rust-koans-answers
[INFO] tweaked toml for git repo https://github.com/alexclear/rust-koans-answers written to /workspace/builds/worker-12/source/Cargo.toml
[INFO] crate git repo https://github.com/alexclear/rust-koans-answers already has a lockfile, it will not be regenerated
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+ce59db7a1b1b012fb2793c4641c1bdecad7a128b" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-12/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-12/source:/opt/rustwide/workdir:ro,Z" "-v" "/var/lib/crater-agent-workspace/cargo-home:/opt/rustwide/cargo-home:ro,Z" "-v" "/var/lib/crater-agent-workspace/rustup-home:/opt/rustwide/rustup-home:ro,Z" "-e" "SOURCE_DIR=/opt/rustwide/workdir" "-e" "CARGO_TARGET_DIR=/opt/rustwide/target" "-e" "CARGO_HOME=/opt/rustwide/cargo-home" "-e" "RUSTUP_HOME=/opt/rustwide/rustup-home" "-w" "/opt/rustwide/workdir" "-m" "1610612736" "--user" "0:0" "--network" "none" "ghcr.io/rust-lang/crates-build-env/linux@sha256:20528e8c29e4536546f0102ce88568b16ea7538393a33fcca951030f7af10457" "/opt/rustwide/cargo-home/bin/cargo" "+ce59db7a1b1b012fb2793c4641c1bdecad7a128b" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 75f6e4f3f384c6913d6f524c7749ca953d1ec13dd9debdd797c9ee1fb274a244
[INFO] running `Command { std: "docker" "start" "-a" "75f6e4f3f384c6913d6f524c7749ca953d1ec13dd9debdd797c9ee1fb274a244", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "75f6e4f3f384c6913d6f524c7749ca953d1ec13dd9debdd797c9ee1fb274a244", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "75f6e4f3f384c6913d6f524c7749ca953d1ec13dd9debdd797c9ee1fb274a244", kill_on_drop: false }`
[INFO] [stdout] 75f6e4f3f384c6913d6f524c7749ca953d1ec13dd9debdd797c9ee1fb274a244
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-12/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-12/source:/opt/rustwide/workdir:ro,Z" "-v" "/var/lib/crater-agent-workspace/cargo-home:/opt/rustwide/cargo-home:ro,Z" "-v" "/var/lib/crater-agent-workspace/rustup-home:/opt/rustwide/rustup-home:ro,Z" "-e" "SOURCE_DIR=/opt/rustwide/workdir" "-e" "CARGO_TARGET_DIR=/opt/rustwide/target" "-e" "CARGO_INCREMENTAL=0" "-e" "RUST_BACKTRACE=full" "-e" "RUSTFLAGS=--cap-lints=forbid" "-e" "CARGO_HOME=/opt/rustwide/cargo-home" "-e" "RUSTUP_HOME=/opt/rustwide/rustup-home" "-w" "/opt/rustwide/workdir" "-m" "1610612736" "--user" "0:0" "--network" "none" "ghcr.io/rust-lang/crates-build-env/linux@sha256:20528e8c29e4536546f0102ce88568b16ea7538393a33fcca951030f7af10457" "/opt/rustwide/cargo-home/bin/cargo" "+ce59db7a1b1b012fb2793c4641c1bdecad7a128b" "build" "--frozen" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 737344b4042e62f3fa3f03e8837b9f4649c0bd1395a3c8307a13ec7313d947dd
[INFO] running `Command { std: "docker" "start" "-a" "737344b4042e62f3fa3f03e8837b9f4649c0bd1395a3c8307a13ec7313d947dd", kill_on_drop: false }`
[INFO] [stderr]    Compiling koans v0.2.0 (/opt/rustwide/workdir)
[INFO] [stderr] error: failed to run custom build command for `koans v0.2.0 (/opt/rustwide/workdir)`
[INFO] [stderr] 
[INFO] [stderr] Caused by:
[INFO] [stderr]   process didn't exit successfully: `/opt/rustwide/target/debug/build/koans-dd4c58307ba92316/build-script-build` (exit status: 101)
[INFO] [stderr]   --- stderr
[INFO] [stderr]   thread 'main' panicked at 'called `Result::unwrap()` on an `Err` value: Os { code: 30, kind: Other, message: "Read-only file system" }', build.rs:7:10
[INFO] [stderr]   stack backtrace:
[INFO] [stderr]      0:     0x55e3da544f00 - std[77c0456e0eb29f0c]::backtrace_rs::backtrace::libunwind::trace
[INFO] [stderr]                                  at /rustc/ce59db7a1b1b012fb2793c4641c1bdecad7a128b/library/std/src/../../backtrace/src/backtrace/libunwind.rs:90:5
[INFO] [stderr]      1:     0x55e3da544f00 - std[77c0456e0eb29f0c]::backtrace_rs::backtrace::trace_unsynchronized::<std[77c0456e0eb29f0c]::sys_common::backtrace::_print_fmt::{closure#1}>
[INFO] [stderr]                                  at /rustc/ce59db7a1b1b012fb2793c4641c1bdecad7a128b/library/std/src/../../backtrace/src/backtrace/mod.rs:66:5
[INFO] [stderr]      2:     0x55e3da544f00 - std[77c0456e0eb29f0c]::sys_common::backtrace::_print_fmt
[INFO] [stderr]                                  at /rustc/ce59db7a1b1b012fb2793c4641c1bdecad7a128b/library/std/src/sys_common/backtrace.rs:67:5
[INFO] [stderr]      3:     0x55e3da544f00 - <std[77c0456e0eb29f0c]::sys_common::backtrace::_print::DisplayBacktrace as core[ee1ca6415511a9c4]::fmt::Display>::fmt
[INFO] [stderr]                                  at /rustc/ce59db7a1b1b012fb2793c4641c1bdecad7a128b/library/std/src/sys_common/backtrace.rs:46:22
[INFO] [stderr]      4:     0x55e3da55e65c - core[ee1ca6415511a9c4]::fmt::write
[INFO] [stderr]                                  at /rustc/ce59db7a1b1b012fb2793c4641c1bdecad7a128b/library/core/src/fmt/mod.rs:1110:17
[INFO] [stderr]      5:     0x55e3da543965 - <std[77c0456e0eb29f0c]::sys::unix::stdio::Stderr as std[77c0456e0eb29f0c]::io::Write>::write_fmt
[INFO] [stderr]                                  at /rustc/ce59db7a1b1b012fb2793c4641c1bdecad7a128b/library/std/src/io/mod.rs:1584:15
[INFO] [stderr]      6:     0x55e3da546b2b - std[77c0456e0eb29f0c]::sys_common::backtrace::_print
[INFO] [stderr]                                  at /rustc/ce59db7a1b1b012fb2793c4641c1bdecad7a128b/library/std/src/sys_common/backtrace.rs:49:5
[INFO] [stderr]      7:     0x55e3da546b2b - std[77c0456e0eb29f0c]::sys_common::backtrace::print
[INFO] [stderr]                                  at /rustc/ce59db7a1b1b012fb2793c4641c1bdecad7a128b/library/std/src/sys_common/backtrace.rs:36:9
[INFO] [stderr]      8:     0x55e3da546b2b - std[77c0456e0eb29f0c]::panicking::default_hook::{closure#1}
[INFO] [stderr]                                  at /rustc/ce59db7a1b1b012fb2793c4641c1bdecad7a128b/library/std/src/panicking.rs:208:50
[INFO] [stderr]      9:     0x55e3da546601 - std[77c0456e0eb29f0c]::panicking::default_hook
[INFO] [stderr]                                  at /rustc/ce59db7a1b1b012fb2793c4641c1bdecad7a128b/library/std/src/panicking.rs:225:9
[INFO] [stderr]     10:     0x55e3da5471d1 - std[77c0456e0eb29f0c]::panicking::rust_panic_with_hook
[INFO] [stderr]                                  at /rustc/ce59db7a1b1b012fb2793c4641c1bdecad7a128b/library/std/src/panicking.rs:622:17
[INFO] [stderr]     11:     0x55e3da546cd7 - std[77c0456e0eb29f0c]::panicking::begin_panic_handler::{closure#0}
[INFO] [stderr]                                  at /rustc/ce59db7a1b1b012fb2793c4641c1bdecad7a128b/library/std/src/panicking.rs:519:13
[INFO] [stderr]     12:     0x55e3da5453fc - std[77c0456e0eb29f0c]::sys_common::backtrace::__rust_end_short_backtrace::<std[77c0456e0eb29f0c]::panicking::begin_panic_handler::{closure#0}, !>
[INFO] [stderr]                                  at /rustc/ce59db7a1b1b012fb2793c4641c1bdecad7a128b/library/std/src/sys_common/backtrace.rs:141:18
[INFO] [stderr]     13:     0x55e3da546c39 - rust_begin_unwind
[INFO] [stderr]                                  at /rustc/ce59db7a1b1b012fb2793c4641c1bdecad7a128b/library/std/src/panicking.rs:515:5
[INFO] [stderr]     14:     0x55e3da535e21 - core[ee1ca6415511a9c4]::panicking::panic_fmt
[INFO] [stderr]                                  at /rustc/ce59db7a1b1b012fb2793c4641c1bdecad7a128b/library/core/src/panicking.rs:92:14
[INFO] [stderr]     15:     0x55e3da535eb3 - core[ee1ca6415511a9c4]::result::unwrap_failed
[INFO] [stderr]                                  at /rustc/ce59db7a1b1b012fb2793c4641c1bdecad7a128b/library/core/src/result.rs:1355:5
[INFO] [stderr]     16:     0x55e3da536fde - <core[ee1ca6415511a9c4]::result::Result<std[77c0456e0eb29f0c]::fs::File, std[77c0456e0eb29f0c]::io::error::Error>>::unwrap
[INFO] [stderr]                                  at /rustc/ce59db7a1b1b012fb2793c4641c1bdecad7a128b/library/core/src/result.rs:1037:23
[INFO] [stderr]     17:     0x55e3da536e11 - build_script_build[447be2d2091140b1]::main
[INFO] [stderr]                                  at /opt/rustwide/workdir/build.rs:4:5
[INFO] [stderr]     18:     0x55e3da536ceb - <fn() as core[ee1ca6415511a9c4]::ops::function::FnOnce<()>>::call_once
[INFO] [stderr]                                  at /rustc/ce59db7a1b1b012fb2793c4641c1bdecad7a128b/library/core/src/ops/function.rs:227:5
[INFO] [stderr]     19:     0x55e3da536abe - std[77c0456e0eb29f0c]::sys_common::backtrace::__rust_begin_short_backtrace::<fn(), ()>
[INFO] [stderr]                                  at /rustc/ce59db7a1b1b012fb2793c4641c1bdecad7a128b/library/std/src/sys_common/backtrace.rs:125:18
[INFO] [stderr]     20:     0x55e3da536ea1 - std[77c0456e0eb29f0c]::rt::lang_start::<()>::{closure#0}
[INFO] [stderr]                                  at /rustc/ce59db7a1b1b012fb2793c4641c1bdecad7a128b/library/std/src/rt.rs:49:18
[INFO] [stderr]     21:     0x55e3da5476c9 - <&dyn core[ee1ca6415511a9c4]::ops::function::Fn<(), Output = i32> + std[77c0456e0eb29f0c]::panic::RefUnwindSafe + core[ee1ca6415511a9c4]::marker::Sync as core[ee1ca6415511a9c4]::ops::function::FnOnce<()>>::call_once
[INFO] [stderr]                                  at /rustc/ce59db7a1b1b012fb2793c4641c1bdecad7a128b/library/core/src/ops/function.rs:259:13
[INFO] [stderr]     22:     0x55e3da5476c9 - std[77c0456e0eb29f0c]::panicking::try::do_call::<&dyn core[ee1ca6415511a9c4]::ops::function::Fn<(), Output = i32> + std[77c0456e0eb29f0c]::panic::RefUnwindSafe + core[ee1ca6415511a9c4]::marker::Sync, i32>
[INFO] [stderr]                                  at /rustc/ce59db7a1b1b012fb2793c4641c1bdecad7a128b/library/std/src/panicking.rs:401:40
[INFO] [stderr]     23:     0x55e3da5476c9 - std[77c0456e0eb29f0c]::panicking::try::<i32, &dyn core[ee1ca6415511a9c4]::ops::function::Fn<(), Output = i32> + std[77c0456e0eb29f0c]::panic::RefUnwindSafe + core[ee1ca6415511a9c4]::marker::Sync>
[INFO] [stderr]                                  at /rustc/ce59db7a1b1b012fb2793c4641c1bdecad7a128b/library/std/src/panicking.rs:365:19
[INFO] [stderr]     24:     0x55e3da5476c9 - std[77c0456e0eb29f0c]::panic::catch_unwind::<&dyn core[ee1ca6415511a9c4]::ops::function::Fn<(), Output = i32> + std[77c0456e0eb29f0c]::panic::RefUnwindSafe + core[ee1ca6415511a9c4]::marker::Sync, i32>
[INFO] [stderr]                                  at /rustc/ce59db7a1b1b012fb2793c4641c1bdecad7a128b/library/std/src/panic.rs:433:14
[INFO] [stderr]     25:     0x55e3da5476c9 - std[77c0456e0eb29f0c]::rt::lang_start_internal
[INFO] [stderr]                                  at /rustc/ce59db7a1b1b012fb2793c4641c1bdecad7a128b/library/std/src/rt.rs:34:21
[INFO] [stderr]     26:     0x55e3da536e80 - std[77c0456e0eb29f0c]::rt::lang_start::<()>
[INFO] [stderr]                                  at /rustc/ce59db7a1b1b012fb2793c4641c1bdecad7a128b/library/std/src/rt.rs:48:5
[INFO] [stderr]     27:     0x55e3da536e4c - main
[INFO] [stderr]     28:     0x7f733a7200b3 - __libc_start_main
[INFO] [stderr]     29:     0x55e3da53657e - _start
[INFO] [stderr]     30:                0x0 - <unknown>
[INFO] running `Command { std: "docker" "inspect" "737344b4042e62f3fa3f03e8837b9f4649c0bd1395a3c8307a13ec7313d947dd", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "737344b4042e62f3fa3f03e8837b9f4649c0bd1395a3c8307a13ec7313d947dd", kill_on_drop: false }`
[INFO] [stdout] 737344b4042e62f3fa3f03e8837b9f4649c0bd1395a3c8307a13ec7313d947dd