[INFO] cloning repository https://github.com/titusdmoore/interpreter-book [INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/titusdmoore/interpreter-book" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Ftitusdmoore%2Finterpreter-book", kill_on_drop: false }` [INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Ftitusdmoore%2Finterpreter-book'... [INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }` [INFO] [stdout] 49681e44ec6c0d1f8ff9336d91750e6e717d947c [INFO] testing titusdmoore/interpreter-book against master#9e297bf54d31eb3b30067208ff9af4416945a2ed for pr-125507 [INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Ftitusdmoore%2Finterpreter-book" "/workspace/builds/worker-4-tc1/source", kill_on_drop: false }` [INFO] [stderr] Cloning into '/workspace/builds/worker-4-tc1/source'... [INFO] [stderr] done. [INFO] validating manifest of git repo https://github.com/titusdmoore/interpreter-book on toolchain 9e297bf54d31eb3b30067208ff9af4416945a2ed [INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+9e297bf54d31eb3b30067208ff9af4416945a2ed" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }` [INFO] started tweaking git repo https://github.com/titusdmoore/interpreter-book [INFO] finished tweaking git repo https://github.com/titusdmoore/interpreter-book [INFO] tweaked toml for git repo https://github.com/titusdmoore/interpreter-book written to /workspace/builds/worker-4-tc1/source/Cargo.toml [INFO] crate git repo https://github.com/titusdmoore/interpreter-book already has a lockfile, it will not be regenerated [INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+9e297bf54d31eb3b30067208ff9af4416945a2ed" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }` [INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-4-tc1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-4-tc1/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:beeedbb442662e57d416641ecc3200b38e573c25b057896194468d05594dd835" "/opt/rustwide/cargo-home/bin/cargo" "+9e297bf54d31eb3b30067208ff9af4416945a2ed" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }` [INFO] [stdout] 6ff0e64d685f9db93e24ad99cfcd5d25c24a01e462e57905384bea85db9f650b [INFO] running `Command { std: "docker" "start" "-a" "6ff0e64d685f9db93e24ad99cfcd5d25c24a01e462e57905384bea85db9f650b", kill_on_drop: false }` [INFO] running `Command { std: "docker" "inspect" "6ff0e64d685f9db93e24ad99cfcd5d25c24a01e462e57905384bea85db9f650b", kill_on_drop: false }` [INFO] running `Command { std: "docker" "rm" "-f" "6ff0e64d685f9db93e24ad99cfcd5d25c24a01e462e57905384bea85db9f650b", kill_on_drop: false }` [INFO] [stdout] 6ff0e64d685f9db93e24ad99cfcd5d25c24a01e462e57905384bea85db9f650b [INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-4-tc1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-4-tc1/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" "RUSTDOCFLAGS=--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:beeedbb442662e57d416641ecc3200b38e573c25b057896194468d05594dd835" "/opt/rustwide/cargo-home/bin/cargo" "+9e297bf54d31eb3b30067208ff9af4416945a2ed" "build" "--frozen" "--message-format=json", kill_on_drop: false }` [INFO] [stdout] 5068a6d6c7e273c75454df79f1fd407efcc94eb90ab356063e743985fcc2ea3a [INFO] running `Command { std: "docker" "start" "-a" "5068a6d6c7e273c75454df79f1fd407efcc94eb90ab356063e743985fcc2ea3a", kill_on_drop: false }` [INFO] [stderr] Compiling interpreter v0.1.0 (/opt/rustwide/workdir) [INFO] [stdout] error: couldn't create a temp dir: No space left on device (os error 28) at path "/opt/rustwide/target/debug/deps/rmetagKdcTZ" [INFO] [stdout] [INFO] [stdout] [INFO] [stderr] error: could not compile `interpreter` (lib) due to 1 previous error [INFO] running `Command { std: "docker" "inspect" "5068a6d6c7e273c75454df79f1fd407efcc94eb90ab356063e743985fcc2ea3a", kill_on_drop: false }` [INFO] running `Command { std: "docker" "rm" "-f" "5068a6d6c7e273c75454df79f1fd407efcc94eb90ab356063e743985fcc2ea3a", kill_on_drop: false }` [INFO] [stdout] 5068a6d6c7e273c75454df79f1fd407efcc94eb90ab356063e743985fcc2ea3a [INFO] testing titusdmoore/interpreter-book against try#61a9ac64344e91d62f5496627ff363d177f9daab for pr-125507 [INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Ftitusdmoore%2Finterpreter-book" "/workspace/builds/worker-4-tc2/source", kill_on_drop: false }` [INFO] [stderr] Cloning into '/workspace/builds/worker-4-tc2/source'... [INFO] [stderr] done. [INFO] validating manifest of git repo https://github.com/titusdmoore/interpreter-book on toolchain 61a9ac64344e91d62f5496627ff363d177f9daab [INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+61a9ac64344e91d62f5496627ff363d177f9daab" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }` [INFO] started tweaking git repo https://github.com/titusdmoore/interpreter-book [INFO] finished tweaking git repo https://github.com/titusdmoore/interpreter-book [INFO] tweaked toml for git repo https://github.com/titusdmoore/interpreter-book written to /workspace/builds/worker-4-tc2/source/Cargo.toml [INFO] crate git repo https://github.com/titusdmoore/interpreter-book already has a lockfile, it will not be regenerated [INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+61a9ac64344e91d62f5496627ff363d177f9daab" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }` [INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-4-tc2/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-4-tc2/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:beeedbb442662e57d416641ecc3200b38e573c25b057896194468d05594dd835" "/opt/rustwide/cargo-home/bin/cargo" "+61a9ac64344e91d62f5496627ff363d177f9daab" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }` [INFO] [stdout] cadd5490e28a65092fbfc4858ff863ab45b7460fee309fffa8c8603e4df764c3 [INFO] running `Command { std: "docker" "start" "-a" "cadd5490e28a65092fbfc4858ff863ab45b7460fee309fffa8c8603e4df764c3", kill_on_drop: false }` [INFO] running `Command { std: "docker" "inspect" "cadd5490e28a65092fbfc4858ff863ab45b7460fee309fffa8c8603e4df764c3", kill_on_drop: false }` [INFO] running `Command { std: "docker" "rm" "-f" "cadd5490e28a65092fbfc4858ff863ab45b7460fee309fffa8c8603e4df764c3", kill_on_drop: false }` [INFO] [stdout] cadd5490e28a65092fbfc4858ff863ab45b7460fee309fffa8c8603e4df764c3 [INFO] testing titusdmoore/interpreter-book against try#61a9ac64344e91d62f5496627ff363d177f9daab for pr-125507 [INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Ftitusdmoore%2Finterpreter-book" "/workspace/builds/worker-4-tc2/source", kill_on_drop: false }` [INFO] [stderr] Cloning into '/workspace/builds/worker-4-tc2/source'... [INFO] [stderr] done. [INFO] validating manifest of git repo https://github.com/titusdmoore/interpreter-book on toolchain 61a9ac64344e91d62f5496627ff363d177f9daab [INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+61a9ac64344e91d62f5496627ff363d177f9daab" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }` [INFO] started tweaking git repo https://github.com/titusdmoore/interpreter-book [INFO] finished tweaking git repo https://github.com/titusdmoore/interpreter-book [INFO] tweaked toml for git repo https://github.com/titusdmoore/interpreter-book written to /workspace/builds/worker-4-tc2/source/Cargo.toml [INFO] crate git repo https://github.com/titusdmoore/interpreter-book already has a lockfile, it will not be regenerated [INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+61a9ac64344e91d62f5496627ff363d177f9daab" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }` [INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-4-tc2/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-4-tc2/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:beeedbb442662e57d416641ecc3200b38e573c25b057896194468d05594dd835" "/opt/rustwide/cargo-home/bin/cargo" "+61a9ac64344e91d62f5496627ff363d177f9daab" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }` [INFO] [stdout] 5f9470c6465fca0714a459f7a84a10209faf9bf6ba2af23a79924407f7758c97 [INFO] running `Command { std: "docker" "start" "-a" "5f9470c6465fca0714a459f7a84a10209faf9bf6ba2af23a79924407f7758c97", kill_on_drop: false }` [INFO] running `Command { std: "docker" "inspect" "5f9470c6465fca0714a459f7a84a10209faf9bf6ba2af23a79924407f7758c97", kill_on_drop: false }` [INFO] running `Command { std: "docker" "rm" "-f" "5f9470c6465fca0714a459f7a84a10209faf9bf6ba2af23a79924407f7758c97", kill_on_drop: false }` [INFO] [stdout] 5f9470c6465fca0714a459f7a84a10209faf9bf6ba2af23a79924407f7758c97 [INFO] testing titusdmoore/interpreter-book against try#61a9ac64344e91d62f5496627ff363d177f9daab for pr-125507 [INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Ftitusdmoore%2Finterpreter-book" "/workspace/builds/worker-4-tc2/source", kill_on_drop: false }` [INFO] [stderr] Cloning into '/workspace/builds/worker-4-tc2/source'... [INFO] [stderr] done. [INFO] validating manifest of git repo https://github.com/titusdmoore/interpreter-book on toolchain 61a9ac64344e91d62f5496627ff363d177f9daab [INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+61a9ac64344e91d62f5496627ff363d177f9daab" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }` [INFO] started tweaking git repo https://github.com/titusdmoore/interpreter-book [INFO] finished tweaking git repo https://github.com/titusdmoore/interpreter-book [INFO] tweaked toml for git repo https://github.com/titusdmoore/interpreter-book written to /workspace/builds/worker-4-tc2/source/Cargo.toml [INFO] crate git repo https://github.com/titusdmoore/interpreter-book already has a lockfile, it will not be regenerated [INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+61a9ac64344e91d62f5496627ff363d177f9daab" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }` [INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-4-tc2/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-4-tc2/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:beeedbb442662e57d416641ecc3200b38e573c25b057896194468d05594dd835" "/opt/rustwide/cargo-home/bin/cargo" "+61a9ac64344e91d62f5496627ff363d177f9daab" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }` [INFO] [stderr] Error response from daemon: mkdir /var/lib/docker/overlay2/6badf665178a9b46e6f9d91ad1ac69f290a4dba9f9b2c9f901f8d0c62d514afd/merged/opt/rustwide/workdir: no space left on device [INFO] testing titusdmoore/interpreter-book against try#61a9ac64344e91d62f5496627ff363d177f9daab for pr-125507 [INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Ftitusdmoore%2Finterpreter-book" "/workspace/builds/worker-4-tc2/source", kill_on_drop: false }` [INFO] [stderr] Cloning into '/workspace/builds/worker-4-tc2/source'... [INFO] [stderr] done. [INFO] validating manifest of git repo https://github.com/titusdmoore/interpreter-book on toolchain 61a9ac64344e91d62f5496627ff363d177f9daab [INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+61a9ac64344e91d62f5496627ff363d177f9daab" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }` [INFO] started tweaking git repo https://github.com/titusdmoore/interpreter-book [INFO] finished tweaking git repo https://github.com/titusdmoore/interpreter-book [INFO] tweaked toml for git repo https://github.com/titusdmoore/interpreter-book written to /workspace/builds/worker-4-tc2/source/Cargo.toml [INFO] crate git repo https://github.com/titusdmoore/interpreter-book already has a lockfile, it will not be regenerated [INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+61a9ac64344e91d62f5496627ff363d177f9daab" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }` [INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-4-tc2/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-4-tc2/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:beeedbb442662e57d416641ecc3200b38e573c25b057896194468d05594dd835" "/opt/rustwide/cargo-home/bin/cargo" "+61a9ac64344e91d62f5496627ff363d177f9daab" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }` [INFO] [stderr] Error response from daemon: mkdir /var/lib/docker/overlay2/5572c79a540cbfc61fed83ea88ff8f85b3bc80e3ce84a4afb07f35f851275537/merged/opt/rustwide: no space left on device [INFO] testing titusdmoore/interpreter-book against try#61a9ac64344e91d62f5496627ff363d177f9daab for pr-125507 [INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Ftitusdmoore%2Finterpreter-book" "/workspace/builds/worker-4-tc2/source", kill_on_drop: false }` [INFO] [stderr] Cloning into '/workspace/builds/worker-4-tc2/source'... [INFO] [stderr] done. [INFO] validating manifest of git repo https://github.com/titusdmoore/interpreter-book on toolchain 61a9ac64344e91d62f5496627ff363d177f9daab [INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+61a9ac64344e91d62f5496627ff363d177f9daab" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }` [INFO] started tweaking git repo https://github.com/titusdmoore/interpreter-book [INFO] finished tweaking git repo https://github.com/titusdmoore/interpreter-book [INFO] tweaked toml for git repo https://github.com/titusdmoore/interpreter-book written to /workspace/builds/worker-4-tc2/source/Cargo.toml [INFO] crate git repo https://github.com/titusdmoore/interpreter-book already has a lockfile, it will not be regenerated [INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+61a9ac64344e91d62f5496627ff363d177f9daab" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }` [INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-4-tc2/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-4-tc2/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:beeedbb442662e57d416641ecc3200b38e573c25b057896194468d05594dd835" "/opt/rustwide/cargo-home/bin/cargo" "+61a9ac64344e91d62f5496627ff363d177f9daab" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }` [INFO] [stderr] Error response from daemon: mkdir /var/lib/docker/overlay2/2582b740cb5c3b4d59a6b05bc5ce34d332dd455fecc650f072e262b7cad9e597/merged/opt/rustwide: no space left on device [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.