Panic when using per-package-target

[Coder-256]

Problem

I am trying to use per-package-target to compile one crate from my workspace into WebAssembly. I am getting the following crash:

$ RUST_BACKTRACE=full cargo build

...

thread 'main' panicked at src/cargo/core/compiler/unit_dependencies.rs:177:34:
no entry found for key
stack backtrace:
   0:        0x102bce9c4 - std::backtrace_rs::backtrace::libunwind::trace::h815672f5996c9e34
                               at /rustc/cc66ad468955717ab92600c770da8c1601a4ff33/library/std/src/../../backtrace/src/backtrace/libunwind.rs:93:5
   1:        0x102bce9c4 - std::backtrace_rs::backtrace::trace_unsynchronized::h2e094b2d8c270437
                               at /rustc/cc66ad468955717ab92600c770da8c1601a4ff33/library/std/src/../../backtrace/src/backtrace/mod.rs:66:5
   2:        0x102bce9c4 - std::sys_common::backtrace::_print_fmt::hae24b71afea95695
                               at /rustc/cc66ad468955717ab92600c770da8c1601a4ff33/library/std/src/sys_common/backtrace.rs:67:5
   3:        0x102bce9c4 - <std::sys_common::backtrace::_print::DisplayBacktrace as core::fmt::Display>::fmt::h6d4268b2ed62fb94
                               at /rustc/cc66ad468955717ab92600c770da8c1601a4ff33/library/std/src/sys_common/backtrace.rs:44:22
   4:        0x102bf3ad8 - core::fmt::rt::Argument::fmt::h835101b6de0df17f
                               at /rustc/cc66ad468955717ab92600c770da8c1601a4ff33/library/core/src/fmt/rt.rs:138:9
   5:        0x102bf3ad8 - core::fmt::write::h5d55d44549819258
                               at /rustc/cc66ad468955717ab92600c770da8c1601a4ff33/library/core/src/fmt/mod.rs:1094:21
   6:        0x102bc8ef4 - std::io::Write::write_fmt::hc515897f91abd6cf
                               at /rustc/cc66ad468955717ab92600c770da8c1601a4ff33/library/std/src/io/mod.rs:1714:15
   7:        0x102bce804 - std::sys_common::backtrace::_print::h5844dab5cfa39fca
                               at /rustc/cc66ad468955717ab92600c770da8c1601a4ff33/library/std/src/sys_common/backtrace.rs:47:5
   8:        0x102bce804 - std::sys_common::backtrace::print::h2c300c1ebedfc73c
                               at /rustc/cc66ad468955717ab92600c770da8c1601a4ff33/library/std/src/sys_common/backtrace.rs:34:9
   9:        0x102bd0450 - std::panicking::default_hook::{{closure}}::h0aa9be5c44269370
                               at /rustc/cc66ad468955717ab92600c770da8c1601a4ff33/library/std/src/panicking.rs:270:22
  10:        0x102bd017c - std::panicking::default_hook::h2c0ef097934ee9e6
                               at /rustc/cc66ad468955717ab92600c770da8c1601a4ff33/library/std/src/panicking.rs:290:9
  11:        0x102bd0998 - std::panicking::rust_panic_with_hook::h84c8637cb6e56008
                               at /rustc/cc66ad468955717ab92600c770da8c1601a4ff33/library/std/src/panicking.rs:707:13
  12:        0x102bd08a4 - std::panicking::begin_panic_handler::{{closure}}::h25482adda06c7b7f
                               at /rustc/cc66ad468955717ab92600c770da8c1601a4ff33/library/std/src/panicking.rs:599:13
  13:        0x102bcee50 - std::sys_common::backtrace::__rust_end_short_backtrace::h0c6f3beb22324a29
                               at /rustc/cc66ad468955717ab92600c770da8c1601a4ff33/library/std/src/sys_common/backtrace.rs:170:18
  14:        0x102bd0608 - rust_begin_unwind
                               at /rustc/cc66ad468955717ab92600c770da8c1601a4ff33/library/std/src/panicking.rs:595:5
  15:        0x102c63c48 - core::panicking::panic_fmt::h9072a0246ecafd14
                               at /rustc/cc66ad468955717ab92600c770da8c1601a4ff33/library/core/src/panicking.rs:67:14
  16:        0x102c63c14 - core::panicking::panic_display::h0fe2ac8b51ec4864
                               at /rustc/cc66ad468955717ab92600c770da8c1601a4ff33/library/core/src/panicking.rs:150:5
  17:        0x102c63c14 - core::panicking::panic_str::h74f5c8d70a577e7e
                               at /rustc/cc66ad468955717ab92600c770da8c1601a4ff33/library/core/src/panicking.rs:134:5
  18:        0x102c63c14 - core::option::expect_failed::h596bc03570a96e73
                               at /rustc/cc66ad468955717ab92600c770da8c1601a4ff33/library/core/src/option.rs:1988:5
  19:        0x1012b517c - core::option::Option<T>::expect::hc8172dad6913d0c6
                               at /rustc/cc66ad468955717ab92600c770da8c1601a4ff33/library/core/src/option.rs:898:21
  20:        0x1012b517c - <std::collections::hash::map::HashMap<K,V,S> as core::ops::index::Index<&Q>>::index::hb71218c8bced2408
                               at /rustc/cc66ad468955717ab92600c770da8c1601a4ff33/library/std/src/collections/hash/map.rs:1341:23
  21:        0x1015785a8 - cargo::core::compiler::unit_dependencies::attach_std_deps::h0c66d5cad903abbd
                               at /Users/jacobgreenfield/git/cargo/src/cargo/core/compiler/unit_dependencies.rs:177:34
  22:        0x1015778d0 - cargo::core::compiler::unit_dependencies::build_unit_dependencies::h3e86a0769525f72b
                               at /Users/jacobgreenfield/git/cargo/src/cargo/core/compiler/unit_dependencies.rs:133:9
  23:        0x1012af3c0 - cargo::ops::cargo_compile::create_bcx::h0ea36e4378361218
                               at /Users/jacobgreenfield/git/cargo/src/cargo/ops/cargo_compile/mod.rs:405:26
  24:        0x1012aca4c - cargo::ops::cargo_compile::compile_ws::h6c7f983cd31a1df6
                               at /Users/jacobgreenfield/git/cargo/src/cargo/ops/cargo_compile/mod.rs:151:15
  25:        0x1012ac9a8 - cargo::ops::cargo_compile::compile_with_exec::h4bbcc2a9af266737
                               at /Users/jacobgreenfield/git/cargo/src/cargo/ops/cargo_compile/mod.rs:141:5
  26:        0x1012ac8f4 - cargo::ops::cargo_compile::compile::h0573fdf8d7df7a91
                               at /Users/jacobgreenfield/git/cargo/src/cargo/ops/cargo_compile/mod.rs:128:5
  27:        0x100d87600 - cargo::commands::check::exec::h44240dae1b35c6e9
                               at /Users/jacobgreenfield/git/cargo/src/bin/cargo/commands/check.rs:56:5
  28:        0x100d53f64 - cargo::cli::Exec::exec::h3a05a69014310f16
                               at /Users/jacobgreenfield/git/cargo/src/bin/cargo/cli.rs:446:36
  29:        0x100d4f328 - cargo::cli::main::hd3d5652893557d43
                               at /Users/jacobgreenfield/git/cargo/src/bin/cargo/cli.rs:184:5
  30:        0x100d818ac - cargo::main::hf890cf6122991998
                               at /Users/jacobgreenfield/git/cargo/src/bin/cargo/main.rs:31:9
  31:        0x100d6eecc - core::ops::function::FnOnce::call_once::h85f91cf47639f35e
                               at /rustc/cc66ad468955717ab92600c770da8c1601a4ff33/library/core/src/ops/function.rs:250:5
  32:        0x100d0bc34 - std::sys_common::backtrace::__rust_begin_short_backtrace::h58a2daf855c87043
                               at /rustc/cc66ad468955717ab92600c770da8c1601a4ff33/library/std/src/sys_common/backtrace.rs:154:18
  33:        0x100d73878 - std::rt::lang_start::{{closure}}::heef3f5f19471e044
                               at /rustc/cc66ad468955717ab92600c770da8c1601a4ff33/library/std/src/rt.rs:166:18
  34:        0x102bc0870 - core::ops::function::impls::<impl core::ops::function::FnOnce<A> for &F>::call_once::h7fff7c88c61df16f
                               at /rustc/cc66ad468955717ab92600c770da8c1601a4ff33/library/core/src/ops/function.rs:284:13
  35:        0x102bc0870 - std::panicking::try::do_call::h5c3526811781b4da
                               at /rustc/cc66ad468955717ab92600c770da8c1601a4ff33/library/std/src/panicking.rs:502:40
  36:        0x102bc0870 - std::panicking::try::h64cb573047f67390
                               at /rustc/cc66ad468955717ab92600c770da8c1601a4ff33/library/std/src/panicking.rs:466:19
  37:        0x102bc0870 - std::panic::catch_unwind::h0ee316aa6f14634c
                               at /rustc/cc66ad468955717ab92600c770da8c1601a4ff33/library/std/src/panic.rs:142:14
  38:        0x102bc0870 - std::rt::lang_start_internal::{{closure}}::hbd896cc316ba7338
                               at /rustc/cc66ad468955717ab92600c770da8c1601a4ff33/library/std/src/rt.rs:148:48
  39:        0x102bc0870 - std::panicking::try::do_call::hbae6886803fae47e
                               at /rustc/cc66ad468955717ab92600c770da8c1601a4ff33/library/std/src/panicking.rs:502:40
  40:        0x102bc0870 - std::panicking::try::hcc0fbb3995231d31
                               at /rustc/cc66ad468955717ab92600c770da8c1601a4ff33/library/std/src/panicking.rs:466:19
  41:        0x102bc0870 - std::panic::catch_unwind::hf36acbaf210582be
                               at /rustc/cc66ad468955717ab92600c770da8c1601a4ff33/library/std/src/panic.rs:142:14
  42:        0x102bc0870 - std::rt::lang_start_internal::hadaf077a6dd0140b
                               at /rustc/cc66ad468955717ab92600c770da8c1601a4ff33/library/std/src/rt.rs:148:20
  43:        0x100d73844 - std::rt::lang_start::h912fac66e698e029
                               at /rustc/cc66ad468955717ab92600c770da8c1601a4ff33/library/std/src/rt.rs:165:17
  44:        0x100d83e94 - _main

It appears to be crashing on this line (ie. std_roots does not contain unit.kind):

cargo/src/cargo/core/compiler/unit_dependencies.rs

Line 177 in 8537dff

deps.extend(std_roots[&unit.kind].iter().map(|unit| UnitDep {

I put in a logging statement and confirmed that unit.kind is Target(CompileTarget { name: "wasm32-unknown-unknown" }).

Steps

1. Set cargo-features = ["per-package-target"] and use forced-target = "wasm32-unknown-unknown"
2. Run cargo build
3. Cargo panics

Possible Solution(s)

Unknown

Notes

I can try to build an example repo if this is difficult to reproduce

Version

$ cargo version --verbose
cargo 1.75.0-nightly (794d0a825 2023-10-03)
release: 1.75.0-nightly
commit-hash: 794d0a82547f3081044c0aca7b6083733ce51344
commit-date: 2023-10-03
host: aarch64-apple-darwin
libgit2: 1.7.1 (sys:0.18.1 vendored)
libcurl: 8.1.2 (sys:0.4.66+curl-8.3.0 system ssl:(SecureTransport) LibreSSL/3.3.6)
ssl: OpenSSL 1.1.1u  30 May 2023
os: Mac OS 14.0.0 [64-bit]

I also tested using a local build of 8537dff (the backtrace comes from this version):

$ ../cargo/target/debug/cargo version --verbose
cargo 1.75.0 (8537dffa1 2023-10-17)
release: 1.75.0
commit-hash: 8537dffa1e4b74804e4af26cc4cb0c50e868df30
commit-date: 2023-10-17
host: aarch64-apple-darwin
libgit2: 1.7.1 (sys:0.18.1 vendored)
libcurl: 8.1.2 (sys:0.4.68+curl-8.4.0 system ssl:(SecureTransport) LibreSSL/3.3.6)
os: Mac OS 14.0.0 [64-bit]

[weihanglo]

Something related to #11898?

Having an example repo would be much appreciated!

[Coder-256]

Maybe, this could be a duplicate. I tried to make the code handle the missing key gracefully, but now I'm getting a different missing-key error, related to the alloc unit.

I'll try to set up a demo.

[Coder-256]

Ok here's a reproducible example repo: https://github.com/Coder-256/per-package-crash

I do think this is likely related to #11898.

[weihanglo]

Thanks for making a repro for this issue! It's great to have a even simpler example.

Since it's a duplicate, I'll close this in favor of the old one #11898.