When I redirect --check output to a pager, I get a compiler panic when I exit the pager (e.g., using the 'q' command in either more or less). If I use more rather than less, and page through the entire output until the pager exits naturally, I get no panic.

My example is asking for no color, but the panic occurs without that.

I'm seeing this in gnome-terminal on a vanilla Fedora 39 box.

Panic output follows

sindisil@barad-dur:~/Projects/lned$ cargo fmt --check -- --color never | less thread 'main' panicked at library/std/src/io/stdio.rs:1030:9: failed printing to stdout: Broken pipe (os error 32) stack backtrace: 0: 0x7f01e833ad16 - std::backtrace_rs::backtrace::libunwind::trace::h10897894958cd49e at /rustc/f2043422f7b161a2fc1a00589a8c4956db963450/library/std/src/../../backtrace/src/backtrace/libunwind.rs:104:5 1: 0x7f01e833ad16 - std::backtrace_rs::backtrace::trace_unsynchronized::h44034e8a12f002c2 at /rustc/f2043422f7b161a2fc1a00589a8c4956db963450/library/std/src/../../backtrace/src/backtrace/mod.rs:66:5 2: 0x7f01e833ad16 - std::sys_common::backtrace::_print_fmt::hf3aee16d36b99950 at /rustc/f2043422f7b161a2fc1a00589a8c4956db963450/library/std/src/sys_common/backtrace.rs:68:5 3: 0x7f01e833ad16 - ::fmt::h4cc0196933b2d33b at /rustc/f2043422f7b161a2fc1a00589a8c4956db963450/library/std/src/sys_common/backtrace.rs:44:22 4: 0x7f01e838d770 - core::fmt::rt::Argument::fmt::hb7b6f634f32478df at /rustc/f2043422f7b161a2fc1a00589a8c4956db963450/library/core/src/fmt/rt.rs:142:9 5: 0x7f01e838d770 - core::fmt::write::h71a912a0876ff953 at /rustc/f2043422f7b161a2fc1a00589a8c4956db963450/library/core/src/fmt/mod.rs:1120:17 6: 0x7f01e832e61f - std::io::Write::write_fmt::hd0e967738786a93f at /rustc/f2043422f7b161a2fc1a00589a8c4956db963450/library/std/src/io/mod.rs:1846:15 7: 0x7f01e833aaf4 - std::sys_common::backtrace::_print::hb4bc24c6a39e5a17 at /rustc/f2043422f7b161a2fc1a00589a8c4956db963450/library/std/src/sys_common/backtrace.rs:47:5 8: 0x7f01e833aaf4 - std::sys_common::backtrace::print::h33f3fe08a229dca2 at /rustc/f2043422f7b161a2fc1a00589a8c4956db963450/library/std/src/sys_common/backtrace.rs:34:9 9: 0x7f01e833d887 - std::panicking::default_hook::{{closure}}::h862a191a664c6dc5 10: 0x7f01e833d5e9 - std::panicking::default_hook::hc92b5312272280af at /rustc/f2043422f7b161a2fc1a00589a8c4956db963450/library/std/src/panicking.rs:292:9 11: 0x7f01e51aa4fc - std[8b2722c11524b2b8]::panicking::update_hook::<alloc[779e24b66daba78d]::boxed::Box<rustc_driver_impl[ea9433488708d8a7]::install_ice_hook::{closure#0}>>::{closure#0} 12: 0x7f01e833dfd6 - <alloc::boxed::Box<F,A> as core::ops::function::Fn>::call::hc4fc7af48e2c3887 at /rustc/f2043422f7b161a2fc1a00589a8c4956db963450/library/alloc/src/boxed.rs:2029:9 13: 0x7f01e833dfd6 - std::panicking::rust_panic_with_hook::had7afe3bd886e7d6 at /rustc/f2043422f7b161a2fc1a00589a8c4956db963450/library/std/src/panicking.rs:785:13 14: 0x7f01e833dd22 - std::panicking::begin_panic_handler::{{closure}}::had698405d69ce54e at /rustc/f2043422f7b161a2fc1a00589a8c4956db963450/library/std/src/panicking.rs:659:13 15: 0x7f01e833b216 - std::sys_common::backtrace::rust_end_short_backtrace::hb2ede901b4663678 at /rustc/f2043422f7b161a2fc1a00589a8c4956db963450/library/std/src/sys_common/backtrace.rs:171:18 16: 0x7f01e833da74 - rust_begin_unwind at /rustc/f2043422f7b161a2fc1a00589a8c4956db963450/library/std/src/panicking.rs:647:5 17: 0x7f01e8389e75 - core::panicking::panic_fmt::hab1e6de73e71f54d at /rustc/f2043422f7b161a2fc1a00589a8c4956db963450/library/core/src/panicking.rs:72:14 18: 0x7f01e832cd48 - std::io::stdio::print_to::h1c464b61f88b65fe at /rustc/f2043422f7b161a2fc1a00589a8c4956db963450/library/std/src/io/stdio.rs:1030:9 19: 0x7f01e832cd48 - std::io::stdio::_print::h83f167e61aa593de at /rustc/f2043422f7b161a2fc1a00589a8c4956db963450/library/std/src/io/stdio.rs:1106:5 20: 0x55e28be0b7c8 - <rustfmt_nightly[194ae070ff7584cb]::rustfmt_diff::OutputWriter>::writeln 21: 0x55e28bd9d785 - <rustfmt_nightly[194ae070ff7584cb]::emitter::diff::DiffEmitter as rustfmt_nightly[194ae070ff7584cb]::emitter::Emitter>::emit_formatted_file 22: 0x55e28bc983f9 - <rustfmt_nightly[194ae070ff7584cb]::Session<std[8b2722c11524b2b8]::io::stdio::Stdout>>::format_input_inner::{closure#0} 23: 0x55e28bcac737 - rustfmt[9bfbb3a37f21832]::format_and_emit_report::<std[8b2722c11524b2b8]::io::stdio::Stdout> 24: 0x55e28bcab01e - rustfmt[9bfbb3a37f21832]::execute 25: 0x55e28bca6826 - rustfmt[9bfbb3a37f21832]::main 26: 0x55e28bc91b03 - std[8b2722c11524b2b8]::sys_common::backtrace::rust_begin_short_backtrace::<fn(), ()> 27: 0x55e28bc93d19 - std[8b2722c11524b2b8]::rt::lang_start::<()>::{closure#0} 28: 0x7f01e831e911 - core::ops::function::impls::<impl core::ops::function::FnOnce for &F>::call_once::h670d35ebe949a3cf at /rustc/f2043422f7b161a2fc1a00589a8c4956db963450/library/core/src/ops/function.rs:284:13 29: 0x7f01e831e911 - std::panicking::try::do_call::h41db3b277bd57798 at /rustc/f2043422f7b161a2fc1a00589a8c4956db963450/library/std/src/panicking.rs:554:40 30: 0x7f01e831e911 - std::panicking::try::hb70956d01a381fdd at /rustc/f2043422f7b161a2fc1a00589a8c4956db963450/library/std/src/panicking.rs:518:19 31: 0x7f01e831e911 - std::panic::catch_unwind::hd1eaf75e3aeaaef8 at /rustc/f2043422f7b161a2fc1a00589a8c4956db963450/library/std/src/panic.rs:142:14 32: 0x7f01e831e911 - std::rt::lang_start_internal::{{closure}}::h9671d32e4cdfebd5 at /rustc/f2043422f7b161a2fc1a00589a8c4956db963450/library/std/src/rt.rs:148:48 33: 0x7f01e831e911 - std::panicking::try::do_call::ha046eb9e51bbf147 at /rustc/f2043422f7b161a2fc1a00589a8c4956db963450/library/std/src/panicking.rs:554:40 34: 0x7f01e831e911 - std::panicking::try::hda56b5674ac03b0a at /rustc/f2043422f7b161a2fc1a00589a8c4956db963450/library/std/src/panicking.rs:518:19 35: 0x7f01e831e911 - std::panic::catch_unwind::h431342979dbf3d57 at /rustc/f2043422f7b161a2fc1a00589a8c4956db963450/library/std/src/panic.rs:142:14 36: 0x7f01e831e911 - std::rt::lang_start_internal::he4de2f11a3fa977e at /rustc/f2043422f7b161a2fc1a00589a8c4956db963450/library/std/src/rt.rs:148:20 37: 0x55e28bcad965 - main 38: 0x7f01e244614a - __libc_start_call_main 39: 0x7f01e244620b - __libc_start_main_impl 40: 0x55e28bc80679 - 41: 0x0 -

error: the compiler unexpectedly panicked. this is a bug.

note: we would appreciate a bug report: https://github.com/rust-lang/rustfmt/issues/new?labels=bug

note: rustc 1.77.0-beta.5 (f2043422f 2024-02-17) running on x86_64-unknown-linux-gnu

query stack during panic: end of query stack sindisil@barad-dur:~/Projects/lned$

rust-lang / rustfmt

Redirecting output with --check to pager causes compiler panic on early exit #6089

Panic output follows