called Result::unwrap() on an Err value: Error { repr: Custom(Custom { kind: Other, error: StringError("MPSC send failed") }) }

[timtadh]

called Result::unwrap() on an Err value: Error { repr: Custom(Custom { kind: Other, error: StringError("MPSC send failed") }) }

URL:

http://acid3.acidtests.org/

Backtrace:

frame #0  - 0x00007fc2e7f4ea0d - backtrace::backtrace::trace::hccde8df28b4db2a2
frame #1  - 0x00007fc2e7f4e995 - backtrace::capture::Backtrace::new::h42f95930bb8c5ee8
frame #2  - 0x00007fc2e66c9487 - _<F as alloc..boxed..FnBox<A>>::call_box::heccbd09ce30bd77e
frame #3  - 0x00007fc2e7f45818 - util::panicking::initiate_panic_hook::_$u7b$$u7b$closure$u7d$$u7d$::_$u7b$$u7b$closure$u7d$$u7d$::hc61828c8a9f6df01
frame #4  - 0x00007fc2e804cdcc - std::panicking::rust_panic_with_hook::h983af77c1a2e581b
frame #5  - 0x00007fc2e80673e1 - std::panicking::begin_panic::he426e15a3766089a
frame #6  - 0x00007fc2e804e63a - std::panicking::begin_panic_fmt::hdddb415186c241e7
frame #7  - 0x00007fc2e806737e - rust_begin_unwind
frame #8  - 0x00007fc2e809d97f - core::panicking::panic_fmt::hf4e16cb7f0d41a25
frame #9  - 0x00007fc2e66bb115 - core::result::unwrap_failed::hf40cb93f6f31ec3d
frame #10 - 0x00007fc2e673281f - layout_thread::LayoutThread::exit_now::hf10c51164062d452
frame #11 - 0x00007fc2e6715db9 - layout_thread::LayoutThread::handle_request_helper::h8d81064be05c6b00
frame #12 - 0x00007fc2e67033f6 - layout_thread::LayoutThread::handle_request::h9b944f2f41c319e5
frame #13 - 0x00007fc2e66c71fa - std::panicking::try::call::h1a5934e90174a4d0
frame #14 - 0x00007fc2e80715db - __rust_try
frame #15 - 0x00007fc2e807157e - __rust_maybe_catch_panic
frame #16 - 0x00007fc2e66c862d - _<F as alloc..boxed..FnBox<A>>::call_box::h2c8a06862bfda3d9
frame #17 - 0x00007fc2e80655a4 - std::sys::thread::Thread::new::thread_start::h9c883b6d445ece46
frame #18 - 0x00007fc2e3c99183 - start_thread
frame #19 - 0x00007fc2e37b037c - clone
frame #20 - 0x0000000000000000 - <unknown>

I looked a few of the other panics with this same issue title. This one looks a bit different as it isn't happening inside of layout_thread::LayoutThread::exit_now. So I do not believe #12030 applies.

[cbrewster]

Thank you for the report! This will be fixed by #12030.

frame #10 - 0x00007fc2e673281f - layout_thread::LayoutThread::exit_now::hf10c51164062d452
This used to call unwrap, but is now silently ignored.