Panic when closing a worker immediately after postMessage

[carlbennettnz]

// main.js
const worker = new Worker('./worker.js', { type: 'module' });
worker.onmessage = ({ data }) => console.log(data);

// worker.js
self.postMessage('message');
self.close();

$ RUST_BACKTRACE=1 deno run main.js
thread 'deno-worker-0' panicked at 'Failed to post message to host: TrySendError { kind: Disconnected }', cli/ops/worker_host.rs:142:7
stack backtrace:
message
   0: <std::sys_common::backtrace::_print::DisplayBacktrace as core::fmt::Display>::fmt
   1: core::fmt::write
   2: std::io::Write::write_fmt
   3: std::panicking::default_hook::{{closure}}
   4: std::panicking::default_hook
   5: std::panicking::rust_panic_with_hook
   6: rust_begin_unwind
   7: core::panicking::panic_fmt
   8: core::result::unwrap_failed
note: Some details are omitted, run with `RUST_BACKTRACE=full` for a verbose backtrace.
thread 'main' panicked at 'Worker thread panicked: Any', cli/ops/worker_host.rs:329:11
stack backtrace:
   0: <std::sys_common::backtrace::_print::DisplayBacktrace as core::fmt::Display>::fmt
   1: core::fmt::write
   2: std::io::Write::write_fmt
   3: std::panicking::default_hook::{{closure}}
   4: std::panicking::default_hook
   5: std::panicking::rust_panic_with_hook
   6: rust_begin_unwind
   7: core::panicking::panic_fmt
   8: core::result::unwrap_failed
   9: <std::future::GenFuture<T> as core::future::future::Future>::poll
  10: futures_util::future::future::chain::Chain<Fut1,Fut2,Data>::poll
  11: <futures_util::future::future::map::Map<Fut,F> as core::future::future::Future>::poll
  12: <futures_util::future::future::map::Map<Fut,F> as core::future::future::Future>::poll
  13: <&mut S as futures_core::stream::Stream>::poll_next
  14: futures_util::stream::stream::StreamExt::poll_next_unpin
  15: <deno_core::isolate::CoreIsolate as core::future::future::Future>::poll
  16: <deno_core::es_isolate::EsIsolate as core::future::future::Future>::poll
  17: <std::future::GenFuture<T> as core::future::future::Future>::poll
  18: std::thread::local::LocalKey<T>::with
  19: tokio::macros::scoped_tls::ScopedKey<T>::set
  20: tokio::runtime::basic_scheduler::BasicScheduler<P>::block_on
  21: tokio::runtime::context::enter
  22: deno::tokio_util::run_basic
  23: deno::main
  24: std::rt::lang_start::{{closure}}
  25: std::panicking::try::do_call
  26: __rust_maybe_catch_panic
  27: std::rt::lang_start_internal
  28: main
note: Some details are omitted, run with `RUST_BACKTRACE=full` for a verbose backtrace.

This works in the browser. Postponing the close until the next tick makes it work in Deno.

self.postMessage('message');
setTimeout(() => self.close(), 0);

[sertsedat]

awaiting somehow works

// worker.js
await self.postMessage('message');
self.close();

[bartlomieju]

you have to use await

// worker.js
await self.postMessage('message');
self.close();

postMessage is a synchronous function. This is a bug in implementation

[brandonkal]

This doesn't appear to be related to postMessage
This also fails

// runnter.ts
new Worker(new URL('worker-test.ts', import.meta.url).href, { type: 'module' })

// worker-test.ts
console.log('hello from worker')
self.close()

brandon@dev:~/worker$ RUST_BACKTRACE=1 deno run -A runner.ts
hello from worker
thread 'deno-worker-0' panicked at 'Failed to post message to host: TrySendError { kind: Disconnected }', cli/ops/worker_host.rs:144:7
stack backtrace:
   0: backtrace::backtrace::libunwind::trace
             at /cargo/registry/src/github.com-1ecc6299db9ec823/backtrace-0.3.46/src/backtrace/libunwind.rs:86
   1: backtrace::backtrace::trace_unsynchronized
             at /cargo/registry/src/github.com-1ecc6299db9ec823/backtrace-0.3.46/src/backtrace/mod.rs:66
   2: std::sys_common::backtrace::_print_fmt
             at src/libstd/sys_common/backtrace.rs:78
   3: <std::sys_common::backtrace::_print::DisplayBacktrace as core::fmt::Display>::fmt
             at src/libstd/sys_common/backtrace.rs:59
   4: core::fmt::write
             at src/libcore/fmt/mod.rs:1069
   5: std::io::Write::write_fmt
             at src/libstd/io/mod.rs:1504
   6: std::sys_common::backtrace::_print
             at src/libstd/sys_common/backtrace.rs:62
   7: std::sys_common::backtrace::print
             at src/libstd/sys_common/backtrace.rs:49
   8: std::panicking::default_hook::{{closure}}
             at src/libstd/panicking.rs:198
   9: std::panicking::default_hook
             at src/libstd/panicking.rs:218
  10: std::panicking::rust_panic_with_hook
             at src/libstd/panicking.rs:511
  11: rust_begin_unwind
             at src/libstd/panicking.rs:419
  12: core::panicking::panic_fmt
             at src/libcore/panicking.rs:111
  13: core::option::expect_none_failed
             at src/libcore/option.rs:1268
note: Some details are omitted, run with `RUST_BACKTRACE=full` for a verbose backtrace.
thread 'main' panicked at 'Worker thread panicked: Any', cli/ops/worker_host.rs:332:11
stack backtrace:
   0: backtrace::backtrace::libunwind::trace
             at /cargo/registry/src/github.com-1ecc6299db9ec823/backtrace-0.3.46/src/backtrace/libunwind.rs:86
   1: backtrace::backtrace::trace_unsynchronized
             at /cargo/registry/src/github.com-1ecc6299db9ec823/backtrace-0.3.46/src/backtrace/mod.rs:66
   2: std::sys_common::backtrace::_print_fmt
             at src/libstd/sys_common/backtrace.rs:78
   3: <std::sys_common::backtrace::_print::DisplayBacktrace as core::fmt::Display>::fmt
             at src/libstd/sys_common/backtrace.rs:59
   4: core::fmt::write
             at src/libcore/fmt/mod.rs:1069
   5: std::io::Write::write_fmt
             at src/libstd/io/mod.rs:1504
   6: std::sys_common::backtrace::_print
             at src/libstd/sys_common/backtrace.rs:62
   7: std::sys_common::backtrace::print
             at src/libstd/sys_common/backtrace.rs:49
   8: std::panicking::default_hook::{{closure}}
             at src/libstd/panicking.rs:198
   9: std::panicking::default_hook
             at src/libstd/panicking.rs:218
  10: std::panicking::rust_panic_with_hook
             at src/libstd/panicking.rs:511
  11: rust_begin_unwind
             at src/libstd/panicking.rs:419
  12: core::panicking::panic_fmt
             at src/libcore/panicking.rs:111
  13: core::option::expect_none_failed
             at src/libcore/option.rs:1268
  14: <core::future::from_generator::GenFuture<T> as core::future::future::Future>::poll
  15: <futures_util::future::future::map::Map<Fut,F> as core::future::future::Future>::poll
  16: <futures_util::future::future::Then<Fut1,Fut2,F> as core::future::future::Future>::poll
  17: <futures_util::future::future::map::Map<Fut,F> as core::future::future::Future>::poll
  18: <futures_util::future::future::map::Map<Fut,F> as core::future::future::Future>::poll
  19: <futures_util::future::future::Map<Fut,F> as core::future::future::Future>::poll
  20: futures_util::stream::stream::StreamExt::poll_next_unpin
  21: <deno_core::core_isolate::CoreIsolate as core::future::future::Future>::poll
  22: <deno_core::es_isolate::EsIsolate as core::future::future::Future>::poll
  23: <core::future::from_generator::GenFuture<T> as core::future::future::Future>::poll
  24: std::thread::local::LocalKey<T>::with
  25: tokio::macros::scoped_tls::ScopedKey<T>::set
  26: tokio::runtime::context::enter
  27: deno::tokio_util::run_basic
  28: deno::main
  29: std::rt::lang_start::{{closure}}
  30: std::rt::lang_start_internal::{{closure}}
             at src/libstd/rt.rs:52
  31: std::panicking::try::do_call
             at src/libstd/panicking.rs:331
  32: std::panicking::try
             at src/libstd/panicking.rs:274
  33: std::panic::catch_unwind
             at src/libstd/panic.rs:394
  34: std::rt::lang_start_internal
             at src/libstd/rt.rs:51
  35: main
  36: __libc_start_main
  37: _start

[jcc10]

I just wanted to add that this may relate to #7620. I didn't check the panic log for the other one but I felt it best to just cross reference them for future people.