LoopExiting happened while not processing events

[jmskov]

Description

I am running the bevy_mobile_example iOS example app from the bevy project. If I force quit the app before the window loop has begun, I get the error trace below.

I am opening an issue here since the error told me so. 😄

thread '<unnamed>' panicked at /Users/X/.cargo/registry/src/index.crates.io-6f17d22bba15001f/winit-0.30.9/src/platform_impl/ios/app_state.rs:407:18:
winit iOS bug, file an issue: `LoopExiting` happened while not processing events Launching { queued_windows: [], queued_events: [], queued_handler: EventLoopHandler { handler: "...", event_loop: ActiveEventLoop { .. } }, queued_gpu_redraws: {} }
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
thread '<unnamed>' panicked at core/src/panicking.rs:227:5:
panic in a function that cannot unwind
stack backtrace:
   0:        0x11c372124 - std::backtrace_rs::backtrace::libunwind::trace::h7e3283cd237cb9ce
                               at /rustc/df4ca44d3fbc9301ee17f30f4d474e6ae4b05252/library/std/src/../../backtrace/src/backtrace/libunwind.rs:116:5
   1:        0x11c372124 - std::backtrace_rs::backtrace::trace_unsynchronized::h1cde4aa24173ab55
                               at /rustc/df4ca44d3fbc9301ee17f30f4d474e6ae4b05252/library/std/src/../../backtrace/src/backtrace/mod.rs:66:5
   2:        0x11c372124 - std::sys::backtrace::_print_fmt::ha54514e77d2f4314
                               at /rustc/df4ca44d3fbc9301ee17f30f4d474e6ae4b05252/library/std/src/sys/backtrace.rs:66:9
   3:        0x11c372124 - <std::sys::backtrace::BacktraceLock::print::DisplayBacktrace as core::fmt::Display>::fmt::ha13ccdaf65fe22bd
                               at /rustc/df4ca44d3fbc9301ee17f30f4d474e6ae4b05252/library/std/src/sys/backtrace.rs:39:26
   4:        0x11c3b2bf0 - core::fmt::rt::Argument::fmt::hb4c992b2fb11c98c
                               at /rustc/df4ca44d3fbc9301ee17f30f4d474e6ae4b05252/library/core/src/fmt/rt.rs:177:76
   5:        0x11c3b2bf0 - core::fmt::write::h85b89aa1471a5db5
                               at /rustc/df4ca44d3fbc9301ee17f30f4d474e6ae4b05252/library/core/src/fmt/mod.rs:1190:21
   6:        0x11c367400 - std::io::Write::write_fmt::h1dfc277258c46374
                               at /rustc/df4ca44d3fbc9301ee17f30f4d474e6ae4b05252/library/std/src/io/mod.rs:1839:15
   7:        0x11c371fd8 - std::sys::backtrace::BacktraceLock::print::h8345e8f44ab6085c
                               at /rustc/df4ca44d3fbc9301ee17f30f4d474e6ae4b05252/library/std/src/sys/backtrace.rs:42:9
   8:        0x11c374374 - std::panicking::default_hook::{{closure}}::hc967705ef66cea7e
                               at /rustc/df4ca44d3fbc9301ee17f30f4d474e6ae4b05252/library/std/src/panicking.rs:268:22
   9:        0x11c3741bc - std::panicking::default_hook::he8307b0f1e065888
                               at /rustc/df4ca44d3fbc9301ee17f30f4d474e6ae4b05252/library/std/src/panicking.rs:295:9
  10:        0x11c374be8 - std::panicking::rust_panic_with_hook::h015da58d7643ba17
                               at /rustc/df4ca44d3fbc9301ee17f30f4d474e6ae4b05252/library/std/src/panicking.rs:801:13
  11:        0x11c37484c - std::panicking::begin_panic_handler::{{closure}}::h452fa54e1d1fd52d
                               at /rustc/df4ca44d3fbc9301ee17f30f4d474e6ae4b05252/library/std/src/panicking.rs:667:13
  12:        0x11c3725e8 - std::sys::backtrace::__rust_end_short_backtrace::hae28cb5295d71bb2
                               at /rustc/df4ca44d3fbc9301ee17f30f4d474e6ae4b05252/library/std/src/sys/backtrace.rs:170:18
  13:        0x11c37452c - rust_begin_unwind
                               at /rustc/df4ca44d3fbc9301ee17f30f4d474e6ae4b05252/library/std/src/panicking.rs:665:5
  14:        0x11c5100cc - core::panicking::panic_nounwind_fmt::runtime::h35fee416d364c568
                               at /rustc/df4ca44d3fbc9301ee17f30f4d474e6ae4b05252/library/core/src/panicking.rs:115:18
  15:        0x11c5100cc - core::panicking::panic_nounwind_fmt::h56d257c9a3c71c83
                               at /rustc/df4ca44d3fbc9301ee17f30f4d474e6ae4b05252/library/core/src/panicking.rs:125:5
  16:        0x11c510144 - core::panicking::panic_nounwind::hfa035f5bedbfc48c
                               at /rustc/df4ca44d3fbc9301ee17f30f4d474e6ae4b05252/library/core/src/panicking.rs:227:5
  17:        0x11c5102bc - core::panicking::panic_cannot_unwind::h3b4232326ded9828
                               at /rustc/df4ca44d3fbc9301ee17f30f4d474e6ae4b05252/library/core/src/panicking.rs:319:5
  18:        0x117061514 - winit::platform_impl::ios::app_delegate::AppDelegate::will_terminate::hc05ab3ae4bb44dde
                               at /Users/X/.cargo/registry/src/index.crates.io-6f17d22bba15001f/objc2-0.5.2/src/macros/declare_class.rs:981:25
  19:        0x185aabf20 - -[UIApplication _terminateWithStatus:]
  20:        0x1850be5c0 - -[_UISceneLifecycleMultiplexer _evalTransitionToSettings:fromSettings:forceExit:withTransitionStore:]
  21:        0x1850be2b0 - -[_UISceneLifecycleMultiplexer forceExitWithTransitionContext:scene:]
  22:        0x185aa40b4 - -[UIApplication workspaceShouldExit:withTransitionContext:]
  23:        0x1879c1a20 - ___63-[FBSWorkspaceScenesClient willTerminateWithTransitionContext:]_block_invoke_2
  24:        0x1879a1618 - -[FBSWorkspace _calloutQueue_executeCalloutFromSource:withBlock:]
  25:        0x1879c19c4 - ___63-[FBSWorkspaceScenesClient willTerminateWithTransitionContext:]_block_invoke
  26:        0x1048827b8 - __dispatch_client_callout
  27:        0x1048863bc - __dispatch_block_invoke_direct
  28:        0x1879e4b58 - ___FBSSERIALQUEUE_IS_CALLING_OUT_TO_A_BLOCK__
  29:        0x1879e4a34 - -[FBSMainRunLoopSerialQueue _targetQueue_performNextIfPossible]
  30:        0x1879e4b8c - -[FBSMainRunLoopSerialQueue _performNextFromRunLoopSource]
  31:        0x18041b324 - ___CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE0_PERFORM_FUNCTION__
  32:        0x18041b26c - ___CFRunLoopDoSource0
  33:        0x18041a9d0 - ___CFRunLoopDoSources0
  34:        0x1804150b0 - ___CFRunLoopRun
  35:        0x180414960 - _CFRunLoopRunSpecific
  36:        0x190183b10 - _GSEventRunModal
  37:        0x185aa2b40 - -[UIApplication _run]
  38:        0x185aa6d38 - _UIApplicationMain
  39:        0x116f35930 - winit::platform_impl::ios::event_loop::EventLoop<T>::run::h831ba9fb11310b53
                               at /Users/X/.cargo/registry/src/index.crates.io-6f17d22bba15001f/winit-0.30.9/src/platform_impl/ios/event_loop.rs:205:13
  40:        0x116f1a990 - winit::event_loop::EventLoop<T>::run_app::hcbfae86fe0683d85
                               at /Users/X/.cargo/registry/src/index.crates.io-6f17d22bba15001f/winit-0.30.9/src/event_loop.rs:265:9
  41:        0x116f1b7dc - bevy_winit::state::winit_runner::hd0154508d8391193
                               at /Users/X/projects/bevy/crates/bevy_winit/src/state.rs:893:31
  42:        0x116f12ea8 - core::ops::function::FnOnce::call_once::hae34978040abc55e
                               at /Users/X/.rustup/toolchains/nightly-aarch64-apple-darwin/lib/rustlib/src/rust/library/core/src/ops/function.rs:250:5
  43:        0x116f12ca8 - core::ops::function::FnOnce::call_once{{vtable.shim}}::hbd95b5b70e32fff5
                               at /Users/X/.rustup/toolchains/nightly-aarch64-apple-darwin/lib/rustlib/src/rust/library/core/src/ops/function.rs:250:5
  44:        0x11bdc5788 - <alloc::boxed::Box<F,A> as core::ops::function::FnOnce<Args>>::call_once::hb62836e0901b9cd2
                               at /Users/X/.rustup/toolchains/nightly-aarch64-apple-darwin/lib/rustlib/src/rust/library/alloc/src/boxed.rs:2454:9
  45:        0x11bdd70a0 - bevy_app::app::App::run::h1b1fcf247e2c4182
                               at /Users/X/projects/bevy/crates/bevy_app/src/app.rs:187:9
  46:        0x116ec1c40 - bevy_mobile_example::main::h146297dec8ba111b
                               at /Users/X/projects/bevy/examples/mobile/src/lib.rs:16:5
  47:        0x116ec1818 - main_rs
                               at /Users/X/projects/bevy/examples/mobile/src/lib.rs:13:1
  48:        0x116ebb470 - main
                               at /Users/X/projects/bevy/examples/mobile/ios-src/main.m:4:5
thread caused non-unwinding panic. aborting.
Type: stdio

Device and iOS version

iPhone 16 simulators 18.X
XCode 16.2
MacOS 15.3

Winit version

0.30.9