called `Option::unwrap()` on a `None` value (Event::new_uninitialized)

[mnordine]

called Option::unwrap() on a None value

URL:

https://features.wearemel.com/ill-retire-when-i-m-dead-why-continuing-to-work-is-good-for-a-man-s-health-c3053052d136?gi=47d56ab34b96

Backtrace:

frame #0  - 0x000000011086c6ce - backtrace::backtrace::trace::hccde8df28b4db2a2
frame #1  - 0x000000011086c651 - backtrace::capture::Backtrace::new::h42f95930bb8c5ee8
frame #2  - 0x000000010fb3d086 - _<F as alloc..boxed..FnBox<A>>::call_box::h6059122298f825d8
frame #3  - 0x00000001107e0947 - util::panicking::initiate_panic_hook::_$u7b$$u7b$closure$u7d$$u7d$::_$u7b$$u7b$closure$u7d$$u7d$::h2c0e77c593c00c08
frame #4  - 0x0000000110a54844 - std::panicking::rust_panic_with_hook::h983af77c1a2e581b
frame #5  - 0x0000000110a6d786 - std::panicking::begin_panic::he426e15a3766089a
frame #6  - 0x0000000110a55e88 - std::panicking::begin_panic_fmt::hdddb415186c241e7
frame #7  - 0x0000000110a6d3df - rust_begin_unwind
frame #8  - 0x0000000110a94260 - core::panicking::panic_fmt::hf4e16cb7f0d41a25
frame #9  - 0x0000000110a9455c - core::panicking::panic::h907815f47e914305
frame #10 - 0x000000010f938895 - script::dom::event::Event::new_uninitialized::he3ccb94702598d61
frame #11 - 0x000000010f940aa7 - script::dom::event::Event::new::h115b505636eaa661
frame #12 - 0x000000010fa0d312 - script::dom::htmlscriptelement::HTMLScriptElement::dispatch_event::hfd4452ea712f8efd
frame #13 - 0x000000010f927241 - script::dom::htmlscriptelement::HTMLScriptElement::execute::hd6eb39d1b33b28da
frame #14 - 0x000000010f37580c - script::dom::document::Document::finish_load::h1ce7e49c25d85fc2
frame #15 - 0x000000010fa069b8 - _<script..dom..htmlscriptelement..ScriptContext as net_traits..AsyncResponseListener>::response_complete::h536287b80705375c
frame #16 - 0x000000010fa0c5c5 - _<script..network_listener..ListenerRunnable<A, Listener> as script..script_thread..Runnable>::handler::h213e3c65c1a0f2f0
frame #17 - 0x000000010fb4895c - script::script_thread::ScriptThread::handle_msg_from_script::hd1f5e7b2423a8c64
frame #18 - 0x000000010fba4a71 - script::script_thread::ScriptThread::handle_msgs::_$u7b$$u7b$closure$u7d$$u7d$::hc67d8b381c013b79
frame #19 - 0x000000010fb8a73f - script::script_thread::ScriptThread::handle_msgs::h236c5be60a207bea
frame #20 - 0x000000010fb3b907 - std::panicking::try::call::h645a328f039d97c6
frame #21 - 0x0000000110a7046b - __rust_try
frame #22 - 0x0000000110a70405 - __rust_maybe_catch_panic
frame #23 - 0x000000010fb3cab4 - _<F as alloc..boxed..FnBox<A>>::call_box::h3db95636eb747818
frame #24 - 0x0000000110a6bee8 - std::sys::thread::Thread::new::thread_start::h9c883b6d445ece46
frame #25 - 0x00007fff94f6f99c - _pthread_body
frame #26 - 0x00007fff94f6f919 - _pthread_start

[jdm]

I hit #12081 while trying to reproduce this.

[jdm]

We have two instances of layout threads being shut down (removing iframes, perhaps?), and then a network response completing and a script attempting to execute in a script thread that was previously shut down.

[cbrewster]

More useful backtrace:

frame #0  - 0x0000000105b4a710 - backtrace::backtrace::trace::hccde8df28b4db2a2
frame #1  - 0x0000000105b4a5ba - backtrace::capture::Backtrace::new::h42f95930bb8c5ee8
frame #2  - 0x00000001037d5095 - util::thread::spawn_named_with_send_on_panic::_$u7b$$u7b$closure$u7d$$u7d$::_$u7b$$u7b$closure$u7d$$u7d$::h8e08bac0ce5835b1
frame #3  - 0x00000001037d5690 - extern $u22$rust.call$u22$$u20$fn$LP$$u5b$closure$SP$DefId$u20$$u7b$$u20$krate.$u20$50$C$$u20$node.$u20$DefIndex$LP$2264$RP$$u20$$u7d$$u20$0.ipc_channel..ipc..IpcSender$LT$$LP$core..option..Option$LT$msg..constellation_msg..PipelineId$GT$$C$$u20$std..string..String$C$$u20$std..string..String$RP$$GT$$C$$u20$1.core..option..Option$LT$msg..constellation_msg..PipelineId$GT$$u5d$$C$$u20$$LP$$RF$core..any..Any$C$$RP$$RP$::once_shim.216715::h3190046b5fea3554
frame #4  - 0x00000001037d563c - _<F as alloc..boxed..FnBox<A>>::call_box::hebb3b95724d7c6a0
frame #5  - 0x0000000105accc8f - util::panicking::initiate_panic_hook::_$u7b$$u7b$closure$u7d$$u7d$::_$u7b$$u7b$closure$u7d$$u7d$::_$u7b$$u7b$closure$u7d$$u7d$::hddf831bcfa835e79
frame #6  - 0x0000000105acc893 - _<std..thread..local..LocalKey<T>>::with::h49e68c592f601e39
frame #7  - 0x0000000105acc6e6 - util::panicking::initiate_panic_hook::_$u7b$$u7b$closure$u7d$$u7d$::_$u7b$$u7b$closure$u7d$$u7d$::h0fcde37d4d058867
frame #8  - 0x0000000105c63f14 - std::panicking::rust_panic_with_hook::h983af77c1a2e581b
frame #9  - 0x0000000105c7cf56 - std::panicking::begin_panic::he426e15a3766089a
frame #10 - 0x0000000105c65558 - std::panicking::begin_panic_fmt::hdddb415186c241e7
frame #11 - 0x0000000105c7cbaf - rust_begin_unwind
frame #12 - 0x0000000105ca3a30 - core::panicking::panic_fmt::hf4e16cb7f0d41a25
frame #13 - 0x0000000105ca3d2c - core::panicking::panic::h907815f47e914305
frame #14 - 0x00000001036da502 - _<core..option..Option<T>>::unwrap::ha9f039774ae8a5ee
frame #15 - 0x0000000102385b70 - script::dom::window::Window::get_cx::h924ad22f09592138
frame #16 - 0x0000000102328c9c - script::dom::bindings::global::GlobalRef::get_cx::h02f273e0685db6d7
frame #17 - 0x0000000103424c40 - script::dom::bindings::reflector::reflect_dom_object::h08182bdb4575a78f
frame #18 - 0x00000001033a3770 - script::dom::event::Event::new_uninitialized::h1c51fe88f444d2d8
frame #19 - 0x00000001033b67e7 - script::dom::event::Event::new::h8b5a22a0acccc5a2
frame #20 - 0x000000010352c68f - script::dom::htmlscriptelement::HTMLScriptElement::dispatch_event::h0c705ca3c8337fe0
frame #21 - 0x000000010352c1fc - script::dom::htmlscriptelement::HTMLScriptElement::dispatch_before_script_execute_event::hb105e55159c7345f
frame #22 - 0x00000001033763a5 - script::dom::htmlscriptelement::HTMLScriptElement::execute::h776378cb1575064b
frame #23 - 0x000000010337274a - script::dom::document::Document::maybe_execute_parser_blocking_script::hf7f77dbf7fa6dd12
frame #24 - 0x0000000102353ccb - script::dom::document::Document::finish_load::h13371ea3d4ab55e4
frame #25 - 0x0000000103523c84 - _<script..dom..htmlscriptelement..ScriptContext as net_traits..AsyncResponseListener>::response_complete::h8b6124ed78c481e9
frame #26 - 0x000000010352b5ad - _<net_traits..ResponseAction as net_traits..Action<T>>::process::hd6faeba416421ac2
frame #27 - 0x000000010352aada - _<script..network_listener..ListenerRunnable<A, Listener> as script..script_thread..Runnable>::handler::hf2abd4b95d493887
frame #28 - 0x00000001037ec6ac - script::script_thread::ScriptThread::handle_msg_from_script::h6a6b4ae37d32650d
frame #29 - 0x0000000103883988 - script::script_thread::ScriptThread::handle_msgs::_$u7b$$u7b$closure$u7d$$u7d$::hdfba591677ee0854
frame #30 - 0x00000001038834f5 - script::script_thread::ScriptThread::profile_event::h180ff2036b8c2783
frame #31 - 0x000000010385142d - script::script_thread::ScriptThread::handle_msgs::h45a47f1f1786f911
frame #32 - 0x00000001037e9dfc - script::script_thread::ScriptThread::start::hf0f02e16b9da3912
frame #33 - 0x00000001037e9dab - _<script..script_thread..ScriptThread as script_traits..ScriptThreadFactory>::create::_$u7b$$u7b$closure$u7d$$u7d$::_$u7b$$u7b$closure$u7d$$u7d$::h60e2514d7c15aeaf
frame #34 - 0x00000001037e9b01 - profile_traits::mem::ProfilerChan::run_with_memory_reporting::h90164fdc02bc9ddf
frame #35 - 0x00000001037d5db6 - _<script..script_thread..ScriptThread as script_traits..ScriptThreadFactory>::create::_$u7b$$u7b$closure$u7d$$u7d$::hc2f6bfd107201055
frame #36 - 0x00000001037d444e - util::thread::spawn_named_with_send_on_panic::_$u7b$$u7b$closure$u7d$$u7d$::h44d46100d4f5f190
frame #37 - 0x00000001037d4207 - _<std..panic..AssertUnwindSafe<F> as core..ops..FnOnce<()>>::call_once::h4974dfb1034d8cd6
frame #38 - 0x00000001037d415b - std::panicking::try::_$u7b$$u7b$closure$u7d$$u7d$::_$u7b$$u7b$closure$u7d$$u7d$::h4326e3cb5bf9d187
frame #39 - 0x00000001037d4a14 - std::panicking::try::call::h78061d8f9ce27ca7
frame #40 - 0x0000000105c7fc3b - __rust_try
frame #41 - 0x0000000105c7fbd5 - __rust_maybe_catch_panic
frame #42 - 0x00000001037d40ad - std::panicking::try::_$u7b$$u7b$closure$u7d$$u7d$::he258e52e28311769
frame #43 - 0x00000001037d3fff - _<std..thread..local..LocalKey<T>>::with::h6a07862be6a45706
frame #44 - 0x00000001037d3e2f - std::panicking::try::h90b38a4a00a80b43
frame #45 - 0x00000001037d3d0e - std::panic::catch_unwind::h066dae249590ffb5
frame #46 - 0x00000001037d3b6c - std::thread::Builder::spawn::_$u7b$$u7b$closure$u7d$$u7d$::hb658a84aa2bff2ef
frame #47 - 0x00000001037d4c17 - _<F as alloc..boxed..FnBox<A>>::call_box::h2ec158fb92e41aca
frame #48 - 0x0000000105c7b6b8 - std::sys::thread::Thread::new::thread_start::h9c883b6d445ece46
frame #49 - 0x00007fff9b96f99c - _pthread_body
frame #50 - 0x00007fff9b96f919 - _pthread_start

[cbrewster]

@jdm in this scenario is there anyway to check if the script thread has been shut down before attempting to execute a script?

[jdm]

There's a mechanism for marking runnables as revocable based on the ignore_further_async_events member in Window (see the use of window.get_runnable_wrapper and wrap_runnable in htmlimageelement.rs). This probably requires making all the runnables created by NetworkListener revocable.

[jdm]

It's possible to write code to not execute script by adding an API to GlobalRef and calling it from evaluate_script_on_global_with_result; it's not really clear to me whether we would end up playing whack-a-mole with non-script related things if we added that restriction instead of the plan in the previous comment.

[cbrewster]

Fixed in #12277