Error when navigating to github.com/features

[atouchet]

Steps to reproduce:

1. Load https://github.com/
2. Click on Features from the GitHub homepage to load https://github.com/features
3. Servo runs into an error and says "Could not load the requested page: Unexpected scheme". This error does not occur if attempting to load https://github.com/features directly

I believe this is a recent regression as I did not run into this behaviour previously.

Tested in Windows 10 with Browser.html.

[nox]

It apparently got worse, on navigating to the features page I now hit a panic:

called `Option::unwrap()` on a `None` value (thread LayoutThread PipelineId { namespace_id: PipelineNamespaceId(0), index: PipelineIndex(NonZero(3)) }, at src/libcore/option.rs:335)
stack backtrace:
   0:        0x10492fb6e - backtrace::backtrace::trace::hd52e5d2b480cf880
   1:        0x104930619 - backtrace::capture::Backtrace::new::h39b4a889ca7dd05a
   2:        0x10439c9a9 - servo::main::_$u7b$$u7b$closure$u7d$$u7d$::h19a57ce8f7a2f840
   3:        0x106ee8bf1 - std::panicking::rust_panic_with_hook::h5684107b64cf4fa5
   4:        0x106ee8a94 - std::panicking::begin_panic::h8e0be770f5663898
   5:        0x106ee8962 - std::panicking::begin_panic_fmt::h209631a6f4346ec1
   6:        0x106ee88ca - rust_begin_unwind
   7:        0x106f22533 - core::panicking::panic_fmt::h50330b144282cfe9
   8:        0x106f22436 - core::panicking::panic::h040ece7cff8cfe53
   9:        0x104ca49b5 - profile_traits::time::profile::h8ad16d0702161a28
  10:        0x104c894d5 - layout_thread::LayoutThread::perform_post_style_recalc_layout_passes::h40febb42462e0ff2
  11:        0x104c88be6 - layout_thread::LayoutThread::tick_all_animations::hdc3c19db19e429aa
  12:        0x104c81e74 - layout_thread::LayoutThread::handle_request_helper::he21c547c66a1f140
  13:        0x104c80851 - layout_thread::LayoutThread::start::h9c46f5087ce0768f
  14:        0x104ca1579 - profile_traits::mem::ProfilerChan::run_with_memory_reporting::h4809dee70600c497
  15:        0x104d2282a - std::sys_common::backtrace::__rust_begin_short_backtrace::h3d6a122d854d2e8e
  16:        0x104cf70cd - _$LT$std..panic..AssertUnwindSafe$LT$F$GT$$u20$as$u20$core..ops..function..FnOnce$LT$$LP$$RP$$GT$$GT$::call_once::h7f0757167da30060
  17:        0x104cf918d - std::panicking::try::do_call::h73d1fb81f46c6be4
  18:        0x106ef59ec - __rust_maybe_catch_panic
  19:        0x104cf904b - std::panicking::try::hbe4431529d579efd
  20:        0x104cf829f - std::panic::catch_unwind::he6c67fb8fe857265
  21:        0x104d2aee8 - _$LT$F$u20$as$u20$alloc..boxed..FnBox$LT$A$GT$$GT$::call_box::hbcb147e1f69066af
  22:        0x106ee793b - std::sys::imp::thread::Thread::new::thread_start::h427874eb2948ff0c
  23:     0x7fffb731793a - _pthread_body
  24:     0x7fffb7317886 - _pthread_start
ERROR:servo: called `Option::unwrap()` on a `None` value
mach_port_mod_refs(-1, 162786800) failed: 0000000f (thread LayoutThread PipelineId { namespace_id: PipelineNamespaceId(0), index: PipelineIndex(NonZero(3)) }, at /Users/nox/.cargo/registry/src/github.com-1ecc6299db9ec823/ipc-channel-0.8.0/src/platform/macos/mod.rs:327)
called `Result::unwrap()` on an `Err` value: "PoisonError { inner: .. }" (thread ScriptThread PipelineId { namespace_id: PipelineNamespaceId(0), index: PipelineIndex(NonZero(1)) }, at src/libcore/result.rs:906)
stack backtrace:
   0:        0x10492fb6e - backtrace::backtrace::trace::hd52e5d2b480cf880
   1:        0x104930619 - backtrace::capture::Backtrace::new::h39b4a889ca7dd05a
   2:        0x10439c9a9 - servo::main::_$u7b$$u7b$closure$u7d$$u7d$::h19a57ce8f7a2f840
   3:        0x106ee8bf1 - std::panicking::rust_panic_with_hook::h5684107b64cf4fa5
   4:        0x106ee8a94 - std::panicking::begin_panic::h8e0be770f5663898
   5:        0x106ee8962 - std::panicking::begin_panic_fmt::h209631a6f4346ec1
   6:        0x106ec2f26 - _$LT$ipc_channel..platform..macos..OsIpcSender$u20$as$u20$core..ops..drop..Drop$GT$::drop::hb1b706a79f59db60
   7:        0x104c859a1 - layout_thread::LayoutThread::handle_request_helper::he21c547c66a1f140
   8:        0x104c80851 - layout_thread::LayoutThread::start::h9c46f5087ce0768f
   9:        0x104ca1579 - profile_traits::mem::ProfilerChan::run_with_memory_reporting::h4809dee70600c497
  10:        0x104d2282a - std::sys_common::backtrace::__rust_begin_short_backtrace::h3d6a122d854d2e8e
  11:        0x104cf70cd - _$LT$std..panic..AssertUnwindSafe$LT$F$GT$$u20$as$u20$core..ops..function..FnOnce$LT$$LP$$RP$$GT$$GT$::call_once::h7f0757167da30060
  12:        0x104cf918d - std::panicking::try::do_call::h73d1fb81f46c6be4
  13:        0x106ef59ec - __rust_maybe_catch_panic
  14:        0x104cf904b - std::panicking::try::hbe4431529d579efd
  15:        0x104cf829f - std::panic::catch_unwind::he6c67fb8fe857265
  16:        0x104d2aee8 - _$LT$F$u20$as$u20$alloc..boxed..FnBox$LT$A$GT$$GT$::call_box::hbcb147e1f69066af
  17:        0x106ee793b - std::sys::imp::thread::Thread::new::thread_start::h427874eb2948ff0c
  18:     0x7fffb731793a - _pthread_body
  19:     0x7fffb7317886 - _pthread_start
ERROR:servo: mach_port_mod_refs(-1, 162786800) failed: 0000000f
thread panicked while panicking. aborting.
ERROR:constellation::constellation: about:failure failed
stack backtrace:
   0:        0x10492fb6e - backtrace::backtrace::trace::hd52e5d2b480cf880
   1:        0x104930619 - backtrace::capture::Backtrace::new::h39b4a889ca7dd05a
   2:        0x10439c9a9 - servo::main::_$u7b$$u7b$closure$u7d$$u7d$::h19a57ce8f7a2f840
   3:        0x106ee8bf1 - std::panicking::rust_panic_with_hook::h5684107b64cf4fa5
   4:        0x106ee8a94 - std::panicking::begin_panic::h8e0be770f5663898
   5:        0x106ee8962 - std::panicking::begin_panic_fmt::h209631a6f4346ec1
   6:        0x106ee88ca - rust_begin_unwind
   7:        0x106f22533 - core::panicking::panic_fmt::h50330b144282cfe9
   8:        0x104d9b16f - core::result::unwrap_failed::h470a7f4b6c146859
   9:        0x104e026cc - _$LT$layout..query..LayoutRPCImpl$u20$as$u20$script_layout_interface..rpc..LayoutRPC$GT$::offset_parent::hbbf99c522ced4668
  10:        0x1056c0d26 - script::dom::window::Window::offset_parent_query::hb990e495fb81a490
  11:        0x10557b258 - _$LT$script..dom..htmlelement..HTMLElement$u20$as$u20$script..dom..bindings..codegen..Bindings..HTMLElementBinding..HTMLElementBinding..HTMLElementMethods$GT$::OffsetHeight::h4e09eaba3525a9e0
  12:        0x10595d714 - _$LT$std..panic..AssertUnwindSafe$LT$F$GT$$u20$as$u20$core..ops..function..FnOnce$LT$$LP$$RP$$GT$$GT$::call_once::hd398d98b922108b4
  13:        0x105abb27b - std::panicking::try::do_call::h457866821356b105
  14:        0x106ef59ec - __rust_maybe_catch_panic
  15:        0x105a146fa - std::panicking::try::h05ecc7402eb4b89a
  16:        0x1059c26bb - std::panic::catch_unwind::h524fcfd51775c4f3
  17:        0x10525d38e - js::panic::wrap_panic::he6c9fd3657d520ee
  18:        0x10530b8b6 - script::dom::bindings::codegen::Bindings::HTMLElementBinding::HTMLElementBinding::get_offsetHeight::he016b20bc2bc6622
  19:        0x105496188 - script::dom::bindings::utils::generic_call::h6ac1f4492ba71380
  20:        0x106c3816d - js::InternalCallOrConstruct(JSContext*, JS::CallArgs const&, js::MaybeConstruct)
  21:        0x106c5c2a9 - CallGetter(JSContext*, JS::Handle<JSObject*>, JS::Handle<JS::Value>, JS::Handle<js::Shape*>, JS::MutableHandle<JS::Value>)
  22:        0x106c3b561 - js::GetProperty(JSContext*, JS::Handle<JS::Value>, JS::Handle<js::PropertyName*>, JS::MutableHandle<JS::Value>)
  23:        0x106c2d1e2 - Interpret(JSContext*, js::RunState&)
  24:        0x106c266e3 - js::RunScript(JSContext*, js::RunState&)
  25:        0x106c381f6 - js::InternalCallOrConstruct(JSContext*, JS::CallArgs const&, js::MaybeConstruct)
  26:        0x106c383b5 - js::Call(JSContext*, JS::Handle<JS::Value>, JS::Handle<JS::Value>, js::AnyInvokeArgs const&, JS::MutableHandle<JS::Value>)
  27:        0x106b6465c - js::fun_call(JSContext*, unsigned int, JS::Value*)
  28:        0x106c3816d - js::InternalCallOrConstruct(JSContext*, JS::CallArgs const&, js::MaybeConstruct)
  29:        0x106c322e9 - Interpret(JSContext*, js::RunState&)
  30:        0x106c266e3 - js::RunScript(JSContext*, js::RunState&)
  31:        0x106c38b09 - js::ExecuteKernel(JSContext*, JS::Handle<JSScript*>, JSObject&, JS::Value const&, js::AbstractFramePtr, JS::Value*)
  32:        0x106c38c3c - js::Execute(JSContext*, JS::Handle<JSScript*>, JSObject&, JS::Value*)
  33:        0x106b1878d - Evaluate(JSContext*, JS::Handle<JSObject*>, JS::Handle<js::StaticScope*>, JS::ReadOnlyCompileOptions const&, JS::SourceBufferHolder&, JS::MutableHandle<JS::Value>)
  34:        0x106b18940 - JS::Evaluate(JSContext*, JS::ReadOnlyCompileOptions const&, char16_t const*, unsigned long, JS::MutableHandle<JS::Value>)
  35:        0x1052785ae - profile_traits::time::profile::h19c65f35bb2b86ea
  36:        0x105558a56 - script::dom::globalscope::GlobalScope::evaluate_script_on_global_with_result::hb2d0fdc16f3c67c9
  37:        0x1055d1a35 - script::dom::htmlscriptelement::HTMLScriptElement::run_a_classic_script::h14d4df647810cddf
  38:        0x1055d12d7 - script::dom::htmlscriptelement::HTMLScriptElement::execute::hdcf8bb23cb63df72
  39:        0x105643a1a - script::dom::servoparser::ServoParser::resume_with_pending_parsing_blocking_script::hf5c1fe431e5942a0
  40:        0x105507498 - script::dom::document::Document::process_pending_parsing_blocking_script::h6098f7248c33beb3
  41:        0x105507049 - script::dom::document::Document::pending_parsing_blocking_script_loaded::h16027a0737117cf4
  42:        0x1055cded7 - _$LT$script..dom..htmlscriptelement..ScriptContext$u20$as$u20$net_traits..FetchResponseListener$GT$::process_response_eof::hd19578986761932d
  43:        0x105272c34 - _$LT$net_traits..FetchResponseMsg$u20$as$u20$net_traits..Action$LT$T$GT$$GT$::process::h2acbbbffc8f9f911
  44:        0x1056f6a61 - _$LT$script..network_listener..ListenerTask$LT$A$C$$u20$Listener$GT$$u20$as$u20$script..task..TaskOnce$GT$::run_once::h8f971012f7cf7c4f
  45:        0x105725b20 - _$LT$T$u20$as$u20$script..task..TaskBox$GT$::run_box::hf7e6b723a130d1b1
  46:        0x10570acb0 - script::script_thread::ScriptThread::handle_msg_from_script::hd58f2deba2d7a601
  47:        0x105716ac9 - script::script_thread::ScriptThread::profile_event::h10402c296247e2bc
  48:        0x105701e0d - script::script_thread::ScriptThread::start::h0e30ea7c3d03492a
  49:        0x105276d8e - profile_traits::mem::ProfilerChan::run_with_memory_reporting::h9d31e9d50f61fd28
  50:        0x105bf808f - std::sys_common::backtrace::__rust_begin_short_backtrace::h71c2c3a07fe8940e
  51:        0x1058b8b8d - _$LT$std..panic..AssertUnwindSafe$LT$F$GT$$u20$as$u20$core..ops..function..FnOnce$LT$$LP$$RP$$GT$$GT$::call_once::h72aa08293dad4bc4
  52:        0x105ab746d - std::panicking::try::do_call::h371039fe18898cba
  53:        0x106ef59ec - __rust_maybe_catch_panic
  54:        0x105a7ed3b - std::panicking::try::hb924b87cac59db31
  55:        0x1059d901f - std::panic::catch_unwind::ha887652aa2c43e14
  56:        0x105fad178 - _$LT$F$u20$as$u20$alloc..boxed..FnBox$LT$A$GT$$GT$::call_box::h718f377e53061d6f
  57:        0x106ee793b - std::sys::imp::thread::Thread::new::thread_start::h427874eb2948ff0c
  58:     0x7fffb731793a - _pthread_body
  59:     0x7fffb7317886 - _pthread_start
ERROR:servo: called `Result::unwrap()` on an `Err` value: "PoisonError { inner: .. }"
Stack trace for thread "LayoutThread PipelineId { namespace_id: PipelineNamespaceId(0), index: PipelineIndex(NonZero(3)) }"
stack backtrace:
   0:        0x10492fb6e - backtrace::backtrace::trace::hd52e5d2b480cf880
   1:        0x104930619 - backtrace::capture::Backtrace::new::h39b4a889ca7dd05a
   2:        0x10439b95c - servo::install_crash_handler::handler::h4fca83ec2c4270e4
   3:     0x7fffb730db39 - _sigtramp
   4:        0x106ee8c43 - std::panicking::rust_panic_with_hook::h5684107b64cf4fa5
   5:        0x106ee8a94 - std::panicking::begin_panic::h8e0be770f5663898
   6:        0x106ee8962 - std::panicking::begin_panic_fmt::h209631a6f4346ec1
   7:        0x106ec2f26 - _$LT$ipc_channel..platform..macos..OsIpcSender$u20$as$u20$core..ops..drop..Drop$GT$::drop::hb1b706a79f59db60
   8:        0x104c859a1 - layout_thread::LayoutThread::handle_request_helper::he21c547c66a1f140
   9:        0x104c80851 - layout_thread::LayoutThread::start::h9c46f5087ce0768f
  10:        0x104ca1579 - profile_traits::mem::ProfilerChan::run_with_memory_reporting::h4809dee70600c497
  11:        0x104d2282a - std::sys_common::backtrace::__rust_begin_short_backtrace::h3d6a122d854d2e8e
  12:        0x104cf70cd - _$LT$std..panic..AssertUnwindSafe$LT$F$GT$$u20$as$u20$core..ops..function..FnOnce$LT$$LP$$RP$$GT$$GT$::call_once::h7f0757167da30060
  13:        0x104cf918d - std::panicking::try::do_call::h73d1fb81f46c6be4
  14:        0x106ef59ec - __rust_maybe_catch_panic
  15:        0x104cf904b - std::panicking::try::hbe4431529d579efd
  16:        0x104cf829f - std::panic::catch_unwind::he6c67fb8fe857265
  17:        0x104d2aee8 - _$LT$F$u20$as$u20$alloc..boxed..FnBox$LT$A$GT$$GT$::call_box::hbcb147e1f69066af
  18:        0x106ee793b - std::sys::imp::thread::Thread::new::thread_start::h427874eb2948ff0c
  19:     0x7fffb731793a - _pthread_body
  20:     0x7fffb7317886 - _pthread_start

[mrobinson]

I managed to capture a trace with debugging symbols:

called `Option::unwrap()` on a `None` value (thread LayoutThread PipelineId { namespace_id: PipelineNamespaceId(0), index: PipelineIndex(NonZero(3)) }, at /checkout/src/libcore/option.rs:335)
stack backtrace:
   0:     0x5652538db59e - backtrace::backtrace::libunwind::trace
                        at /home/martin/.cargo/registry/src/github.com-1ecc6299db9ec823/backtrace-0.3.2/src/backtrace/libunwind.rs:53
                         - backtrace::backtrace::trace<closure>
                        at /home/martin/.cargo/registry/src/github.com-1ecc6299db9ec823/backtrace-0.3.2/src/backtrace/mod.rs:42
   1:     0x5652538db5d3 - backtrace::capture::{{impl}}::new
                        at /home/martin/.cargo/registry/src/github.com-1ecc6299db9ec823/backtrace-0.3.2/src/capture.rs:64
   2:     0x5652521cbe58 - servo::main::{{closure}}
                        at /home/martin/work/mozilla/servo-alt/ports/servo/main.rs:130
   3:     0x5652544214c6 - std::panicking::rust_panic_with_hook
                        at /checkout/src/libstd/panicking.rs:578
   4:     0x5652544212e4 - std::panicking::begin_panic<alloc::string::String>
                        at /checkout/src/libstd/panicking.rs:538
   5:     0x565254421259 - std::panicking::begin_panic_fmt
                        at /checkout/src/libstd/panicking.rs:522
   6:     0x5652544211ea - std::panicking::rust_begin_panic
                        at /checkout/src/libstd/panicking.rs:498
   7:     0x56525445b550 - core::panicking::panic_fmt
                        at /checkout/src/libcore/panicking.rs:71
   8:     0x56525445b486 - core::panicking::panic
                        at /checkout/src/libcore/panicking.rs:51
   9:     0x565252420a6b - core::option::{{impl}}::unwrap<&alloc::arc::Arc<gfx::display_list::DisplayList>>
                        at /checkout/src/libcore/macros.rs:20
                         - layout_thread::{{impl}}::compute_abs_pos_and_build_display_list::{{closure}}
                        at /home/martin/work/mozilla/servo-alt/components/layout_thread/lib.rs:1021
                         - profile_traits::time::profile<(),closure>
                        at /home/martin/work/mozilla/servo-alt/components/profile_traits/time.rs:124
                         - layout_thread::{{impl}}::compute_abs_pos_and_build_display_list
                        at /home/martin/work/mozilla/servo-alt/components/layout_thread/lib.rs:962
                         - layout_thread::{{impl}}::perform_post_main_layout_passes
                        at /home/martin/work/mozilla/servo-alt/components/layout_thread/lib.rs:1611
                         - layout_thread::{{impl}}::perform_post_style_recalc_layout_passes
                        at /home/martin/work/mozilla/servo-alt/components/layout_thread/lib.rs:1596
  10:     0x56525241e28a - layout_thread::{{impl}}::tick_animations
                        at /home/martin/work/mozilla/servo-alt/components/layout_thread/lib.rs:1499
                         - layout_thread::{{impl}}::tick_all_animations
                        at /home/martin/work/mozilla/servo-alt/components/layout_thread/lib.rs:1461
  11:     0x56525240d936 - layout_thread::{{impl}}::handle_request_helper
                        at /home/martin/work/mozilla/servo-alt/components/layout_thread/lib.rs:700
  12:     0x565252409363 - layout_thread::{{impl}}::handle_request
                        at /home/martin/work/mozilla/servo-alt/components/layout_thread/lib.rs:625
                         - layout_thread::{{impl}}::start
                        at /home/martin/work/mozilla/servo-alt/components/layout_thread/lib.rs:555
                         - layout_thread::{{impl}}::create::{{closure}}::{{closure}}
                        at /home/martin/work/mozilla/servo-alt/components/layout_thread/lib.rs:315
                         - profile_traits::mem::{{impl}}::run_with_memory_reporting<closure,fn(profile_traits::mem::ReportsChan) -> script_layout_interface::message::Msg,script_layout_interface::message::Msg,std::sync::mpsc::Sender<script_layout_interface::message::Msg>>
                        at /home/martin/work/mozilla/servo-alt/components/profile_traits/mem.rs:63
                         - layout_thread::{{impl}}::create::{{closure}}
                        at /home/martin/work/mozilla/servo-alt/components/layout_thread/lib.rs:314
  13:     0x56525237114d - std::sys_common::backtrace::__rust_begin_short_backtrace<closure,()>
                        at /checkout/src/libstd/sys_common/backtrace.rs:136
  14:     0x565252376c5d - std::thread::{{impl}}::spawn::{{closure}}::{{closure}}<closure,()>
                        at /checkout/src/libstd/thread/mod.rs:400
                         - std::panic::{{impl}}::call_once<(),closure>
                        at /checkout/src/libstd/panic.rs:296
                         - std::panicking::try::do_call<std::panic::AssertUnwindSafe<closure>,()>
                        at /checkout/src/libstd/panicking.rs:480
  15:     0x5652544285cc - panic_unwind::__rust_maybe_catch_panic
                        at /checkout/src/libpanic_unwind/lib.rs:99
  16:     0x5652523a3585 - std::panicking::try<(),std::panic::AssertUnwindSafe<closure>>
                        at /checkout/src/libstd/panicking.rs:459
                         - std::panic::catch_unwind<std::panic::AssertUnwindSafe<closure>,()>
                        at /checkout/src/libstd/panic.rs:361
                         - std::thread::{{impl}}::spawn::{{closure}}<closure,()>
                        at /checkout/src/libstd/thread/mod.rs:399
                         - alloc::boxed::{{impl}}::call_box<(),closure>
                        at /checkout/src/liballoc/boxed.rs:728
  17:     0x56525442016b - alloc::boxed::{{impl}}::call_once<(),()>
                        at /checkout/src/liballoc/boxed.rs:738
                         - std::sys_common::thread::start_thread
                        at /checkout/src/libstd/sys_common/thread.rs:24
                         - std::sys::imp::thread::{{impl}}::new::thread_start
                        at /checkout/src/libstd/sys/unix/thread.rs:90
  18:     0x7f39bb9336d9 - start_thread
  19:     0x7f39bb456d7e - __clone
  20:                0x0 - <unknown>

[mrobinson]

I should have a PR for this in a little bit.