1593396 - Assertion failure: target->IsApplication() || target->IsOuterDoc() || target->IsXULTree() (Only app or outerdoc accessible reorder events are in the queue)

Status: RESOLVED FIXED

(Core :: Disability Access APIs, defect, P1)

Description

[Tyson Smith [:tsmith]]

Attachment: testcase.html

Reduced with m-c:
BuildID=20191101215002
SourceStamp=518df4329a20f76b3bffd5f6201b007fdebc274f

Not sure if we are hitting this quite as frequently as bug 1415667 but looking at the test case it will be a lot.

Assertion failure: target->IsApplication() || target->IsOuterDoc() || target->IsXULTree() (Only app or outerdoc accessible reorder events are in the queue), at src/accessible/base/EventQueue.cpp:90

#0 mozilla::a11y::EventQueue::CoalesceEvents() src/accessible/base/EventQueue.cpp:173:23
#1 mozilla::a11y::EventQueue::PushEvent(mozilla::a11y::AccEvent*) src/accessible/base/EventQueue.cpp:37:3
#2 mozilla::a11y::NotificationController::QueueEvent(mozilla::a11y::AccEvent*) src/accessible/base/NotificationController.h:111:9
#3 mozilla::a11y::DocAccessible::DoInitialUpdate() src/accessible/generic/DocAccessible.cpp:1595:23
#4 mozilla::a11y::NotificationController::WillRefresh(mozilla::TimeStamp) src/accessible/base/NotificationController.cpp:636:16
#5 nsRefreshDriver::Tick(mozilla::layers::BaseTransactionId<mozilla::VsyncIdType>, mozilla::TimeStamp) src/layout/base/nsRefreshDriver.cpp:1939:12
#6 mozilla::RefreshDriverTimer::TickRefreshDrivers(mozilla::layers::BaseTransactionId<mozilla::VsyncIdType>, mozilla::TimeStamp, nsTArray<RefPtr<nsRefreshDriver> >&) src/layout/base/nsRefreshDriver.cpp:350:7
#7 mozilla::RefreshDriverTimer::Tick(mozilla::layers::BaseTransactionId<mozilla::VsyncIdType>, mozilla::TimeStamp) src/layout/base/nsRefreshDriver.cpp:367:5
#8 mozilla::VsyncRefreshDriverTimer::RefreshDriverVsyncObserver::TickRefreshDriver(mozilla::layers::BaseTransactionId<mozilla::VsyncIdType>, mozilla::TimeStamp) src/layout/base/nsRefreshDriver.cpp:727:16
#9 mozilla::VsyncRefreshDriverTimer::RefreshDriverVsyncObserver::NotifyVsync(mozilla::VsyncEvent const&) src/layout/base/nsRefreshDriver.cpp:622:9
#10 mozilla::layout::VsyncChild::RecvNotify(mozilla::VsyncEvent const&) src/layout/ipc/VsyncChild.cpp:65:16
#11 mozilla::layout::PVsyncChild::OnMessageReceived(IPC::Message const&) src/obj-firefox/ipc/ipdl/PVsyncChild.cpp:187:54
#12 mozilla::ipc::PBackgroundChild::OnMessageReceived(IPC::Message const&) src/obj-firefox/ipc/ipdl/PBackgroundChild.cpp:5876:32
#13 mozilla::ipc::MessageChannel::DispatchAsyncMessage(mozilla::ipc::ActorLifecycleProxy*, IPC::Message const&) src/ipc/glue/MessageChannel.cpp:2208:25
#14 mozilla::ipc::MessageChannel::DispatchMessage(IPC::Message&&) src/ipc/glue/MessageChannel.cpp:2130:9
#15 mozilla::ipc::MessageChannel::RunMessage(mozilla::ipc::MessageChannel::MessageTask&) src/ipc/glue/MessageChannel.cpp:1972:3
#16 mozilla::ipc::MessageChannel::MessageTask::Run() src/ipc/glue/MessageChannel.cpp:2003:13
#17 nsThread::ProcessNextEvent(bool, bool*) src/xpcom/threads/nsThread.cpp:1225:14
#18 NS_ProcessNextEvent(nsIThread*, bool) src/xpcom/threads/nsThreadUtils.cpp:486:10
#19 mozilla::ipc::MessagePump::Run(base::MessagePump::Delegate*) src/ipc/glue/MessagePump.cpp:110:5
#20 MessageLoop::RunInternal() src/ipc/chromium/src/base/message_loop.cc:315:10
#21 MessageLoop::Run() src/ipc/chromium/src/base/message_loop.cc:290:3
#22 nsBaseAppShell::Run() src/widget/nsBaseAppShell.cpp:137:27
#23 XRE_RunAppShell() src/toolkit/xre/nsEmbedFunctions.cpp:934:20
#24 mozilla::ipc::MessagePumpForChildProcess::Run(base::MessagePump::Delegate*) src/ipc/glue/MessagePump.cpp:238:9
#25 MessageLoop::RunInternal() src/ipc/chromium/src/base/message_loop.cc:315:10
#26 MessageLoop::Run() src/ipc/chromium/src/base/message_loop.cc:290:3
#27 XRE_InitChildProcess(int, char**, XREChildData const*) src/toolkit/xre/nsEmbedFunctions.cpp:769:34
#28 content_process_main(mozilla::Bootstrap*, int, char**) src/browser/app/../../ipc/contentproc/plugin-container.cpp:56:28
#29 main src/browser/app/nsBrowserApp.cpp:272:18

Comment 1

[Tyson Smith [:tsmith]]

A Pernosco session is available here: https://pernos.co/debug/31IGnURK0sNXuKYZK1T4gQ/index.html
It will expire in 7 days.

Comment 2

[James Teh [:Jamie]]

I think what's happening here is that the embed starts out as a generic HyperTextAccessible, since we don't know it's going to be an OuterDoc at that point. However, it never gets re-created as an OuterDoc. We're probably going to need an explicit condition to re-create embed (and object) accessibles if their URL changes (src for embed, data for object).

Comment 3

[James Teh [:Jamie]]

Attachment: Bug 1593396: If the content of an embed or object element changes to be web content, recreate as an OuterDocAccessible.

If an embed or object doesn't specify a URL (or specifies a URL which isn't web content), it won't be created as an OuterDocAccessible.
For example, an embed with no src will be created as a generic HyperTextAccessible.
If the URL later changes to refer to web content, we must recreate as an OuterDocAccessible.
Previously, we didn't recreate, which was causing an assertion and may have caused other strange issues as well.

Comment 4

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/d7bee8f2fa9a
If the content of an embed or object element changes to be web content, recreate as an OuterDocAccessible. r=MarcoZ

Comment 5

[Narcis Beleuzu [:NarcisB]]

https://hg.mozilla.org/mozilla-central/rev/d7bee8f2fa9a