Bug 126021 – Different and incorrect flags are passed to sendSync when accessibility is enabled, SpinRunLoopWhileWaitingForReply

• Status: RESOLVED
• Resolution: FIXED
• Component: Accessibility

[Alexey Proskuryakov]

In WebKit2, we have multiple places where sendSync flags depend on whether accessibility is enabled.

    unsigned syncSendFlags = (WebCore::AXObjectCache::accessibilityEnabled()) ? CoreIPC::SpinRunLoopWhileWaitingForReply : 0;
    WebProcess::shared().parentProcessConnection()->sendSync(Messages::WebPageProxy::RunJavaScriptAlert(webFrame->frameID(), alertText), Messages::WebPageProxy::RunJavaScriptAlert::Reply(), m_page->pageID(), CoreIPC::Connection::NoTimeout, syncSendFlags);

It is unfortunate to have such differences, because we get to support two runtime behaviors instead of one. I think that we should either make SpinRunLoopWhileWaitingForReply unconditional, or stop passing SpinRunLoopWhileWaitingForReply, and find different fixes for bugs it was needed for.

Bug 126014 is one case where SpinRunLoopWhileWaitingForReply was found to cause significant trouble.

[Alexey Proskuryakov]

See also: bug 123828.

[Radar WebKit Bug Importer]

<rdar://problem/15703778>

[Alexey Proskuryakov]

Removing "possibly" from the title, as it's certainly incorrect given the test crashes seen in blocking bugs.

Now that accessibility gets disabled after each test, this should affect testing, but it may cause instability in real life.

Created attachment 267719 [details]
Get rid of SpinRunLoopWhileWaitingForReply

Committed <http://trac.webkit.org/r194330>.