[webkit-qt] QtWebkit 2.2.1 - Script Debugger Locks Inspector UI

[Jarred Nicholls]

On Tue, Jan 10, 2012 at 9:37 PM, Leo Franchi <lfranchi at gmail.com> wrote:

> On Jan 10, 2012, at 2:45 PM, Jarred Nicholls wrote:
>
> Hey qtwebkittens,
>
> My company has charged me with resolving a very nasty issue with QtWebKit
> 2.2.1's web inspector interface (built from Qt 4.8.0 source), which locks
> up when one pauses script at a breakpoint.
>
> https://bugs.webkit.org/show_bug.cgi?id=71271
>
> CPU on the process goes to 100% and it looks like the EventLoop just runs
> on and on (calling QCoreApplication::processEvents), but isn't processing
> UI events in the inspector interface at all.
>
> Before spending much more time trying to analyze this issue and scouring
> changesets, has anyone experienced this themself and/or have any indication
> of what the issue is or how to fix it?  This appears to have been an issue
> in the past (https://bugs.webkit.org/show_bug.cgi?id=41142) but I have a
> trunk build of QtWebKit @ r84622 (against Qt 4.7.4) that does not have this
> issue.
>
>
> It might be the issue I fixed recently in my qtwebkit fork---I added
> support for phantomjs remote debugging, and ran into this exact same thing.
> Turns out in a few places setting a breakpoint caused processing of the
> incoming events from the JS side of the debugger to fail.
>
> I mentioned my fixes to jturcotte but didn't get much interest---if there
> is interest I will gladly clean up my patches and get these fixes upstream.
>
> Here's the work to see if it fixes for you:
>
> 1) Updated Websocket implementation to latest spec to work against a
> recent chrome/webkit browser:
>
>
> https://gitorious.org/~lfranchi/webkit/lfranchis-qtwebkit/commit/93a72f2657c2a8bb6863d5d2ffe8ce6faedd4598
>
> 2) 2 fixes for hanging on breakpoint (one requires the above commit, but
> is easy enough to apply against trunk if you read the code)
>
>
> https://gitorious.org/~lfranchi/webkit/lfranchis-qtwebkit/commit/4e104bc438c21ef63a6a4227a142d36bf2401b2e
>
> https://gitorious.org/~lfranchi/webkit/lfranchis-qtwebkit/commit/1606e202891b856ad0fdae80288ccdbf8d6765e1
>
> The latter two patches I hope should fix your issue. All 3 are also
> available as a standalone patch against qt 4.8 here:
>
>
> https://github.com/ariya/phantomjs/blob/master/deploy/qt48_fix_inspector.patch
>
> cheers,
> leo
>
> --
> leo at kdab.com                                 KDAB (USA), LLC
> lfranchi at kde.org                             The KDE Project
>
>
Thanks very much Leo for the information!  I did indeed see the patches for
the websocket server on phantomjs issues, but didn't catch the latter two.
 I will check them out right now and see how they fare!

Many thanks,
Jarred
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