Bug 78086 – Web Inspector: hovering over element with :hover style halts inspector

• Component: Web Inspector (Deprecated)
• Status: RESOLVED FIXED

[Pavel Feldman]

- Inspect the inspector
- Choose inspect element on one of the watch expressions
- Select <li> in the elements panel
- Hover over the watch expression in the UI

Actual: inspector front-end hangs

The reason is that while moving the mouse over the watch expression, Element::didModifyAttribute is called and propagated to InspectorInstrumentation::didModifyDOMAttr hundreds time a second. There is no throttling, so front-end is trying to update styles infinite amount of times.

[Alexander Pavlov (apavlov)]

Created attachment 126062 [details]
Patch

[WebKit Review Bot]

Comment on attachment 126062 [details]
Patch

Attachment 126062 [details] did not pass chromium-ews (chromium-xvfb):
Output: http://queues.webkit.org/results/11461399

New failing tests:
inspector/styles/commit-selector.html
inspector/styles/styles-change-node-while-editing.html
inspector/styles/override-screen-size.html
inspector/styles/styles-disable-inherited.html

[Pavel Feldman]

Comment on attachment 126062 [details]
Patch

View in context: https://bugs.webkit.org/attachment.cgi?id=126062&action=review

> Source/WebCore/inspector/front-end/StylesSidebarPane.js:240
> +        this._executeRebuildUpdateTimer = setTimeout(this._executeRebuildUpdate.bind(this, node, callback));

As we agreed offline, we should not rely on the atomic nature of incoming event sequences.

[Alexander Pavlov (apavlov)]

Created attachment 126082 [details]
Patch

[Alexander Pavlov (apavlov)]

Committed r107201: <http://trac.webkit.org/changeset/107201>