Bug 104961 – Add a missing nullity check in RenderObject::containingBlock

• Component: WebKit Misc.
• Status: RESOLVED FIXED

At one point we assert that !o->isAnonymousBlock(), but it's quite possible that o is null.

Created attachment 179347 [details]
Patch

[Adrienne Walker]

Comment on attachment 179347 [details]
Patch

R=me.  That looks safe.  Later in the function there's a similar !o || !o->foo() assert.

[WebKit Review Bot]

Comment on attachment 179347 [details]
Patch

Clearing flags on attachment: 179347

Committed r137674: <http://trac.webkit.org/changeset/137674>

[WebKit Review Bot]

All reviewed patches have been landed.  Closing bug.

[Alexey Proskuryakov]

Why didn't this patch have a regression test? It's not OK to ignore those for fixes made through code inspection (I'd say that it's even more important for those fixes).

(In reply to comment #5)
> Why didn't this patch have a regression test? It's not OK to ignore those for fixes made through code inspection (I'd say that it's even more important for those fixes).

This patch was not initiated by code inspection, it was made to fix a debug-only crash in a layout test http://test-results.appspot.com/dashboards/flakiness_dashboard.html#tests=fullscreen%2Ffull-screen-fixed-pos-parent.html%2Cfullscreen%2Ffull-screen-iframe-without-allow-attribute-allowed-from-parent.html

The crash resulted from asking a valid RenderObject what its containing block was -- something that, I believe, shouldn't run you the risk of crashing -- and appeared to be an oversight when the assertion was written.