Created attachment 631688 [details] testcase ###!!! ASSERTION: parentSize should be valid: 'parentSize.width != NS_INTRINSICSIZE && parentSize.height != NS_INTRINSICSIZE', file layout/base/nsCSSFrameConstructor.cpp, line 11994 This assertion was added in bug 157681.
So the right padding here is a large value, which causes tons of these types of warnings: "have unconstrained width; this should only result from very large sizes, not attempts at intrinsic width calculation: 'aContainingBlockWidth != NS_UNCONSTRAINEDSIZE'", and also causes the width value to be unconstrained size, which triggers this assertion. How are we supposed to handle cases like this with huge values in layout?
We don't really have a plan for these. :(
So there isn't too much we can do about this assertion, except for taking it out?
I have an idea in bug 765861. For now, this should probably be downgraded to a warning.
Created attachment 634258 [details] [diff] [review] Patch (v1) This patch converts the assertion into a warning.
Comment on attachment 634258 [details] [diff] [review] Patch (v1) Please use NS_WARN_IF_FALSE instead of the #ifdef and NS_WARNING. r=dbaron with that