Re: Proposal: use MOZ_LOG instead of NS_WARNING for spammy warnings about huge nscoord values

On 06/10/2015 03:48 PM, [email protected] wrote:
> Bug 1171528 has landed on inbound.

Great! (erahm filed bug 1173858 on the other main culprits here, too.)

Thanks for jumping on these!

> It looks like layout/generic/crashtests/421671.html is responsible for almost all of the other top layout warnings.

Yeah -- it uses multicol layout + ends up producing a huge sizes from
the insanely-large number of columns, it looks like.

Multicol layout can require multiple reflows to establish the optimum
column height (and here we have 99999999 columns = 99999999 things being
reflowed each time, I think).  And the huge sizes produced by that
column-count will mean we trip lots of warning about working with values
near NS_UNCONSTRAINEDSIZE when we don't expect to see that sentinel-value.

So, we trip a few warnings, and we trip them manymany times. This is
just a pathological testcase (unsurprising for a crashtest).

> I wonder if we just want to remove these as well.

I don't think so; I think we should just make them opt-in (ideally at
runtime with MOZ_LOG).  These warnings can be quite useful when
debugging reflow issues (with normal, non-99999999-columned content).
More thoughts on this in
https://bugzilla.mozilla.org/show_bug.cgi?id=1173858#c3