797666 - Build warning: TiledLayerBuffer.h:368:12: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]

Status: RESOLVED FIXED

(Core :: Graphics, defect)

Description

[Daniel Holbert [:dholbert]]

{
Warning: -Wsign-compare in /mozilla/gfx/layers/TiledLayerBuffer.h: comparison between signed and unsigned integer expressions
/mozilla/gfx/layers/TiledLayerBuffer.h:368:12: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
}

for this line:
> NS_ABORT_IF_FALSE(index >= 0 && index < newRetainedTiles.Length(), "index out of range"); 

I think we want to just cast index to unsigned before we compare it to .Length().  (We know it's safe to do that cast, because we've just checked that it's >= 0.)

Note that jdm posted a patch that includes a different fix for this over in bug 755031, but I don't think the strategy is right (making index unsigned), because index is set from a number of other signed variables.  Also, that other bug seems to have gone silent, and this warning is bugging me, so I'm filing a one-off for just this particular warning.

Comment 1

[Daniel Holbert [:dholbert]]

Attachment: fix

Comment 2

[Daniel Holbert [:dholbert]]

https://hg.mozilla.org/integration/mozilla-inbound/rev/2b80eca0f4fb

Comment 3

[Ed Morley [:emorley]]

https://hg.mozilla.org/mozilla-central/rev/2b80eca0f4fb