1348414 - reftest-wait seems to snapshot at the wrong time with WR

Status: RESOLVED FIXED

(Core :: Graphics: WebRender, defect)

Description

[Mason Chang [Inactive] [:mchang]]

I'm getting failures not due to wrong rendering, but seems like it's snapshotting too early or before WR finishes rendering an update after a reftest-wait.

See /layout/reftests/bugs/1003425-1.html

Comment 1

[Mason Chang [Inactive] [:mchang]]

Tracked this down. We keep sending an EmptyRect during invalidation detection in [1]. This empty rect is passed onto NotifyPaintEvent, which is fired after we paint. The reftest framework looks for client rects to determine that it should snapshot again. Since we return an empty rect, the reftest doesn't think it needs to snapshot again and dies.

I tried caching the display item geometry via a LayerTreeProperty and then call nsDisplayList::ComputeInvalidationRegion. However, the display item's lifetimes are shorter than the Layer trees. Also, since we recycle display item layers, there's no guarantee that the display item in a recycled layer would be the same time and the geometry would apply to check against anyway.

Going back through some old comments, I saw [2]. Specifically, I think we'd change the tests to just wait until there are no more scheduled paints.

[1] http://searchfox.org/mozilla-central/source/layout/painting/nsDisplayList.cpp#2281
[2] https://bugzilla.mozilla.org/show_bug.cgi?id=1337130#c14

Comment 2

[Mason Chang [Inactive] [:mchang]]

Attachment: Always snapshot after no more paints are pending if WR is enabled

Try: https://treeherder.mozilla.org/#/jobs?repo=try&revision=32b3a83e08296fadbf5cd4852273c88b3f7baea1

Comment 3

[Mason Chang [Inactive] [:mchang]]

Attachment: Always snapshot after no more paints are pending if WR is enabled

Fixed a bug where we wouldn't detect if WR was enabled on non-windows platforms.

Comment 4

[Mason Chang [Inactive] [:mchang]]

Try all - https://treeherder.mozilla.org/#/jobs?repo=try&revision=770a52918e1d6f73dbd26f013e660969e1e4b90c

Try WR - https://treeherder.mozilla.org/#/jobs?repo=try&revision=de9eaca21a005b448d68f69d42ffb93b89fc833f

Comment 5

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/projects/graphics/rev/f39045b90aa9
Always snapshot after no more paints are pending if WR is enabled. r=mattwoodrow

Comment 6

[Kartikaya Gupta (email:[e-mail])]

https://hg.mozilla.org/mozilla-central/rev/f39045b90aa9