1504423 - Explicit CSS clip ignored by fixed position transformed children

Status: RESOLVED DUPLICATE of bug 1495791

(Core :: Graphics: WebRender, defect, P2)

Description

[Andrew Osmond [:aosmond] (he/him)]

While making a reduced test case for bug 1499015, I found a different problem. Here there is a clip making the div contents clipped at 100x100, which renders fine in non-WebRender and Chrome. In WebRender however, it overflows the parents clip. This is because it doesn't regenerate the currently applied clip and scroll info when it is overridden.

Comment 1

[Andrew Osmond [:aosmond] (he/him)]

try with new reftest to demonstrate WR broken: https://treeherder.mozilla.org/#/jobs?repo=try&revision=e974dc9e4a3f54a364c1aa3f24c035896b219aeb

Comment 2

[Andrew Osmond [:aosmond] (he/him)]

Failing three old reftests with my fix:

https://treeherder.mozilla.org/#/jobs?repo=try&revision=a1ebb8d5183882fd0021da89f6a973155a4e32e7&selectedJob=209631331

Will investigate.

Comment 3

[Andrew Osmond [:aosmond] (he/him)]

Today I learned we can push multiple overrides for the same scroll ID, and to the same mapping. This appears to be interacting with my changes. Also, I am now questioning what stacking context should be used if we need to regenerate the clips -- the original stacking context, or the new stacking context (e.g. the new list may have created a new one)?

Comment 4

[Andrew Osmond [:aosmond] (he/him)]

This actually got fixed by bug 1503447 over the weekend. I can land the test case at least.

Comment 5

[Andrew Osmond [:aosmond] (he/him)]

try proving it was fixed: https://treeherder.mozilla.org/#/jobs?repo=try&revision=333482b951afde13cbcddb0b863452546eb37cb4

Comment 6

[Emilio Cobos Álvarez [:emilio]]

Ah, I think this is a dupe of bug 1495791, I just pushed a reftest for that.