Bug 226823

Summary: Scrollbars are not clipped to layer bounds in RenderLayerBacking
Product: WebKit Reporter: Chris Lord <clord>
Component: Layout and RenderingAssignee: Chris Lord <clord>
Status: RESOLVED FIXED    
Severity: Normal CC: bfulgham, cdumez, changseok, darin, esprehn+autocc, ews-watchlist, fred.wang, glenn, kondapallykalyan, pdr, sam, simon.fraser, thorton, webkit-bug-importer, zalan
Priority: P2 Keywords: InRadar
Version: WebKit Nightly Build   
Hardware: Unspecified   
OS: Unspecified   
Bug Depends on:    
Bug Blocks: 224596    
Attachments:
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Description Chris Lord 2021-06-09 09:15:42 PDT
As in the summary - perhaps it's intentional that scrollbars can appear outside of the content they correspond to, but this is causing some tests to fail with async overflow scroll enabled; namely imported/w3c/web-platform-tests/css/css-flexbox/overflow-auto-001.html (and perhaps more that we'll find out via EWS/bots if this lands)
Comment 1 Chris Lord 2021-06-09 09:18:00 PDT
Created attachment 430970 [details]
Patch
Comment 2 Chris Lord 2021-06-14 08:40:19 PDT
Created attachment 431325 [details]
Patch
Comment 3 Chris Lord 2021-06-14 09:15:50 PDT
Comment on attachment 431325 [details]
Patch

The 1 failure on Mac is because the expectations don't expect the overflow container layer to clip its children (which is what this patch modifies) - assuming the approach is deemed correct, I'll modify the expectations.
Comment 4 Chris Lord 2021-06-15 03:26:47 PDT
Created attachment 431419 [details]
Patch
Comment 5 Chris Lord 2021-06-15 04:04:23 PDT
Created attachment 431420 [details]
Patch
Comment 6 Chris Lord 2021-06-15 06:13:42 PDT
Comment on attachment 431420 [details]
Patch

Added a test for this in compositing/scrolling/async-overflow-scrolling as the only test that was hitting this was in WPT.
Comment 7 EWS 2021-06-15 11:12:41 PDT
Committed r278883 (238825@main): <https://commits.webkit.org/238825@main>

All reviewed patches have been landed. Closing bug and clearing flags on attachment 431420 [details].
Comment 8 Radar WebKit Bug Importer 2021-06-15 11:13:20 PDT
<rdar://problem/79351898>