Bug 243363

Summary: Prevent background propagation on <html> with any containment
Product: WebKit Reporter: Tim Nguyen (:ntim) <ntim>
Component: Layout and RenderingAssignee: zalan <zalan>
Status: RESOLVED FIXED    
Severity: Normal CC: bfulgham, cathiechen, changseok, esprehn+autocc, ews-watchlist, glenn, Hironori.Fujii, kondapallykalyan, pdr, rbuis, simon.fraser, webkit-bug-importer, zalan
Priority: P2 Keywords: InRadar
Version: Safari 14   
Hardware: Unspecified   
OS: Unspecified   
Attachments:
Description Flags
Patch
none
Patch none

Description Tim Nguyen (:ntim) 2022-07-29 19:43:27 PDT 
WPTs:

css/css-contain/contain-html-bg-001.html
css/css-contain/contain-html-bg-002.html
css/css-contain/contain-html-bg-003.html

The results make it pretty clear what this is about:

https://wpt.fyi/analyzer?screenshot=sha1%3A93c3c4c555b8fa38035d23b475072ba6c920aaf7&screenshot=sha1%3A422ed5a9b8fce6673dbb700360cefb1ba06af8fa

If <html> has a fixed size and contain: layout, the background shouldn't spread above that size.
Comment 1 Radar WebKit Bug Importer 2022-08-01 11:56:04 PDT 
<rdar://problem/97927457>
Comment 2 zalan 2022-08-01 16:51:51 PDT 
Created attachment 461344 [details]
Patch
Comment 3 zalan 2022-08-01 21:32:37 PDT 
Created attachment 461348 [details]
Patch
Comment 4 EWS 2022-08-02 07:10:42 PDT 
Committed 253031@main (320ad146e7fa): <https://commits.webkit.org/253031@main>

All reviewed patches have been landed. Closing bug and clearing flags on attachment 461348 [details].