Bug 182595

Summary: WebKit mistakenly adds "margin-top" to intrinsic *width* calculation for floats
Product: WebKit Reporter: Daniel Holbert <dholbert>
Component: Layout and RenderingAssignee: Nobody <webkit-unassigned>
Status: RESOLVED CONFIGURATION CHANGED    
Severity: Normal CC: ahmad.saleem792, bfulgham, browserbugs2, simon.fraser, webkit-bug-importer, zalan
Priority: P2 Keywords: InRadar
Version: Safari 11   
Hardware: Unspecified   
OS: macOS 10.13   
Attachments:
Description Flags
STP165 matches Firefox Nightly 113 but differ from Chrome Canary 113 none

Description Daniel Holbert 2018-02-07 19:18:46 PST
What steps will reproduce the problem?
(1) Visit https://jsfiddle.net/5rwq3m0o/

What is the expected result?
Each teal div should have the same width.

What happens instead?
Each teal div is wider than the last.

Please use labels and text to provide additional information.
The only difference between the divs are "margin-top" values on their children. Apparently WebKit is mistakenly factoring this vertical margin into the width calculation, when accounting for the writing-mode difference between parent & child.

Note:
 - Edge 16 gives "Expected results", with the teal divs all being just wide enough to fit the text.
 - Firefox Nightly 60 gives a less pretty version of "expected results", with the divs all being 4px wide (not doing layout on the text -- only wide enough for the borders)
 - Safari 11 and Chrome give the results that I'm reporting as buggy here, with the divs being wider if there's a larger 'margin-top' value on the child.

Chrome version of this bug:
https://bugs.chromium.org/p/chromium/issues/detail?id=810231
Comment 1 Radar WebKit Bug Importer 2018-02-08 16:38:11 PST
<rdar://problem/37371418>
Comment 2 GĂ©rard Talbot 2018-03-06 11:12:52 PST
Test on other shrink-to-fit width code scenarios:

http://www.gtalbot.org/BrowserBugsSection/CSS3WritingModes/Issue810231-margin-top-added-to-width-001.html
Comment 3 Ahmad Saleem 2023-03-20 17:03:46 PDT
Created attachment 465530 [details]
STP165 matches Firefox Nightly 113 but differ from Chrome Canary 113

Just wanted to share updated test result. Thanks!
Comment 4 zalan 2023-03-23 15:45:16 PDT
Looks to be fixed.