256754 2023-05-13 01:34:01 -0700 Align with 'UA' Stylesheet for 'lists' by changing '1__qem' to '1em' for `margin-block-start` 2023-05-22 15:09:37 -0700 1 1 1 Unclassified WebKit CSS WebKit Nightly Build Unspecified Unspecified NEW https://bugs.webkit.org/show_bug.cgi?id=253177 https://bugs.webkit.org/show_bug.cgi?id=256760 BrowserCompat, InRadar P2 Normal --- 1 ahmad.saleem792 webkit-unassigned karlcow ntim simon.fraser webkit-bug-importer zalan oldest_to_newest 1955215 0 ahmad.saleem792 2023-05-13 01:34:01 -0700 Hi Team, While we are going to sync-up partial UA rules, based on Tim's suggestion, I am tackling this case separately since it would require further discussion. HTML Spec: https://html.spec.whatwg.org/#lists Current use of '1__qem': ol { ... margin-block-start: 1__qem; ... } and dl { ... margin-block-start: 1__qem; ... } __________________ As per Web-Spec and aligning with 'Firefox', we have to use '1em'. This was added by this commit in 2002 - https://github.com/WebKit/WebKit/commit/ad72cdff4371a3c296ab7a7e162620ebdc940325 __________________ Just wanted to raise this. Thanks! 1955217 1 ahmad.saleem792 2023-05-13 01:39:23 -0700 Also: ul, menu, dir { ... margin-block-start: 1__qem; ... } 1955250 2 ahmad.saleem792 2023-05-13 11:43:02 -0700 (In reply to Ahmad Saleem from comment #1) > Also: > > ul, menu, dir { > ... > margin-block-start: 1__qem; > ... > } Also this bit: ul, menu { counter-reset: list-item; } 1956702 3 webkit-bug-importer 2023-05-20 01:34:17 -0700 <rdar://problem/109600780> 1956834 4 karlcow 2023-05-21 21:30:44 -0700 tldr: * safe to remove from html.css * Quirk Unit code could be removed in another bug(?) Let's ask Alan? Details: Before making a decision on that, it would be good to check in the code. I see in the code some specific usage for qem * CSS_QUIRKY_EMS https://searchfox.org/wubkat/search?q=CSS_QUIRKY_EMS&path=&case=false&regexp=false * isQuirkyEms() https://searchfox.org/wubkat/search?q=isquirkyems&path=&case=false&regexp=false isQuirkyEms is not used at all in the code, apart its declaration. Probably can be removed. https://searchfox.org/wubkat/rev/622bd3bfe173b244d3cc68f2cb14ebbf987e14dd/Source/WebCore/css/parser/CSSPropertyParserHelpers.cpp#542-545 case CSSUnitType::CSS_QUIRKY_EMS: if (parserMode != UASheetMode) return std::nullopt; FALLTHROUGH; and other cases with no difference with the standard ems. but I'm not even sure it has the impact it had in the past. https://searchfox.org/wubkat/rev/622bd3bfe173b244d3cc68f2cb14ebbf987e14dd/Source/WebCore/css/CSSUnits.h#121-125 // This value is used to handle quirky margins in reflow roots (body, td, and th) like WinIE. // The basic idea is that a stylesheet can use the value __qem (for quirky em) instead of em. // When the quirky value is used, if you're in quirks mode, the margin will collapse away // inside a table cell. This quirk is specified in the HTML spec but our impl is different. CSS_QUIRKY_EMS https://bugs.webkit.org/show_bug.cgi?id=204101 Is the implementation handling it now directly? https://searchfox.org/wubkat/rev/622bd3bfe173b244d3cc68f2cb14ebbf987e14dd/Source/WebCore/layout/formattingContexts/table/TableFormattingGeometry.cpp#46-62 when this was written? https://searchfox.org/wubkat/commit/ab3b5a332211ad9e67239fe06dce4ec9f5d155b7 I wonder if all of this can be retired Probably it would be safe to remove from the css. https://searchfox.org/wubkat/search?q=_qem&path=&case=false&regexp=false And there is a need for a followup bug on removing the QEM code. 1957119 5 karlcow 2023-05-22 15:09:37 -0700 Ah wait, I'm walking back my previous comment. I had missed this part https://searchfox.org/wubkat/rev/622bd3bfe173b244d3cc68f2cb14ebbf987e14dd/Source/WebCore/style/StyleBuilderConverter.h#233-237 which associates the qem to the quirk behavior. if (primitiveValue.isLength()) { Length length = primitiveValue.computeLength<Length>(conversionData); length.setHasQuirk(primitiveValue.primitiveType() == CSSUnitType::CSS_QUIRKY_EMS); return length; } ok we should make a test and change the CSS to see what differences it creates for the tables.