Bug 191865

Summary: [css-scroll-snap] scroll snap align two value parsing is incorrect/backwards
Product: WebKit Reporter: Majid Valipour <majidvp>
Component: CSSAssignee: Nobody <webkit-unassigned>
Status: NEW ---    
Severity: Normal CC: m.goleb+bugzilla, simon.fraser, webkit-bug-importer, wenson_hsieh
Priority: P2 Keywords: BrowserCompat, InRadar
Version: Safari 12   
Hardware: Unspecified   
OS: Unspecified   

Description Majid Valipour 2018-11-20 12:58:58 PST
CSSWG has resolved [1] to change the ordering of scroll-snap-align property to be in "block inline" order. WebKit parsing logic appear to do "inline, block" order.
I have changed Chromium implementation to match the specification but it is now different from Safari.
The current usage of two value is low but as it grows the interop issue problem grows.

Additional links:
- My backward compat analysis suggested the risk is low [2]
- Relevant WPT test [3].


I tested this on Safari 12.0.1.

[1] https://github.com/w3c/csswg-drafts/issues/2232
[2] https://github.com/w3c/csswg-drafts/issues/2232#issuecomment-399961633
[3] https://wpt.fyi/results/css/css-scroll-snap/snap-inline-block.html?label=stable&aligned
Comment 1 Radar WebKit Bug Importer 2018-11-29 10:35:08 PST
<rdar://problem/46346516>