Created attachment 311761 [details] Test case to reproduce the issue There are some cases where right/left margin is applied to determine an orthogonal item's width. This is incorrect because right/left are absolute directions which can operate along inline or block item's axis depending on its writing-mode. It seems we are using the grid container's writing-mode to determine the logical size of the margin. This is incorrect for orthogonal items, as it's shown in the attached test case.
This issue has been already solved in Blink, so it'd be a matter of porting the following patch: https://codereview.chromium.org/2543193002/
Created attachment 311765 [details] Patch
Comment on attachment 311765 [details] Patch View in context: https://bugs.webkit.org/attachment.cgi?id=311765&action=review > LayoutTests/fast/css-grid-layout/grid-track-sizing-with-margins-and-orthogonal-flows.html:7 > +.item { margin: 10px 5px 5px 15px; } I'd use a different value for each margin property, so we're sure we're not mixing margin-right and margin-bottom. What about something like: 10px 5px 20px 15px ?
Created attachment 311818 [details] Patch
Comment on attachment 311818 [details] Patch Clearing flags on attachment: 311818 Committed r217709: <http://trac.webkit.org/changeset/217709>
All reviewed patches have been landed. Closing bug.