252403 2023-02-16 08:33:36 -0800 HTMLStyleElement mangles -webkit-mask-repeat into unsupported mask-repeat 2023-12-17 04:09:41 -0800 1 1 1 Unclassified WebKit CSS Safari 16 Unspecified Unspecified RESOLVED DUPLICATE 243915 InRadar P2 Normal --- 1 clshortfuse webkit-unassigned annevk ntim webkit-bug-importer oldest_to_newest 1934189 0 clshortfuse 2023-02-16 08:33:36 -0800 When creating an HTMLStyleElement with `-webkit-mask-repeat` included, the property is mangled to `mask-repeat`. Webkit supports `-webkit-mask-repeat`, but not `mask-repeat`. Therefore, when attempting to reflect back into another HTMLStyleElement, the style is invalid. This is used to ponyfill/polyfill CSS Modules (native ones). Test: https://codepen.io/shortfuse/pen/PodwrJE Chrome PASS Firefox PASS WebKit/Safari FAIL Unprefixing is fine if it's supported. Firefox unprefixes and that's fine. Chrome doesn't unprefix, so that's also fine. But Webkit will unprefix and break the ability to replicate styles. Related: * https://bugs.webkit.org/show_bug.cgi?id=167255 * https://bugs.webkit.org/show_bug.cgi?id=227967 * https://bugs.webkit.org/show_bug.cgi?id=229082 1936200 1 webkit-bug-importer 2023-02-23 08:34:17 -0800 <rdar://problem/105835488> 1936264 2 ntim 2023-02-23 11:09:31 -0800 The unprefixed mask-repeat is supported by Safari, and -webkit-mask-repeat is an alias of it. 1936376 3 clshortfuse 2023-02-23 16:12:29 -0800 CSS.supports("mask-repeat-x", "initial") and CSS.supports("mask-repeat-y", "initial") reports false on iPad 16.1 The codepen shows this pretty clearly. "-webkit-mask-repeat" gets mangled to "mask-repeat-x" and "mask-repeat-y" and neither are supported. 1944421 4 ntim 2023-03-27 16:39:38 -0700 mask-repeat-x/mask-repeat-y shouldn't exist, only -webkit-mask-repeat-x/-webkit-mask-repeat-y should. 1944422 5 ntim 2023-03-27 16:41:06 -0700 Actually, -webkit-mask-repeat-x/-webkit-mask-repeat-y should have been removed as well 2000264 6 annevk 2023-12-17 04:09:41 -0800 The -x/-y variants were removed in bug 243915. *** This bug has been marked as a duplicate of bug 243915 ***