RFC 136: Remove the CSS build system (#136)

Author: foolip

rfcs/css_build_system.md

@@ -0,0 +1,24 @@
+# RFC 136: Remove the CSS build system
+
+## Summary
+
+Remove CSS build system in `css/tools/` and the path lint rules for `css/` that support that build system.
+
+## Details
+
+http://test.csswg.org/suites/ hasn't been updated in some time, which led to a [discussion](https://github.com/w3c/csswg-drafts/issues/6896) in the CSS Working Group about how to fix it. Ultimately, the CSS Working Group [resolved](https://github.com/w3c/csswg-drafts/issues/6896#issuecomment-1499457107) to remove the now unused CSS build system, and this RFC implements that decision.
+
+These lint rules will be removed:
+
+- CSS-COLLIDING-TEST-NAME ("The filename ... in the ... testsuite is shared by: ...")
+- CSS-COLLIDING-REF-NAME ("The filename ... is shared by: ...")
+- CSS-COLLIDING-SUPPORT-NAME ("The filename ... is shared by: ...")
+- SUPPORT-WRONG-DIR ("Support file not in support directory")
+
+The MISSING-LINK ("Testcase file must have a link to a spec") rule which also applies only to `css/` will _not_ be removed, as it isn't only used by the build system, but is also a matter of style and preference. This may be revisited later.
+
+This RFC will be implemented by https://github.com/web-platform-tests/wpt/pull/38976.
+
+## Risks
+
+Reviving http://test.csswg.org/suites/ becomes harder with this removal, so if that system has important functionality, it will require more work to meet those needs again. However, the web-platform-tests project remains open to contributions to support missing use cases, should the need arise.