Selector: Stop relying on CSS.supports( "selector(...)" )

`CSS.supports( "selector(...)" )` has different semantics than selectors passed
to `querySelectorAll`. Apart from the fact that the former returns `false` for
unrecognized selectors and the latter throws, `qSA` is more forgiving and
accepts some invalid selectors, auto-correcting them where needed - for
example, mismatched brackers are auto-closed. This behavior difference is
breaking for many users.

To add to that, a recent CSSWG resolution made `:is()` & `:where()` the only
pseudos with forgiving parsing; browsers are in the process of making `:has()`
parsing unforgiving.

Taking all that into account, we go back to our previous try-catch approach
without relying on `CSS.supports( "selector(...)" )`. The only difference
is we detect forgiving parsing in `:has()` and mark the selector as buggy.

The PR also updates `playwright-webkit` so that we test against a version
of WebKit that already has non-forgiving `:has()`.

Fixes gh-5194
Closes gh-5206
Ref gh-5098
Ref gh-5107
Ref w3c/csswg-drafts#7676

Co-authored-by: Richard Gibson <richard.gibson@gmail.com>

1 files changed, 0 insertions, 27 deletions

diff --git a/src/selector.js b/src/selector.js
index 328eca45f..c995a65fe 100644
--- a/src/selector.js
+++ b/src/selector.js
@@ -22,7 +22,6 @@ import selectorError from "./selector/selectorError.js";
 import unescapeSelector from "./selector/unescapeSelector.js";
 import tokenize from "./selector/tokenize.js";
 import toSelector from "./selector/toSelector.js";
-import support from "./selector/support.js";
 
 // The following utils are attached directly to the jQuery object.
 import "./selector/escapeSelector.js";
@@ -189,32 +188,6 @@ function find( selector, context, results, seed ) {
 				}
 
 				try {
-
-					// `qSA` may not throw for unrecognized parts using forgiving parsing:
-					// https://drafts.csswg.org/selectors/#forgiving-selector
-					// like the `:is()` pseudo-class:
-					// https://drafts.csswg.org/selectors/#matches
-					// `CSS.supports` is still expected to return `false` then:
-					// https://drafts.csswg.org/css-conditional-4/#typedef-supports-selector-fn
-					// https://drafts.csswg.org/css-conditional-4/#dfn-support-selector
-					if ( support.cssSupportsSelector &&
-
-						// `CSS.supports( "selector(...)" )` requires the argument to the
-						// `selector` function to be a `<complex-selector>`, not
-						// a `<complex-selector-list>` which our selector may be. Wrapping with
-						// `:is` works around the issue and is supported by all browsers
-						// we support except for IE which will fail the support test anyway.
-						// eslint-disable-next-line no-undef
-						!CSS.supports( "selector(:is(" + newSelector + "))" ) ) {
-
-						// Support: IE 11+
-						// Throw to get to the same code path as an error directly in qSA.
-						// Note: once we only support browser supporting
-						// `CSS.supports('selector(...)')`, we can most likely drop
-						// the `try-catch`. IE doesn't implement the API.
-						throw new Error();
-					}
-
 					push.apply( results,
 						newContext.querySelectorAll( newSelector )
 					);