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Selector: Use Sizzle :has if CSS.supports(selector(...)) non-comp…
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…liant

Sizzle has followed the following logic for selector handling for ages:
1. Modify the selector to adhere to scoping rules jQuery mandates.
2. Try `qSA` on the modified selector. If it succeeds, use the results.
3. If `qSA` threw an error, run the Sizzle custom traversal instead.

It worked fine so far but now CSS has a concept of forgiving selector lists that
some selectors like `:is()` & `:has()` use. That means providing unrecognized
selectors as parameters to `:is()` & `:has()` no longer throws an error, it will
just return no results. That made browsers with native `:has()` support break
selectors using jQuery extensions inside, e.g. `:has(:contains("Item"))`.

Detecting support for selectors can also be done via:

```js
CSS.supports( "selector(SELECTOR_TO_BE_TESTED)" )
```
which returns a boolean. There was a recent spec change requiring this API to
always use non-forgiving parsing:
w3c/csswg-drafts#7280 (comment)
However, no browsers have implemented this change so far.

To solve this, two changes are being made:
1. In browsers supports the new spec change to `CSS.supports( "selector()" )`,
   use it before trying `qSA`.
2. Otherwise, add `:has` to the buggy selectors list.

Fixes jquery/jquery#5098
Closes gh-486
Ref jquery/jquery#5107
Ref w3c/csswg-drafts#7676
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mgol committed Sep 19, 2022
1 parent d3af661 commit 3798e3d
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Showing 2 changed files with 68 additions and 2 deletions.
60 changes: 59 additions & 1 deletion src/sizzle.js
Original file line number Diff line number Diff line change
Expand Up @@ -356,6 +356,27 @@ function Sizzle( selector, context, results, seed ) {
}

try {

// `qSA` may not throw for unrecognized parts using forgiving parsing:
// https://drafts.csswg.org/selectors/#forgiving-selector
// like the `:has()` pseudo-class:
// https://drafts.csswg.org/selectors/#relational
// `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 &&

// eslint-disable-next-line no-undef
!CSS.supports( "selector(" + 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 )
);
Expand Down Expand Up @@ -651,6 +672,31 @@ setDocument = Sizzle.setDocument = function( node ) {
!el.querySelectorAll( ":scope fieldset div" ).length;
} );

// Support: Chrome 105+, Firefox 104+, Safari 15.4+
// Make sure forgiving mode is not used in `CSS.supports( "selector(...)" )`.
//
// `:is()` uses a forgiving selector list as an argument and is widely
// implemented, so it's a good one to test against.
support.cssSupportsSelector = assert( function() {
/* eslint-disable no-undef */

return CSS.supports( "selector(*)" ) &&

// Support: Firefox 78-81 only
// In old Firefox, `:is()` didn't use forgiving parsing. In that case,
// fail this test as there's no selector to test against that.
// `CSS.supports` uses unforgiving parsing
document.querySelectorAll( ":is(:jqfake)" ) &&

// `*` is needed as Safari & newer Chrome implemented something in between
// for `:has()` - it throws in `qSA` if it only contains an unsupported
// argument but multiple ones, one of which is supported, are fine.
// We want to play safe in case `:is()` gets the same treatment.
!CSS.supports( "selector(:is(*,:jqfake))" );

/* eslint-enable */
} );

/* Attributes
---------------------------------------------------------------------- */

Expand Down Expand Up @@ -917,6 +963,18 @@ setDocument = Sizzle.setDocument = function( node ) {
} );
}

if ( !support.cssSupportsSelector ) {

// Support: Chrome 105+, Safari 15.4+
// `:has()` uses a forgiving selector list as an argument so our regular
// `try-catch` mechanism fails to catch `:has()` with arguments not supported
// natively like `:has(:contains("Foo"))`. Where supported & spec-compliant,
// we now use `CSS.supports("selector(SELECTOR_TO_BE_TESTED)")` but outside
// that, let's mark `:has` as buggy to always use jQuery traversal for
// `:has()`.
rbuggyQSA.push( ":has" );
}

rbuggyQSA = rbuggyQSA.length && new RegExp( rbuggyQSA.join( "|" ) );
rbuggyMatches = rbuggyMatches.length && new RegExp( rbuggyMatches.join( "|" ) );

Expand Down Expand Up @@ -1719,7 +1777,7 @@ Expr = Sizzle.selectors = {
return elem.nodeName.toLowerCase() === "input" &&
elem.type === "text" &&

// Support: IE<8
// Support: IE <10 only
// New HTML5 attribute values (e.g., "search") appear with elem.type === "text"
( ( attr = elem.getAttribute( "type" ) ) == null ||
attr.toLowerCase() === "text" );
Expand Down
10 changes: 9 additions & 1 deletion test/unit/selector.js
Original file line number Diff line number Diff line change
Expand Up @@ -842,11 +842,19 @@ QUnit.test( "pseudo - nth-last-of-type", function( assert ) {
} );

QUnit.test( "pseudo - has", function( assert ) {
assert.expect( 3 );
assert.expect( 4 );

t( "Basic test", "p:has(a)", [ "firstp", "ap", "en", "sap" ] );
t( "Basic test (irrelevant whitespace)", "p:has( a )", [ "firstp", "ap", "en", "sap" ] );
t( "Nested with overlapping candidates", "#qunit-fixture div:has(div:has(div:not([id])))", [ "moretests", "t2037" ] );

// Support: Safari 15.4+, Chrome 107+?
// `qSA` in Safari throws for `:has()` with only unsupported arguments
// but if you add a supported arg to the list, it will run and just potentially
// return no results. Make sure this is accounted for.
t( "Nested with list arguments",
"#qunit-fixture div:has(faketag, div:has(faketag, div:not([id])))",
[ "moretests", "t2037" ] );
} );

QUnit.test( "pseudo - contains", function( assert ) {
Expand Down

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