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

jQuery 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 jQuery 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 gh-5098
Closes gh-5107
Ref w3c/csswg-drafts#7676
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mgol committed Sep 19, 2022
1 parent 78321f0 commit d153c37
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Showing 5 changed files with 97 additions and 17 deletions.
22 changes: 22 additions & 0 deletions src/selector.js
Expand Up @@ -9,6 +9,7 @@ import whitespace from "./var/whitespace.js";
import rbuggyQSA from "./selector/rbuggyQSA.js";
import rtrim from "./var/rtrim.js";
import isIE from "./var/isIE.js";
import support from "./selector/support.js";

// The following utils are attached directly to the jQuery object.
import "./selector/contains.js";
Expand Down Expand Up @@ -252,6 +253,27 @@ 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 `: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
41 changes: 30 additions & 11 deletions src/selector/rbuggyQSA.js
@@ -1,19 +1,38 @@
import isIE from "../var/isIE.js";
import whitespace from "../var/whitespace.js";
import support from "./support.js";

var rbuggyQSA = isIE && new RegExp(
var rbuggyQSA = [];

// Support: IE 9 - 11+
// IE's :disabled selector does not pick up the children of disabled fieldsets
":enabled|:disabled|" +
if ( isIE ) {
rbuggyQSA.push(

// Support: IE 11+
// IE 11 doesn't find elements on a `[name='']` query in some cases.
// Adding a temporary attribute to the document before the selection works
// around the issue.
"\\[" + whitespace + "*name" + whitespace + "*=" +
whitespace + "*(?:''|\"\")"
// Support: IE 9 - 11+
// IE's :disabled selector does not pick up the children of disabled fieldsets
":enabled",
":disabled",

);
// Support: IE 11+
// IE 11 doesn't find elements on a `[name='']` query in some cases.
// Adding a temporary attribute to the document before the selection works
// around the issue.
"\\[" + whitespace + "*name" + whitespace + "*=" +
whitespace + "*(?:''|\"\")"
);
}

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( "|" ) );

export default rbuggyQSA;
24 changes: 24 additions & 0 deletions src/selector/support.js
@@ -0,0 +1,24 @@
import support from "../var/support.js";

try {
/* eslint-disable no-undef */

// 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 = CSS.supports( "selector(*)" ) &&

// `*` 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 */
} catch ( e ) {
support.cssSupportsSelector = false;
}

export default support;
12 changes: 11 additions & 1 deletion test/unit/selector.js
Expand Up @@ -931,13 +931,23 @@ QUnit.test( "pseudo - nth-last-of-type", function( assert ) {
} );

QUnit[ QUnit.jQuerySelectors ? "test" : "skip" ]( "pseudo - has", function( assert ) {
assert.expect( 3 );
assert.expect( 4 );

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

// Support: Safari 15.4+, Chrome 105+
// `qSA` in Safari/Chrome 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. (gh-5098)
// Note: Chrome 105 has this behavior only in 105.0.5195.125 or newer;
// initially it shipped with a fully forgiving parsing in `:has()`.
assert.t( "Nested with list arguments",
"#qunit-fixture div:has(faketag, div:has(faketag, div:not([id])))",
[ "moretests", "t2037", "fx-test-group", "fx-queue" ] );
} );

QUnit[ QUnit.jQuerySelectors ? "test" : "skip" ]( "pseudo - contains", function( assert ) {
Expand Down
15 changes: 10 additions & 5 deletions test/unit/support.js
Expand Up @@ -59,19 +59,24 @@ testIframe(
userAgent = window.navigator.userAgent,
expectedMap = {
ie_11: {
"reliableTrDimensions": false
cssSupportsSelector: false,
reliableTrDimensions: false
},
chrome: {
"reliableTrDimensions": true
cssSupportsSelector: false,
reliableTrDimensions: true
},
safari: {
"reliableTrDimensions": true
cssSupportsSelector: false,
reliableTrDimensions: true
},
firefox: {
"reliableTrDimensions": false
cssSupportsSelector: false,
reliableTrDimensions: false
},
ios: {
"reliableTrDimensions": true
cssSupportsSelector: false,
reliableTrDimensions: true
}
};

Expand Down

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