fix: implement nested selector parsing (#12587)

packages/puppeteer-core/src/common/PSelectorParser.test.ts

@@ -0,0 +1,50 @@
+/**
+ * @license
+ * Copyright 2024 Google Inc.
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+import {describe, it} from 'node:test';
+
+import expect from 'expect';
+
+import {parsePSelectors} from './PSelectorParser.js';
+
+describe('PSelectorParser', () => {
+  describe('parsePSelectors', () => {
+    it('parses nested selectors', () => {
+      const [updatedSelector, isPureCSS, hasPseudoClasses] =
+        parsePSelectors('& > div');
+      expect(updatedSelector).toEqual([[['&>div']]]);
+      expect(isPureCSS).toBeTruthy();
+      expect(hasPseudoClasses).toBeFalsy();
+    });
+
+    it('parses nested selectors with p-selector syntax', () => {
+      const [updatedSelector, isPureCSS, hasPseudoClasses] =
+        parsePSelectors('& > div >>> button');
+      expect(updatedSelector).toEqual([[['&>div'], '>>>', ['button']]]);
+      expect(isPureCSS).toBeFalsy();
+      expect(hasPseudoClasses).toBeFalsy();
+    });
+
+    it('parses selectors with pseudo classes', () => {
+      const [updatedSelector, isPureCSS, hasPseudoClasses] =
+        parsePSelectors('div:focus');
+      expect(updatedSelector).toEqual([[['div:focus']]]);
+      expect(isPureCSS).toBeTruthy();
+      expect(hasPseudoClasses).toBeTruthy();
+    });
+
+    it('parses nested selectors with pseudo classes and p-selector syntax', () => {
+      const [updatedSelector, isPureCSS, hasPseudoClasses] = parsePSelectors(
+        '& > div:focus >>>> button:focus'
+      );
+      expect(updatedSelector).toEqual([
+        [['&>div:focus'], '>>>>', ['button:focus']],
+      ]);
+      expect(isPureCSS).toBeFalsy();
+      expect(hasPseudoClasses).toBeTruthy();
+    });
+  });
+});

packages/puppeteer-core/src/common/PSelectorParser.ts

@@ -17,6 +17,7 @@ import type {
 } from '../injected/PQuerySelector.js';
 import {PCombinator} from '../injected/PQuerySelector.js';
 
+TOKENS['nesting'] = /&/g;
 TOKENS['combinator'] = /\s*(>>>>?|[\s>+~])\s*/g;
 
 const ESCAPE_REGEXP = /\\[\s\S]/g;
@@ -94,7 +95,7 @@ export function parsePSelectors(
         continue;
       case 'pseudo-class':
         hasPseudoClasses = true;
-        continue;
+        break;
       case 'comma':
         if (storage.length) {
           compoundSelector.push(stringify(storage));