Improve core library file detection

includes/Checker/Checks/Plugin_Repo/File_Type_Check.php

@@ -375,62 +375,20 @@ function ( $file ) use ( $plugin_path ) {
 	 * @param array        $files  List of absolute file paths.
 	 */
 	protected function look_for_library_core_files( Check_Result $result, array $files ) {
-		// Known libraries that are part of WordPress core.
-		// https://meta.trac.wordpress.org/browser/sites/trunk/api.wordpress.org/public_html/core/credits/wp-59.php#L739 .
-		$look_known_libraries_core_services = array(
-			'(?<![\.|-])jquery(-[0-9|\.]*)?(\.slim)?(\.min)?\.js(?!\/)',
-			'jquery-ui(-[0-9|\.]*)?(\.slim)?(\.min)?\.js(?!\/)',
-			'jquery.color(\.slim)?(\.min)?\.js(?!\/)',
-			'jquery.ui.touch-punch(?!\/)',
-			'jquery.hoverintent(?!\/)',
-			'jquery.imgareaselect(?!\/)',
-			'jquery.hotkeys(?!\/)',
-			'jquery.ba-serializeobject(?!\/)',
-			'jquery.query-object(?!\/)',
-			'jquery.suggest(?!\/)',
-			'polyfill(\.min)?\.js(?!\/)',
-			'iris(\.min)?\.js(?!\/)',
-			'backbone(\.min)?\.js(?!\/)',
-			'clipboard(\.min)?\.js(?!\/)',
-			'closest(\.min)?\.js(?!\/)',
-			'codemirror(\.min)?\.js(?!\/)',
-			'formdata(\.min)?\.js(?!\/)',
-			'json2(\.min)?\.js(?!\/)',
-			'lodash(\.min)?\.js(?!\/)',
-			'masonry(\.pkgd)(\.min)?\.js(?!\/)',
-			'mediaelement-and-player(\.min)?\.js(?!\/)',
-			'moment(\.min)?\.js(?!\/)',
-			'plupload(\.full)(\.min)?\.js(?!\/)',
-			'thickbox(\.min)?\.js(?!\/)',
-			'twemoji(\.min)?\.js(?!\/)',
-			'underscore([\.|-]min)?\.js(?!\/)',
-			'moxie(\.min)?\.js(?!\/)',
-			'zxcvbn(\.min)?\.js(?!\/)',
-			'getid3\.php(?!\/)',
-			'pclzip\.lib\.php(?!\/)',
-			'PasswordHash\.php(?!\/)',
-			'PHPMailer\.php(?!\/)',
-			'SimplePie\.php(?!\/)',
-		);
-
-		$combined_pattern = '/(' . implode( ')|(', $look_known_libraries_core_services ) . ')/i';
-
 		$plugin_path = $result->plugin()->path();
 
-		$files = array_map(
-			function ( $file ) use ( $plugin_path ) {
-				return str_replace( $plugin_path, '', $file );
-			},
-			$files
-		);
-
+		$relative_files = array();
 		foreach ( $files as $file ) {
-			if ( preg_match( $combined_pattern, $file ) ) {
+			$relative_files[ $file ] = str_replace( $plugin_path, '', $file );
+		}
+
+		foreach ( $relative_files as $file => $relative_file ) {
+			if ( Core_Library_File_Signature_Checker::file_matches_core_library_signature( $file, $relative_file ) ) {
 				$this->add_result_error_for_file(
 					$result,
 					__( 'Library files that are already in the WordPress core are not permitted.', 'plugin-check' ),
 					'library_core_files',
-					$file,
+					$relative_file,
 					0,
 					0,
 					'',

tests/phpunit/testdata/plugins/test-plugin-file-type-library-core-errors/PHPMailer.php

@@ -1 +1,5 @@
 <?php
+
+namespace PHPMailer\PHPMailer;
+
+class PHPMailer {}

tests/phpunit/testdata/plugins/test-plugin-file-type-library-core-errors/clipboard.js

@@ -0,0 +1,2 @@
+/*! clipboard.js v2.0.11 */
+window.ClipboardJS = function ClipboardJS() {};

tests/phpunit/testdata/plugins/test-plugin-file-type-library-core-errors/jquery.js

@@ -1 +1,2 @@
-// For testing purposes, this file is empty.
+/*! jQuery JavaScript Library v3.7.1 | jquery.org/license */
+window.jQuery = window.jQuery || {};

tests/phpunit/testdata/plugins/test-plugin-file-type-library-core-without-errors/assets/polyfill.js

@@ -0,0 +1,5 @@
+/**
+ * Custom feature detection helper that happens to use a generic polyfill.js
+ * filename without bundling WordPress core's registered polyfill script.
+ */
+window.examplePluginPolyfill = true;

tests/phpunit/testdata/plugins/test-plugin-file-type-library-core-without-errors/includes/PHPMailer.php

@@ -0,0 +1,5 @@
+<?php
+
+namespace ExamplePlugin\Mail;
+
+class PHPMailer {}

tests/phpunit/testdata/plugins/test-plugin-file-type-library-core-without-errors/load.php

@@ -0,0 +1,18 @@
+<?php
+/**
+ * Plugin Name: Test Plugin File Type Library Core Files Without Errors
+ * Plugin URI: https://github.com/WordPress/plugin-check
+ * Description: Some plugin description.
+ * Author: WordPress Performance Team
+ * Author URI: https://make.wordpress.org/plugins/
+ * License: GPLv2 or later
+ * License URI: https://www.gnu.org/licenses/old-licenses/gpl-2.0.html
+ * Text Domain: test-plugin-file-type-library-core-without-errors
+ *
+ * @package test-plugin-file-type-library-core-without-errors
+ */
+
+/**
+ * Plugin folder contains files with core-library-like names that are not
+ * bundled copies of WordPress core libraries.
+ */

tests/phpunit/testdata/plugins/test-plugin-file-type-library-core-without-errors/src/utils/clipboard.js

@@ -0,0 +1,8 @@
+/**
+ * Copies text to the clipboard using browser APIs.
+ *
+ * This is a custom helper and not a bundled copy of a third-party package.
+ */
+export function copyToClipboard( text ) {
+	return navigator.clipboard.writeText( text );
+}

tests/phpunit/tests/Checker/Checks/File_Type_Check_Tests.php

@@ -211,7 +211,7 @@ public function test_run_with_library_core_errors() {
 		$errors = $check_result->get_errors();
 
 		$this->assertNotEmpty( $errors );
-		$this->assertEquals( 2, $check_result->get_error_count() );
+		$this->assertEquals( 3, $check_result->get_error_count() );
 
 		// Check for core PHPMailer.
 		$this->assertArrayHasKey( 0, $errors['PHPMailer.php'] );
@@ -222,6 +222,22 @@ public function test_run_with_library_core_errors() {
 		$this->assertArrayHasKey( 0, $errors['jquery.js'] );
 		$this->assertArrayHasKey( 0, $errors['jquery.js'][0] );
 		$this->assertCount( 1, wp_list_filter( $errors['jquery.js'][0][0], array( 'code' => 'library_core_files' ) ) );
+
+		// Check for core ClipboardJS.
+		$this->assertArrayHasKey( 0, $errors['clipboard.js'] );
+		$this->assertArrayHasKey( 0, $errors['clipboard.js'][0] );
+		$this->assertCount( 1, wp_list_filter( $errors['clipboard.js'][0][0], array( 'code' => 'library_core_files' ) ) );
+	}
+
+	public function test_run_with_library_core_filename_false_positives() {
+		$check_context = new Check_Context( UNIT_TESTS_PLUGIN_DIR . 'test-plugin-file-type-library-core-without-errors/load.php' );
+		$check_result  = new Check_Result( $check_context );
+
+		$check = new File_Type_Check( File_Type_Check::TYPE_LIBRARY_CORE );
+		$check->run( $check_result );
+
+		$this->assertSame( 0, $check_result->get_error_count() );
+		$this->assertEmpty( $check_result->get_errors() );
 	}
 
 	public function test_run_with_composer_errors() {