HTML API: Return subclass from ::create_fragment

When the `WP_HTML_Processor` was introduced with its `::create_fragment()` static creator method, that method has been returning a `new self(...)`. Unfortunately, this means that subclasses cannot use that method since it will return the `WP_HTML_Processor` instead of the subclass. With this patch, the static creator method returns `new static(...)` to preserve the intended behavior. A new test asserts this behavior for future changes. Developed in #6729 Discussed in https://core.trac.wordpress.org/ticket/61374 Props dmsnell, jonsurrell. Follow-up to [56274]. Fixes #61374. git-svn-id: https://develop.svn.wordpress.org/trunk@58363 602fd350-edb4-49c9-b593-d223f7449a82
WordPress · Jun 8, 2024 · 0cad031 · 0cad031
1 parent 1ea82dc
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Showing 2 changed files with 22 additions and 2 deletions.
diff --git a/src/wp-includes/html-api/class-wp-html-processor.php b/src/wp-includes/html-api/class-wp-html-processor.php
@@ -276,18 +276,19 @@ class WP_HTML_Processor extends WP_HTML_Tag_Processor {
 	 *  - The only supported document encoding is `UTF-8`, which is the default value.
 	 *
 	 * @since 6.4.0
+	 * @since 6.6.0 Returns `static` instead of `self` so it can create subclass instances.
 	 *
 	 * @param string $html     Input HTML fragment to process.
 	 * @param string $context  Context element for the fragment, must be default of `<body>`.
 	 * @param string $encoding Text encoding of the document; must be default of 'UTF-8'.
-	 * @return WP_HTML_Processor|null The created processor if successful, otherwise null.
+	 * @return static|null The created processor if successful, otherwise null.
 	 */
 	public static function create_fragment( $html, $context = '<body>', $encoding = 'UTF-8' ) {
 		if ( '<body>' !== $context || 'UTF-8' !== $encoding ) {
 			return null;
 		}
 
-		$processor                        = new self( $html, self::CONSTRUCTOR_UNLOCK_CODE );
+		$processor                        = new static( $html, self::CONSTRUCTOR_UNLOCK_CODE );
 		$processor->state->context_node   = array( 'BODY', array() );
 		$processor->state->insertion_mode = WP_HTML_Processor_State::INSERTION_MODE_IN_BODY;
 

diff --git a/tests/phpunit/tests/html-api/wpHtmlProcessor.php b/tests/phpunit/tests/html-api/wpHtmlProcessor.php
@@ -517,4 +517,23 @@ public static function data_html_with_target_element_and_depth_of_next_node_in_b
 			'Funky comment'                     => array( '<div><p>What <br class="target"><//wp:post-author></p></div>', 5 ),
 		);
 	}
+
+	/**
+	 * Ensures that subclasses can be created from ::create_fragment method.
+	 *
+	 * @ticket 61374
+	 */
+	public function test_subclass_create_fragment_creates_subclass() {
+		$processor = WP_HTML_Processor::create_fragment( '' );
+		$this->assertInstanceOf( WP_HTML_Processor::class, $processor, '::create_fragment did not return class instance.' );
+
+		$subclass_instance = new class('') extends WP_HTML_Processor {
+			public function __construct( $html ) {
+				parent::__construct( $html, parent::CONSTRUCTOR_UNLOCK_CODE );
+			}
+		};
+
+		$subclass_processor = call_user_func( array( get_class( $subclass_instance ), 'create_fragment' ), '' );
+		$this->assertInstanceOf( get_class( $subclass_instance ), $subclass_processor, '::create_fragment did not return subclass instance.' );
+	}
 }