Block Bindings: Add filter to set supported block attributes.

Add a new filter, `block_bindings_supported_attributes_{$block_type}`, that allows customizing which of a block's attributes can be connected to a Block Bindings source.

Props bernhard-reiter, gziolo, maxschmeling.
Closes #62090.

git-svn-id: https://develop.svn.wordpress.org/trunk@60611 602fd350-edb4-49c9-b593-d223f7449a82

Author: ockham

src/wp-includes/class-wp-block.php

@@ -98,6 +98,22 @@ class WP_Block {
 	 */
 	public $inner_content = array();
 
+	/**
+	 * List of supported block attributes for block bindings.
+	 *
+	 * @since 6.9.0
+	 * @var array
+	 *
+	 * @see WP_Block::process_block_bindings()
+	 */
+	private const BLOCK_BINDINGS_SUPPORTED_ATTRIBUTES = array(
+		'core/paragraph' => array( 'content' ),
+		'core/heading'   => array( 'content' ),
+		'core/image'     => array( 'id', 'url', 'title', 'alt' ),
+		'core/button'    => array( 'url', 'text', 'linkTarget', 'rel' ),
+		'core/post-date' => array( 'datetime' ),
+	);
+
 	/**
 	 * Constructor.
 	 *
@@ -278,20 +294,33 @@ public function __get( $name ) {
 	 * @return array The computed block attributes for the provided block bindings.
 	 */
 	private function process_block_bindings() {
+		$block_type                 = $this->name;
 		$parsed_block               = $this->parsed_block;
 		$computed_attributes        = array();
-		$supported_block_attributes = array(
-			'core/paragraph' => array( 'content' ),
-			'core/heading'   => array( 'content' ),
-			'core/image'     => array( 'id', 'url', 'title', 'alt' ),
-			'core/button'    => array( 'url', 'text', 'linkTarget', 'rel' ),
-			'core/post-date' => array( 'datetime' ),
+
+		$supported_block_attributes =
+			self::BLOCK_BINDINGS_SUPPORTED_ATTRIBUTES[ $block_type ] ??
+			array();
+
+		/**
+		 * Filters the supported block attributes for block bindings.
+		 *
+		 * The dynamic portion of the hook name, `$block_type`, refers to the block type
+		 * whose attributes are being filtered.
+		 *
+		 * @since 6.9.0
+		 *
+		 * @param string[] $supported_block_attributes The block's attributes that are supported by block bindings.
+		 */
+		$supported_block_attributes = apply_filters(
+			"block_bindings_supported_attributes_{$block_type}",
+			$supported_block_attributes
 		);
 
 		// If the block doesn't have the bindings property, isn't one of the supported
 		// block types, or the bindings property is not an array, return the block content.
 		if (
-			! isset( $supported_block_attributes[ $this->name ] ) ||
+			empty( $supported_block_attributes ) ||
 			empty( $parsed_block['attrs']['metadata']['bindings'] ) ||
 			! is_array( $parsed_block['attrs']['metadata']['bindings'] )
 		) {
@@ -315,7 +344,7 @@ private function process_block_bindings() {
 			 * Note that this also omits the `__default` attribute from the
 			 * resulting array.
 			 */
-			foreach ( $supported_block_attributes[ $parsed_block['blockName'] ] as $attribute_name ) {
+			foreach ( $supported_block_attributes as $attribute_name ) {
 				// Retain any non-pattern override bindings that might be present.
 				$updated_bindings[ $attribute_name ] = isset( $bindings[ $attribute_name ] )
 					? $bindings[ $attribute_name ]
@@ -334,7 +363,7 @@ private function process_block_bindings() {
 
 		foreach ( $bindings as $attribute_name => $block_binding ) {
 			// If the attribute is not in the supported list, process next attribute.
-			if ( ! in_array( $attribute_name, $supported_block_attributes[ $this->name ], true ) ) {
+			if ( ! in_array( $attribute_name, $supported_block_attributes, true ) ) {
 				continue;
 			}
 			// If no source is provided, or that source is not registered, process next attribute.

tests/phpunit/tests/block-bindings/render.php

@@ -16,6 +16,27 @@ class WP_Block_Bindings_Render extends WP_UnitTestCase {
 		'label' => 'Test source',
 	);
 
+	/**
+	 * Sets up shared fixtures.
+	 *
+	 * @since 6.9.0
+	 */
+	public static function wpSetUpBeforeClass() {
+		register_block_type(
+			'test/block',
+			array(
+				'attributes'      => array(
+					'myAttribute' => array(
+						'type' => 'string',
+					),
+				),
+				'render_callback' => function ( $attributes ) {
+					return '<p>' . esc_html( $attributes['myAttribute'] ) . '</p>';
+				},
+			)
+		);
+	}
+
 	/**
 	 * Tear down after each test.
 	 *
@@ -31,6 +52,15 @@ public function tear_down() {
 		parent::tear_down();
 	}
 
+	/**
+	 * Tear down after class.
+	 *
+	 * @since 6.9.0
+	 */
+	public static function wpTearDownAfterClass() {
+		unregister_block_type( 'test/block' );
+	}
+
 	/**
 	 * Test if the block content is updated with the value returned by the source.
 	 *
@@ -72,6 +102,53 @@ public function test_update_block_with_value_from_source() {
 		);
 	}
 
+	/**
+	 * Test if the block_bindings_supported_attributes_{$block_type} filter is applied correctly.
+	 *
+	 * @ticket 62090
+	 */
+	public function test_filter_block_bindings_supported_attributes() {
+		$get_value_callback = function () {
+			return 'test source value';
+		};
+
+		register_block_bindings_source(
+			self::SOURCE_NAME,
+			array(
+				'label'              => self::SOURCE_LABEL,
+				'get_value_callback' => $get_value_callback,
+			)
+		);
+
+		add_filter(
+			'block_bindings_supported_attributes_test/block',
+			function ( $supported_attributes ) {
+				$supported_attributes[] = 'myAttribute';
+				return $supported_attributes;
+			}
+		);
+
+		$block_content = <<<HTML
+<!-- wp:test/block {"metadata":{"bindings":{"myAttribute":{"source":"test/source"}}}} -->
+<p>This should not appear</p>
+<!-- /wp:test/block -->
+HTML;
+		$parsed_blocks = parse_blocks( $block_content );
+		$block         = new WP_Block( $parsed_blocks[0] );
+		$result        = $block->render();
+
+		$this->assertSame(
+			'test source value',
+			$block->attributes['myAttribute'],
+			"The 'myAttribute' attribute should be updated with the value returned by the source."
+		);
+		$this->assertSame(
+			'<p>test source value</p>',
+			trim( $result ),
+			'The block content should be updated with the value returned by the source.'
+		);
+	}
+
 	/**
 	 * Test passing arguments to the source.
 	 *