General: Add `block_hooks` field to block type registration, REST API.

In order to implement Block Hooks, we need to add a new `block_hooks` field to the `WP_Block_Type` class, as well as to block registration related functions, the block types REST API controller, etc.

Props gziolo.
Fixes #59346. See #59313.
Built from https://develop.svn.wordpress.org/trunk@56587


git-svn-id: http://core.svn.wordpress.org/trunk@56099 1a063a9b-81f0-0310-95a4-ce76da25c4cd

wp-admin/includes/post.php

@@ -2207,6 +2207,7 @@ function taxonomy_meta_box_sanitize_cb_input( $taxonomy, $terms ) {
  *
  * @since 5.0.0
  * @since 6.3.0 Added `selectors` field.
+ * @since 6.4.0 Added `block_hooks` field.
  *
  * @return array An associative array of registered block data.
  */
@@ -2221,6 +2222,7 @@ function get_block_editor_server_block_settings() {
 		'attributes'       => 'attributes',
 		'provides_context' => 'providesContext',
 		'uses_context'     => 'usesContext',
+		'block_hooks'      => 'blockHooks',
 		'selectors'        => 'selectors',
 		'supports'         => 'supports',
 		'category'         => 'category',

wp-includes/blocks.php

@@ -342,6 +342,7 @@ function get_block_metadata_i18n_schema() {
  * @since 5.9.0 Added support for `variations` and `viewScript` fields.
  * @since 6.1.0 Added support for `render` field.
  * @since 6.3.0 Added `selectors` field.
+ * @since 6.4.0 Added support for `blockHooks` field.
  *
  * @param string $file_or_folder Path to the JSON file with metadata definition for
  *                               the block or path to the folder where the `block.json` file is located.
@@ -513,6 +514,39 @@ function register_block_type_from_metadata( $file_or_folder, $args = array() ) {
 		}
 	}
 
+	if ( ! empty( $metadata['blockHooks'] ) ) {
+		/**
+		 * Map camelCased position string (from block.json) to snake_cased block type position.
+		 *
+		 * @var array
+		 */
+		$position_mappings = array(
+			'before'     => 'before',
+			'after'      => 'after',
+			'firstChild' => 'first_child',
+			'lastChild'  => 'last_child',
+		);
+
+		$settings['block_hooks'] = array();
+		foreach ( $metadata['blockHooks'] as $anchor_block_name => $position ) {
+			// Avoid infinite recursion (hooking to itself).
+			if ( $metadata['name'] === $anchor_block_name ) {
+				_doing_it_wrong(
+					__METHOD__,
+					__( 'Cannot hook block to itself.', 'gutenberg' ),
+					'6.4.0'
+				);
+				continue;
+			}
+
+			if ( ! isset( $position_mappings[ $position ] ) ) {
+				continue;
+			}
+
+			$settings['block_hooks'][ $anchor_block_name ] = $position_mappings[ $position ];
+		}
+	}
+
 	if ( ! empty( $metadata['render'] ) ) {
 		$template_path = wp_normalize_path(
 			realpath(

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

@@ -173,6 +173,18 @@ class WP_Block_Type {
 	 */
 	public $provides_context = null;
 
+	/**
+	 * Block hooks for this block type.
+	 *
+	 * A block hook is specified by a block type and a relative position.
+	 * The hooked block will be automatically inserted in the given position
+	 * next to the "anchor" block whenever the latter is encountered.
+	 *
+	 * @since 6.4.0
+	 * @var array[]
+	 */
+	public $block_hooks = array();
+
 	/**
 	 * Block type editor only script handles.
 	 *
@@ -254,6 +266,7 @@ class WP_Block_Type {
 	 *              `editor_style_handles`, and `style_handles` properties.
 	 *              Deprecated the `editor_script`, `script`, `view_script`, `editor_style`, and `style` properties.
 	 * @since 6.3.0 Added the `selectors` property.
+	 * @since 6.4.0 Added the `block_hooks` property.
 	 *
 	 * @see register_block_type()
 	 *
@@ -284,6 +297,7 @@ class WP_Block_Type {
 	 *     @type array|null    $attributes               Block type attributes property schemas.
 	 *     @type string[]      $uses_context             Context values inherited by blocks of this type.
 	 *     @type string[]|null $provides_context         Context provided by blocks of this type.
+	 *     @type array[]       $block_hooks              Block hooks.
 	 *     @type string[]      $editor_script_handles    Block type editor only script handles.
 	 *     @type string[]      $script_handles           Block type front end and editor script handles.
 	 *     @type string[]      $view_script_handles      Block type front end only script handles.

wp-includes/rest-api/endpoints/class-wp-rest-block-types-controller.php

@@ -291,6 +291,7 @@ class WP_REST_Block_Types_Controller extends WP_REST_Controller {
 				'editor_style_handles',
 				'style_handles',
 				'variations',
+				'block_hooks',
 			),
 			$deprecated_fields
 		);
@@ -706,6 +707,19 @@ class WP_REST_Block_Types_Controller extends WP_REST_Controller {
 				),
 				'keywords'              => $keywords_definition,
 				'example'               => $example_definition,
+				'block_hooks'           => array(
+					'description'       => __( 'This block is automatically inserted near any occurence of the block types used as keys of this map, into a relative position given by the corresponding value.' ),
+					'type'              => 'object',
+					'patternProperties' => array(
+						'^[a-zA-Z0-9-]+/[a-zA-Z0-9-]+$' => array(
+							'type' => 'string',
+							'enum' => array( 'before', 'after', 'first_child', 'last_child' ),
+						),
+					),
+					'default'           => array(),
+					'context'           => array( 'embed', 'view', 'edit' ),
+					'readonly'          => true,
+				),
 			),
 		);
 

wp-includes/version.php

@@ -16,7 +16,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '6.4-alpha-56586';
+$wp_version = '6.4-alpha-56587';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.