Move image and gallery blocks to dynamic block registration

src/wp-includes/blocks/gallery.php

@@ -0,0 +1,52 @@
+<?php
+/**
+ * Server-side rendering of the `core/image` block.
+ *
+ * @package WordPress
+ */
+
+/**
+ * Handles backwards compatibility for Gallery Blocks,
+ * whose images feature a `data-id` attribute.
+ *
+ * Now that the Gallery Block contains inner Image Blocks,
+ * we add a custom `data-id` attribute before rendering the gallery
+ * so that the Image Block can pick it up in its render_callback.
+ *
+ * @param  array $parsed_block A single parsed block object.
+ *
+ * @return array               The migrated block object.
+ */
+function render_block_core_gallery_data( $parsed_block ) {
+	if ( 'core/gallery' === $parsed_block['blockName'] ) {
+		foreach ( $parsed_block['innerBlocks'] as $key => $inner_block ) {
+			if ( 'core/image' === $inner_block['blockName'] ) {
+				if ( ! isset( $parsed_block['innerBlocks'][ $key ]['attrs']['data-id'] ) && isset( $inner_block['attrs']['id'] ) ) {
+					$parsed_block['innerBlocks'][ $key ]['attrs']['data-id'] = esc_attr( $inner_block['attrs']['id'] );
+				}
+			}
+		}
+	}
+
+	return $parsed_block;
+}
+
+add_filter( 'render_block_data', 'render_block_core_gallery_data' );
+
+/**
+ * Registers the `core/gallery` block on server.
+ * This render callback needs to be here
+ * so that the gallery styles are loaded in block-based themes.
+ */
+function gutenberg_register_block_core_gallery() {
+	register_block_type_from_metadata(
+		__DIR__ . '/gallery',
+		array(
+			'render_callback' => function ( $attributes, $content ) {
+				return $content;
+			},
+		)
+	);
+}
+
+add_action( 'init', 'gutenberg_register_block_core_gallery', 20 );

src/wp-includes/blocks/image.php

@@ -0,0 +1,42 @@
+<?php
+/**
+ * Server-side rendering of the `core/image` block.
+ *
+ * @package WordPress
+ */
+
+/**
+ * Renders the `core/image` block on the server,
+ * adding a data-id attribute to the element if core/gallery has added on pre-render.
+ *
+ * @param  array $attributes The block attributes.
+ * @param  array $content    The block content.
+ * @return string            Returns the block content with the data-id attribute added.
+ */
+function render_block_core_image( $attributes, $content ) {
+	if ( isset( $attributes['data-id'] ) ) {
+		// Add the data-id="$id" attribute to the img element
+		// to provide backwards compatibility for the Gallery Block,
+		// which now wraps Image Blocks within innerBlocks.
+		// The data-id attribute is added in a core/gallery `render_block_data` hook.
+		$data_id_attribute = 'data-id="' . esc_attr( $attributes['data-id'] ) . '"';
+		if ( ! strpos( $content, $data_id_attribute ) ) {
+			$content = str_replace( '<img', '<img ' . $data_id_attribute . ' ', $content );
+		}
+	}
+	return $content;
+}
+
+
+/**
+ * Registers the `core/image` block on server.
+ */
+function register_block_core_image() {
+	register_block_type_from_metadata(
+		__DIR__ . '/image',
+		array(
+			'render_callback' => 'render_block_core_image',
+		)
+	);
+}
+add_action( 'init', 'register_block_core_image' );

src/wp-includes/blocks/index.php

@@ -11,6 +11,8 @@
 require ABSPATH . WPINC . '/blocks/calendar.php';
 require ABSPATH . WPINC . '/blocks/categories.php';
 require ABSPATH . WPINC . '/blocks/file.php';
+require ABSPATH . WPINC . '/blocks/gallery.php';
+require ABSPATH . WPINC . '/blocks/image.php';
 require ABSPATH . WPINC . '/blocks/latest-comments.php';
 require ABSPATH . WPINC . '/blocks/latest-posts.php';
 require ABSPATH . WPINC . '/blocks/legacy-widget.php';
@@ -64,11 +66,9 @@ function register_core_block_types_from_metadata() {
 		'cover',
 		'embed',
 		'freeform',
-		'gallery',
 		'group',
 		'heading',
 		'html',
-		'image',
 		'list',
 		'media-text',
 		'missing',

tests/phpunit/includes/functions.php

@@ -307,6 +307,8 @@ function _unhook_block_registration() {
 	remove_action( 'init', 'register_block_core_calendar' );
 	remove_action( 'init', 'register_block_core_categories' );
 	remove_action( 'init', 'register_block_core_file' );
+	remove_action( 'init', 'gutenberg_register_block_core_gallery', 20 );
+	remove_action( 'init', 'register_block_core_image' );
 	remove_action( 'init', 'register_block_core_latest_comments' );
 	remove_action( 'init', 'register_block_core_latest_posts' );
 	remove_action( 'init', 'register_block_core_legacy_widget' );

tools/webpack/blocks.js

@@ -28,6 +28,8 @@ module.exports = function( env = { environment: 'production', watch: false, buil
 		'calendar',
 		'categories',
 		'file',
+		'gallery',
+		'image',
 		'latest-comments',
 		'latest-posts',
 		'loginout',
@@ -73,11 +75,9 @@ module.exports = function( env = { environment: 'production', watch: false, buil
 		'cover',
 		'embed',
 		'freeform',
-		'gallery',
 		'group',
 		'heading',
 		'html',
-		'image',
 		'list',
 		'media-text',
 		'missing',