Block Hooks: Suppress insertion next to post content wrapper block.

As of [59523], Block Hooks are applied to post content. In order to allow for insertion of a hooked block as `first_child` or `last_child` of the containing Post Content block, we wrap the block's post content (as obtained from the DB) in a temporary `<!-- wp:post-content -->` wrapper block, apply the Block Hooks algorithm to the resulting markup, and remove the wrapper block. (The same technique is applied for the Synced Pattern block -- see [59543] -- as well as the Navigation block.)

However, this caused a problem when a hooked block was marked for insertion before `before` or `after` a Post Content block: The logic that's supposed to remove the temporary wrapper block after the Block Hooks algorithm runs erroneously removed that hooked block's delimiter instead of the wrapper block, producing garbled markup as a result.

This changeset fixes the issue by adding a `hooked_block_types` filter (with `PHP_INT_MAX` priority) that removes any blocks hooked `before` or `after` a Post Content block, ''if'' the current context is a post object. This prevents any blocks hooked that way from being "absorbed" into the corresponding post object's content; it retains the ability to hook blocks `before` and `after` a Post Content block in any other context (e.g. a template). (The same principle is applied to Synced Pattern and Navigation blocks.)

Props obenland, jorbin, gziolo, bernhard-reiter.
Fixes #63287.

git-svn-id: https://develop.svn.wordpress.org/trunk@60173 602fd350-edb4-49c9-b593-d223f7449a82

Author: ockham

src/wp-includes/blocks.php

@@ -1248,8 +1248,25 @@ function apply_block_hooks_to_content_from_post_object( $content, $post = null,
 		$content
 	);
 
+	/*
+	 * We need to avoid inserting any blocks hooked into the `before` and `after` positions
+	 * of the temporary wrapper block that we create to wrap the content.
+	 * See https://core.trac.wordpress.org/ticket/63287 for more details.
+	 */
+	$suppress_blocks_from_insertion_before_and_after_wrapper_block = static function ( $hooked_block_types, $relative_position, $anchor_block_type ) use ( $wrapper_block_type ) {
+		if (
+			$wrapper_block_type === $anchor_block_type &&
+			in_array( $relative_position, array( 'before', 'after' ), true )
+		) {
+			return array();
+		}
+		return $hooked_block_types;
+	};
+
 	// Apply Block Hooks.
+	add_filter( 'hooked_block_types', $suppress_blocks_from_insertion_before_and_after_wrapper_block, PHP_INT_MAX, 3 );
 	$content = apply_block_hooks_to_content( $content, $post, $callback );
+	remove_filter( 'hooked_block_types', $suppress_blocks_from_insertion_before_and_after_wrapper_block, PHP_INT_MAX );
 
 	// Finally, we need to remove the temporary wrapper block.
 	$content = remove_serialized_parent_block( $content );

tests/phpunit/tests/blocks/applyBlockHooksToContent.php

@@ -17,13 +17,14 @@ class Tests_Blocks_ApplyBlockHooksToContent extends WP_UnitTestCase {
 	 * Set up.
 	 *
 	 * @ticket 61902.
+	 * @ticket 63287.
 	 */
 	public static function wpSetUpBeforeClass() {
 		register_block_type(
 			'tests/hooked-block',
 			array(
 				'block_hooks' => array(
-					'tests/anchor-block' => 'after',
+					'core/post-content' => 'after',
 				),
 			)
 		);
@@ -79,23 +80,25 @@ public function test_apply_block_hooks_to_content_sets_theme_attribute_on_templa
 
 	/**
 	 * @ticket 61902
+	 * @ticket 63287
 	 */
 	public function test_apply_block_hooks_to_content_inserts_hooked_block() {
 		$context          = new WP_Block_Template();
-		$context->content = '<!-- wp:tests/anchor-block /-->';
+		$context->content = '<!-- wp:post-content /-->';
 
 		$actual = apply_block_hooks_to_content( $context->content, $context, 'insert_hooked_blocks' );
 		$this->assertSame(
-			'<!-- wp:tests/anchor-block /--><!-- wp:tests/hooked-block /-->',
+			'<!-- wp:post-content /--><!-- wp:tests/hooked-block /-->',
 			$actual
 		);
 	}
 
 	/**
 	 * @ticket 61074
+	 * @ticket 63287
 	 */
 	public function test_apply_block_hooks_to_content_with_context_set_to_null() {
-		$content = '<!-- wp:tests/anchor-block /-->';
+		$content = '<!-- wp:post-content /-->';
 
 		/*
 		 * apply_block_hooks_to_content() will fall back to the global $post object (via get_post())
@@ -106,7 +109,7 @@ public function test_apply_block_hooks_to_content_with_context_set_to_null() {
 
 		$actual = apply_block_hooks_to_content( $content, null, 'insert_hooked_blocks' );
 		$this->assertSame(
-			'<!-- wp:tests/anchor-block /--><!-- wp:tests/hooked-block /-->',
+			'<!-- wp:post-content /--><!-- wp:tests/hooked-block /-->',
 			$actual
 		);
 	}

tests/phpunit/tests/blocks/applyBlockHooksToContentFromPostObject.php

@@ -88,6 +88,17 @@ public static function wpSetUpBeforeClass() {
 				),
 			)
 		);
+
+		register_block_type(
+			'tests/hooked-block-after-post-content',
+			array(
+				'block_hooks' => array(
+					'core/post-content' => 'after',
+				),
+			)
+		);
+
+		register_block_type( 'tests/dynamically-hooked-block-before-post-content' );
 	}
 
 	/**
@@ -100,6 +111,8 @@ public static function wpTearDownAfterClass() {
 
 		$registry->unregister( 'tests/hooked-block' );
 		$registry->unregister( 'tests/hooked-block-first-child' );
+		$registry->unregister( 'tests/hooked-block-after-post-content' );
+		$registry->unregister( 'tests/dynamically-hooked-block-before-post-content' );
 	}
 
 	/**
@@ -130,6 +143,33 @@ public function test_apply_block_hooks_to_content_from_post_object_respects_igno
 		$this->assertSame( $expected, $actual );
 	}
 
+	/**
+	 * @ticket 63287
+	 */
+	public function test_apply_block_hooks_to_content_from_post_object_does_not_insert_hooked_block_before_container_block() {
+		$filter = function ( $hooked_block_types, $relative_position, $anchor_block_type ) {
+			if ( 'core/post-content' === $anchor_block_type && 'before' === $relative_position ) {
+				$hooked_block_types[] = 'tests/dynamically-hooked-block-before-post-content';
+			}
+
+			return $hooked_block_types;
+		};
+
+		$expected = '<!-- wp:tests/hooked-block-first-child /-->' .
+			self::$post->post_content .
+			'<!-- wp:tests/hooked-block /-->';
+
+		add_filter( 'hooked_block_types', $filter, 10, 3 );
+		$actual = apply_block_hooks_to_content_from_post_object(
+			self::$post->post_content,
+			self::$post,
+			'insert_hooked_blocks'
+		);
+		remove_filter( 'hooked_block_types', $filter, 10 );
+
+		$this->assertSame( $expected, $actual );
+	}
+
 	/**
 	 * @ticket 62716
 	 */