Add/move comments

Author: ockham

src/wp-includes/blocks.php

@@ -1125,11 +1125,12 @@ function apply_block_hooks_to_content( $content, $context = null, $callback = 'i
 		}
 	}
 
-	/*
-	 * We also need to cover the case where the hooked block is not present in
-	 * `$content` at first and we're allowed to insert it once -- but not again.
-	 */
 	$suppress_single_instance_blocks = static function ( $hooked_block_types, $relative_position, $anchor_block_type ) use ( &$block_allows_multiple_instances, $content, $context ) {
+		/*
+		 * If the context is a post object, 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.
+		 */
 		if ( $context instanceof WP_Post ) {
 			$wrapper_block_type = 'core/post-content';
 			if ( 'wp_navigation' === $context->post_type ) {
@@ -1146,6 +1147,10 @@ function apply_block_hooks_to_content( $content, $context = null, $callback = 'i
 			}
 		}
 
+		/*
+		 * We also need to cover the case where a hooked block with `multiple: false` is not
+		 * present in `$content` at first and we're allowed to insert it once -- but not again.
+		 */
 		static $single_instance_blocks_present_in_content = array();
 		foreach ( $hooked_block_types as $index => $hooked_block_type ) {
 			if ( ! isset( $block_allows_multiple_instances[ $hooked_block_type ] ) ) {