Build correct context for the block hooks API when the post type is a…

… wp_template_part

src/wp-includes/blocks.php

@@ -1118,9 +1118,25 @@ function update_ignored_hooked_blocks_postmeta( $post ) {
  $post->post_content
  );
 
+ /**
+ * We need to merge incoming changes with existing data so the block hooks API gets the correct context.
+ * For `wp_template_part` post type, we need to convert the post object to a block template object.
+ */
  $existing_post = isset( $post->ID ) ? get_post( $post->ID ) : array();
- // Merge the existing post object with the updated post object to pass to the block hooks algorithm for context.
- $context = (object) array_merge( (array) $existing_post, (array) $post );
+ $context = (object) array_merge( (array) $existing_post, (array) $post );
+ // Convert the $context object to a WP_Post object.
+ $context = get_post( $context );
+ if ( 'wp_template_part' === $post_type ) {
+ // Convert the $context object to a WP_Block_Template object.
+ if ( isset( $post->ID ) ) {
+ $context = _build_block_template_result_from_post( $context );
+ } else {
+ $meta = isset( $context->meta_input ) ? $context->meta_input : array();
+ $terms = isset( $context->tax_input ) ? $context->tax_input : array();
+ $context = _build_block_template_object_from_post_object( get_post( $context ), $terms, $meta );
+ }
+ }
+
  $serialized_block = apply_block_hooks_to_content( $markup, $context, 'set_ignored_hooked_blocks_metadata' );
  $root_block = parse_blocks( $serialized_block )[0];