Block Hooks: Don't erase post content if it isn't changed by client.

The `inject_ignored_hooked_blocks_metadata_attributes` filter that is attached to both the `rest_pre_insert_wp_template` and `rest_pre_insert_wp_template_part` hooks receives a `stdClass` object from the Templates REST API controller that contains all fields that the client would like to modify when making a `POST` request (plus the `id` to identify the relevant template or template part, respectively).

There are cases when the `post_content` field is not set, e.g. when the client would like to rename an existing template (in which case it would only set the `title` field).

Prior to this changeset, the filter would erroneously apply the Block Hooks algorithm to the non-existent `post_content` field regardless, which would result in it being set to the empty string `''`. As a consequence, renaming a template would have the unwanted side effect of wiping its contents.

This changeset fixes the issue by returning early from the filter if the `post_content` field is not set.

Reviewed by gziolo.
Merges [58785] to the 6.6 branch.

Props alshakero, bernhard-reiter.
Fixes #61550.
Built from https://develop.svn.wordpress.org/branches/6.6@58802


git-svn-id: http://core.svn.wordpress.org/branches/6.6@58198 1a063a9b-81f0-0310-95a4-ce76da25c4cd

wp-includes/block-template-utils.php

@@ -1562,6 +1562,10 @@ function inject_ignored_hooked_blocks_metadata_attributes( $changes, $deprecated
 		_deprecated_argument( __FUNCTION__, '6.5.3' );
 	}
 
+	if ( ! isset( $changes->post_content ) ) {
+		return $changes;
+	}
+
 	$hooked_blocks = get_hooked_blocks();
 	if ( empty( $hooked_blocks ) && ! has_filter( 'hooked_block_types' ) ) {
 		return $changes;

wp-includes/version.php

@@ -16,7 +16,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '6.6.2-alpha-58788';
+$wp_version = '6.6.2-alpha-58802';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.