Revisions: Prevent fatal error in PHP 8+ when saving a post revision with revisioned non-scalar post meta.

Developed in WordPress/wordpress-develop#10560

Follow-up to [56714].

Props LAPSrj, manhphucofficial, westonruter.
See #20299.
Fixes #64314.

Built from https://develop.svn.wordpress.org/trunk@61372


git-svn-id: https://core.svn.wordpress.org/trunk@60684 1a063a9b-81f0-0310-95a4-ce76da25c4cd

Author: westonruter

wp-includes/revision.php

@@ -187,7 +187,7 @@ function wp_save_post_revision( $post_id ) {
 			$post_has_changed = false;
 
 			foreach ( array_keys( _wp_post_revision_fields( $post ) ) as $field ) {
-				if ( normalize_whitespace( $post->$field ) !== normalize_whitespace( $latest_revision->$field ) ) {
+				if ( normalize_whitespace( maybe_serialize( $post->$field ) ) !== normalize_whitespace( maybe_serialize( $latest_revision->$field ) ) ) {
 					$post_has_changed = true;
 					break;
 				}

wp-includes/version.php

@@ -16,7 +16,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '7.0-alpha-61371';
+$wp_version = '7.0-alpha-61372';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.