Ticket #49532: 49532.diff

src/wp-includes/rest-api/endpoints/class-wp-rest-autosaves-controller.php

@@ -352 +352 @@
                         return $post;
                 }
 
-                $user_id = get_current_user_id();
+                // If the autosave content matches the post content, do not create an autosave and delete any existing autosave.
+                $autosave_is_different = false;
+                $new_autosave          = _wp_post_revision_data( $post_data, true );
+
+                foreach ( array_intersect( array_keys( $new_autosave ), array_keys( _wp_post_revision_fields( $post ) ) ) as $field ) {
+                        if ( normalize_whitespace( $new_autosave[ $field ] ) !== normalize_whitespace( $post->$field ) ) {
+                                $autosave_is_different = true;
+                                break;
+                        }
+                }
 
-                // Store one autosave per author. If there is already an autosave, overwrite it.
+                // Store one autosave per author. If there is already an autosave for the current author, overwrite it.
+                $user_id      = get_current_user_id();
                 $old_autosave = wp_get_post_autosave( $post_id, $user_id );
 
                 if ( $old_autosave ) {
-                        $new_autosave                = _wp_post_revision_data( $post_data, true );
                         $new_autosave['ID']          = $old_autosave->ID;
                         $new_autosave['post_author'] = $user_id;
 
-                        // If the new autosave has the same content as the post, delete the autosave.
-                        $autosave_is_different = false;
-
-                        foreach ( array_intersect( array_keys( $new_autosave ), array_keys( _wp_post_revision_fields( $post ) ) ) as $field ) {
-                                if ( normalize_whitespace( $new_autosave[ $field ] ) !== normalize_whitespace( $post->$field ) ) {
-                                        $autosave_is_different = true;
-                                        break;
-                                }
-                        }
-
                         if ( ! $autosave_is_different ) {
                                 wp_delete_post_revision( $old_autosave->ID );
                                 return new WP_Error(
@@ -388 +387 @@
                         return wp_update_post( wp_slash( $new_autosave ) );
                 }
 
+                if ( ! $autosave_is_different ) {
+                        return new WP_Error(
+                                'rest_autosave_no_changes',
+                                __( 'There is nothing to save. The autosave and the post content are the same.' ),
+                                array( 'status' => 400 )
+                        );
+                }
+
                 // Create the new autosave as a special post revision.
                 return _wp_put_post_revision( $post_data, true );
         }