Ticket #63503: 63503.patch

wp-admin/includes/export.php

@@ -406 +406 @@
 
                 if ( ! empty( $post_ids ) ) {
                         $post_ids = array_map( 'absint', $post_ids );
-                        $and      = 'AND ID IN ( ' . implode( ', ', $post_ids ) . ')';
+                        $chunks   = array_chunk( $post_ids, 20 );
                 } else {
-                        $and = '';
+                        $chunks   = [[]];
                 }
 
                 $authors = array();
-                $results = $wpdb->get_results( "SELECT DISTINCT post_author FROM $wpdb->posts WHERE post_status != 'auto-draft' $and" );
-                foreach ( (array) $results as $result ) {
-                        $authors[] = get_userdata( $result->post_author );
+
+                foreach ( $chunks as $chunk ) {
+                        $and = ! empty( $chunk ) ? 'AND ID IN (' . implode( ', ', $chunk ) . ')' : '';
+                        
+                        $results = $wpdb->get_results( "SELECT DISTINCT post_author FROM $wpdb->posts WHERE post_status != 'auto-draft' $and" );
+                        
+                        foreach ( (array) $results as $result ) {
+                                $authors[] = get_userdata( $result->post_author );
+                        }
                 }
-
+                
                 $authors = array_filter( $authors );
-
+                $authors = array_unique( $authors, SORT_REGULAR ); // Remove duplicate authors
                 foreach ( $authors as $author ) {
                         echo "\t<wp:author>";
                         echo '<wp:author_id>' . (int) $author->ID . '</wp:author_id>';