Refactor WP_Query ordering logic to ensure consistent results by appending ID as a secondary sort field. Update related unit tests to reflect changes in expected SQL output for various orderby scenarios

Author: ramonjd

src/wp-includes/class-wp-query.php

@@ -2523,7 +2523,6 @@ public function get_posts() {
 				'post_date',
 				'post_title',
 				'post_modified',
-				'post_mime_type',
 				'post_parent',
 				'post_type',
 				'name',
@@ -2578,7 +2577,7 @@ public function get_posts() {
 						continue;
 					}
 
-					$orderby_array[] = $parsed;
+					$orderby_array[] = $parsed . ' ' . $query_vars['order'];
 
 					// Check if this field needs deterministic ordering
 					if ( in_array( $orderby, $fields_requiring_deterministic_orderby, true ) ) {
@@ -2587,7 +2586,7 @@ public function get_posts() {
 						$has_id_orderby = true;
 					}
 				}
-				$orderby = implode( ' ' . $query_vars['order'] . ', ', $orderby_array );
+				$orderby = implode( ', ', $orderby_array );
 
 				if ( empty( $orderby ) ) {
 					$orderby = "{$wpdb->posts}.post_date " . $query_vars['order'] . ', ' . "{$wpdb->posts}.ID " . $query_vars['order'];

tests/phpunit/tests/admin/wpPrivacyRequestsTable.php

@@ -99,7 +99,13 @@ public function test_columns_should_be_sortable( $order, $orderby, $search, $exp
 		unset( $_REQUEST['orderby'] );
 		unset( $_REQUEST['s'] );
 
-		$this->assertStringContainsString( "ORDER BY {$wpdb->posts}.{$expected}", $this->sql );
+		$expected_query = explode( ', ', $expected );
+		$expected_query = array_map( function( $item ) use ( $wpdb ) {
+			return "{$wpdb->posts}.{$item}";
+		}, $expected_query );
+		$expected_query = implode( ', ', $expected_query );
+
+		$this->assertStringContainsString( "ORDER BY {$expected_query}", $this->sql );
 	}
 
 	/**
@@ -136,42 +142,42 @@ public function data_columns_should_be_sortable() {
 				'order'    => null,
 				'orderby'  => null,
 				's'        => null,
-				'expected' => 'post_date DESC',
+				'expected' => 'post_date DESC, ID DESC',
 			),
 			// Default order (ID) DESC.
 			array(
 				'order'    => '',
 				'orderby'  => '',
 				's'        => '',
-				'expected' => 'post_date DESC',
+				'expected' => 'post_date DESC, ID DESC',
 			),
 			// Order by requester (post_title) ASC.
 			array(
 				'order'    => 'ASC',
 				'orderby'  => 'requester',
 				's'        => '',
-				'expected' => 'post_title ASC',
+				'expected' => 'post_title ASC, ID ASC',
 			),
 			// Order by requester (post_title) DESC.
 			array(
 				'order'    => 'DESC',
 				'orderby'  => 'requester',
 				's'        => null,
-				'expected' => 'post_title DESC',
+				'expected' => 'post_title DESC, ID DESC',
 			),
 			// Order by requested (post_date) ASC.
 			array(
 				'order'    => 'ASC',
 				'orderby'  => 'requested',
 				's'        => null,
-				'expected' => 'post_date ASC',
+				'expected' => 'post_date ASC, ID ASC',
 			),
 			// Order by requested (post_date) DESC.
 			array(
 				'order'    => 'DESC',
 				'orderby'  => 'requested',
 				's'        => null,
-				'expected' => 'post_date DESC',
+				'expected' => 'post_date DESC, ID DESC',
 			),
 			// Search and order by relevance.
 			array(