Upgrade/Install: Send language pack updates to copy_dir().

If the `clear_working` flag in `WP_Upgrader::install_package()` is false, the source should not be removed, so `copy_dir()` should be used instead.

Partial updates, like language packs, may want to retain the destination. If the destination exists or has contents, this may be a partial update, and the destination should not be removed, so `copy_dir()` should be used instead.

Follow-up to [55204], [55219], [55220], [55223], [55226].

Props afragen, costdev, swissspidy.
See #57557.
Built from https://develop.svn.wordpress.org/trunk@55229


git-svn-id: http://core.svn.wordpress.org/trunk@54762 1a063a9b-81f0-0310-95a4-ce76da25c4cd

wp-admin/includes/class-wp-upgrader.php

@@ -588,15 +588,19 @@ public function install_package( $args = array() ) {
 		}
 
 		/*
-		 * Partial updates may want to retain the destination.
-		 * move_dir() returns a WP_Error when the destination exists,
-		 * so copy_dir() should be used.
+		 * If 'clear_working' is false, the source should not be removed, so use copy_dir() instead.
 		 *
-		 * If 'clear_working' is false, the source shouldn't be removed.
-		 * After move_dir() runs, the source will no longer exist.
-		 * Therefore, copy_dir() should be used.
+		 * Partial updates, like language packs, may want to retain the destination.
+		 * If the destination exists or has contents, this may be a partial update,
+		 * and the destination should not be removed, so use copy_dir() instead.
 		 */
-		if ( $clear_destination && $args['clear_working'] ) {
+		if ( $args['clear_working']
+			&& (
+				// Destination does not exist or has no contents.
+				! $wp_filesystem->exists( $remote_destination )
+				|| empty( $wp_filesystem->dirlist( $remote_destination ) )
+			)
+		) {
 			$result = move_dir( $source, $remote_destination, true );
 		} else {
 			// Create destination if needed.

wp-includes/version.php

@@ -16,7 +16,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '6.2-alpha-55228';
+$wp_version = '6.2-alpha-55229';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.