Filesystem API: Attempt to create directory in `copy_dir()`.

Adds a check to the start of `copy_dir()` that the destination directory exists and attempts to create it if it does not.

An error is returned if the directory can not be created, either due to a permissions error or the parent directory not existing.

Props caraffande, costdev, zunaid321.
Fixes #41855.


Built from https://develop.svn.wordpress.org/trunk@55938


git-svn-id: http://core.svn.wordpress.org/trunk@55450 1a063a9b-81f0-0310-95a4-ce76da25c4cd

wp-admin/includes/file.php

@@ -1910,6 +1910,14 @@ function copy_dir( $from, $to, $skip_list = array() ) {
 	$from = trailingslashit( $from );
 	$to   = trailingslashit( $to );
 
+	if ( ! $wp_filesystem->exists( $to ) && ! $wp_filesystem->mkdir( $to ) ) {
+		return new WP_Error(
+			'mkdir_destination_failed_copy_dir',
+			__( 'Could not create the destination directory.' ),
+			basename( $to )
+		);
+	}
+
 	foreach ( (array) $dirlist as $filename => $fileinfo ) {
 		if ( in_array( $filename, $skip_list, true ) ) {
 			continue;

wp-includes/version.php

@@ -16,7 +16,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '6.3-alpha-55937';
+$wp_version = '6.3-alpha-55938';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.