General: Revert the last use of `str_starts_with()` in `update-core.php`.

Fixes updating WordPress from 5.7 and earlier versions. When doing the update this file runs first in the old version where the polifills may not be available.

Props frankit, azaozz.
Reviewed by audrasjb.
Merges [56417] to the 6.3 branch.
Fixes #59145.



Built from https://develop.svn.wordpress.org/branches/6.3@56425


git-svn-id: http://core.svn.wordpress.org/branches/6.3@55937 1a063a9b-81f0-0310-95a4-ce76da25c4cd

wp-admin/includes/update-core.php

@@ -1431,9 +1431,13 @@ function update_core( $from, $to ) {
 		} else {
 			$lang_dir = WP_CONTENT_DIR . '/languages';
 		}
-
+		/*
+		 * Note: str_starts_with() is not used here, as this file is included
+		 * when updating from older WordPress versions, in which case
+		 * the polyfills from wp-includes/compat.php may not be available.
+		 */
 		// Check if the language directory exists first.
-		if ( ! @is_dir( $lang_dir ) && str_starts_with( $lang_dir, ABSPATH ) ) {
+		if ( ! @is_dir( $lang_dir ) && 0 === strpos( $lang_dir, ABSPATH ) ) {
 			// If it's within the ABSPATH we can handle it here, otherwise they're out of luck.
 			$wp_filesystem->mkdir( $to . str_replace( ABSPATH, '', $lang_dir ), FS_CHMOD_DIR );
 			clearstatcache(); // For FTP, need to clear the stat cache.

wp-includes/version.php

@@ -16,7 +16,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '6.3.1-alpha-56423';
+$wp_version = '6.3.1-alpha-56425';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.