From afbb9ef0e343fb78f420df688bc495c02e0f91cc Mon Sep 17 00:00:00 2001
From: Sergey Biryukov <sergeybiryukov@git.wordpress.org>
Date: Thu, 16 Mar 2023 16:12:51 +0000
Subject: [PATCH] Filesystem API: Return `false` for empty paths in FTP
 `::exists()` methods.

When `ftp_nlist()` receives an empty path, it checks the current working directory and may return `true`.

This affects:
* `WP_Filesystem_FTPext::exists()`
* `WP_Filesystem_ftpsockets::exists()`

As the purpose of the API is to provide a consistent interface for various filesystem implementations, this commit updates the affected methods to returns `false` when an empty path is provided, bringing consistency with the other filesystem abstraction classes, specifically `WP_Filesystem_Direct` and `WP_Filesystem_SSH2`.

Follow-up to [6779], [11821], [25274], [31815].

Props mkox, costdev, Zdrobau, dd32, pbiron, azaozz, mukesh27, SergeyBiryukov.
Fixes #33058.

git-svn-id: https://develop.svn.wordpress.org/trunk@55556 602fd350-edb4-49c9-b593-d223f7449a82
---
 src/wp-admin/includes/class-wp-filesystem-ftpext.php  | 11 +++++++++++
 .../includes/class-wp-filesystem-ftpsockets.php       | 11 +++++++++++
 2 files changed, 22 insertions(+)

diff --git a/src/wp-admin/includes/class-wp-filesystem-ftpext.php b/src/wp-admin/includes/class-wp-filesystem-ftpext.php
index 975a4dd717..3ce8b67996 100644
--- a/src/wp-admin/includes/class-wp-filesystem-ftpext.php
+++ b/src/wp-admin/includes/class-wp-filesystem-ftpext.php
@@ -419,11 +419,22 @@ class WP_Filesystem_FTPext extends WP_Filesystem_Base {
 	 * Checks if a file or directory exists.
 	 *
 	 * @since 2.5.0
+	 * @since 6.3.0 Returns false for an empty path.
 	 *
 	 * @param string $path Path to file or directory.
 	 * @return bool Whether $path exists or not.
 	 */
 	public function exists( $path ) {
+		/*
+		 * Check for empty path. If ftp_nlist() receives an empty path,
+		 * it checks the current working directory and may return true.
+		 *
+		 * See https://core.trac.wordpress.org/ticket/33058.
+		 */
+		if ( '' === $path ) {
+			return false;
+		}
+
 		$list = ftp_nlist( $this->link, $path );
 
 		if ( empty( $list ) && $this->is_dir( $path ) ) {
diff --git a/src/wp-admin/includes/class-wp-filesystem-ftpsockets.php b/src/wp-admin/includes/class-wp-filesystem-ftpsockets.php
index da771e4156..1e213ea123 100644
--- a/src/wp-admin/includes/class-wp-filesystem-ftpsockets.php
+++ b/src/wp-admin/includes/class-wp-filesystem-ftpsockets.php
@@ -421,11 +421,22 @@ class WP_Filesystem_ftpsockets extends WP_Filesystem_Base {
 	 * Checks if a file or directory exists.
 	 *
 	 * @since 2.5.0
+	 * @since 6.3.0 Returns false for an empty path.
 	 *
 	 * @param string $path Path to file or directory.
 	 * @return bool Whether $path exists or not.
 	 */
 	public function exists( $path ) {
+		/*
+		 * Check for empty path. If ftp::nlist() receives an empty path,
+		 * it checks the current working directory and may return true.
+		 *
+		 * See https://core.trac.wordpress.org/ticket/33058.
+		 */
+		if ( '' === $path ) {
+			return false;
+		}
+
 		$list = $this->ftp->nlist( $path );
 
 		if ( empty( $list ) && $this->is_dir( $path ) ) {