Issue #2818031 by phenaproxima, Berdir, alexpott: Trailing slashes can cause...

Issue #2818031 by phenaproxima, Berdir, alexpott: Trailing slashes can cause FileSystem::mkdir() to return a false negative

core/lib/Drupal/Core/File/FileSystem.php

@@ -181,8 +181,10 @@ public function mkdir($uri, $mode = NULL, $recursive = FALSE, $context = NULL) {
     // If recursive, create each missing component of the parent directory
     // individually and set the mode explicitly to override the umask.
     if ($recursive) {
-      // Ensure the path is using DIRECTORY_SEPARATOR.
-      $uri = str_replace('/', DIRECTORY_SEPARATOR, $uri);
+      // Ensure the path is using DIRECTORY_SEPARATOR, and trim off any trailing
+      // slashes because they can throw off the loop when creating the parent
+      // directories.
+      $uri = rtrim(str_replace('/', DIRECTORY_SEPARATOR, $uri), DIRECTORY_SEPARATOR);
       // Determine the components of the path.
       $components = explode(DIRECTORY_SEPARATOR, $uri);
       // If the filepath is absolute the first component will be empty as there

core/tests/Drupal/KernelTests/Core/File/DirectoryTest.php

@@ -161,4 +161,17 @@ function testFileDirectoryTemp() {
     $this->assertEqual($config->get('path.temporary'), $tmp_directory);
   }
 
+  /**
+   * Tests directory creation.
+   */
+  public function testDirectoryCreation() {
+    /** @var \Drupal\Core\File\FileSystemInterface $file_system */
+    $file_system = $this->container->get('file_system');
+
+    // mkdir() recursion should work with or without a trailing slash.
+    $dir = $this->siteDirectory . '/files';
+    $this->assertTrue($file_system->mkdir($dir . '/foo/bar', 0775, TRUE));
+    $this->assertTrue($file_system->mkdir($dir . '/foo/baz/', 0775, TRUE));
+  }
+
 }