Issue #2834525 by alexpott, kim.pepper, jummonk, joshua.roberson, Ruu…

…ds: Permission denied caused by race condition during ensureDirectory should be silenced

(cherry picked from commit 16209df49673e360579af9efcaa242c1014565ce)

lib/Drupal/Component/FileSecurity/FileSecurity.php

@@ -26,7 +26,7 @@ class FileSecurity {
    *   TRUE if the file already exists or was created. FALSE otherwise.
    */
   public static function writeHtaccess($directory, $deny_public_access = TRUE, $force = FALSE) {
-    return self::writeFile($directory, '/.htaccess', self::htaccessLines($deny_public_access), $force);
+    return self::writeFile($directory, '.htaccess', self::htaccessLines($deny_public_access), $force);
   }
 
   /**
@@ -110,7 +110,7 @@ protected static function denyPublicAccess() {
    *   TRUE if the file already exists or was created. FALSE otherwise.
    */
   public static function writeWebConfig($directory, $force = FALSE) {
-    return self::writeFile($directory, '/web.config', self::webConfigLines(), $force);
+    return self::writeFile($directory, 'web.config', self::webConfigLines(), $force);
   }
 
   /**
@@ -152,7 +152,12 @@ protected static function writeFile($directory, $filename, $contents, $force) {
     if (file_exists($file_path) && !$force) {
       return TRUE;
     }
-    if (file_exists($directory) && is_writable($directory) && file_put_contents($file_path, $contents)) {
+    // Writing the file can fail if:
+    // - concurrent requests are both trying to write at the same time.
+    // - $directory does not exist or is not writable.
+    // Testing for these conditions introduces windows for concurrency issues to
+    // occur.
+    if (@file_put_contents($file_path, $contents)) {
       return @chmod($file_path, 0444);
     }
     return FALSE;