Merge branch '5.4' into 6.0

* 5.4: (33 commits)
  do not pass a boolean to the constructor of the Dotenv class
  [Notifier] Fix low-deps tests
  Deprecate Composer 1
  [Filesystem] Add third argument `$lockFile` to `Filesystem::appendToFile()`
  [TwigBundle] fix auto-enabling assets/expression/routing/yaml/workflow extensions
  [PhpUnitBridge] fix symlink to bridge in docker by making its path relative
  [Dotenv] Duplicate $_SERVER values in $_ENV if they don't exist
  Fix markup
  [Notifier] Add Expo bridge
  Add polish translations (#43725)
  Rename translation:update to translation:extract
  [String] Add PLURAL_MAP "zombies" -- fix #43789
  Added support for `statusCode` default parameter when loading a template directly from route using the `Symfony\Bundle\FrameworkBundle\Controller\TemplateController` controller.
  [Validator] Update validators.bs.xlf
  Cache voters that will always abstain
  [Messenger] Fix `TraceableMessageBus` implementation so it can compute caller even when used within a callback
  [Validator] Add the missing translations for Russian (ru)
  [Validator] Added missing translations for Latvian (lv)
  [Validator] Added missing translations
  [Validator] Add missing translations for Vietnamese (VI)
  ...

Author: xabbuh

CHANGELOG.md

@@ -5,6 +5,7 @@ CHANGELOG
 ---
 
  * Add `Path` class
+ * Add `$lock` argument to `Filesystem::appendToFile()`
 
 5.0.0
 -----

Filesystem.php

@@ -665,10 +665,11 @@ public function dumpFile(string $filename, $content)
      * Appends content to an existing file.
      *
      * @param string|resource $content The content to append
+     * @param bool            $lock    Whether the file should be locked when writing to it
      *
      * @throws IOException If the file is not writable
      */
-    public function appendToFile(string $filename, $content)
+    public function appendToFile(string $filename, $content/*, bool $lock = false*/)
     {
         if (\is_array($content)) {
             throw new \TypeError(sprintf('Argument 2 passed to "%s()" must be string or resource, array given.', __METHOD__));
@@ -680,7 +681,9 @@ public function appendToFile(string $filename, $content)
             $this->mkdir($dir);
         }
 
-        if (false === self::box('file_put_contents', $filename, $content, \FILE_APPEND)) {
+        $lock = \func_num_args() > 2 && func_get_arg(2);
+
+        if (false === self::box('file_put_contents', $filename, $content, \FILE_APPEND | ($lock ? \LOCK_EX : 0))) {
             throw new IOException(sprintf('Failed to write file "%s": ', $filename).self::$lastError, 0, null, $filename);
         }
     }