Merge branch '4.4'

* 4.4:
  [Debug] Improve UPGRADE files
  remove wrongly added legacy group from test
  consistently throw NotSupportException
  [HttpKernel] Clarify error handler restoring process again
  [HttpClient] Remove CURLOPT_CONNECTTIMEOUT_MS curl opt
  add missing conflict rule
  [Intl] fix nullable phpdocs and useless method visibility of internal class
  remove some more useless phpdocs
  Resilience against file_get_contents() race conditions.
  Turned return type annotations of private methods into php return types.

Author: nicolas-grekas

Encoder/EncoderFactory.php

@@ -65,7 +65,7 @@ public function getEncoder($user)
      *
      * @throws \InvalidArgumentException
      */
-    private function createEncoder(array $config)
+    private function createEncoder(array $config): PasswordEncoderInterface
     {
         if (isset($config['algorithm'])) {
             $config = $this->getEncoderConfigFromAlgorithm($config);

User/InMemoryUserProvider.php

@@ -93,11 +93,9 @@ public function supportsClass(string $class)
     /**
      * Returns the user by given username.
      *
-     * @return User
-     *
      * @throws UsernameNotFoundException if user whose given username does not exist
      */
-    private function getUser(string $username)
+    private function getUser(string $username): User
     {
         if (!isset($this->users[strtolower($username)])) {
             $ex = new UsernameNotFoundException(sprintf('Username "%s" does not exist.', $username));