Merge branch '2.7' into 2.8

* 2.7:
  [PhpUnitBridge] Revert 7f62133939b1172e1c9924d211e1d315230b3be8
  bumped Symfony version to 2.3.40
  set s-maxage only if all responses are cacheable
  updated VERSION for 2.3.39
  update CONTRIBUTORS for 2.3.39
  updated CHANGELOG for 2.3.39
  Improved the "branch" row of the PR table
  [Debug] Replaced logic for detecting filesystem case sensitivity
  [Process] Wait a bit less on Windows
  Use debug member variable
  Fix typos #18090 1. PHPs session design to PHP's session design 2. Symfony HttpKernel offers to Symfony's HttpKernel offers 3. in which case it it should to in which case it should
  Fix for Isssue #18091
  replace perfom by perform
  minor #18088 Fix typo for profiler
  [ci] remove token for composer now that rate limiting is off

Conflicts:
	src/Symfony/Bridge/PhpUnit/composer.json

Debug.php

@@ -45,7 +45,7 @@ class Debug
             error_reporting(-1);
         }
 
-        if ('cli' !== php_sapi_name()) {
+        if ('cli' !== PHP_SAPI) {
             ini_set('display_errors', 0);
             ExceptionHandler::register();
         } elseif ($displayErrors && (!ini_get('log_errors') || ini_get('error_log'))) {

DebugClassLoader.php

@@ -51,7 +51,16 @@ class DebugClassLoader
         }
 
         if (!isset(self::$caseCheck)) {
-            self::$caseCheck = false !== stripos(PHP_OS, 'win') ? (false !== stripos(PHP_OS, 'darwin') ? 2 : 1) : 0;
+            if(!file_exists(strtolower(__FILE__))) {
+                // filesystem is case sensitive
+                self::$caseCheck = 0;
+            } elseif(realpath(strtolower(__FILE__)) === __FILE__) {
+                // filesystem is not case sensitive
+                self::$caseCheck = 1;
+            } else {
+                // filesystem is not case sensitive AND realpath() fails to normalize case
+                self::$caseCheck = 2;
+            }
         }
     }
 
@@ -193,17 +202,17 @@ class DebugClassLoader
                             break;
                     }
                 }
-                $parent = $refl->getParentClass();
+                $parent = get_parent_class($class);
 
-                if (!$parent || strncmp($ns, $parent->name, $len)) {
-                    if ($parent && isset(self::$deprecated[$parent->name]) && strncmp($ns, $parent->name, $len)) {
-                        @trigger_error(sprintf('The %s class extends %s that is deprecated %s', $name, $parent->name, self::$deprecated[$parent->name]), E_USER_DEPRECATED);
+                if (!$parent || strncmp($ns, $parent, $len)) {
+                    if ($parent && isset(self::$deprecated[$parent]) && strncmp($ns, $parent, $len)) {
+                        @trigger_error(sprintf('The %s class extends %s that is deprecated %s', $name, $parent, self::$deprecated[$parent]), E_USER_DEPRECATED);
                     }
 
                     $parentInterfaces = array();
                     $deprecatedInterfaces = array();
                     if ($parent) {
-                        foreach ($parent->getInterfaceNames() as $interface) {
+                        foreach (class_implements($parent) as $interface) {
                             $parentInterfaces[$interface] = 1;
                         }
                     }

README.md

@@ -1,42 +1,13 @@
 Debug Component
 ===============
 
-Debug provides tools to make debugging easier.
-
-Enabling all debug tools is as easy as calling the `enable()` method on the
-main `Debug` class:
-
-```php
-use Symfony\Component\Debug\Debug;
-
-Debug::enable();
-```
-
-You can also use the tools individually:
-
-```php
-use Symfony\Component\Debug\DebugClassLoader;
-use Symfony\Component\Debug\ErrorHandler;
-use Symfony\Component\Debug\ExceptionHandler;
-
-if ('cli' !== php_sapi_name()) {
-    ini_set('display_errors', 0);
-    ExceptionHandler::register();
-} elseif (!ini_get('log_errors') || ini_get('error_log')) {
-    ini_set('display_errors', 1);
-}
-ErrorHandler::register();
-DebugClassLoader::enable();
-```
-
-This component can optionally take advantage of the features of the HttpKernel
-and HttpFoundation components.
+The Debug component provides tools to ease debugging PHP code.
 
 Resources
 ---------
 
-You can run the unit tests with the following command:
-
-    $ cd path/to/Symfony/Component/Debug/
-    $ composer install
-    $ phpunit
+  * [Documentation](https://symfony.com/doc/current/components/debug/index.html)
+  * [Contributing](https://symfony.com/doc/current/contributing/index.html)
+  * [Report issues](https://github.com/symfony/symfony/issues) and
+    [send Pull Requests](https://github.com/symfony/symfony/pulls)
+    in the [main Symfony repository](https://github.com/symfony/symfony)