bug #49745 [FrameworkBundle] Fix wiring session.handler when handler_id is null (nicolas-grekas)

This PR was merged into the 5.4 branch.

Discussion
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[FrameworkBundle] Fix wiring session.handler when handler_id is null

| Q             | A
| ------------- | ---
| Branch?       | 5.4
| Bug fix?      | yes
| New feature?  | no
| Deprecations? | no
| Tickets       | -
| License       | MIT
| Doc PR        | -

When the session `handler_id` is null, we currently set the `$handler` argument of the storage/factory services to null, which means to them "create your own handler internally from the native one". This means that the `session.handler` service is "a lie": it's not the real handler used by the storage. It also means that the `%session.save_path%` parameter is lying too, because it is set to `%kernel.cache_dir%/sessions` (by default), while the storage will use `ini_get('session.save_path')` in practice.

This issue is 10 years old... #5290

Commits
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e23be58348 [FrameworkBundle] Fix wiring session.handler when handler_id is null

Author: nicolas-grekas

Session/Storage/Handler/NativeFileSessionHandler.php

@@ -49,7 +49,11 @@ public function __construct(string $savePath = null)
             throw new \RuntimeException(sprintf('Session Storage was not able to create directory "%s".', $baseDir));
         }
 
-        ini_set('session.save_path', $savePath);
-        ini_set('session.save_handler', 'files');
+        if ($savePath !== \ini_get('session.save_path')) {
+            ini_set('session.save_path', $savePath);
+        }
+        if ('files' !== \ini_get('session.save_handler')) {
+            ini_set('session.save_handler', 'files');
+        }
     }
 }

Session/Storage/NativeSessionStorage.php

@@ -455,9 +455,10 @@ public function setOptions(array $options)
      */
     public function setSaveHandler($saveHandler = null)
     {
-        if (!$saveHandler instanceof AbstractProxy &&
-            !$saveHandler instanceof \SessionHandlerInterface &&
-            null !== $saveHandler) {
+        if (!$saveHandler instanceof AbstractProxy
+            && !$saveHandler instanceof \SessionHandlerInterface
+            && null !== $saveHandler
+        ) {
             throw new \InvalidArgumentException('Must be instance of AbstractProxy; implement \SessionHandlerInterface; or be null.');
         }