Allow setting Symfony's version explicitly (#351)

README.md

@@ -114,6 +114,18 @@ If you're getting the following error
 </issueHandlers>
 ```
 
+#### Symfony version
+
+By default, the plugin uses the `Kernel::MAJOR_VERSION` constant to determine your version of Symfony. However, this
+might not be accurate if you have Psalm installed globally. You can set the version explicitly using
+the `symfonyMajorVersion` configuration option:
+
+```xml
+<pluginClass class="Psalm\SymfonyPsalmPlugin\Plugin">
+    <symfonyMajorVersion>6</symfonyMajorVersion>
+</pluginClass>
+```
+
 ### Twig tainting (experimental)
 
 When it comes to taint analysis for Twig templates, there are currently two approaches:

src/Plugin.php

@@ -89,7 +89,7 @@ public function __invoke(RegistrationInterface $registration, ?\SimpleXMLElement
         $registration->registerHooksFromClass(ContainerHandler::class);
 
         $this->addStubs($registration, __DIR__.'/Stubs/common');
-        $this->addStubs($registration, __DIR__.'/Stubs/'.Kernel::MAJOR_VERSION);
+        $this->addStubs($registration, __DIR__.'/Stubs/'.($config->symfonyMajorVersion ?? Kernel::MAJOR_VERSION));
         $this->addStubs($registration, __DIR__.'/Stubs/php');
 
         if (isset($config->twigCachePath)) {