Issue #2468499 by webflo: Add vendor libs to classmap through composer script event

core/composer.json

@@ -48,19 +48,14 @@
       "lib/Drupal/Core/Database/Database.php",
       "lib/Drupal/Core/DrupalKernel.php",
       "lib/Drupal/Core/DrupalKernelInterface.php",
-      "lib/Drupal/Core/Site/Settings.php",
-      "vendor/symfony/http-foundation/Symfony/Component/HttpFoundation/Request.php",
-      "vendor/symfony/http-foundation/Symfony/Component/HttpFoundation/ParameterBag.php",
-      "vendor/symfony/http-foundation/Symfony/Component/HttpFoundation/FileBag.php",
-      "vendor/symfony/http-foundation/Symfony/Component/HttpFoundation/ServerBag.php",
-      "vendor/symfony/http-foundation/Symfony/Component/HttpFoundation/HeaderBag.php",
-      "vendor/symfony/http-kernel/Symfony/Component/HttpKernel/HttpKernel.php",
-      "vendor/symfony/http-kernel/Symfony/Component/HttpKernel/HttpKernelInterface.php",
-      "vendor/symfony/http-kernel/Symfony/Component/HttpKernel/TerminableInterface.php"
+      "lib/Drupal/Core/Site/Settings.php"
     ]
   },
   "config": {
     "preferred-install": "dist",
     "autoloader-suffix": "Drupal8"
+  },
+  "scripts": {
+    "pre-autoload-dump": "Drupal\\Core\\Composer\\Composer::preAutoloadDump"
   }
 }

core/lib/Drupal/Core/Composer/Composer.php

+<?php
+
+/**
+ * @file
+ * Contains \Drupal\Core\Composer\Composer.
+ */
+
+namespace Drupal\Core\Composer;
+
+use Composer\Script\Event;
+
+/**
+ * Provides static functions for composer script events.
+ *
+ * @see https://getcomposer.org/doc/articles/scripts.md
+ */
+class Composer {
+
+  /**
+   * Add vendor classes to composers static classmap.
+   */
+  public static function preAutoloadDump(Event $event) {
+    $composer = $event->getComposer();
+    $package = $composer->getPackage();
+    $autoload = $package->getAutoload();
+    $autoload['classmap'] = array_merge($autoload['classmap'], array(
+      'vendor/symfony/http-foundation/Symfony/Component/HttpFoundation/Request.php',
+      'vendor/symfony/http-foundation/Symfony/Component/HttpFoundation/ParameterBag.php',
+      'vendor/symfony/http-foundation/Symfony/Component/HttpFoundation/FileBag.php',
+      'vendor/symfony/http-foundation/Symfony/Component/HttpFoundation/ServerBag.php',
+      'vendor/symfony/http-foundation/Symfony/Component/HttpFoundation/HeaderBag.php',
+      'vendor/symfony/http-kernel/Symfony/Component/HttpKernel/HttpKernel.php',
+      'vendor/symfony/http-kernel/Symfony/Component/HttpKernel/HttpKernelInterface.php',
+      'vendor/symfony/http-kernel/Symfony/Component/HttpKernel/TerminableInterface.php'
+    ));
+    $package->setAutoload($autoload);
+  }
+
+}