[ClassLoader] Fix undefined index in ClassCollectionLoader

src/Symfony/Component/ClassLoader/ClassCollectionLoader.php

@@ -353,14 +353,17 @@ class ClassCollectionLoader
             $unresolved = new \ArrayObject();
         }
         $nodeName = $node->getName();
-        $unresolved[$nodeName] = $node;
+
-        foreach ($tree[$nodeName] as $dependency) {
+        if (isset($tree[$nodeName])) {
-            if (!$resolved->offsetExists($dependency->getName())) {
+            $unresolved[$nodeName] = $node;
-                self::resolveDependencies($tree, $dependency, $resolved, $unresolved);
+            foreach ($tree[$nodeName] as $dependency) {
+                if (!$resolved->offsetExists($dependency->getName())) {
+                    self::resolveDependencies($tree, $dependency, $resolved, $unresolved);
+                }
             }
+            $resolved[$nodeName] = $node;
+            unset($unresolved[$nodeName]);
         }
-        $resolved[$nodeName] = $node;
-        unset($unresolved[$nodeName]);
 
         return $resolved;
     }

src/Symfony/Component/ClassLoader/Tests/ClassCollectionLoaderTest.php

@@ -146,6 +146,38 @@ class ClassCollectionLoaderTest extends \PHPUnit_Framework_TestCase
         );
     }
 
+    public function testFixClassWithTraitsOrdering()
+    {
+        if (PHP_VERSION_ID < 50400) {
+            $this->markTestSkipped('Requires PHP > 5.4');
+
+            return;
+        }
+
+        require_once __DIR__.'/Fixtures/ClassesWithParents/CTrait.php';
+        require_once __DIR__.'/Fixtures/ClassesWithParents/F.php';
+        require_once __DIR__.'/Fixtures/ClassesWithParents/G.php';
+
+        $classes = array(
+            'ClassesWithParents\\F',
+            'ClassesWithParents\\G',
+        );
+
+        $expected = array(
+            'ClassesWithParents\\CTrait',
+            'ClassesWithParents\\F',
+            'ClassesWithParents\\G',
+        );
+
+        $r = new \ReflectionClass('Symfony\Component\ClassLoader\ClassCollectionLoader');
+        $m = $r->getMethod('getOrderedClasses');
+        $m->setAccessible(true);
+
+        $ordered = $m->invoke('Symfony\Component\ClassLoader\ClassCollectionLoader', $classes);
+
+        $this->assertEquals($expected, array_map(function ($class) { return $class->getName(); }, $ordered));
+    }
+
     /**
      * @dataProvider getFixNamespaceDeclarationsData
      */

src/Symfony/Component/ClassLoader/Tests/Fixtures/ClassesWithParents/F.php

@@ -0,0 +1,8 @@
+<?php
+
+namespace ClassesWithParents;
+
+class F
+{
+    use CTrait;
+}

src/Symfony/Component/ClassLoader/Tests/Fixtures/ClassesWithParents/G.php

@@ -0,0 +1,8 @@
+<?php
+
+namespace ClassesWithParents;
+
+class G
+{
+    use CTrait;
+}