symfony
diff --git a/‎src/Symfony/Component/DependencyInjection/Compiler/MergeExtensionConfigurationPass.php
Lines changed: 18 additions & 10 deletions b/‎src/Symfony/Component/DependencyInjection/Compiler/MergeExtensionConfigurationPass.php
Lines changed: 18 additions & 10 deletions
diff --git a/‎src/Symfony/Component/DependencyInjection/Tests/Compiler/MergeExtensionConfigurationPassTest.php
Lines changed: 34 additions & 0 deletions b/‎src/Symfony/Component/DependencyInjection/Tests/Compiler/MergeExtensionConfigurationPassTest.php
Lines changed: 34 additions & 0 deletions
@@ -52,18 +52,26 @@ public function process(ContainerBuilder $container)
             }
             $config = $resolvingBag->resolveValue($config);
 
-            $tmpContainer = new ContainerBuilder($resolvingBag);
-            $tmpContainer->setResourceTracking($container->isTrackingResources());
-            $tmpContainer->addObjectResource($extension);
-            if ($extension instanceof ConfigurationExtensionInterface && null !== $configuration = $extension->getConfiguration($config, $tmpContainer)) {
-                $tmpContainer->addObjectResource($configuration);
-            }
+            try {
+                $tmpContainer = new ContainerBuilder($resolvingBag);
+                $tmpContainer->setResourceTracking($container->isTrackingResources());
+                $tmpContainer->addObjectResource($extension);
+                if ($extension instanceof ConfigurationExtensionInterface && null !== $configuration = $extension->getConfiguration($config, $tmpContainer)) {
+                    $tmpContainer->addObjectResource($configuration);
+                }
 
-            foreach ($exprLangProviders as $provider) {
-                $tmpContainer->addExpressionLanguageProvider($provider);
-            }
+                foreach ($exprLangProviders as $provider) {
+                    $tmpContainer->addExpressionLanguageProvider($provider);
+                }
 
-            $extension->load($config, $tmpContainer);
+                $extension->load($config, $tmpContainer);
+            } catch (\Exception $e) {
+                if ($resolvingBag instanceof MergeExtensionConfigurationParameterBag) {
+                    $container->getParameterBag()->mergeEnvPlaceholders($resolvingBag);
+                }
+
+                throw $e;
+            }
 
             if ($resolvingBag instanceof MergeExtensionConfigurationParameterBag) {
                 // don't keep track of env vars that are *overridden* when configs are merged
 
@@ -84,6 +84,22 @@ public function testOverriddenEnvsAreMerged()
         $this->assertSame(array('BAZ', 'FOO'), array_keys($container->getParameterBag()->getEnvPlaceholders()));
         $this->assertSame(array('BAZ' => 1, 'FOO' => 0), $container->getEnvCounters());
     }
+
+    public function testThrowingExtensionsGetMergedBag()
+    {
+        $container = new ContainerBuilder();
+        $container->registerExtension(new ThrowingExtension());
+        $container->prependExtensionConfig('throwing', array('bar' => '%env(FOO)%'));
+
+        try {
+            $pass = new MergeExtensionConfigurationPass();
+            $pass->process($container);
+            $this->fail('An exception should have been thrown.');
+        } catch (\Exception $e) {
+        }
+
+        $this->assertSame(array('FOO'), array_keys($container->getParameterBag()->getEnvPlaceholders()));
+    }
 }
 
 class FooConfiguration implements ConfigurationInterface
@@ -125,3 +141,21 @@ public function load(array $configs, ContainerBuilder $container)
         }
     }
 }
+
+class ThrowingExtension extends Extension
+{
+    public function getAlias()
+    {
+        return 'throwing';
+    }
+
+    public function getConfiguration(array $config, ContainerBuilder $container)
+    {
+        return new FooConfiguration();
+    }
+
+    public function load(array $configs, ContainerBuilder $container)
+    {
+        throw new \Exception();
+    }
+}