Merge branch '3.4' into 4.2

* 3.4:
  [DI] fix processing of regular parameter bags by MergeExtensionConfigurationPass
  [FrameworkBundle] reset cache pools between requests

Author: nicolas-grekas

Compiler/MergeExtensionConfigurationPass.php

@@ -200,6 +200,10 @@ public function resolveEnvPlaceholders($value, $format = null, array &$usedEnvs
         $bag = $this->getParameterBag();
         $value = $bag->resolveValue($value);
 
+        if (!$bag instanceof EnvPlaceholderParameterBag) {
+            return parent::resolveEnvPlaceholders($value, $format, $usedEnvs);
+        }
+
         foreach ($bag->getEnvPlaceholders() as $env => $placeholders) {
             if (false === strpos($env, ':')) {
                 continue;