N°6934 - Symfony 6.4 - upgrade Symfony bundles to 6.4 (#580)

* Update Symfony lib to version ~6.4.0
* Update code missing return type
* Add an iTop general configuration entry to store application secret (Symfony mandatory parameter)
* Use dependency injection in ExceptionListener & UserProvider classes

lib/symfony/config/Definition/Builder/TreeBuilder.php

@@ -20,19 +20,26 @@ use Symfony\Component\Config\Definition\NodeInterface;
  */
 class TreeBuilder implements NodeParentInterface
 {
+    /**
+     * @var NodeInterface|null
+     */
     protected $tree;
+
+    /**
+     * @var NodeDefinition
+     */
     protected $root;
 
     public function __construct(string $name, string $type = 'array', NodeBuilder $builder = null)
     {
-        $builder = $builder ?? new NodeBuilder();
+        $builder ??= new NodeBuilder();
         $this->root = $builder->node($name, $type)->setParent($this);
     }
 
     /**
      * @return NodeDefinition|ArrayNodeDefinition The root node (as an ArrayNodeDefinition when the type is 'array')
      */
-    public function getRootNode(): NodeDefinition
+    public function getRootNode(): NodeDefinition|ArrayNodeDefinition
     {
         return $this->root;
     }
@@ -40,19 +47,16 @@ class TreeBuilder implements NodeParentInterface
     /**
      * Builds the tree.
      *
-     * @return NodeInterface
-     *
      * @throws \RuntimeException
      */
-    public function buildTree()
+    public function buildTree(): NodeInterface
     {
-        if (null !== $this->tree) {
-            return $this->tree;
-        }
-
-        return $this->tree = $this->root->getNode(true);
+        return $this->tree ??= $this->root->getNode(true);
     }
 
+    /**
+     * @return void
+     */
     public function setPathSeparator(string $separator)
     {
         // unset last built as changing path separator changes all nodes