Deprecate TreeBuilder::root

Author: gharlan

CHANGELOG.md

@@ -6,6 +6,7 @@ CHANGELOG
 
  * deprecated using environment variables with `cannotBeEmpty()` if the value is validated with `validate()`
  * made `Resource\*` classes final and not implement `Serializable` anymore
+ * deprecated the `root()` method in `TreeBuilder`, pass the root node information to the constructor instead
 
 4.2.0
 -----

Definition/Builder/TreeBuilder.php

@@ -29,7 +29,8 @@ public function __construct(string $name = null, string $type = 'array', NodeBui
         if (null === $name) {
             @trigger_error('A tree builder without a root node is deprecated since Symfony 4.2 and will not be supported anymore in 5.0.', E_USER_DEPRECATED);
         } else {
-            $this->root($name, $type, $builder);
+            $builder = $builder ?: new NodeBuilder();
+            $this->root = $builder->node($name, $type)->setParent($this);
         }
     }
 
@@ -43,9 +44,13 @@ public function __construct(string $name = null, string $type = 'array', NodeBui
      * @return ArrayNodeDefinition|NodeDefinition The root node (as an ArrayNodeDefinition when the type is 'array')
      *
      * @throws \RuntimeException When the node type is not supported
+     *
+     * @deprecated since Symfony 4.3, pass the root name to the constructor instead
      */
     public function root($name, $type = 'array', NodeBuilder $builder = null)
     {
+        @trigger_error(sprintf('The "%s()" method called for the "%s" configuration is deprecated since Symfony 4.3, pass the root name to the constructor instead.', __METHOD__, $name), E_USER_DEPRECATED);
+
         $builder = $builder ?: new NodeBuilder();
 
         return $this->root = $builder->node($name, $type)->setParent($this);

Tests/Definition/Builder/TreeBuilderTest.php

@@ -197,4 +197,14 @@ public function testInitializingTreeBuildersWithoutRootNode()
     {
         new TreeBuilder();
     }
+
+    /**
+     * @group legacy
+     * @expectedDeprecation The "Symfony\Component\Config\Definition\Builder\TreeBuilder::root()" method called for the "foo" configuration is deprecated since Symfony 4.3, pass the root name to the constructor instead.
+     */
+    public function testRoot()
+    {
+        $builder = new TreeBuilder('foo');
+        $builder->root('foo');
+    }
 }