[Form] Add support for sorting fields

src/Symfony/Component/Form/CHANGELOG.md

@@ -15,6 +15,7 @@ CHANGELOG
  * Added a `choice_translation_parameters` option to `ChoiceType`
  * Add `UuidType` and `UlidType`
  * Dependency on `symfony/intl` was removed. Install `symfony/intl` if you are using `LocaleType`, `CountryType`, `CurrencyType`, `LanguageType` or `TimezoneType`.
+ * Add `priority` option to `BaseType` and sorting view fields
 
 5.2.0
 -----

src/Symfony/Component/Form/Extension/Core/Type/BaseType.php

@@ -107,6 +107,7 @@ abstract class BaseType extends AbstractType
             'translation_domain' => $translationDomain,
             'label_translation_parameters' => $labelTranslationParameters,
             'attr_translation_parameters' => $attrTranslationParameters,
+            'priority' => $options['priority'],
             // Using the block name here speeds up performance in collection
             // forms, where each entry has the same full block name.
             // Including the type is important too, because if rows of a
@@ -135,11 +136,15 @@ abstract class BaseType extends AbstractType
             'attr' => [],
             'translation_domain' => null,
             'auto_initialize' => true,
+            'priority' => 0,
         ]);
 
         $resolver->setAllowedTypes('block_prefix', ['null', 'string']);
         $resolver->setAllowedTypes('attr', 'array');
         $resolver->setAllowedTypes('row_attr', 'array');
         $resolver->setAllowedTypes('label_html', 'bool');
+        $resolver->setAllowedTypes('priority', 'int');
+
+        $resolver->setInfo('priority', 'The form rendering priority (higher priorities will be rendered first)');
     }
 }

src/Symfony/Component/Form/Form.php

@@ -1044,11 +1044,38 @@ class Form implements \IteratorAggregate, FormInterface, ClearableErrorsInterfac
             $view->children[$name] = $child->createView($view);
         }
 
+        $this->sort($view->children);
+
         $type->finishView($view, $this, $options);
 
         return $view;
     }
 
+    /**
+     * Sorts view fields based on their priority value.
+     */
+    private function sort(array &$children): void
+    {
+        $c = [];
+        $i = 0;
+        $needsSorting = false;
+        foreach ($children as $name => $child) {
+            $c[$name] = ['p' => $child->vars['priority'] ?? 0, 'i' => $i++];
+
+            if (0 !== $c[$name]['p']) {
+                $needsSorting = true;
+            }
+        }
+
+        if (!$needsSorting) {
+            return;
+        }
+
+        uksort($children, static function ($a, $b) use ($c): int {
+            return [$c[$b]['p'], $c[$a]['i']] <=> [$c[$a]['p'], $c[$b]['i']];
+        });
+    }
+
     /**
      * Normalizes the underlying data if a model transformer is set.
      *

src/Symfony/Component/Form/Tests/Extension/Core/Type/FormTypeTest.php

@@ -836,6 +836,29 @@ class FormTypeTest extends BaseTypeTest
         $this->assertSame($view->vars['id'], $view['child1']->vars['attr']['form']);
         $this->assertSame($view->vars['id'], $view['child2']->vars['attr']['form']);
     }
+
+    public function testSortingViewChildrenBasedOnPriorityOption()
+    {
+        $view = $this->factory->createNamedBuilder('parent', self::TESTED_TYPE)
+            ->add('child1', null, ['priority' => -1])
+            ->add('child2')
+            ->add('child3', null, ['priority' => -1])
+            ->add('child4')
+            ->add('child5', null, ['priority' => 1])
+            ->add('child6')
+            ->getForm()
+            ->createView();
+
+        $expected = [
+            'child5',
+            'child2',
+            'child4',
+            'child6',
+            'child1',
+            'child3',
+        ];
+        $this->assertSame($expected, array_keys($view->children));
+    }
 }
 
 class Money

src/Symfony/Component/Form/Tests/Fixtures/Descriptor/resolved_form_type_1.json

@@ -57,6 +57,7 @@
                 "mapped",
                 "method",
                 "post_max_size_message",
+                "priority",
                 "property_path",
                 "required",
                 "row_attr",

src/Symfony/Component/Form/Tests/Fixtures/Descriptor/resolved_form_type_1.txt

@@ -34,6 +34,7 @@ Symfony\Component\Form\Extension\Core\Type\ChoiceType (Block prefix: "choice")
                                                        mapped                                                
                                                        method                                                
                                                        post_max_size_message                                 
+                                                       priority                                              
                                                        property_path                                         
                                                        required                                              
                                                        row_attr                                              

src/Symfony/Component/Form/Tests/Fixtures/Descriptor/resolved_form_type_2.json

@@ -35,6 +35,7 @@
             "mapped",
             "method",
             "post_max_size_message",
+            "priority",
             "property_path",
             "required",
             "row_attr",

src/Symfony/Component/Form/Tests/Fixtures/Descriptor/resolved_form_type_2.txt

@@ -37,6 +37,7 @@ Symfony\Component\Form\Extension\Core\Type\FormType (Block prefix: "form")
   mapped                        
   method                        
   post_max_size_message         
+  priority                      
   property_path                 
   required                      
   row_attr