GraphQL-123: Fix regexp when filter by root category id

-- fix coupling between object in CategoryTree

Author: Valeriy Nayda

app/code/Magento/CatalogGraphQl/Model/Resolver/CategoryTree.php

@@ -7,6 +7,7 @@
 
 namespace Magento\CatalogGraphQl\Model\Resolver;
 
+use Magento\CatalogGraphQl\Model\Resolver\Products\DataProvider\ExtractDataFromCategoryTree;
 use Magento\Framework\GraphQl\Schema\Type\ResolveInfo;
 use Magento\Framework\GraphQl\Config\Element\Field;
 use Magento\Framework\GraphQl\Exception\GraphQlInputException;
@@ -27,13 +28,21 @@ class CategoryTree implements ResolverInterface
      */
     private $categoryTree;
 
+    /**
+     * @var ExtractDataFromCategoryTree
+     */
+    private $extractDataFromCategoryTree;
+
     /**
      * @param \Magento\CatalogGraphQl\Model\Resolver\Products\DataProvider\CategoryTree $categoryTree
+     * @param ExtractDataFromCategoryTree $extractDataFromCategoryTree
      */
     public function __construct(
-        \Magento\CatalogGraphQl\Model\Resolver\Products\DataProvider\CategoryTree $categoryTree
+        \Magento\CatalogGraphQl\Model\Resolver\Products\DataProvider\CategoryTree $categoryTree,
+        ExtractDataFromCategoryTree $extractDataFromCategoryTree
     ) {
         $this->categoryTree = $categoryTree;
+        $this->extractDataFromCategoryTree = $extractDataFromCategoryTree;
     }
 
     /**
@@ -62,7 +71,8 @@ public function resolve(Field $field, $context, ResolveInfo $info, array $value
         $rootCategoryId = $this->getCategoryId($args);
         $categoriesTree = $this->categoryTree->getTree($info, $rootCategoryId);
         if (!empty($categoriesTree)) {
-            return current($categoriesTree);
+            $result = $this->extractDataFromCategoryTree->execute($categoriesTree);
+            return current($result);
         } else {
             return null;
         }

app/code/Magento/CatalogGraphQl/Model/Resolver/Products/DataProvider/CategoryTree.php

@@ -9,7 +9,6 @@
 
 use GraphQL\Language\AST\FieldNode;
 use Magento\CatalogGraphQl\Model\Category\DepthCalculator;
-use Magento\CatalogGraphQl\Model\Category\Hydrator;
 use Magento\CatalogGraphQl\Model\Category\LevelCalculator;
 use Magento\Framework\EntityManager\MetadataPool;
 use Magento\Framework\GraphQl\Schema\Type\ResolveInfo;
@@ -54,41 +53,35 @@ class CategoryTree
      */
     private $metadata;
 
-    /**
-     * @var Hydrator
-     */
-    private $hydrator;
-
     /**
      * @param CollectionFactory $collectionFactory
      * @param AttributesJoiner $attributesJoiner
      * @param DepthCalculator $depthCalculator
      * @param LevelCalculator $levelCalculator
      * @param MetadataPool $metadata
-     * @param Hydrator $hydrator
      */
     public function __construct(
         CollectionFactory $collectionFactory,
         AttributesJoiner $attributesJoiner,
         DepthCalculator $depthCalculator,
         LevelCalculator $levelCalculator,
-        MetadataPool $metadata,
-        Hydrator $hydrator
+        MetadataPool $metadata
     ) {
         $this->collectionFactory = $collectionFactory;
         $this->attributesJoiner = $attributesJoiner;
         $this->depthCalculator = $depthCalculator;
         $this->levelCalculator = $levelCalculator;
         $this->metadata = $metadata;
-        $this->hydrator = $hydrator;
     }
 
     /**
+     * Get category tree
+     *
      * @param ResolveInfo $resolveInfo
      * @param int $rootCategoryId
-     * @return array
+     * @return \Iterator
      */
-    public function getTree(ResolveInfo $resolveInfo, int $rootCategoryId) : array
+    public function getTree(ResolveInfo $resolveInfo, int $rootCategoryId): \Iterator
     {
         $categoryQuery = $resolveInfo->fieldNodes[0];
         $collection = $this->collectionFactory->create();
@@ -113,28 +106,7 @@ public function getTree(ResolveInfo $resolveInfo, int $rootCategoryId) : array
             $this->metadata->getMetadata(CategoryInterface::class)->getIdentifierField() . ' = ?',
             $rootCategoryId
         );
-        return $this->processTree($collection->getIterator());
-    }
-
-    /**
-     * @param \Iterator $iterator
-     * @return array
-     */
-    private function processTree(\Iterator $iterator) : array
-    {
-        $tree = [];
-        while ($iterator->valid()) {
-            /** @var CategoryInterface $category */
-            $category = $iterator->current();
-            $iterator->next();
-            $nextCategory = $iterator->current();
-            $tree[$category->getId()] = $this->hydrator->hydrateCategory($category);
-            if ($nextCategory && (int) $nextCategory->getLevel() !== (int) $category->getLevel()) {
-                $tree[$category->getId()]['children'] = $this->processTree($iterator);
-            }
-        }
-
-        return $tree;
+        return $collection->getIterator();
     }
 
     /**

app/code/Magento/CatalogGraphQl/Model/Resolver/Products/DataProvider/ExtractDataFromCategoryTree.php

@@ -0,0 +1,52 @@
+<?php
+/**
+ * Copyright © Magento, Inc. All rights reserved.
+ * See COPYING.txt for license details.
+ */
+declare(strict_types=1);
+
+namespace Magento\CatalogGraphQl\Model\Resolver\Products\DataProvider;
+
+use Magento\CatalogGraphQl\Model\Category\Hydrator;
+use Magento\Catalog\Api\Data\CategoryInterface;
+
+/**
+ * Extarct data from category tree
+ */
+class ExtractDataFromCategoryTree
+{
+    /**
+     * @var Hydrator
+     */
+    private $categoryHydrator;
+
+    /**
+     * @param Hydrator $categoryHydrator
+     */
+    public function __construct(
+        Hydrator $categoryHydrator
+    ) {
+        $this->categoryHydrator = $categoryHydrator;
+    }
+
+    /**
+     * @param \Iterator $iterator
+     * @return array
+     */
+    public function execute(\Iterator $iterator): array
+    {
+        $tree = [];
+        while ($iterator->valid()) {
+            /** @var CategoryInterface $category */
+            $category = $iterator->current();
+            $iterator->next();
+            $nextCategory = $iterator->current();
+            $tree[$category->getId()] = $this->categoryHydrator->hydrateCategory($category);
+            if ($nextCategory && (int) $nextCategory->getLevel() !== (int) $category->getLevel()) {
+                $tree[$category->getId()]['children'] = $this->execute($iterator);
+            }
+        }
+
+        return $tree;
+    }
+}