Root Catalog has a negative children count, how it is possible?

Question

I've been playing with the Catalog classes for a while, deleting and importing root categories, subcategories, stores and store groups, and I just discovered that every time I delete a root category the root catalog children count is decreasing.

I get this using $rootCatalog->getChildrenCount() and it has now reached -249.

I must have done something dirty somewhere in my process, but I cannot find the source of this strange behavior.

This is the way I create root categories :

public function createRootCategory($name)
    {
        $parentCategory = $this->_categoryFactory->create()->load(\Magento\Catalog\Model\Category::TREE_ROOT_ID);
        $category = $this->_categoryFactory->create();

        $category->setPath($parentCategory->getPath());
        $category->setStoreId(0);
        $category->setName($name);
        $category->setIsActive(1);
        $category->setDisplayMode('PRODUCTS');
        $category->setParentId(\Magento\Catalog\Model\Category::TREE_ROOT_ID);
        $category->save();

        return $category->getId();
    }

Do you have any clue about the source of this behavior?

Do you know if it may impact Magento in any way?

How do I solve this?

Answer 1

The most likely cause of this behavior is the _beforeDelete method in \Magento\Catalog\Model\ResourceModel\Category, specifically this line:

$this->getAggregateCount()->processDelete($object);

This will run processDelete() within \Magento\Catalog\Model\ResourceModel\Category\AggregateCount, which decreases children_count for all parent categories via:

$data = ['children_count' => new \Zend_Db_Expr('children_count - ' . $childDecrease)];
$where = ['entity_id IN(?)' => $parentIds];
$resourceModel->getConnection()->update($resourceModel->getEntityTable(), $data, $where);

However, it is weird that you end up with a negative number here, since the children_count should increase when you first assign a category as a child. It could be that your custom code never increments the value in the first place, so definitely debug this, you may be doing something which is not "the Magento way". Since I do not know what your code looks like, I cannot say for sure, but definitely have a look at the core logic of the class I mentioned above.

You should fix the value manually after you have figured out what the problem was just to be on the safe side.

Answer 2

<?php
$categoryCollection = $objectManager->get('\Magento\Catalog\Model\ResourceModel\Category\CollectionFactory');

$categories = $categoryCollection->create();

$categories->addAttributeToSelect('*');
$categories->addAttributeToFilter('level', array('eq'=>2));
$categories->load();

foreach($categories as $category):

    $catId = $category->getId();

    $category = $objectManager->create('Magento\Catalog\Model\CategoryFactory')->create()->setStoreId(0)->load($catId);

    $childrenCategories = $category->getChildrenCategories();

        if(!$childrenCategories->count()) continue; //Chiled Category Count
            $CategoryName = $category->getName();
            echo "<pre>";
            print_r($CategoryName);
            echo "<pre>";
    endforeach;
?>