CatalogInventory Decoupling Report¶

Module Scanned¶

Magento_CatalogInventory (app/code/Magento/CatalogInventory)

Scale of the Problem¶

24 external modules with CatalogInventory coupling
83 PHP use imports (production code, excl. tests)
25 XML references (di.xml, layout, module.xml)
23 modules with hard require in composer.json
6 modules with <sequence> in module.xml

Key Constants (Most Likely Referenced Externally)¶

StockStatusInterface (`Api\Data\StockStatusInterface`)¶

Constant	Value
`STATUS_OUT_OF_STOCK`	`0`
`STATUS_IN_STOCK`	`1`
`PRODUCT_ID`	`'product_id'`
`STOCK_ID`	`'stock_id'`
`QTY`	`'qty'`
`STOCK_STATUS`	`'stock_status'`
`STOCK_ITEM`	`'stock_item'`

StockItemInterface (`Api\Data\StockItemInterface`)¶

Constant	Value
`BACKORDERS_NO`	`0`
`ITEM_ID`	`'item_id'`
`PRODUCT_ID`	`'product_id'`
`STOCK_ID`	`'stock_id'`
`QTY`	`'qty'`
`IS_QTY_DECIMAL`	`'is_qty_decimal'`
`IS_IN_STOCK`	`'is_in_stock'`
`MANAGE_STOCK`	`'manage_stock'`
`BACKORDERS`	`'backorders'`
`MIN_QTY`	`'min_qty'`
`MIN_SALE_QTY`	`'min_sale_qty'`
`MAX_SALE_QTY`	`'max_sale_qty'`
`QTY_INCREMENTS`	`'qty_increments'`
(+ 10 more USE_CONFIG_ and other fields)*

Stock Model (`Model\Stock`)¶

Constant	Value
`BACKORDERS_NO`	`0`
`BACKORDERS_YES_NONOTIFY`	`1`
`BACKORDERS_YES_NOTIFY`	`2`
`STOCK_OUT_OF_STOCK`	`0`
`STOCK_IN_STOCK`	`1`
`DEFAULT_STOCK_ID`	`1`

Configuration (`Model\Configuration`)¶

Constant	Value
`XML_PATH_SHOW_OUT_OF_STOCK`	`'cataloginventory/options/show_out_of_stock'`
`XML_PATH_MANAGE_STOCK`	`'cataloginventory/item_options/manage_stock'`
`XML_PATH_BACKORDERS`	`'cataloginventory/item_options/backorders'`
`XML_PATH_MIN_QTY`	`'cataloginventory/item_options/min_qty'`
`XML_PATH_MIN_SALE_QTY`	`'cataloginventory/item_options/min_sale_qty'`
`XML_PATH_MAX_SALE_QTY`	`'cataloginventory/item_options/max_sale_qty'`
(+ 8 more XML_PATH_ constants)*

Stock Indexer (`Model\Indexer\Stock\Processor`)¶

Constant	Value
`INDEXER_ID`	`'cataloginventory_stock'`

Coupling by Module (Production Code Only)¶

Tier 1: Heaviest Coupling (10+ PHP imports)¶

ConfigurableProduct — 20 PHP uses, 5 XML refs¶

File	CatalogInventory Classes Used
`Model/Inventory/ChangeParentStockStatus.php`	`StockItemInterface`, `StockConfigurationInterface`, `StockItemCriteriaInterfaceFactory`, `StockItemRepositoryInterface`
`Model/Inventory/ParentItemProcessor.php`	`StockItemCriteriaInterfaceFactory`, `StockItemRepositoryInterface`, `StockConfigurationInterface`, `ParentItemProcessorInterface`
`Model/Plugin/UpdateStockChangedAuto.php`	`Stock\Item` (ResourceModel)
`Model/Product/Type/Collection/SalableProcessor.php`	`Stock\StatusFactory`
`Model/ResourceModel/Indexer/Stock/Configurable.php`	`Indexer\Stock\Action\Full`
`Model/ResourceModel/Product/Indexer/Price/BaseStockStatusSelectProcessor.php`	`Stock`, `StockConfigurationInterface`
`Model/ResourceModel/Product/StockStatusBaseSelectProcessor.php`	`StockConfigurationInterface`, `Stock\Status`, `Stock\Status` (Resource)
`Plugin/Model/ResourceModel/Attribute/InStockOptionSelectBuilder.php`	`StockConfigurationInterface`, `Stock\Status` (Resource)
`Pricing/Price/ConfigurableOptionsStockStatusFilter.php`	`StockConfigurationInterface`
`Ui/DataProvider/Product/Form/Modifier/Data/AssociatedProducts.php`	`StockRegistryInterface`
`etc/di.xml`	3 type configs (QuantityValidator, SaveInventoryDataObserver, Stock\Item)
`etc/module.xml`	sequence dependency
`view/frontend/layout/catalog_product_view_type_configurable.xml`	`Stockqty\Type\Configurable` block

Bundle — 11 PHP uses, 5 XML refs¶

File	CatalogInventory Classes Used
`Model/Inventory/ChangeParentStockStatus.php`	`StockItemInterface`, `StockConfigurationInterface`, `StockItemCriteriaInterfaceFactory`, `StockItemRepositoryInterface`
`Model/Inventory/ParentItemProcessor.php`	`ParentItemProcessorInterface`
`Model/ResourceModel/Indexer/DefaultInventoryStockStatusQueryProcessor.php`	`StockConfigurationInterface`, `Stock`
`Model/ResourceModel/Indexer/SelectionPriceModifier.php`	`StockConfigurationInterface`
`Model/ResourceModel/Indexer/Stock.php`	`Indexer\Stock\Action\Full`, `Indexer\Stock\DefaultStock`
`Ui/DataProvider/Product/Form/Modifier/AddSelectionQtyTypeToProductsData.php`	`StockRegistryPreloader`
`etc/di.xml`	`StockRegistryInterface\Proxy`, `StockStateInterface\Proxy`, `Indexer\Stock\Action\Full`, `SaveInventoryDataObserver`
`view/frontend/layout/catalog_product_view_type_bundle.xml`	`Qtyincrements` block

Tier 2: Moderate Coupling (4-9 PHP imports)¶

CatalogImportExport — 7 PHP uses, 1 XML ref¶

File	CatalogInventory Classes Used
`Model/Export/Product.php`	`StockConfigurationInterface`
`Model/Export/Product/Stock.php`	`Configuration`, `Stock\Item` (Resource)
`Model/Import/Product.php`	`StockItemInterface`
`Model/Import/Product/Validator/Backorders.php`	`Source\Backorders`
`Model/StockItemImporter.php`	`Stock\Item` (Resource), `Stock\ItemFactory`
`etc/di.xml`	`Indexer\Stock\Processor::INDEXER_ID`

GroupedProduct — 7 PHP uses, 4 XML refs¶

File	CatalogInventory Classes Used
`Model/Inventory/ChangeParentStockStatus.php`	`StockItemInterface`, `StockConfigurationInterface`, `StockItemCriteriaInterfaceFactory`, `StockItemRepositoryInterface`
`Model/Inventory/ParentItemProcessor.php`	`ParentItemProcessorInterface`
`Model/ResourceModel/Indexer/Stock/Grouped.php`	`Indexer\Stock\Action\Full`
`ViewModel/ValidateQuantity.php`	`Product\QuantityValidator`
`etc/di.xml`	`SaveInventoryDataObserver`, `MassUpdateProductAttribute`
`etc/module.xml`	sequence dependency
`view/frontend/layout/catalog_product_view_type_grouped.xml`	`Stockqty\Type\Grouped` block

QuoteGraphQl — 6 PHP uses, 1 XML ref¶

File	CatalogInventory Classes Used
`Model/Cart/MergeCarts/CartQuantityValidator.php`	`StockRegistryInterface`, `Stock`
`Model/CartItem/ProductStock.php`	`StockStatusInterface`, `StockRegistryInterface`, `Configuration`, `StockState`
`etc/graphql/di.xml`	`CatalogInventoryGraphQl\Helper\Error\MessageFormatters`

ConfigurableProductGraphQl — 5 PHP uses, 1 XML ref¶

File	CatalogInventory Classes Used
`Model/Cart/BuyRequest/SuperAttributeDataProvider.php`	`StockStateInterface`, `StockStateException`
`Model/Formatter/OptionValue.php`	`StockRegistry`
`Model/Options/DataProvider/Variant.php`	`Stock\StatusFactory`
`Plugin/AddStockStatusToCollection.php`	`Stock\Status` (Resource)
`etc/module.xml`	sequence dependency

Catalog — 5 PHP uses, 2 XML refs¶

File	CatalogInventory Classes Used
`Controller/Adminhtml/Product/Initialization/StockDataFilter.php`	`StockConfigurationInterface`
`Setup/CategorySetup.php`	`Form\Field\Stock`, `Source\Stock`, `Stock` model
`ViewModel/Product/Checker/AddToCompareAvailability.php`	`StockConfigurationInterface`
`etc/di.xml`	`Config\Backend\ShowOutOfStock`, `StockItemInterface[]`

Wishlist — 5 PHP uses, 2 XML refs¶

File	CatalogInventory Classes Used
`Model/ResourceModel/Item/Collection.php`	`StockStatusFilterInterface`
`Model/Wishlist.php`	`StockConfigurationInterface`, `StockRegistryInterface`, `StockStateException`
`ViewModel/AllowedQuantity.php`	`StockRegistry`
`view/frontend/layout/wishlist_index_configure_type_bundle.xml`	`Qtyincrements` block
`view/frontend/layout/wishlist_index_configure_type_downloadable.xml`	`Stockqty\DefaultStockqty` block

CatalogSearch — 4 PHP uses, 1 XML ref¶

File	CatalogInventory Classes Used
`Model/Indexer/Plugin/StockedProductsFilterPlugin.php`	`StockConfigurationInterface`, `StockStatusRepositoryInterface`, `StockStatusCriteriaInterfaceFactory`, `StockStatusInterface`
`etc/module.xml`	sequence dependency

Tier 3: Light Coupling (1-3 PHP imports)¶

Sales — 3 PHP uses¶

File	CatalogInventory Classes Used
`Block/Adminhtml/Order/Create/Items/Grid.php`	`StockRegistryInterface`, `StockStateInterface`
`CustomerData/LastOrderedItems.php`	`StockRegistryInterface`

SalesInventory — 2 PHP uses, 1 XML ref¶

File	CatalogInventory Classes Used
`Observer/RefundOrderInventoryObserver.php`	`StockConfigurationInterface`, `StockManagementInterface`
`etc/module.xml`	sequence dependency

GroupedCatalogInventory — 2 PHP uses¶

File	CatalogInventory Classes Used
`Plugin/OutOfStockFilter.php`	`StockStatusInterface`, `StockRegistryInterface`

CatalogGraphQl — 2 PHP uses¶

File	CatalogInventory Classes Used
`Model/Resolver/Products/DataProvider/Product/CollectionProcessor/StockProcessor.php`	`StockConfigurationInterface`, `Stock\Status` (Resource)

Dhl — 1 PHP use¶

File	CatalogInventory Classes Used
`Model/Carrier.php`	`StockRegistryInterface`

Ups — 1 PHP use¶

File	CatalogInventory Classes Used
`Model/Carrier.php`	`StockRegistryInterface`

Downloadable — 1 PHP use, 1 XML ref¶

File	CatalogInventory Classes Used
`Controller/Download/Sample.php`	`StockConfigurationInterface`
`view/frontend/layout/catalog_product_view_type_downloadable.xml`	`Stockqty\DefaultStockqty` block

Checkout — 1 PHP use, 1 XML ref¶

File	CatalogInventory Classes Used
`Block/Cart/Crosssell.php`	`Stock` helper
`etc/module.xml`	sequence dependency

Elasticsearch — 1 PHP use¶

File	CatalogInventory Classes Used
`Model/Indexer/Plugin/DependencyUpdaterPlugin.php`	`Indexer\Stock\Processor`

Quote — 1 PHP use¶

File	CatalogInventory Classes Used
`Model/Cart/AddProductsToCart.php`	`StockRegistryInterface`

Tier 4: Composer-Only Dependency (no PHP imports found)¶

Module	Notes
AdvancedPricingImportExport	~~Hard require~~ DONE — removed from composer.json
Fedex	~~Hard require~~ DONE — removed from composer.json
Reports	~~Hard require~~ DONE — removed from composer.json
Shipping	~~Hard require~~ DONE — removed from composer.json
Usps	~~Hard require~~ DONE — removed from composer.json

Most Referenced CatalogInventory Interfaces¶

Interface / Class	# External References	Role
`StockConfigurationInterface`	~15	Check stock settings (manage stock, show OOS, backorders)
`StockRegistryInterface`	~10	Get stock item/status by product
`StockItemInterface`	~6	Stock item data object
`StockStatusInterface`	~5	Stock status data + IN_STOCK/OUT_OF_STOCK constants
`Stock` (model)	~5	BACKORDERS_*, STOCK_IN/OUT constants, DEFAULT_STOCK_ID
`Stock\Status` (resource model)	~5	Join stock status to product collections
`StockItemRepositoryInterface`	~4	CRUD for stock items
`StockItemCriteriaInterfaceFactory`	~4	Build stock item search criteria
`ParentItemProcessorInterface`	~3	Parent stock recalculation (Bundle, Configurable, Grouped)
`Indexer\Stock\Action\Full`	~3	Stock indexer extension point

Coupling Pattern Analysis¶

Pattern 1: Parent Stock Status Recalculation¶

Modules: Bundle, ConfigurableProduct, GroupedProduct Classes: ChangeParentStockStatus, ParentItemProcessor What it does: When a child product's stock changes, recalculates parent's stock status. Coupling: 4 CatalogInventory interfaces per module (StockItemInterface, StockConfigurationInterface, StockItemCriteriaInterfaceFactory, StockItemRepositoryInterface)

Deep Dive: Code Duplication Analysis¶

Each product type has 2 classes: ParentItemProcessor (thin wrapper implementing the interface) and ChangeParentStockStatus (actual logic).

ParentItemProcessorInterface — defined in CatalogInventory\Observer, depends only on Catalog\Api\Data\ProductInterface. All 3 implementations are trivial one-liner delegates to ChangeParentStockStatus::execute(). The Configurable version still carries deprecated constructor params (Configurable $configurableType, StockItemCriteriaInterfaceFactory, StockItemRepositoryInterface, StockConfigurationInterface) that it no longer uses.

ChangeParentStockStatus — 3 separate implementations sharing identical code:

Identical across all 3:

// isNeedToUpdateParent() — copy-pasted verbatim in all 3
private function isNeedToUpdateParent(StockItemInterface $parentStockItem, bool $childrenIsInStock): bool
{
    return $parentStockItem->getIsInStock() !== $childrenIsInStock &&
        ($childrenIsInStock === false || $parentStockItem->getStockStatusChangedAuto());
}

// Stock item loading — same logic in all 3
$criteria = $this->criteriaInterfaceFactory->create();
$criteria->setScopeFilter($this->stockConfiguration->getDefaultScopeId());
$criteria->setProductsFilter($productIds);
$stockItemCollection = $this->stockItemRepository->getList($criteria);

// Parent update — same in all 3
$parentStockItem->setIsInStock($childrenIsInStock);
$parentStockItem->setStockStatusChangedAuto(1);
$this->stockItemRepository->save($parentStockItem);

Same 4 CatalogInventory dependencies in all 3: - StockItemInterface - StockConfigurationInterface - StockItemCriteriaInterfaceFactory - StockItemRepositoryInterface

Only difference — "is children in stock" logic:

Module	Children Check	execute() Signature
Bundle	Per-option: at least 1 in-stock child per required option	`execute(array $childrenIds)`
Configurable	Flat: any single child in-stock = parent in-stock	`execute(array $childrenIds)`
Grouped	Flat: any single child in-stock = parent in-stock (same as Configurable)	`execute(int $productId)`

Configurable and Grouped processStockForParent() methods are nearly identical. Grouped has an extra getParentEntityIdsByChild() that does a raw SQL query instead of using the type model.

Recommended Refactoring¶

Extract an abstract base class in CatalogInventory (e.g. AbstractChangeParentStockStatus) that handles: - Stock item loading via criteria factory - isNeedToUpdateParent() check - Parent stock item save

Each product type module would only provide: - A method to resolve parent IDs from child IDs (delegates to its own type model) - A method to determine if children are in-stock (flat check vs per-option check)

This reduces the CatalogInventory coupling surface from 4 interfaces per module to 1 abstract class, and eliminates ~60% of duplicated code across the 3 modules.

Alternatively, ParentItemProcessorInterface could be moved out of CatalogInventory\Observer to Catalog\Api (it only depends on ProductInterface), and the stock-specific abstract base would implement it.

Pattern 2: Stock Status Collection Filtering¶

Modules: ConfigurableProduct, CatalogGraphQl, CatalogSearch, Wishlist What it does: Joins stock_status table to product collections to filter out-of-stock products. Coupling: StockConfigurationInterface (to check show_out_of_stock setting) + Stock\Status resource model or StockStatusFilterInterface.

Pattern 3: Stock Indexer Extension¶

Modules: Bundle, ConfigurableProduct, GroupedProduct, Elasticsearch What it does: Extends the stock indexer with product-type-specific logic. Coupling: Indexer\Stock\Action\Full, Indexer\Stock\DefaultStock

Pattern 4: Stock Registry Lookups¶

Modules: Sales, Quote, Dhl, Ups, Wishlist, QuoteGraphQl, GroupedCatalogInventory What it does: Looks up stock info for a specific product (qty, is_in_stock, min/max sale qty). Coupling: StockRegistryInterface

Pattern 5: Stock Validation in Cart/Checkout¶

Modules: Quote, ConfigurableProductGraphQl, QuoteGraphQl What it does: Validates quantities against stock rules during add-to-cart. Coupling: StockStateInterface, StockStateException, StockRegistryInterface

Decoupling Difficulty Assessment¶

Category	Modules	Difficulty	Approach
Composer-only (no code)	AdvancedPricingImportExport, Fedex, Reports, Shipping, Usps	Trivial	Remove from `require`
Layout XML only	Downloadable (partial), Wishlist (partial)	Easy	Type-handle layouts, safe to leave or move
Light API usage (1-3 interfaces)	Dhl, Ups, Quote, Sales, Checkout, Elasticsearch, SalesInventory	Moderate	Make interfaces optional/nullable
Collection filtering	CatalogSearch, CatalogGraphQl, Wishlist, ConfigurableProduct (partial)	Moderate	Abstract behind a stock filter interface in Catalog
Indexer extension	Bundle, ConfigurableProduct, GroupedProduct, Elasticsearch	Hard	Needs indexer plugin architecture rework
Deep integration (10+ refs)	ConfigurableProduct, Bundle, GroupedProduct	Very Hard	Parent stock recalc + indexer + collection filtering — needs a stock abstraction layer

Recommended Priority¶

~~Quick wins (Tier 4): Remove phantom composer.json dependencies from AdvancedPricingImportExport, Fedex, Reports, Shipping, Usps~~ DONE
Shipping carriers: Dhl, Ups — single StockRegistryInterface usage each, easy to make optional
Sales/Quote/Checkout: Light usage, can be made optional with null checks
Catalog core: StockDataFilter and CategorySetup — needs careful handling as these are setup/init paths
Product types (Bundle/Configurable/Grouped): Heaviest coupling — the ChangeParentStockStatus pattern is duplicated across all 3 and deeply tied to CatalogInventory internals. Would benefit from a shared stock abstraction layer before decoupling.
GraphQL modules: Should follow their parent module's decoupling (e.g., decouple ConfigurableProductGraphQl after ConfigurableProduct)