magento2-dev-core

Magento 2 Developer Core

This skill provides the foundational patterns all Magento 2 developers must follow. It covers architectural decisions, security, and best practices that apply to every part of a Magento project.

Related Skills

This is the foundation the other Magento 2 skills build on: magento2-frontend-dev and magento2-hyva-dev cover the two mutually exclusive theme stacks (check the theme's theme.xml parent to see which one the project actually uses — Luma vs Hyvä), magento2-backend-dev covers APIs/CLI/cron, and magento2-linter, magento2-security-scan, magento2-performance-audit verify the patterns below — magento2-code-review orchestrates all three (plus this skill's own anti-pattern checks) into one report scoped to a PR/module/theme/project. In a Govard environment, pair this with govard-magento for the container/CLI side.

Core Architectural Standards

Note: For framework-agnostic PHP (PSR-12/Composer/PDO) see php-dev-core. This skill covers Magento-specific DI/Repository/Plugin.

Dependency Injection (DI)

DO: Use Constructor Injection for all dependencies.

class MyService
{
    public function __construct(
        private readonly ProductRepositoryInterface $productRepository,
        private readonly LoggerInterface $logger
    ) {}

    public function getProduct(int $id): ?ProductInterface
    {
        return $this->productRepository->get($id);
    }
}

NEVER: Use ObjectManager::getInstance() (Service Locator anti-pattern).

// WRONG - Never do this
$objectManager = \Magento\Framework\App\ObjectManager::getInstance();
$product = $objectManager->create(Product::class);

// CORRECT
public function __construct(ProductFactory $productFactory) {
    $this->productFactory = $productFactory;
}

Service Contracts

Always prefer interfaces in Api/ folders over concrete classes:

// WRONG
public function __construct(Product $product) { }

// CORRECT
public function __construct(ProductInterface $product) { }