PHP Ecosystem

        public function label(): string
        {
            return match($this) {
                self::Draft => 'Draft',
                self::Published => 'Published',
                self::Archived => 'Archived',
            };
        }
    }

    // Usage
    $status = Status::from('published');
    $value = $status->value; // 'published'
  </example>
</pattern>

<pattern name="unit-enum">
  <description>Enum without backing value</description>
  <example>
    enum Suit
    {
        case Hearts;
        case Diamonds;
        case Clubs;
        case Spades;

        public function color(): string
        {
            return match($this) {
                self::Hearts, self::Diamonds =&gt; 'red',
                self::Clubs, self::Spades =&gt; 'black',
            };
        }
    }
  </example>
</pattern>

<pattern name="readonly-class">
  <description>All properties become readonly (PHP 8.2+)</description>
  <example>
    readonly class ValueObject
    {
        public function __construct(
            public string $name,
            public int $value,
        ) {}
    }
  </example>
</pattern>

    class UserController
    {
        #[Route('/users', 'GET')]
        public function index(): array
        {
            return [];
        }
    }

    // Reading attributes via reflection
    $method = new ReflectionMethod(UserController::class, 'index');
    $attributes = $method->getAttributes(Route::class);
    foreach ($attributes as $attribute) {
        $route = $attribute->newInstance();
        echo $route->path; // '/users'
    }
  </example>
</pattern>

        public function getName(): string
        {
            return $this->name;
        }
    }
  </example>
</pattern>

    // Usage with named arguments
    $user = createUser(
        email: 'user@example.com',
        name: 'John Doe',
        role: 'admin',
    );
  </example>
  <decision_tree name="when_to_use">
    <question>Are you skipping optional parameters or improving readability?</question>
    <if_yes>Use named arguments</if_yes>
    <if_no>Use positional arguments for simple calls</if_no>
  </decision_tree>
</pattern>

  // File: src/Domain/User/Entity/User.php
  namespace App\Domain\User\Entity;

  class User
  {
      // Fully qualified: App\Domain\User\Entity\User
  }
</example>

  class UserService
  {
      public function __construct(
          private LoggerInterface $logger,
      ) {}

      public function create(array $data): User
      {
          $this->logger->info('Creating user', ['email' => $data['email']]);

          try {
              $user = new User($data);
              $this->logger->debug('User created', ['id' => $user->getId()]);
              return $user;
          } catch (\Exception $e) {
              $this->logger->error('Failed to create user', [
                  'exception' => $e,
                  'data' => $data,
              ]);
              throw $e;
          }
      }
  }
</example>

  function handleRequest(ServerRequestInterface $request): ResponseInterface
  {
      $method = $request->getMethod();
      $uri = $request->getUri();
      $body = $request->getParsedBody();
      $query = $request->getQueryParams();

      // PSR-7 messages are immutable
      $response = new Response();
      return $response
          ->withStatus(200)
          ->withHeader('Content-Type', 'application/json');
  }
</example>

  class ServiceLocator
  {
      public function __construct(
          private ContainerInterface $container,
      ) {}

      public function getUserService(): UserService
      {
          return $this->container->get(UserService::class);
      }
  }
</example>

  class AuthMiddleware implements MiddlewareInterface
  {
      public function process(
          ServerRequestInterface $request,
          RequestHandlerInterface $handler
      ): ResponseInterface {
          $token = $request->getHeaderLine('Authorization');

          if (!$this->validateToken($token)) {
              return new Response(401);
          }

          return $handler->handle($request);
      }
  }
</example>

  class JsonResponder
  {
      public function __construct(
          private ResponseFactoryInterface $responseFactory,
          private StreamFactoryInterface $streamFactory,
      ) {}

      public function respond(array $data, int $status = 200): ResponseInterface
      {
          $json = json_encode($data, JSON_THROW_ON_ERROR);
          $body = $this->streamFactory->createStream($json);

          return $this->responseFactory->createResponse($status)
              ->withHeader('Content-Type', 'application/json')
              ->withBody($body);
      }
  }
</example>

  class ApiClient
  {
      public function __construct(
          private ClientInterface $httpClient,
          private RequestFactoryInterface $requestFactory,
      ) {}

      public function get(string $url): array
      {
          $request = $this->requestFactory->createRequest('GET', $url);
          $response = $this->httpClient->sendRequest($request);

          return json_decode(
              $response->getBody()->getContents(),
              true,
              512,
              JSON_THROW_ON_ERROR
          );
      }
  }
</example>

      public function add(Money $other): self
      {
          if ($this->currency !== $other->currency) {
              throw new InvalidArgumentException('Currency mismatch');
          }
          return new self($this->amount + $other->amount, $this->currency);
      }

      public function equals(Money $other): bool
      {
          return $this->amount === $other->amount
              && $this->currency === $other->currency;
      }
  }
</example>

  class PdoUserRepository implements UserRepositoryInterface
  {
      public function __construct(
          private PDO $pdo,
      ) {}

      public function find(UserId $id): ?User
      {
          $stmt = $this->pdo->prepare(
              'SELECT * FROM users WHERE id = :id'
          );
          $stmt->execute(['id' => $id->toString()]);
          $row = $stmt->fetch(PDO::FETCH_ASSOC);

          return $row ? $this->hydrate($row) : null;
      }

      public function save(User $user): void
      {
          $stmt = $this->pdo->prepare(
              'INSERT INTO users (id, email, name)
               VALUES (:id, :email, :name)
               ON DUPLICATE KEY UPDATE email = :email, name = :name'
          );
          $stmt->execute([
              'id' => $user->getId()->toString(),
              'email' => $user->getEmail()->toString(),
              'name' => $user->getName(),
          ]);
      }
  }
</example>
<decision_tree name="when_to_use">
  <question>Do you need to abstract persistence details from domain logic?</question>
  <if_yes>Use Repository pattern</if_yes>
  <if_no>Direct database access may be sufficient for simple CRUD</if_no>
</decision_tree>

      public function handle(CreateUserCommand $command): UserId
      {
          $email = new Email($command->email);

          if ($this->userRepository->findByEmail($email) !== null) {
              throw new UserAlreadyExistsException($email);
          }

          $user = User::create(
              UserId::generate(),
              $email,
              $command->name,
              $this->passwordHasher->hash($command->password),
          );

          $this->userRepository->save($user);
          $this->eventDispatcher->dispatch(new UserCreatedEvent($user));

          return $user->getId();
      }
  }
</example>

  // Concrete implementation
  class RedisCache implements CacheInterface
  {
      public function __construct(
          private \Redis $redis,
      ) {}

      public function get(string $key): mixed
      {
          $value = $this->redis->get($key);
          return $value !== false ? unserialize($value) : null;
      }

      public function set(string $key, mixed $value, int $ttl = 3600): void
      {
          $this->redis->setex($key, $ttl, serialize($value));
      }
  }

  // Service depending on abstraction
  class ProductService
  {
      public function __construct(
          private ProductRepositoryInterface $repository,
          private CacheInterface $cache,
      ) {}
  }
</example>

<pattern name="require-dev">
  <description>Add development dependencies</description>
  <example>
    composer require --dev phpunit/phpunit
    composer require --dev phpstan/phpstan
    composer require --dev friendsofphp/php-cs-fixer
  </example>
</pattern>

<pattern name="version-constraints">
  <description>Specify version requirements</description>
  <example>
    {
        "require": {
            "php": "^8.2",
            "psr/log": "^3.0",
            "guzzlehttp/guzzle": "^7.0"
        },
        "require-dev": {
            "phpunit/phpunit": "^10.0 || ^11.0",
            "phpstan/phpstan": "^1.10"
        }
    }
  </example>
  <note>^ allows minor version updates, ~ allows patch updates only</note>
</pattern>

<pattern name="composer-json">
  <description>Complete composer.json for library</description>
  <example>
    {
        "name": "vendor/my-package",
        "description": "My awesome PHP package",
        "type": "library",
        "license": "MIT",
        "authors": [
            {
                "name": "Your Name",
                "email": "you@example.com"
            }
        ],
        "require": {
            "php": "^8.2"
        },
        "require-dev": {
            "phpunit/phpunit": "^11.0",
            "phpstan/phpstan": "^1.10"
        },
        "autoload": {
            "psr-4": {
                "Vendor\\MyPackage\\": "src/"
            }
        },
        "autoload-dev": {
            "psr-4": {
                "Vendor\\MyPackage\\Tests\\": "tests/"
            }
        },
        "scripts": {
            "test": "phpunit",
            "analyse": "phpstan analyse",
            "cs-fix": "php-cs-fixer fix"
        },
        "config": {
            "sort-packages": true
        }
    }
  </example>
</pattern>

<pattern name="scripts">
  <description>Automate common tasks with Composer scripts</description>
  <example>
    {
        "scripts": {
            "test": "phpunit --colors=always",
            "test:coverage": "phpunit --coverage-html coverage",
            "analyse": "phpstan analyse --memory-limit=512M",
            "cs-check": "php-cs-fixer fix --dry-run --diff",
            "cs-fix": "php-cs-fixer fix",
            "ci": [
                "@cs-check",
                "@analyse",
                "@test"
            ]
        }
    }
  </example>
</pattern>

    class CalculatorTest extends TestCase
    {
        private Calculator $calculator;

        protected function setUp(): void
        {
            $this->calculator = new Calculator();
        }

        #[Test]
        public function itAddsNumbers(): void
        {
            $result = $this->calculator->add(2, 3);

            $this->assertSame(5, $result);
        }

        #[Test]
        #[DataProvider('additionProvider')]
        public function itAddsVariousNumbers(int $a, int $b, int $expected): void
        {
            $this->assertSame($expected, $this->calculator->add($a, $b));
        }

        public static function additionProvider(): array
        {
            return [
                'positive numbers' => [1, 2, 3],
                'negative numbers' => [-1, -2, -3],
                'mixed numbers' => [-1, 2, 1],
                'zeros' => [0, 0, 0],
            ];
        }
    }
  </example>
</pattern>

<pattern name="mocking">
  <description>Create test doubles with PHPUnit</description>
  <example>
    use PHPUnit\Framework\TestCase;

    class UserServiceTest extends TestCase
    {
        #[Test]
        public function itCreatesUser(): void
        {
            // Arrange
            $repository = $this-&gt;createMock(UserRepositoryInterface::class);
            $repository
                -&gt;expects($this-&gt;once())
                -&gt;method('save')
                -&gt;with($this-&gt;isInstanceOf(User::class));

            $hasher = $this-&gt;createMock(PasswordHasherInterface::class);
            $hasher
                -&gt;method('hash')
                -&gt;willReturn('hashed_password');

            $service = new UserService($repository, $hasher);

            // Act
            $userId = $service-&gt;create('test@example.com', 'password');

            // Assert
            $this-&gt;assertInstanceOf(UserId::class, $userId);
        }
    }
  </example>
</pattern>

<pattern name="config">
  <description>PHPUnit configuration file</description>
  <example>
    &lt;!-- phpunit.xml.dist --&gt;
    &lt;?xml version="1.0" encoding="UTF-8"?&gt;
    &lt;phpunit xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
             xsi:noNamespaceSchemaLocation="vendor/phpunit/phpunit/phpunit.xsd"
             bootstrap="vendor/autoload.php"
             colors="true"
             cacheDirectory=".phpunit.cache"&gt;
        &lt;testsuites&gt;
            &lt;testsuite name="Unit"&gt;
                &lt;directory&gt;tests/Unit&lt;/directory&gt;
            &lt;/testsuite&gt;
            &lt;testsuite name="Integration"&gt;
                &lt;directory&gt;tests/Integration&lt;/directory&gt;
            &lt;/testsuite&gt;
        &lt;/testsuites&gt;
        &lt;source&gt;
            &lt;include&gt;
                &lt;directory&gt;src&lt;/directory&gt;
            &lt;/include&gt;
        &lt;/source&gt;
    &lt;/phpunit&gt;
  </example>
</pattern>

    beforeEach(function () {
        $this->calculator = new Calculator();
    });

    test('it adds numbers', function () {
        expect($this->calculator->add(2, 3))->toBe(5);
    });

    test('it subtracts numbers', function () {
        expect($this->calculator->subtract(5, 3))->toBe(2);
    });

    it('throws on division by zero', function () {
        $this->calculator->divide(10, 0);
    })->throws(DivisionByZeroError::class);
  </example>
</pattern>

<pattern name="datasets">
  <description>Pest datasets for parameterized tests</description>
  <example>
    dataset('addition', [
        'positive' =&gt; [1, 2, 3],
        'negative' =&gt; [-1, -2, -3],
        'mixed' =&gt; [-1, 2, 1],
    ]);

    test('it adds numbers correctly', function (int $a, int $b, int $expected) {
        expect($this-&gt;calculator-&gt;add($a, $b))-&gt;toBe($expected);
    })-&gt;with('addition');
  </example>
</pattern>

<pattern name="expectations">
  <description>Pest expectation API</description>
  <example>
    test('user properties', function () {
        $user = new User('john@example.com', 'John Doe');

        expect($user)
            -&gt;toBeInstanceOf(User::class)
            -&gt;email-&gt;toBe('john@example.com')
            -&gt;name-&gt;toBe('John Doe')
            -&gt;isActive()-&gt;toBeTrue();
    });
  </example>
</pattern>

<pattern name="levels">
  <description>PHPStan strictness levels (0-9)</description>
  <levels>
    <level number="0">Basic checks</level>
    <level number="1">Possibly undefined variables</level>
    <level number="2">Unknown methods on $this</level>
    <level number="3">Wrong return types</level>
    <level number="4">Dead code</level>
    <level number="5">Argument types</level>
    <level number="6">Missing type hints</level>
    <level number="7">Partial union types</level>
    <level number="8">No mixed types</level>
    <level number="9">Mixed type operations</level>
    <level number="10">Stricter implicit mixed (PHPStan 2.0+)</level>
  </levels>
  <note>Start at level 5-6 for existing projects, level 9-10 for new projects. Use --level max for highest available.</note>
</pattern>

<pattern name="generics">
  <description>Generic types with PHPStan annotations</description>
  <example>
    /**
     * @template T
     * @param class-string&lt;T&gt; $class
     * @return T
     */
    public function create(string $class): object
    {
        return new $class();
    }

    /**
     * @template T of object
     * @param T $entity
     * @return T
     */
    public function save(object $entity): object
    {
        // persist
        return $entity;
    }
  </example>
</pattern>

<pattern name="annotations">
  <description>Psalm-specific annotations</description>
  <example>
    /**
     * @psalm-immutable
     */
    readonly class ImmutableValue
    {
        public function __construct(
            public string $value,
        ) {}
    }

    /**
     * @psalm-assert-if-true User $user
     */
    function isActiveUser(?User $user): bool
    {
        return $user !== null &amp;&amp; $user-&gt;isActive();
    }
  </example>
</pattern>

    return (new PhpCsFixer\Config())
        ->setRules([
            '@PER-CS2.0' => true,
            '@PHP82Migration' => true,
            'strict_types' => true,
            'declare_strict_types' => true,
            'array_syntax' => ['syntax' => 'short'],
            'no_unused_imports' => true,
            'ordered_imports' => ['sort_algorithm' => 'alpha'],
            'trailing_comma_in_multiline' => true,
        ])
        ->setFinder($finder)
        ->setRiskyAllowed(true);
  </example>
</pattern>

    return RectorConfig::configure()
        ->withPaths([
            __DIR__ . '/src',
            __DIR__ . '/tests',
        ])
        ->withSets([
            SetList::CODE_QUALITY,
            SetList::DEAD_CODE,
            SetList::TYPE_DECLARATION,
        ])
        ->withPhpSets(php83: true);
  </example>
  <note>LevelSetList (e.g., UP_TO_PHP_83) deprecated since Rector 0.19.2. Use -&gt;withPhpSets() instead.</note>
</pattern>

    $pdo = new PDO($dsn, $username, $password, $options);
  </example>
</pattern>

<pattern name="prepared-statements">
  <description>Secure parameterized queries</description>
  <example>
    // Named parameters
    $stmt = $pdo-&gt;prepare('SELECT * FROM users WHERE email = :email');
    $stmt-&gt;execute(['email' =&gt; $email]);
    $user = $stmt-&gt;fetch();

    // Positional parameters
    $stmt = $pdo-&gt;prepare('INSERT INTO users (email, name) VALUES (?, ?)');
    $stmt-&gt;execute([$email, $name]);
    $id = $pdo-&gt;lastInsertId();
  </example>
  <warning>Never concatenate user input into SQL queries</warning>
</pattern>

<pattern name="transactions">
  <description>Database transactions with PDO</description>
  <example>
    try {
        $pdo-&gt;beginTransaction();

        $stmt = $pdo-&gt;prepare('UPDATE accounts SET balance = balance - ? WHERE id = ?');
        $stmt-&gt;execute([$amount, $fromAccount]);

        $stmt = $pdo-&gt;prepare('UPDATE accounts SET balance = balance + ? WHERE id = ?');
        $stmt-&gt;execute([$amount, $toAccount]);

        $pdo-&gt;commit();
    } catch (\Exception $e) {
        $pdo-&gt;rollBack();
        throw $e;
    }
  </example>
</pattern>

Preload classes at startup (PHP 7.4+) <?php // preload.php require DIR . '/vendor/autoload.php';

    // Preload commonly used classes
    $classesToPreload = [
        App\Domain\User\User::class,
        App\Domain\Order\Order::class,
    ];

    foreach ($classesToPreload as $class) {
        class_exists($class);
    }
  </example>
  <config>
    ; php.ini
    opcache.preload=/path/to/preload.php
    opcache.preload_user=www-data
  </config>
</pattern>

  // Specific exceptions
  class EntityNotFoundException extends DomainException
  {
      public static function forClass(string $class, string $id): self
      {
          return new self(sprintf('%s with id "%s" not found', $class, $id));
      }
  }

  class ValidationException extends DomainException
  {
      public function __construct(
          string $message,
          public readonly array $errors = [],
      ) {
          parent::__construct($message);
      }
  }

  // Usage
  throw EntityNotFoundException::forClass(User::class, $userId);
</example>

      /** @return self<T, never> */
      public static function ok(mixed $value): self
      {
          return new self(true, $value);
      }

      /** @return self<never, E> */
      public static function error(mixed $error): self
      {
          return new self(false, $error);
      }

      public function isSuccess(): bool { return $this->success; }
      public function isError(): bool { return !$this->success; }
      public function getValue(): mixed { return $this->value; }
  }

  // Usage
  function divide(int $a, int $b): Result
  {
      if ($b === 0) {
          return Result::error('Division by zero');
      }
      return Result::ok($a / $b);
  }
</example>

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