PHP Developer Core

Foundation skill for framework-agnostic PHP. Covers coding standards, Composer, static analysis, security, and testing across Magento 2, Laravel, Symfony, and WordPress. Pair with govard-toolbox for container and environment commands (govard up, govard sh, govard audit). For framework-specific tooling see govard-laravel, govard-symfony, govard-wordpress, or magento2-dev-core for Magento DI and service contracts.

Related Skills

REQUIRED BACKGROUND: Load govard-toolbox first for environment lifecycle and audit matrix. This skill adds language-level patterns. Framework skills (govard-laravel, govard-symfony, govard-wordpress) depend on both govard-toolbox and php-dev-core; magento2-dev-core cross-references this skill for generic PHP and owns Magento-specific DI and plugins.

1. Coding Standards & Types

Every new PHP file MUST start with strict types:

<?php
declare(strict_types=1);

PSR-12 is the default. When framework conventions diverge, PSR-12 wins for generic code.

PSR-4 autoloading is required. Map namespaces in composer.json:

{
  "autoload": {
    "psr-4": { "Vendor\\Package\\": "src/" }
  }
}

PHP 8.1-8.4 idioms to prefer:

• readonly properties and readonly class for DTOs (8.1+), constructor promotion.
• enum for closed sets instead of class constants (8.1+).
• match over switch for exhaustive mapping; never for functions that always throw.
• Intersection types (X&Y) and mixed where genuinely needed; avoid untyped parameters.
• final classes by default; open only with documented reason.

Example with promotion and readonly:

<?php
declare(strict_types=1);

namespace Vendor\Package;

final readonly class UserDto
{
    public function __construct(
        public int $id,
        public string $email,
        public string $name,
    ) {}
}

function resolveStatus(string $raw): Status
{
    return match ($raw) {
        'active' => Status::Active,
        'inactive' => Status::Inactive,
        default => throw new \InvalidArgumentException("Unknown status: $raw"),
    };
}

Run composer dump-autoload --optimize after changing autoload maps and verify with composer validate --strict.

2. Composer

Composer is the single source for dependencies, autoloading, and scripts.

composer validate --strict                           # validate before commit
composer audit                                       # known vulnerabilities
composer install --no-dev --optimize-autoloader      # CI/production
composer outdated                                    # check outdated
composer update vendor/package --with-dependencies   # update with care

Version constraints: prefer ^ (caret) for semver (^8.1 allows 8.x but not 9.0). Never commit vendor/; always commit composer.lock for applications, omit for libraries.

composer.json essentials:

{
  "name": "vendor/package",
  "type": "library",
  "require": { "php": "^8.1" },
  "autoload": { "psr-4": { "Vendor\\Package\\": "src/" } },
  "scripts": {
    "lint": "phpcs --standard=PSR12 src tests",
    "analyse": "phpstan analyse -c phpstan.neon",
    "test": "phpunit --testdox"
  }
}

Private package auth belongs in auth.json (gitignored) or env vars, never in composer.json.

3. Static Analysis

Two gates: PHPCS for style, PHPStan for types. Both must pass before merge.

PHPCS (PSR-12)

vendor/bin/phpcs --standard=PSR12 src tests
govard audit run --checks lint --lint-provider govard --mode project --format json
govard audit run --checks lint --lint-provider govard --mode project  # text, capped

Fix auto-fixable violations with phpcbf --standard=PSR12 src.

PHPStan (Level 6+)

Level 6 is the minimum; raise to 8 when possible.

vendor/bin/phpstan analyse -c phpstan.neon
govard audit run --checks lint --lint-provider govard --mode project --format json

Sample phpstan.neon (full config in references/coding-standards.md):

parameters:
  level: 6
  paths: [src]
  checkMissingIterableValueType: false

Govard audit is the source of truth for CI — it runs PHPCS PSR12 plus PHPStan and the pub/media guard. The lint check is the only audit check for generic PHP; other values are rejected. Use --mode project for full scans, --mode standalone for isolated packages, --scope diff --base origin/master for PR quick scans (see govard-toolbox ## Audit). Fallback without Govard is phpcs --standard=PSR12 plus standalone phpstan. Treat every PHPStan error as a defect — add types instead of baseline ignores.

4. Security Baseline

Apply these rules to every PHP change regardless of framework.

Input — Never Trust Superglobals

NEVER read $_GET, $_POST, $_REQUEST, $_SESSION, $_COOKIE directly. Use filter_input or framework request objects.

// WRONG
$id = $_GET['id'];

// CORRECT — filter_input with explicit filter
$id = filter_input(INPUT_GET, 'id', FILTER_VALIDATE_INT);
$name = filter_input(INPUT_POST, 'name', FILTER_SANITIZE_FULL_SPECIAL_CHARS);

// Fallback when filter_input not available
$id = filter_var($_GET['id'] ?? null, FILTER_VALIDATE_INT);
if ($id === false || $id === null) {
    throw new \InvalidArgumentException('Invalid id');
}

Output — Escape on Render

Escape at the boundary where data becomes HTML, JS, URL, or CSS:

echo htmlspecialchars($userInput, ENT_QUOTES | ENT_SUBSTITUTE, 'UTF-8');
echo '<div data-id="' . htmlspecialchars($id, ENT_QUOTES | ENT_SUBSTITUTE, 'UTF-8') . '">';
echo '<script>var name = ' . json_encode($name, JSON_HEX_TAG | JSON_HEX_APOS | JSON_HEX_QUOT) . ';</script>';

For plain PHP templates, htmlspecialchars with ENT_QUOTES | ENT_SUBSTITUTE and explicit UTF-8 is the baseline. Framework escapers (Magento Escaper, Laravel e(), Symfony Twig autoescape) build on the same principle.

Database — Prepared Statements Only

NEVER interpolate variables into SQL. Use PDO::prepare with bound parameters:

// WRONG — SQL injection
$pdo->query("SELECT * FROM users WHERE email = '$email'");

// CORRECT — PDO::prepare with named placeholders
$stmt = $pdo->prepare('SELECT * FROM users WHERE email = :email AND status = :status');
$stmt->bindValue(':email', $email, \PDO::PARAM_STR);
$stmt->bindValue(':status', $status, \PDO::PARAM_STR);
$stmt->execute();
$rows = $stmt->fetchAll(\PDO::FETCH_ASSOC);

// Also correct — execute with array
$stmt = $pdo->prepare('SELECT * FROM users WHERE id = :id');
$stmt->execute([':id' => $id]);

Disable emulated prepares when possible (PDO::ATTR_EMULATE_PREPARES => false).

Cryptography — Use Modern Primitives

$hash = password_hash($password, PASSWORD_DEFAULT);
if (!password_verify($password, $hash)) {
    throw new \RuntimeException('Invalid credentials');
}
$token = bin2hex(random_bytes(32));
$json = json_encode($data, JSON_THROW_ON_ERROR);

Store secrets in .env (never in code). Generate CSRF tokens with random_bytes and validate with hash_equals. Finding codes: PHP-SEC-xxx / PHP-ARCH-xxx — see references/security-best-practices.md.

5. Testing & Verification

Test Layout

• PHPUnit (or Pest) under tests/ mirroring src/ via PSR-4 autoload-dev.
• Unit tests: typed mocks, no real I/O; integration tests: real container/DB with isolation.

vendor/bin/phpunit --testdox
vendor/bin/pest --coverage
php -l src/Service/UserService.php
vendor/bin/phpcs --standard=PSR12 src tests
vendor/bin/phpstan analyse -c phpstan.neon
composer validate --strict
composer audit

Verification Checklist (Run Before Every Commit)

php -l src/**/*.php                          # 1. Syntax
vendor/bin/phpcs --standard=PSR12 src tests  # 2. Style PSR-12
vendor/bin/phpstan analyse -c phpstan.neon  # 3. Types L6+
composer validate --strict                   # 4. Manifest valid
composer audit                               # 5. No known CVEs
vendor/bin/phpunit --testdox                 # 6. Tests green
govard audit run --checks lint --lint-provider govard --mode project --format json  # 7. Govard gate

Govard audit (--checks lint) bundles PHPCS, PHPStan, and the pub/media guard. Keep it green in --scope project for releases and --scope diff --base origin/master for PRs.

Audit

For the 4-framework audit matrix (quick vs deep scope, --scope diff vs --scope project, base branch, timing, provider rules) see govard-toolbox ## Audit. This skill delegates all audit-mode and provider specifics there. Fallback without Govard is phpcs --standard=PSR12 plus phpstan analyse -c phpstan.neon at level 6+. No nesting — govard audit and govard tool are host-side commands, not container-nested (do not wrap them with govard sh -c).

References

• references/coding-standards.md — PSR-12 checklist, phpstan.neon sample, and strict-types patterns.
• references/security-best-practices.md — XSS, SQL injection, CSRF, and cryptography examples.
• references/architecture-patterns.md — Service, DTO (readonly class), factory, and PSR-11 container patterns.