PHP Modernization Skill

Modernize PHP applications to PHP 8.x with type safety, PSR compliance, and static analysis.

Expertise Areas

• PHP 8.x: Constructor promotion, readonly, enums, match, attributes, union types
• PSR/PER Compliance: Active PHP-FIG standards
• Static Analysis: PHPStan (level 9+), PHPat, Rector, PHP-CS-Fixer
• Type Safety: DTOs/VOs over arrays, generics via PHPDoc

Reference Files

Reference	Purpose
references/php8-features.md	PHP 8.0-8.5 features
references/psr-per-compliance.md	Active PSR/PER standards
references/static-analysis-tools.md	PHPStan, PHPat, Rector, PHP-CS-Fixer configs
references/type-safety.md	Type system strategies
references/request-dtos.md	Request DTOs, safe integer handling
references/symfony-patterns.md	Modern Symfony architecture

Required Tools

Tool	Requirement
PHPStan	Level 9 minimum, level 10 recommended
PHPat	Required for defined architectures
Rector	Required for modernization
PHP-CS-Fixer	Required with @PER-CS

See references/static-analysis-tools.md for configuration examples.

Core Rules

DTOs Required - Never pass raw arrays for structured data:

// Bad: public function createUser(array $data): array
// Good: public function createUser(CreateUserDTO $dto): UserDTO

Enums Required - Never use string/int constants for fixed values:

// Bad: const STATUS_DRAFT = 'draft'; function setStatus(string $s)
// Good: enum Status: string { case Draft = 'draft'; }

PSR Compliance - Type-hint against PSR interfaces (PSR-3, PSR-6, PSR-7, PSR-11, PSR-14, PSR-18).

Migration Checklist

• declare(strict_types=1) in all files
• PER Coding Style via PHP-CS-Fixer (@PER-CS)
• PHPStan level 9+ (level 10 for new projects)
• PHPat architecture tests
• Return types and parameter types on all methods
• DTOs for data transfer, no array params/returns
• Backed enums for all status/type values
• Type-hint against PSR interfaces

Scoring

Criterion	Requirement
PHPStan	Level 9 minimum
PHP-CS-Fixer	@PER-CS zero violations
DTOs/VOs	No array params/returns for structured data
Enums	Backed enums for fixed value sets

Verification

./scripts/verify-php-project.sh /path/to/project

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Contributing: https://github.com/netresearch/php-modernization-skill