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/intersection types, #[Override], typed constants, #[SensitiveParameter], property hooks
• PSR/PER Compliance: Active PHP-FIG standards (PSR-3/4/6/7/11/14/15/16/17/18/20, PER-CS)
• Static Analysis: PHPStan (level 9+, treatPhpDocTypesAsCertain: false), PHPat, Rector, PHP-CS-Fixer
• Type Safety: DTOs/VOs over arrays, generics via PHPDoc, copy-on-write awareness
• Pitfalls: DOMDocument UTF-8 encoding, PHP-CS-Fixer deprecated aliases

Reference Documentation

Topic	Reference File
PHP 8.0-8.5 features	references/php8-features.md
PSR/PER compliance	references/psr-per-compliance.md
PHPStan levels	references/phpstan-compliance.md
Static analysis tools	references/static-analysis-tools.md
PHP-CS-Fixer deprecations	references/php-cs-fixer-deprecations.md
Type safety, DTOs	references/type-safety.md
Request DTOs	references/request-dtos.md
Adapter registry	references/adapter-registry-pattern.md
Multi-version adapters	references/multi-version-adapters.md
Symfony patterns	references/symfony-patterns.md
TYPO3 PSR patterns	references/typo3-psr-patterns.md
Migration planning	references/migration-strategies.md

Always run vendor/bin/php-cs-fixer fix --dry-run 2>&1 | grep -A 20 "Detected deprecations" to check for deprecated rules.

Running Scripts

Verify a project: scripts/verify-php-project.sh /path/to/project

Required Tools

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

Core Rules

• DTOs required over arrays for structured data
• Backed enums required for fixed value sets (not constants)
• PSR interfaces for type-hinting dependencies (PSR-3, PSR-6, PSR-7, PSR-11, PSR-14, PSR-18)

See references/core-rules.md for code examples and scoring criteria.

Migration Checklist

• declare(strict_types=1) in all files
• PER Coding Style via PHP-CS-Fixer (@PER-CS) with no deprecated aliases
• PHPStan level 9+ (treatPhpDocTypesAsCertain: false, level 10 for new projects)
• PHPat architecture tests for layer boundaries
• 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, not implementations
• #[Override] on overridden methods (PHP 8.3+)
• #[SensitiveParameter] on password/secret params (PHP 8.2+)
• Typed class constants (PHP 8.3+)

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