Crafting Custom PHPStan Rules for Symfony Apps

Static analysis tools like PHPStan have become essential for PHP developers, and Symfony projects can greatly benefit from custom rules tailored to their specific needs. In this talk, I will guide Symfony developers through the process of writing custom PHPStan rules to enforce project-specific standards and catch domain-specific bugs, and freeing up valuable time by automating repetitive code review tasks.

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1. Cra ft ing Custom PHPStan Rules for Symfony Apps Ondřej Mirtes SymfonyCon, December 6th 2024
2. $ composer require --dev phpstan/phpstan What is PHPStan? $ vendor/bin/phpstan analyse src/ tests/
3. What is PHPStan?
5. phpstan.org/merch order until December 8th
7. Motivation for custom rules Make code reviews easier Prevent bugs and production incidents Achieve consistency & quality
8. Custom rule new FooService() Do not instantiate DI service directly, inject it via constructor
9. Abstract syntax tree (AST) $this->foo && self::bar() BooleanAnd PropertyFetch StaticCall Variable ("this") "foo" "self" "bar" le f right var name class name
10. Abstract syntax tree (AST) github.com/nikic/PHP-Parser
11. apiref.phpstan.org
12. Writing custom rules interface Rule { /** * @return string Class implementing \PhpParser\Node */ public function getNodeType(): string; /** * @param \PhpParser\Node $node * @param \PHPStan\Analyser\Scope $scope * @return RuleError[] errors */ public function processNode(Node $node, Scope $scope): array; }
13. Demo time! Let's write our new FooService() rule
14. Scope getFile(): string getNamespace(): ?string isInClass(): bool getClassReflection(): ?ClassReflection isInTrait(): bool getTraitReflection(): ?ClassReflection getFunction(): ?FunctionReflection|?MethodReflection getType(Expr $expr): Type isInExpressionAssign(Expr $expr): bool canAccessProperty(PropertyReflection $property): bool canCallMethod(MethodReflection $methodReflection): bool
15. Demo time! Let's use Scope in our new FooService() rule!
16. Ideas for custom rules Enforce single-action controllers with a single public __invoke() method
17. Ideas for custom rules Do not allow extending from AbstractController
18. Ideas for custom rules Require named arguments for attributes: ✅ #[Autowire(service: 'app.foo.bar')] ❌ #[Autowire('app.foo.bar')]
19. Virtual nodes
20. Collectors phpstan.org Documentation » Developing Extensions » Collectors
21. Testing rules with PHPUnit phpstan.org Documentation » Developing Extensions » Testing
22. Core Concepts Abstract Syntax Tree Scope Type System Reflection Dependency Injection & Configuration
23. Documentation phpstan.org Documentation » Developing Extensions » Core Concepts Documentation » Developing Extensions » Custom Rules
24. ChatGPT
27. github.com/phpstan/phpstan
28. @OndrejMirtes @OndrejMirtes@phpc.social