This extension is a work in progress. Use at your own risk.

PHPStan Elegant Object Rules

This PHPStan extension adds custom rules to encourage and validate elegant object design principles in your PHP code.

It's based on Yegor Bugayenko's books :

• Elegant Objects (Volume 1)
• Elegant Objects (Volume 2)

Installation

composer require --dev atournayre/phpstan-elegant-object

Configuration

Include the extension in your phpstan.neon file:

# Include the extension config if you want extra strict rules
includes:
    - vendor/atournayre/phpstan-elegant-object/phpstan.neon

It is recommended to configure each rule separately.

Available Rules

See configuration for a list of available rules.

Creating Custom Rules

To create a new rule:

1. Create a class in the src/Analyzer/ folder that implements Atournayre\PHPStan\ElegantObject\Analyzer\RuleAnalyzer
2. Define the node type to analyze with getNodeType()
3. Override shouldSkipAnalysis() if necessary
4. Implement your analysis logic in analyze()
5. Create a class in the src/Rules/ folder that extends Atournayre\PHPStan\ElegantObject\Rules\ComposableRule (see existing rules for examples)
6. Register your rule in phpstan.neon

Tests

To run the tests:

vendor/bin/phpunit

Rules

From the book:

• Never use -er names (chapter 1.1)
• Keep constructors code-free (chapter 1.3)
• Always use interface (chapter 2.3)
• Don't use public constant (chapter 2.5)
• Be immutable (chapter 2.6)
• Keep interfaces short (chapter 2.9)
• Expose fewer than 5 public methods (chapter 3.1)
• Don't use static methods (chapter 3.2)
• Never accept null arguments (chapter 3.3)
• Never use getters and setters (chapter 3.5)
• Don't use new outside of secondary constructors (chapter 3.6)
• Avoid type introspection and casting (chapter 3.7)
• Never return Null (chapter 4.1)
• Throw only checked exceptions (chapter 4.2)
• Be either final or abstract (chapter 4.3)
• Private static literals (chapter 5.4)

Other:

• All properties must be private
• Constructor objects only