PHP CodeSniffer vs Psalm: What are the differences?

Introduction

In this article, we will discuss the key differences between PHP CodeSniffer and Psalm.

1. Rule-based vs Type-based Analysis: PHP CodeSniffer is a rule-based linter and static analysis tool that checks code against a set of predefined coding standards. It focuses on ensuring code consistency and adherence to certain coding styles. On the other hand, Psalm is a type-based static analysis tool that uses PHP's type annotations and inference to analyze code for type-related issues, potential errors, and other type-related discrepancies.

2. Coding Standards vs Type Errors: PHP CodeSniffer primarily checks the code for adherence to coding standards like code formatting, naming conventions, and documentation standards. It helps in enforcing a uniform coding style across a project. In contrast, Psalm focuses more on detecting type errors, such as incorrect type usage, undefined variables, invalid method calls, and other type-related issues that may lead to runtime errors.

3. Automatic Fixing vs Error Reporting: PHP CodeSniffer provides automatic code fixing capabilities for certain rule violations, allowing it to automatically correct code according to the defined coding standards. It can be used to automatically format code and resolve some rule violations. In comparison, Psalm is primarily focused on error reporting and provides detailed information about type errors and potential issues, helping developers to identify and fix problematic code themselves.

4. Integration with IDEs and Frameworks: Both PHP CodeSniffer and Psalm can be integrated into popular IDEs like PHPStorm and Visual Studio Code. However, PHP CodeSniffer has better support for various coding standards and can be customized more extensively. Psalm, on the other hand, has better integration with modern PHP frameworks like Laravel or Symfony, providing more accurate analysis and understanding of framework-specific patterns and code structure.

5. Coverage of Code Analysis: PHP CodeSniffer offers a wide range of predefined coding standards, including PSR-1, PSR-2, and many more. It covers a broad spectrum of coding style rules and can be customized with additional rules. In contrast, Psalm focuses more on analyzing and detecting type-related issues and potential errors, making it a powerful tool for catching type errors and improving code reliability.

6. Ease of Use and Configuration: PHP CodeSniffer is relatively easier to set up and configure, as it mainly requires defining coding standards or using existing ones. It provides a command-line interface for running analysis and can be integrated into build systems easily. On the other hand, configuring Psalm requires setting up type annotations and configuring the tool to understand project-specific code patterns. It may require additional effort in ensuring accurate type annotations and initial setup.

In summary, PHP CodeSniffer is a rule-based linter that focuses on enforcing coding standards and has better support for customization and auto-fixing, while Psalm is a type-based static analysis tool that detects type errors and provides accurate analysis in the context of modern PHP frameworks.