Code Quality Tools

In the previous parts of this book, we learned the basics of clean code. Now, it is time to apply that knowledge to our everyday work. There are literally dozens of tools available for the PHP ecosystem that can help us detect flaws and potential bugs, apply the correct code styling, and generally inform us about quality issues.

To ensure a quick and easy start within the world of code quality tools, this section will introduce you to the most commonly used ones. For each, you will learn how to install, configure, and use it directly on your code. You will also learn about some useful extra features they provide.

We will look at the following groups of tools:

• Syntax checking and code styling
• Static code analysis
• IDE extensions

Technical requirements

For this chapter, you only need a bare minimum of tools to already be set up. The chances are high that you already have them installed if you have ever worked with PHP code before:

• A local installation of a recent PHP version (PHP 8.0 or higher is recommended).
• A code editor – often called an Integrated Development Environment (IDE).
• Composer, either installed as binary or globally. Please check https://getcomposer.org/ if you are not familiar with Composer yet.

Please note that for the rest of this book, all examples are based on a Linux environment such as Ubuntu or macOS. If you are using Windows for development, you will most likely need to make some adjustments, as described here: https://www.php.net/manual/en/install.windows.commandline.php.

The code files for this chapter can be found here: https://github.com/PacktPublishing/Clean-Code-in-PHP

Syntax checking and code styling

The first group of tools we want to discuss helps us keep our code syntactically correct (i.e., it can be executed correctly by PHP) and formatted in a structured way. It seems to be obvious that the code needs to be written without errors, but it is always good to double-check, as some tools can actively change your code. Having a simple and fast way to ensure this will be essential when we automate the whole code quality process later in this book.

Having your code formatted following a common style guide reduces the effort required to read and understand your code, as well as the code of others. Especially when you are working in a team, an accepted style guide saves you hours of discussions about how to correctly format the code.

We will learn about the following tools:

• A PHP built-in linter
• The PHP CS Fixer tool

The PHP built-in linter

The first tool we want to look at is actually not a code quality tool of its own but...

Static Code Analysis

Static Code Analysis means that the only source of information is the code itself. Just by scanning the source code, these tools will find issues and problems that even the most senior developer in your team would miss during a code review.

These are the tools we would like to introduce you to in the next sections:

• phpcpd
• PHPMD
• PHPStan
• Psalm

phpcpd – the copy and paste detector

Copy and paste programming can be anything from simply annoying to a real threat to your projects. Bugs, security issues, and bad practices will get copied around and thus become harder to fix. Think of it as though it were a plague spreading through your code.

This form of programming is quite common, especially among less experienced developers, or in projects where the deadlines are very tight. Luckily, our clean code toolkit offers a remedy – the PHP copy and paste detector (phpcpd).

Installation and usage

This tool can only be...

IDE extensions

The tools we looked at so far share something in common: they need to be applied to our code after we have written it. Of course, this is much better than nothing, but wouldn’t it be great if the tools gave us their feedback immediately at the time that we wrote the code?

That is what many other developers thought as well, so they created extensions for the most popular IDEs, which are currently Visual Studio Code (VS Code) and PhpStorm:

• PhpStorm is an established, commercial IDE from JetBrains with several PHP-specific tools, checks, and built-in integrations for many of the code quality tools we discussed in this chapter. There are many useful extensions available for it as well. You can try it out for 30 days for free.
• VS Code is a highly flexible code editor from Microsoft with tons of third-party (partly commercial) extensions that can turn these tools into an IDE for virtually every relevant programming language today. Because the code editor...

Summary

In this chapter, we learned about state-of-the-art tools to assist you in creating high-quality PHP code. They will help you spot issues early in the Software Development Life Cycle (SDLC), which saves you vast amounts of time. The PHP community is still vivid and very productive, and we were not able to cover all the fantastic software that exists out there in this book. However, with the tools we introduced in this chapter, you are now well equipped for your journey towards clean code.

In the next chapter, you will learn about how to evaluate code quality by using the established metrics and, of course, the necessary tools to gather them. See you there!

Further reading

If you want to try out even more code quality tools, consider the following projects:

• Exakat (https://www.exakat.io) – A tool that also covers security issues and performance, for example. It can fix issues automatically, too.
• Phan (https://github.com/phan/phan) – A static code analyzer that you can try out immediately in your browser
• PHP Insights (https://phpinsights.com/) – Another analyzer, yet with easy-to-use metrics in terms of the code, architecture, complexity, and style