Extension Types
PHPStan’s behavior can be customized in various ways.
Core concepts #
Many basic concepts about static analysis are shared among all the extension types.
Custom rules #
PHPStan allows writing custom rules to check for specific situations in your own codebase.
Error formatters #
PHPStan outputs errors via so-called error formatters. You can implement your own format.
Class reflection extensions #
Classes in PHP can expose “magic” properties and methods decided in run-time using class methods like __get, __set, and __call. Because PHPStan is all about static analysis (testing code for errors without running it), it has to know about those properties and methods beforehand.
Dynamic return type extensions #
If the return type of a method is not always the same, but depends on an argument passed to the method, you can specify the return type by writing and registering an extension.
Dynamic throw type extensions #
To support precise try-catch-finally analysis, you can write a dynamic throw type extension to describe functions and methods that might throw an exception only when specific types of arguments are passed during a call.
Type-specifying extensions #
These extensions allow you to specify types of expressions based on certain type-checking function and method calls, like is_int() or self::assertNotNull().
Custom PHPDoc Types #
PHPStan lets you override how it converts PHPDoc AST coming from its phpdoc-parser library into its typesystem representation. This can be used to introduce custom utility types.
Always-read and written properties #
This extension allows you to mark private properties as always-read and written even if the surrounding code doesn’t look like that.
Always-used class constants #
This extension allows you to mark private class constants as always-used even if the surrounding code doesn’t look like that.
Allowed subtypes #
PHP language doesn’t have a concept of sealed classes - a way to restrict class hierarchies and provide more control over inheritance. So any interface or non-final class can have an infinite number of child classes. But PHPStan provides an extension type to tell the analyzer the complete list of allowed child classes.