impure.require

Code example

<?php declare(strict_types = 1);

/** @phpstan-pure */
function loadConfig(string $path): mixed
{
	return require $path;
}

Why is it reported?

A function marked as @phpstan-pure must not have side effects and must depend only on its parameters. Using require or require_once inside a pure function is a side effect because it reads a file from disk and executes its contents, which can produce different results depending on external state.

How to fix it

Remove the @phpstan-pure annotation if the function needs to use require:

 <?php declare(strict_types = 1);

-/** @phpstan-pure */
 function loadConfig(string $path): mixed
 {
 	return require $path;
 }

Alternatively, restructure the code so that the file loading happens outside the pure function, and pass the data as a parameter.