staabm/side-effects-detector

A static analysis tool to detect side effects in PHP code


Keywords
static analysis
License
MIT

Documentation

Analyzes php-code for side-effects.

When code has no side-effects it can e.g. be used with eval($code) in the same process without interfering. Side-effects are classified into categories to filter them more easily depending on your use-case.

Install

composer require staabm/side-effects-detector

Usage

Example:

use staabm\SideEffectsDetector\SideEffectsDetector;

$code = '<?php version_compare(PHP_VERSION, "8.0", ">=") or echo("skip because attributes are only available since PHP 8.0");';

$detector = new SideEffectsDetector();
// [SideEffect::STANDARD_OUTPUT]
var_dump($detector->getSideEffects($code));

In case functions are called which are not known to have side-effects - e.g. userland functions - null is returned.

use staabm\SideEffectsDetector\SideEffectsDetector;

$code = '<?php userlandFunction();';

$detector = new SideEffectsDetector();
// [SideEffect::MAYBE]
var_dump($detector->getSideEffects($code));

Code might have multiple side-effects:

use staabm\SideEffectsDetector\SideEffectsDetector;

$code = '<?php include "some-file.php"; echo "hello world"; exit(1);';

$detector = new SideEffectsDetector();
// [SideEffect::SCOPE_POLLUTION, SideEffect::STANDARD_OUTPUT, SideEffect::PROCESS_EXIT]
var_dump($detector->getSideEffects($code));

Disclaimer

Non goals are:

  • find the best possible answer for all cases
  • add runtime dependencies

If you are in need of a fully fledged side-effect analysis, use more advanced tools like PHPStan.

Look at the test-suite to get an idea of supported use-cases.