Disallowed calls for PHPStan

PHPStan rules to detect disallowed calls, without running the code.

There are some functions and methods which should not be used in production code. One good example is var_dump(), it is often used to quickly debug problems but should be removed before commiting the code. And sometimes it's not.

Another example would be a generic logger. Let's say you're using one of the generic logging libraries but you have your own logger that will add some more info, or sanitize data, before calling the generic logger. Your code should not call the generic logger directly but should instead use your custom logger.

This PHPStan extension will detect such usage, if configured. It should be noted that this extension is not a way to defend against or detect hostile developers, as they can obfuscate the calls for example. This extension is meant to be another pair of eyes, detecting your own mistakes.

Installation

Install the extension using Composer:

composer require --dev spaze/phpstan-disallowed-calls

PHPStan, the PHP Static Analysis Tool, is a requirement.

If you use phpstan/extension-installer, you are all set and can skip to configuration.

For manual installation, add this to your phpstan.neon:

includes:
    - vendor/spaze/phpstan-disallowed-calls/extension.neon

Configuration

You can start by including disallowed-dangerous-calls.neon in your phpstan.neon:

includes:
    - vendor/spaze/phpstan-disallowed-calls/disallowed-dangerous-calls.neon

disallowed-dangerous-calls.neon can also serve as a template when you'd like to extend the configuration to disallow some other functions or methods, copy it and modify to your needs.

There are three different disallowed types (and configuration keys) that can be disallowed:

disallowedMethodCalls - for detecting $object->method() calls
disallowedStaticCalls - for static calls Class::method()
disallowedFunctionCalls - for functions like function()

Use them to add rules to your phpstan.neon config file. I like to use a separate file (disallowed-calls.neon) for these which I'll include later on in the main phpstan.neon config file. Here's an example, update to your needs:

parameters:
    disallowedMethodCalls:
        -
            method: 'PotentiallyDangerous\Logger::log()'
            message: 'use our own logger instead'
        -
            method: 'Redis::connect()'
            message: 'use our own Redis instead'

    disallowedStaticCalls:
        -
            method: 'PotentiallyDangerous\Debugger::log()'
            message: 'use our own logger instead'

    disallowedFunctionCalls:
        -
            function: 'var_dump()'
            message: 'use logger instead'
        -
            function: 'print_r()'
            message: 'use logger instead'

The message key is optional.

Example output

 ------ --------------------------------------------------------
  Line   libraries/Report/Processor/CertificateTransparency.php
 ------ --------------------------------------------------------
  116    Calling var_dump() is forbidden, use logger instead
 ------ --------------------------------------------------------

Allow some previously disallowed calls

Sometimes, the method or the function needs to be called once in your code, for example in a custom wrapper. You can use PHPStan's ignoreErrors feature to ignore that one call:

ignoreErrors:
    -
        message: '#^Calling Redis::connect\(\) is forbidden, use our own Redis instead#'  # Needed for the constructor
        path: application/libraries/Redis/Redis.php
    -
        message: '#^Calling print_r\(\) is forbidden, use logger instead#'  # Used with $return = true
        paths:
            - application/libraries/Tls/Certificate.php
            - application/libraries/Tls/CertificateSigningRequest.php
            - application/libraries/Tls/PublicKey.php

You can also allow some previously disallowed calls using the allowIn configuration key, for example:

parameters:
    disallowedMethodCalls:
        -
            method: 'PotentiallyDangerous\Logger::log()'
            message: 'use our own logger instead'
            allowIn:
                - path/to/some/file-*.php
                - tests/*.test.php

The paths in allowIn are relative to the config file location and support fnmatch() patterns.

You can also narrow down the allowed items when called with some parameters. For example, you want to disallow calling print_r() but want to allow print_r(..., true). This can be done with optional allowParamsInAllowed or allowParamsAnywhere configuration keys:

parameters:
    disallowedMethodCalls:
        -
            method: 'PotentiallyDangerous\Logger::log()'
            message: 'use our own logger instead'
            allowIn:
                - path/to/some/file-*.php
                - tests/*.test.php
            allowParamsInAllowed:
                1: 'foo'
                2: true
            allowParamsAnywhere:
                2: true

When using allowParamsInAllowed, calls will be allowed only when they are in one of the allowIn paths, and are called with all parameters listed in allowParamsInAllowed. With allowParamsAnywhere, calls are allowed when called with all parameters listed no matter in which file. In the example above, the log() method will be disallowed unless called as:

log(..., true) anywhere
log('foo', true) in another/file.php or optional/path/to/log.tests.php

Running tests

If you want to contribute (awesome, thanks!), you should add/run tests for your contributions. First install dev dependencies by running composer install, then run PHPUnit tests with composer test, see scripts in composer.json. Tests are also run on GitHub with Actions on each push.

enumag / phpstan-disallowed-calls