Diagnose Extensions

PHPStan can output diagnostic information when running the analyse command with the -vvv CLI option, or when using the diagnose command. If your extension has configuration or runtime state that could help users troubleshoot issues, you can write a diagnose extension to include it in this output.

This is the interface your extension needs to implement:

namespace PHPStan\Diagnose;

use PHPStan\Command\Output;

interface DiagnoseExtension
{

	public function print(Output $output): void;

}

The print() method receives an Output instance that writes to stderr. Use its methods to write formatted output:

$output->writeLineFormatted(string $message) — writes a line with formatting
$output->writeRaw(string $message) — writes raw text without formatting

Here’s an example extension that outputs OS-dependent PHP constants relevant to file handling:

namespace App\PHPStan;

use PHPStan\Command\Output;
use PHPStan\Diagnose\DiagnoseExtension;

class FileSystemDiagnoseExtension implements DiagnoseExtension
{

	public function print(Output $output): void
	{
		$output->writeLineFormatted(sprintf(
			'PHP_OS: <info>%s</info>',
			PHP_OS,
		));
		$output->writeLineFormatted(sprintf(
			'PHP_MAXPATHLEN: <info>%d</info>',
			PHP_MAXPATHLEN,
		));
		$output->writeLineFormatted(sprintf(
			'DIRECTORY_SEPARATOR: <info>%s</info>',
			DIRECTORY_SEPARATOR,
		));
	}

}

The implementation needs to be registered in your configuration file:

services:
	-
		class: App\PHPStan\FileSystemDiagnoseExtension
		tags:
			- phpstan.diagnoseExtension

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