Find unused symfony services

find-unused-services.php

<?php

$filename = './srcApp_KernelDevDebugContainer.xml';
$content = file_get_contents($filename);
// the \> at the end of a service definition means this service has no dependencies.
preg_match_all('/\<service id="(App.+?)".* autowire="true" .*?\/>/', $content, $matches);

$serviceIds = $matches[1];

foreach ($serviceIds as $serviceId) {
    $serviceId = str_replace('\\', '\\\\', $serviceId);

    if (!preg_match(sprintf('/\<argument (key=".*?")? type="service" id="%s"\/>/', $serviceId), $content)) {
        echo sprintf("Unused service: %s\n", $serviceId);
    }
}