Also updated the dev Dockerfile to maintain consistency. Using (false) as a string literal in ENV causes it to be evaluated as true in PHP's loose typing, which defeats the purpose of disabling the cache in development. "dev.Dockerfile"
➜ hyperf-test docker run --rm --entrypoint php hyperftest:v1.0.2 -r "var_dump(getenv('SCAN_CACHEABLE'));"
string(7) "(false)"

Router::addRoute(['GET', 'POST', 'HEAD'], '/', function () {
    return [
        'method' => 'GET',
        'message' => 'Checking environment variable',
        // Мы возвращаем и тип, и значение
        'scan_cacheable_raw' => getenv('SCAN_CACHEABLE'),
        'scan_cacheable_type' => gettype(getenv('SCAN_CACHEABLE')),
    ];
});

{"method":"GET","message":"Checking environment variable","scan_cacheable_raw":"(false)","scan_cacheable_type":"string"}