This "hack" grants external callers read-, write- and execution-access to private and protected members of an instance. Beware that this violates the idea of oop and should therefore only be the last resort before giving up.

AccessEnforcer.php

<?php

use Closure;
use Exception;
use ReflectionException;
use ReflectionMethod;

/**
 * Class AccessEnforcer
 */
class AccessEnforcer
{
    /**
     * Reads a private attribute of the given
     * instance. Cannot read private attributes
     * of any parent classes.
     *
     * @param $instance
     * @param $name
     * @return mixed
     * @throws Exception
     */
    public static function forceRead($instance, $name)
    {
        if (!is_object($instance)) {
            throw new Exception('$instance must be an object.');
        }

        $spoof = Closure::bind(function ($instance) use ($name) {
            return $instance->{$name};
        }, null, $instance);
        return $spoof($instance);
    }

    /**
     * Writes a value to a specific private
     * attribute of the given instance.
     * Cannot override private attributes of
     * any parent classes.
     *
     * @param $instance
     * @param $name
     * @param $value
     * @throws Exception
     */
    public static function forceWrite($instance, $name, $value)
    {
        if (!is_object($instance)) {
            throw new Exception('$instance must be an object.');
        }

        $spoof = Closure::bind(function ($instance) use ($name, $value) {
            $instance->{$name} = $value;
        }, null, $instance);
        $spoof($instance);
    }

    /**
     * Calls a private method of the given
     * instance with the given parameters
     * and returns its return value.
     *
     * @param $instance
     * @param $name
     * @param array ...$arguments
     * @return mixed
     * @throws Exception
     * @throws ReflectionException
     */
    public static function forceCallMethod($instance, $name, ...$arguments)
    {
        if (!is_object($instance)) {
            throw new Exception('$instance must be an object.');
        }

        $method = new ReflectionMethod(get_class($instance), $name);
        $method->setAccessible(true);

        return $method->invoke($instance, ...$arguments);
    }
}