Symfony 4: Doctrine ORM Mapping for PaymentToken not added in prod-Environment

When using PayumBundle in Symfony 4 (flex), the Doctrine ORM mapping information for the PaymentToken Entity are not loaded when APP_ENV=prod.

This leads to an exception when trying to override the definition of the hash-Column (via @attributeOverride) to make it comaptible with utf8mb4_unicode_ci encoding (see Issue #319 ). More information below.

The cause of this problem seems to be if there is a additional config/packages/prod/doctrine.yaml (as created by the default Symfony 4 setup) file with some additional configuration for Doctrine in the Production-Environment. The issue seems to be in the prepend()-Method of the Payum\Bundle\PayumBundle\DependencyInjection\PayumExtension class (see https://github.com/Payum/PayumBundle/blob/master/DependencyInjection/PayumExtension.php#L81 )

If I delete the file config/packages/prod/doctrine.yaml or when APP_ENV=dev, everything works fine.

Further information

Error when running `composer install`

The Command composer install --no-dev outputs the following:

Loading composer repositories with package information
Installing dependencies from lock file
Nothing to install or update
Generating autoload files
ocramius/package-versions:  Generating version class...
ocramius/package-versions: ...done generating version class
Executing script cache:clear [KO]
 [KO]
Script cache:clear returned with error code 1
!!  
!!  In MappingException.php line 139:
!!                                                                              
!!    Invalid field override named 'hash' for class 'App\Entity\PaymentToken'.  
!!                                                                              
!!  
!!  
Script @auto-scripts was called via post-install-cmd

`.env`

APP_ENV=prod
# ...

`PaymentToken.php`

<?php
/**
 * PaymentToken.php
 * @author: Kim D. Jeker <kim.jeker@suxesiv.ch>
 * @since 15.03.2019
 */
declare(strict_types=1);

namespace App\Entity;

use Doctrine\ORM\Mapping as ORM;
use Payum\Core\Model\Token;

/**
 * @ORM\Table
 * @ORM\Entity
 * @ORM\AttributeOverrides({
 *      @ORM\AttributeOverride(name="hash",
 *          column=@ORM\Column(
 *              type     = "string",
 *              length   = 191,
 *          )
 *      )
 * })
 */
class PaymentToken extends Token
{

}

`config/packages/prod/doctrine.yaml`

doctrine:
    orm:
        auto_generate_proxy_classes: false
        metadata_cache_driver:
            type: service
            id: doctrine.system_cache_provider
        query_cache_driver:
            type: service
            id: doctrine.system_cache_provider
        result_cache_driver:
            type: service
            id: doctrine.result_cache_provider

services:
    doctrine.result_cache_provider:
        class: Symfony\Component\Cache\DoctrineProvider
        public: false
        arguments:
            - '@doctrine.result_cache_pool'
    doctrine.system_cache_provider:
        class: Symfony\Component\Cache\DoctrineProvider
        public: false
        arguments:
            - '@doctrine.system_cache_pool'

framework:
    cache:
        pools:
            doctrine.result_cache_pool:
                adapter: cache.app
            doctrine.system_cache_pool:
                adapter: cache.system

Payum / PayumBundle