Force Doctrien to create GUID fields as VARCHAR(255) or to update exsting fields to CHAR(36)

I am using Doctrine within a Symfony 2.8 project. The entities / DB tables within the project are using a GUID field as ID. In previous Doctrine Versions these field where created as VARCHAR(255), while after an Update (see below), they are now created as CHAR(36):

doctrine/dbal               v2.4.4  --> 2.5.5
doctrine/doctrine-bundle    v1.2.0  --> 1.6.2           
doctrine/orm                v2.4.8  --> 2.5.5

The code change can be found in dbal/lib/Doctrine/DBAL/Platforms/AbstractPlatform.php in the getGuidTypeDeclarationSQL method.

Of course it makes sense to store GUIDs as CHAR(36) since this is their defined length and thus a VARCHAR(255) wastes space. However this change brings up a new Problem:

I added a new entity that should use a ManyToOne relationship to an existing entity via its guid field:

// OtherEntity

/**
 * @ORM\Id
 * @ORM\Column(name="guid", type="guid", unique=true)
 */
protected $guid;

// New Entity

/**
 * @ORM\ManyToOne(targetEntity="OtherEntity")
 * @ORM\JoinColumn(name="other_guid", referencedColumnName="guid", nullable=false, onDelete="SET NULL")
 */
protected $otherEntity;

Doctrine dumps the following SQL staments to create the table for the NewEntity when using php app/console doctrine:schema:update --dump-sql:

CREATE TABLE new_entity (guid CHAR(36) NOT NULL COMMENT '(DC2Type:guid)', other_guid CHAR(36) NOT NULL COMMENT '(DC2Type:guid)', ...

ALTER TABLE new_entity ADD CONSTRAINT FK_D3D1CD16A7FC4818 FOREIGN KEY (other_guid) REFERENCES other_entity (guid) ON DELETE SET NULL;

The execution however fails with

[Doctrine\DBAL\Exception\DriverException]                                                                                                                                     
An exception occurred while executing 'ALTER TABLE new_entity ADD CONSTRAINT FK_D3D1CD16A7FC4818 FOREIGN KEY (other_guid) REFERENCES other_entity (guid) ON DELETE SET NULL':  
SQLSTATE[HY000]: General error: 1215 Cannot add foreign key constraint

The problem is, that the guid field of other_entity is defined as VARCHAR(255) (created with old Doctrine version), while the other_guid field of new_entity is now created as CHAR(36). Mapping field of different types is not possible and leads to the error shown above. When I manually create the new_entity table using VARCHAR(255) instead, everything works fine.

How can I solve this?

Is it possible to force Doctrine to create guidas as VARCHAR(255)? Of course it would be better to update the existing tables to also use CHAR(36), but doctrine:schema:update does not do that.

Any idea?

doctrine / orm

Force Doctrien to create GUID fields as VARCHAR(255) or to update exsting fields to CHAR(36) #6093