未知列类型“Varchar”

Using Doctrine, I am being presented the following error:

[2016-09-14 21:24:44] request.CRITICAL: Uncaught PHP Exception Doctrine\DBAL\DBALException: "Unknown column type "varchar" requested. Any Doctrine type that you use has to be registered with \Doctrine\DBAL\Types\Type::addType(). You can get a list of all the known types with \Doctrine\DBAL\Types\Type::getTypeMap(). If this error occurs during database introspection then you might have forgot to register all database types for a Doctrine Type. Use AbstractPlatform#registerDoctrineTypeMapping() or have your custom types implement Type#getMappedDatabaseTypes(). If the type name is empty you might have a problem with the cache or forgot some mapping information." at /var/www/project/apps/ProjectName/trunk/vendor/doctrine/dbal/lib/Doctrine/DBAL/DBALException.php line 114 {"exception":"[object] (Doctrine\\DBAL\\DBALException(code: 0): Unknown column type \"varchar\" requested. Any Doctrine type that you use has to be registered with \\Doctrine\\DBAL\\Types\\Type::addType(). You can get a list of all the known types with \\Doctrine\\DBAL\\Types\\Type::getTypeMap(). If this error occurs during database introspection then you might have forgot to register all database types for a Doctrine Type. Use AbstractPlatform#registerDoctrineTypeMapping() or have your custom types implement Type#getMappedDatabaseTypes(). If the type name is empty you might have a problem with the cache or forgot some mapping information. at /var/www/project/apps/ProjectName/trunk/vendor/doctrine/dbal/lib/Doctrine/DBAL/DBALException.php:114)"} []

the relevant class looks as such

<?php

namespace Project\DBALBundle\Entity\Url;

use Doctrine\ORM\Mapping as ORM;
use JMS\Serializer\Annotation as JMSS;

/**
 * Profile
 *
 * @ORM\Table(name="Profile")
 * @ORM\Entity(repositoryClass="Project\DBALBundle\Entity\Url\ProfileRepository")
 */
class ProfileRepository {
    /**
     * @var string $id
     *
     * @ORM\Column(name="id", type="integer", length=11, nullable=false)
     * @ORM\Id
     * @ORM\GeneratedValue(strategy="AUTO")
     */
    private $id;
    /**
     * @var string $label
     *
     * @ORM\Column(name="label", type="string", length=50, nullable=false)
     */
    private $label;

    /**
     * @return string
     */
    public function getId()
    {
        return $this->id;
    }

    /**
     * @param string $id
     */
    public function setId($id)
    {
        $this->id = $id;
    }

    /**
     * @return string
     */
    public function getLabel()
    {
        return $this->label;
    }

    /**
     * @param string $label
     */
    public function setLabel($label)
    {
        $this->label = $label;
    }

    public function __toString()
    {
        return $this->label;
    }
}

With the above class and annotation-defined mappings, I receive the error. However, if I change the field private $label to private $labelField and update the associated references, everything works just fine and the data is accessed as expected.

Insofar as I have been able to search, there is nothing special about the field private $label. It is not a reserved keyword, and I can find nothing mentioning anything special about it either with PHP itself or Doctrine specifically. So why does this break?

My guess will be it's a caching problem. You had probably tried at some point this code,

/**
 * @var string $label
 *
 * @ORM\Column(name="label", type="varchar", length=50, nullable=false)
 */
private $label;

and this class has got cached by opcache (or similar). Opcache pays no attention to annotations (it's just a comments for it), so no matter what you change in annotations, it's still using this cached version of the code.

But when you change a property name, it realizes that it's a newer version of class and parses annotations once again (that's why with labelField code worked).

But that's just a speculation. I would try to debug it with Xdebug to find out an exact problem.

P.S. Doctrine version 2.3 is quite old, isn't it?