[DBAL-1087] Length of fixed string type (char) is ignored on Postgre schema update

[SenseException]

This PR should fix an issue for the fixed string type columns using PostgreSQL.

I've created a basic Symfony 2.6. Application and using a PostgreSQL 9.3. database. In this dummy project, I've created the following Entity:

<?php

namespace Acme\DemoBundle\Entity;

use Doctrine\ORM\Mapping AS ORM;

/**
 * @ORM\Entity
 * @ORM\Table(name="test")
 */
class Test
{
    /**
     * @ORM\Id
     * @ORM\Column(type="integer", name="id")
     * @ORM\GeneratedValue
     */
    public $id;

    /**
     * @ORM\Column(type="string", name="name", length=2, options={"fixed" = true})
     */
    public $name;
}

The table is successfully created after a schema update, but when another schema update is executed without any changes to the entity, an ALTER query is executed:

ALTER TABLE test ALTER name TYPE CHAR(2);

After I searched in the code of doctrine dbal, I discovered that the length of the char column is not fetched correctly in PostgreSqlSchemaManager::_getPortableTableColumnDefinition(). In my example, length results as null and will be later set to 255 in the Comparator, which isn't the correct length from the database column. The comparation of the schemas results in a change of char-length.

For simplicity, I extended the if-condition in PostgreSqlSchemaManager to:

if (strtolower($tableColumn['type']) === 'varchar' || strtolower($tableColumn['type']) === 'bpchar') {

The fix I've contributed does help to parse the length in my case, but when I look into PostgreSqlPlatform::initializeDoctrineTypeMappings() there could be other types with the same problem, that are mapped to the doctrine string type.

// ... part of PostgreSqlPlatform::initializeDoctrineTypeMappings()
            'varchar'       => 'string',
            'interval'      => 'string',
            '_varchar'      => 'string',
            'char'          => 'string',
            'bpchar'        => 'string',
            'inet'          => 'string',

I guess we need to cover char and the others too.

PostgreSqlSchemaManagerTest also doesn't cover existing code. How is this going to be tested? Does the SchemaManagers need some tests in general?

[doctrinebot]

Hello,

thank you for creating this pull request. I have automatically opened an issue
on our Jira Bug Tracker for you. See the issue link:

http://www.doctrine-project.org/jira/browse/DBAL-1087

We use Jira to track the state of pull requests and the versions they got
included in.

[stof]

Please add a test covering this

[SenseException]

@stof It sure need a test for my case, but there need to be more tests for the SchemaManagers at all.

But I'm going to add one for this issue first.

[SenseException]

@stof A test for my case is now added.

[deeky666]

Adjusted the test case and merged manually, thanks!