Symfony Migrations Bundle creating the same migration over and over again

I added an auto-update timestamp to an entity like in this blog post and it works just fine.

Here is the code snippet:

#[Entity]
class Article
{
    #[Column(type: "datetime",
        columnDefinition: "TIMESTAMP DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP",
        insertable: false,
        updatable: false,
        generated: "ALWAYS")]
    public $created;
}

The first time I run php bin/console make:migration the correct migration is generated:

$this->addSql('ALTER TABLE article ADD created TIMESTAMP DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP');

This works just fine and any DB update now updates created. However, this is also where the problems begin. Whenever I make another migration now, it tries to apply the same changes again:

$this->addSql('ALTER TABLE article CHANGE created created TIMESTAMP DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP');

How can this be, and does anyone know how to fix this?

Thank you very much for your input, I really appreciate it.

So I didn't figure out why this happens. But the solution to this problem is to check if the property in question already exists, and then ignore it when diffing: https://www.liip.ch/en/blog/doctrine-and-generated-columns

Edit:

So, the classes used in the blog article above are deprecated and I had to dig a little deeper into Doctrine on how to exclude specific table columns.

I performed the following steps, and it works like a charm:

• Read the official documentation on schema managers: https://www.doctrine-project.org/projects/doctrine-dbal/en/current/reference/schema-manager.html
• Implement a custom SchemaManagerFactory
• Implement a custom custom MySQLSchemaManager (at least if you use MySQL, that is)
• Make the schema manager use a custom Comparator
• Add schema_manager_factory: doctrine.dbal.default_schema_manager_factory to my entries in connections in doctrine.yaml
• Alias doctrine.dbal.default_schema_manager_factory in services.yaml

Here is some example code to make this more clear.

doctrine:
    dbal:
        default_connection: default
        connections:
            default:
                server_version: 8.0.25
                schema_manager_factory: doctrine.dbal.default_schema_manager_factory

services:
    doctrine.dbal.default_schema_manager_factory:
        class: App\Service\Doctrine\CustomSchemaManagerFactory

<?php

namespace App\Service\Doctrine;

use Doctrine\DBAL\Connection;
use Doctrine\DBAL\Exception;
use Doctrine\DBAL\Platforms\MySQL80Platform;
use Doctrine\DBAL\Schema\AbstractSchemaManager;
use Doctrine\DBAL\Schema\DefaultSchemaManagerFactory;
use Doctrine\DBAL\Schema\SchemaManagerFactory;

final class CustomSchemaManagerFactory implements SchemaManagerFactory
{
    private readonly SchemaManagerFactory $defaultFactory;

    public function __construct()
    {
        $this->defaultFactory = new DefaultSchemaManagerFactory();
    }

    /**
     * @throws Exception
     */
    public function createSchemaManager(Connection $connection): AbstractSchemaManager
    {
        $platform = $connection->getDatabasePlatform();
        if ($platform instanceof MySQL80Platform) {
            return new CustomMySQLSchemaManager($connection, $platform);
        }

        return $this->defaultFactory->createSchemaManager($connection);
    }
}

<?php

namespace App\Service\Doctrine;

use Doctrine\DBAL\Platforms\MySQL\CollationMetadataProvider\CachingCollationMetadataProvider;
use Doctrine\DBAL\Platforms\MySQL\CollationMetadataProvider\ConnectionCollationMetadataProvider;
use Doctrine\DBAL\Schema\Comparator;
use Doctrine\DBAL\Schema\MySQLSchemaManager;

final class CustomMySQLSchemaManager extends MySQLSchemaManager
{
    public function createComparator(): Comparator
    {
        return new CustomComparator(
            $this->_platform,
            new CachingCollationMetadataProvider(
                new ConnectionCollationMetadataProvider($this->_conn),
            ),
        );
    }
}

<?php

namespace App\Service\Doctrine;

use Doctrine\DBAL\Platforms\MySQL\Comparator;
use Doctrine\DBAL\Schema\Table;
use Doctrine\DBAL\Schema\TableDiff;

final class CustomComparator extends Comparator
{
    public function compareTables(Table $fromTable, Table $toTable): TableDiff
    {
        $diff = parent::compareTables($fromTable, $toTable);
        
        # Your custom logic here!

        return $diff;
    }
}