Custom datetime with support of microseconds always generate unnecessary migration after update of dbal from 3.6 to 4.2.1

[bogdandubyk]

Bug Report

Q	A
BC Break	no
Version	3.8.2
dbla version	4.2.1

Summary

I have a custom type

final class DateTimeImmutableMicrosecondsType extends DateTimeTzImmutableType
{
    private const FORMAT = 'Y-m-d H:i:s.u';

    /**
     * @param T $value
     *
     * @return (T is null ? null : string)
     *
     * @throws ConversionException
     *
     * @template T
     */
    public function convertToDatabaseValue(mixed $value, AbstractPlatform $platform): ?string
    {
        if (
            $value instanceof DateTimeImmutable &&
            $platform instanceof PostgreSQLPlatform
        ) {
            return $value->format(self::FORMAT);
        }

        return parent::convertToDatabaseValue($value, $platform);
    }

    /**
     * @param T $value
     *
     * @return (T is null ? null : DateTimeImmutable)
     *
     * @template T
     * @throws InvalidFormat
     */
    public function convertToPHPValue(mixed $value, AbstractPlatform $platform): ?DateTimeImmutable
    {
        if ($value === null || $value instanceof DateTimeImmutable) {
            return $value;
        }

        if ($platform instanceof PostgreSQLPlatform) {
            try {
                $dateTime = DateTimeImmutable::createFromFormat(self::FORMAT, $value);
            } catch (\Throwable) {
                throw InvalidFormat::new(
                    $value,
                    self::class,
                    $platform->getDateTimeTzFormatString(),
                );
            }

            if ($dateTime !== false) {
                return $dateTime;
            }

            throw InvalidFormat::new(
                $value,
                self::class,
                $platform->getDateTimeTzFormatString(),
            );
        }

        return parent::convertToPHPValue($value, $platform);
    }

    /** @param mixed[] $column */
    public function getSQLDeclaration(array $column, AbstractPlatform $platform): string
    {
        if ($platform instanceof PostgreSQLPlatform) {
            return 'TIMESTAMP(6) WITH TIME ZONE';
        }

        return $platform->getDateTimeTzTypeDeclarationSQL($column);
    }
}

in my Symfony app it registered like this

doctrine:
    dbal:
        types:
            datetimetz_immutable: App\Doctrine\Types\DateTimeImmutableMicrosecondsType

and in my XML entity mapping, I use it like this

<field name="updatedAt" type="datetimetz_immutable" column="updated_at" nullable="true"/>

All worked perfectly, diff command generated migration like this:

 updated_at TIMESTAMP(6) WITH TIME ZONE

and added commend like this

'COMMENT ON COLUMN updated_at IS \'(DC2Type:datetimetz_immutable)\''

But now I updated DDBAL to version 4.2.1 and when I run a diff it generates a new migration

        $this->addSql('ALTER TABLE table ALTER updated_at TYPE TIMESTAMP(6) WITH TIME ZONE');
        $this->addSql('COMMENT ON COLUMN updated_at IS \'\'');

First of all for some reason removing comment, and altering table to set same type again :)

Okay, I run that migration and run diff again and it generate migration like this

    $this->addSql('ALTER TABLE table ALTER updated_at TYPE TIMESTAMP(6) WITH TIME ZONE');

So it's always trying to convert type to TIMESTAMP(6) WITH TIME ZONE but that type is already correct one.

Current behavior

Doctrime diff always generating migration like this

    $this->addSql('ALTER TABLE table ALTER updated_at TYPE TIMESTAMP(6) WITH TIME ZONE');

How to reproduce

Have a custom type from above, dbal 4.2.1 and run diff command

[derrabus]

Duplicate of #1441.