ReflectionDescriptor: deduce database internal type based on parent

[janedbal]

Separated from #506.

This is crucial for every codebase that utilizes custom types a lot. Previously any AVG(t.customTypedField) was mixed. Now, it can produce proper type.

[janedbal]

I also have another idea how to implement this without the requirement of known parent. Then, you can extend even abstract Doctrine\DBAL\Types\Type and still have proper type (which is not working in the implementation here).

We use it our codebase, but it may feel a bit more hacky:

public function getDatabaseInternalType(): Type {
        /** @var DbalType $dbalType */
        $dbalType = new $this->type();
        $schemaColumn = new SchemaColumn('dummy', $dbalType, []);
        $fullSqlType = strtolower($dbalType->getSQLDeclaration($schemaColumn->toArray(), new MySQL80Platform()));

        $typeName = Strings::replace($fullSqlType, '~^([a-z ]+).*?$~', '$1');

        return match ($typeName) {
            'tinyint',
            'smallint',
            'mediumint',
            'int',
            'bigint' => new IntegerType(),
            'decimal',
            'numeric' => new IntersectionType([new StringType(), new AccessoryNumericStringType()]),
            'double precision' => new FloatType(),
            'varchar',
            'char',
            'binary',
            'tinytext',
            'text',
            'longtext',
            'json',
            'date',
            'datetime',
            'time' => new StringType(),
            default => throw new LogicException("Unexpected type: $fullSqlType"),
        };
    }

If you feel that this more generic approach is suitable even for phpstan-doctrine, I can try implementing it in #506 (as ReflectionDescriptor actually need to implement DoctrineTypeDriverAwareDescriptor).

[ondrejmirtes]

What about combining both, to cover more use-cases?

[janedbal]

If both, I think we can merge this and add that extra layer using getSQLDeclaration on top of this later.

[ondrejmirtes]

Thank you!