Handle PHP8.2 readonly classes

[Korbeil]

I'm not sure we should throw an exception here, the current behavior seems fine to me: when using a readonly class as object to populate, it's simply ignored.

Here is a sample mapper from the test I added in this PR

    public function &map($value, array $context = array())
    {
        if (null === $value) {
            return $value;
        }
        $result = $context['target_to_populate'] ?? null;
        if (null === $result) {
            if (\Jane\Component\AutoMapper\MapperContext::hasConstructorArgument($context, 'Jane\\Component\\AutoMapper\\Tests\\Fixtures\\AddressDTOReadonlyClass', 'city')) {
                $constructarg = \Jane\Component\AutoMapper\MapperContext::getConstructorArgument($context, 'Jane\\Component\\AutoMapper\\Tests\\Fixtures\\AddressDTOReadonlyClass', 'city');
            } else {
                $constructarg = $value['city'];
            }
            $result = new \Jane\Component\AutoMapper\Tests\Fixtures\AddressDTOReadonlyClass($constructarg);
        }
        return $result;
    }

@nikophil any feedback here ?

[nikophil]

I don't have a strong opinion on this, but I'm a little bit more in favor of throwing an exception in order to prevent some WTF moment for user which would not understand directly why the data is not mapped

[damienalexandre]

Agreed, having a RuntimeException is better for DX in my opinion. The Exception should educate about the readonly status and about alternatives.

[Korbeil]

After thinking a bit more about this, I'll make it an exception by default and add an opt-out to disable it if required.
It could happen that someone is using some library that has a read-only class that you can't really change and I don't want him to be blocked by this in this case.

[Korbeil]

Here is a sample generated Mapper after this changes:

final class Mapper_array_Jane_Component_AutoMapper_Tests_Fixtures_AddressDTOReadonlyClass extends \Jane\Component\AutoMapper\GeneratedMapper
{
    public function __construct()
    {
    }
    public function &map($value, array $context = array())
    {
        if (null === $value) {
            return $value;
        }
        $result = $context['target_to_populate'] ?? null;
        if (!($context['allow_readonly_target_to_populate'] ?? false) && is_object($context['target_to_populate'] ?? null)) {
            throw new Jane\Component\AutoMapper\Exception\ReadOnlyTargetException();
        }
        if (null === $result) {
            if (\Jane\Component\AutoMapper\MapperContext::hasConstructorArgument($context, 'Jane\\Component\\AutoMapper\\Tests\\Fixtures\\AddressDTOReadonlyClass', 'city')) {
                $constructarg = \Jane\Component\AutoMapper\MapperContext::getConstructorArgument($context, 'Jane\\Component\\AutoMapper\\Tests\\Fixtures\\AddressDTOReadonlyClass', 'city');
            } else {
                $constructarg = $value['city'];
            }
            $result = new \Jane\Component\AutoMapper\Tests\Fixtures\AddressDTOReadonlyClass($constructarg);
        }
        return $result;
    }
}

There is two levels where you can setup this check:

• in the Generator class, you have an opt-out that adds a check if the target class is a readonly class which throw a ReadOnlyTargetException
• in the context during runtime, you can add allow_readonly_target_to_populate field to opt-out this validation

[nikophil]

😎