Array-Properties with the SeralizedPath-Attribute can't be serialized by Serializer - php

Question

I have the problem that Properties with SerializedPath attributes, which I convert to an XML via Symfony Serializer (SerializerInterface, symfony/serializer-pack), does not have an expected behavior with arrays. Instead, the AbstractObjectNormalizer throws an exception. Symfony and related packages are using v6.2.5.
My goal is to create an XML like this one, with e.g. the following Object:
<?xml version="1.0"?>
<response>
<payment>
<allowedMethods>
<include name="Method A"/>
<include name="Method B"/>
</allowedMethods>
</payment>
</response>
// This is not working
class Payment
{
#[SerializedPath('[payment][allowedMethods][include][#name]')]
public array $methods = ['Method A', 'Method B'];
}
// ...
$this->serializer->serialize(new Payment(), 'xml');
But it results to the following Exception: The element you are trying to set is already populated: "[payment][allowedMethods][include][#name]".
which is thrown in the AbstractObjectNormalizer of Symfony:
if (null !== $classMetadata && null !== $serializedPath = ($attributesMetadata[$attribute] ?? null)?->getSerializedPath()) {
$propertyAccessor = PropertyAccess::createPropertyAccessor();
if ($propertyAccessor->isReadable($data, $serializedPath) && null !== $propertyAccessor->getValue($data, $serializedPath)) {
throw new LogicException(sprintf('The element you are trying to set is already populated: "%s".', (string) $serializedPath));
}
$propertyAccessor->setValue($data, $serializedPath, $attributeValue);
return $data;
}
My expected behavior would be that it behaves identically to the scalar values and therefore recognizes the # as an XML attribute and the rest as nodes:
// This is working great!
class Payment
{
#[SerializedPath('[payment][usedMethod][#name]')]
public string $usedMethod = 'Method A';
}
<?xml version="1.0"?>
<response>
<payment>
<usedMethod name="Method A"/>
</payment>
</response>
I've been trying to identify the exact problem and find a solution for some time, but since SerializedPath is very new (since Symfony 6.2), there is no great documentation for it. Internally it uses the PropertyAccessor, but where I could not find a suitable solution either.
Can someone maybe explain me the problem in more detail or even know a solution? Or even an alternative way. I'm trying to do it via the SerializedPath to avoid all the nested DTOs that are just there to map the (not always plausible) data model of the XML.
Another quite interesting fact is, if you comment out the thrown Exception in the AbstractObjectNormalizer it kind of works (for json fully, for xml partially, because the array can only hold one entry because of the annotation key):
class Payment
{
#[SerializedPath('[payment][allowedMethods][include]')]
public array $methods = [
'#name' => 'Method A'
];
}
<?xml version="1.0"?>
<response>
<payment>
<allowedMethods>
<include name="Method A"/>
</allowedMethods>
</payment>
</response>