Shopware 6: Extend existing core DAL entities with a reference - shopware

Question

I'm trying to create a connection between 2 existing entities PropertyGroup and CustomFieldSet. Use-case is irrelevant.
So I created an EntityExtension:
public function extendFields(FieldCollection $collection): void
{
$collection->add(
(new ManyToOneAssociationField('customFieldSet', 'custom_field_set', CustomFieldSetDefinition::class))
);
}
public function getDefinitionClass(): string
{
return PropertyGroupDefinition::class;
}
And override the administration component to also include this association when loading the entity:
Component.override('sw-property-detail', {
methods: {
loadEntityData() {
this.isLoading = true;
const criteria = this.defaultCriteria;
criteria.addAssociation('customFieldSet', new Criteria(1, 500));
this.propertyRepository.get(this.groupId, Shopware.Context.api, criteria)
.then((currentGroup) => {
this.propertyGroup = currentGroup;
this.isLoading = false;
}).catch(() => {
this.isLoading = false;
});
}
}
});
(I tried to override defaultCriteria but that didn't work because of this.$super being unable to access computed properties).
But it keeps saying FRAMEWORK__ASSOCIATION_NOT_FOUND. I debugged the EntityDefinition and it seems that this extension is not even loaded.
I checked if my EntityExtension is loaded in the Symfony container and it is, but it seems that it doesn't reach the entity definition.

Answer 1

The EntityExtension seems to be missing the addition of a FkField inside the function extendFields:
public function extendFields(FieldCollection $collection): void
{
$collection->add(
(new FkField('custom_field_set', 'customFieldSetId', CustomFieldSetDefinition::class)),
);
$collection->add(
(new ManyToOneAssociationField('customFieldSet', 'custom_field_set', CustomFieldSetDefinition::class))
);
}
A new use statement has to be added for the FkField:
use Shopware\Core\Framework\DataAbstractionLayer\Field\FkField;