Problems when Serializing instance of a derived class that is also the target of a OneToOneField #4290
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added 6 commits
July 20, 2016 14:11
Previously could fail when serializing a model that: 1. was derived (subclassed) from a model 2. was itself referenced via a one-to-one relationship by a third model 3. had a serializer that listed the referring model in its Meta.fields Now we recursively check up inheritance chain for the referenced field
Exhibits the problem that occurs when a model has a one-to-one relationship with another model that is itself derived (subclassed) from a third model.
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I wonder if we could get the same result by calling Django API. Surely other projects will run into that one and we should consider pushing that to Django |
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I looked into that. In the scenario described, the value stored in the table with the one-to-one field really is the value of the ptr to the parent table so the "to_field" variable really is correct when it refers to that field name even though it is not on the original table. |
tomchristie
reviewed
Oct 11, 2016
| field_kwargs['slug_field'] = to_field | ||
| field_class = self.serializer_related_to_field | ||
| if to_field: | ||
| def get_related_field(related_model, to_field): |
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Haven't looked into the issue in any depth, but we'd certainly want to factor this out. Eg have it as a function somewhere in rest_framework.utils
This was referenced Oct 13, 2016
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I have found that when attempting to serialize an instance of a model that:
A FieldDoesNotExist exception would be thrown indicating that the model with the OneToOne field has no field named _ptr where parent is the lower-cased name of the model at the top of the inheritance chain.
The attached pull request searches the inheritance chain recursively to find the correct field.
A unit test has also been included. My fork includes a branch called "foreign-key-to-derived-model-tests' which includes only the unit test. It may be used to verify the problem this pull request resolves.