graphql-python / graphql-python/graphene-sqlalchemy
Hybrid properties don't work in the presence of future annotations
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Descrição
This has been driving me a bit nuts since the columns/hybrids refactor, and I haven't been able to figure out if it's something new, expected, or something I'm doing wrong. Here's the simplest scenario I could come up with to demonstrate it.
```python
@declarative_mixin
@as_declarative()
class Base:
pass
class Person(Base):
__tablename__ = "person"
id = Column(postgresql.UUID(as_uuid=True), primary_key=True)
@hybrid_property
def hello(self) -> str:
return "world"
class GPerson(SQLAlchemyObjectType):
class Meta:
model = Person
class GQuery(ObjectType):
person = Field(GPerson)
schema = Schema(query=GQuery)
```
I would expect this to work, and it does. It even works if I make my `hello` property return a `list[list[str]]` or something weird like that. But! If you import `__future__` annotations, this scenario no longer works:
```python
from __future__ import annotations
```
```
Traceback (most recent call last):
File "/home/vscode/.local/share/virtualenvs/bios-backend-rDkHOn2N/lib/python3.10/site-packages/graphql/type/definition.py", line 808, in fields
fields = resolve_thunk(self._fields)
File "/home/vscode/.local/share/virtualenvs/bios-backend-rDkHOn2N/lib/python3.10/site-packages/graphql/type/definition.py", line 300, in resolve_thunk
return thunk() if callable(thunk) else thunk
File "/home/vscode/.local/share/virtualenvs/bios-backend-rDkHOn2N/lib/python3.10/site-packages/graphene/types/schema.py", line 305, in create_fields_for_type
field_type = create_graphql_type(field.type)
File "/home/vscode/.local/share/virtualenvs/bios-backend-rDkHOn2N/lib/python3.10/site-packages/graphene/types/field.py", line 116, in type
return get_type(self._type)
File "/home/vscode/.local/share/virtualenvs/bios-backend-rDkHOn2N/lib/python3.10/site-packages/graphene/types/utils.py", line 42, in get_type
return _type()
File "/home/vscode/.local/share/virtualenvs/bios-backend-rDkHOn2N/lib/python3.10/site-packages/graphene_sqlalchemy/converter.py", line 615, in forward_reference_solver
raise TypeError(
TypeError: No model found in Registry for forward reference for type ForwardRef('str'). Only forward references to other SQLAlchemy Models mapped to SQLAlchemyObjectTypes are allowed.
```
This is because with `__future__` annotations, `-> str` creates a `ForwardRef`, and forward refs (unlike normal types) have to be SQLAlchemy models (https://github.com/graphql-python/graphene-sqlalchemy/blob/master/graphene_sqlalchemy/converter.py#L610). So you have to explicitly supply hybrid field definitions, even for methods that return simple primitive types. This is a huge inconvenience, as we have many of these kinds of computed properties in our codebase.
Any ideas if this is something fixable? Or are we just stuck with having to manually add field definitions everywhere?
Guia de contribuição
Direção de pesquisa
Comece reproduzindo o exemplo com `from __future__ import annotations`; em seguida, inspecione `graphene_sqlalchemy/converter.py` ao redor de `forward_reference_solver` e o tratamento de referências antecipadas próximo à linha 610. Confirme que propriedades híbridas que retornam tipos primitivos funcionam sem definições de campos fornecidas manualmente, enquanto as referências antecipadas de modelos mantêm seu comportamento existente.
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Avaliação
- Stack de tecnologia
- python, sqlalchemy
- Domínio
- api, backend
- Tipo de issue
- Bug
- Dificuldade
- 4/5
- Tempo estimado
- 3-5 dias
- Status de atividade
- Estagnada
- Clareza
- Razoavelmente clara
- Facilidade para iniciantes
- 35/100