[BUG] ModelSchema with ManyToManyField won't work under async views about django-ninja HOT 5 CLOSED

You'll get the same error with any related fields on a model, it doesn't matter if you're using a ModelSchema or a base Schema.

From what I gather, the issue comes from the getattr call on the DjangoGetter class. Since the attributes are related fields, django will make a DB call to retrieve the values synchronously, causing the SynchronousOnlyOperation exception.

I'm not sure if this can be handled by ninja directly, but you can avoid this error by prefetching the related objects, using either prefetch_related or select_related depending on the type of relation.

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check this, maybe it would help https://django-ninja.dev/guides/async-support/#using-orm ,
but he is using aget, which is actually async get, i didn't see afilter or something like that

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Thank you. I understand how to use ORM with async. But ModelSchema seems not to be supporting this right now?

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_convert_result doesn't indeed seem to support async operations, so whenever a database hit is required, the function will fail.

To add to @ariponce's comment and workaround, if you need to do this for a single model instance, you can use (a)prefetch_related_objects. e.g.:

await aprefetch_related_objects([user_instance], "groups", "user_permissions")

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@ariponce Thanks. Not familiar with prefetch_related, but for now it works as expected.

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