Support read_only nested serializer fields (use allOf to improve schema generation)

[bendavis78]

Serializer fields that point to other serializers and are read_only should be marked as readOnly in the schema.

For example, I have an AccountSerializer with a field called user that points to UserSerializer, and is read_only. The schema definition for the user field is generated as:

{
    "$ref": "#/definitions/User"
}

Instead it should be:

{
    "readOnly": true,
    "allOf": [
        {"$ref": "#/definitions/User"}
    ]
}

[axnsan12]

This is indeed something that might need to be addressed. However I believe there are lots of tools which get confused by allOf constructs, so I think this would need to sit behind a feature flag.

I think there might also be other places where we could use allOf to improve detailing of schemas.

[hedleyroos]

@bendavis78 removing the line https://github.com/axnsan12/drf-yasg/blob/master/src/drf_yasg/inspectors/field.py#L136 respects the read_only value of the nested serializer. @axnsan12 can you perhaps explain how this works? The comment at https://github.com/axnsan12/drf-yasg/blob/master/src/drf_yasg/openapi.py#L504 does not fully explain why the property is popped.

[axnsan12]

@hedleyroos because readOnly is not valid when a Schema is defined in a definitions section. It is only valid when it is a direct child of another Schema via properties. The proper way to use readOnly with references is already outlined in the OP.

[MeRuslan]

Soooo, whats' going on in here? Is it going to ever happen?

[Arti3DPlayer]

same issue +1

[Schwankenson]

Same issue: +1

[NurElHuda]

Same issue: +1

[athish-t]

Any updates on this?

[Schwankenson]

I think we have to update to https://github.com/tfranzel/drf-spectacular to get this feature...looks like a lot of work.