openapi spec improperly uses allOf when not needed

[jlsherrill]

Version
3.22.2

Describe the bug
The openapi spec is written in such a way that is valid, but makes generating bindings problematic for some languages.

properties such as:

                    "policy": {
                        "allOf": [
                            {
                                "$ref": "#/components/schemas/PolicyDb6Enum"
                            }
                        ],
                        "default": "immediate",
                        "description": "The policy to use when downloading content."
                    },

could be re-written to be:

                    "policy": {
                       "$ref": "#/components/schemas/PolicyDb6Enum"
                        "default": "immediate",
                        "description": "The policy to use when downloading content."
                    },

and thus the property would only have a single type, and can be more easily handled by the openapi-generator, since the type is known and singular

To Reproduce
see this bug: OpenAPITools/openapi-generator#14665

Expected behavior
allOf should not be used in the spec when there is only a single type

Additional context
this prevents go bindings from being generated properly without patching

[jlsherrill]

this is also an issue for the exporter part:

                    "method": { 
                        "allOf": [
                            {
                                "$ref": "#/components/schemas/MethodEnum"
                            }
                        ],
                        "default": "write",
                        "description": "Method of exporting"
                    }

[mdellweg]

I do believe that the generated schema is correct, and that it cannot be simplified using $ref directly.

$ref and Sibling Elements

Any sibling elements of a $ref are ignored. This is because $ref works by replacing itself and everything on its level with the definition it is pointing at.

from: https://swagger.io/docs/specification/using-ref/

[jlsherrill]

In the second schema, the description and default properties are ignored, so this schema ends up exactly the same as the referenced Date schema.
I see. I'm guessing you need the description & default value to be set on a per property basis too

[mdellweg]

Well maybe, first off all, this is what drf-spectacular generates for us. It may be redundant, yes. But we cannot have "$ref" and "description" without composing it with the help of "allOf".

[dkliban]

@jlsherrill can we close this now that your openapi-generator PR has been merged?

[jlsherrill]

yes sir!