Discriminator does not switch schema

[5thWall]

Using Swagger UI v2.2.3

Swagger file:

{
    "swagger": "2.0",
    "info": {
        "title": "Animals yo!",
        "description": "An API for animals",
        "version": "1.0.0"
    },
    "produces": [
        "application/json"
    ],
    "paths": {
        "/animal": {
            "get": {
                "summary": "Retrieves an animal",
                "responses": {
                    "200": {
                        "description": "Animal",
                        "schema": {
                            "$ref": "#/definitions/Animal"
                        }
                    }
                }
            },
            "post": {
                "summary": "Animal",
                "parameters": [
                    {
                        "in": "body",
                        "name": "animal",
                        "required": true,
                        "schema": {
                            "$ref": "#/definitions/Animal"
                        }
                    }
                ],
                "responses": {
                    "200": {
                        "description": "Animal",
                        "schema": {
                            "$ref": "#/definitions/Animal"
                        }
                    }
                }
            }
        }
    },
    "definitions": {
        "Animal": {
            "additionalProperties": true,
            "discriminator": "animalType",
            "required": [
                "name",
                "animalType"
            ],
            "properties": {
                "name": {
                    "type": "string"
                },
                "animalType": {
                    "type": "string",
                    "enum": [
                        "Cat",
                        "Dog"
                    ]
                }
            }
        },
        "Cat": {
            "allOf": [
                {
                    "$ref": "#/definitions/Animal"
                }
            ],
            "required": [
                "huntingSkill"
            ],
            "properties": {
                "huntingSkill": {
                    "type": "string",
                    "description": "Skill of hunting",
                    "default": "lazy",
                    "enum": [
                        "lazy",
                        "clueless",
                        "adventurous",
                        "aggressive"
                    ]
                }
            }
        },
        "Dog": {
            "allOf": [
                {
                    "$ref": "#/definitions/Animal"
                }
            ],
            "required": [
                "packSize"
            ],
            "properties": {
                "packSize": {
                    "type": "integer",
                    "format": "int32",
                    "description": "Size of the pack",
                    "default": 0,
                    "minimum": 0
                }
            }
        }
    }
}

What I expect to see:
Under GET /animals some indication that a Dog or Cat may actually be returned with corresponding huntingSkill or packSize parameters.

Under POST /animals parameters section a text box corresponding to huntingSkill when animalType dropdown is set to Cat, and a packSize text box when animalType is set to Dog

What I actually see:
Basic Animal represented for both GET and POST.

If I change the schema $ref in GET or POST to one of the options then the model will show all fields for an Animal plus the specific type of animal. However the animalType parameter can still be changed to the other type.

[helgridly]

I'm also seeing this. There's a lot of conflicting information across Swagger repos regarding support for allOf and discriminator but as an end-user the above snippet is a succinct demonstration of how it doesn't work. I can confirm it still doesn't work in v2.2.5.

[chriswebster]

I see the same in v2.2.6

[ringgelerch]

This is a very important feature for us as well. We use a workaround at the moment:

For the GET method we define multiple responses like "200 Cat" and "200 Dog".
For PUT and POST we use different paths like "path/to/animals/animal (Cat)". To use the "try out" feature of swagger ui we created a PUT and POST with the valid path "path/to/animals/animal". To send a request just copy the body content from the Cat PUT or POST to the generic one.

It would be greate to see the discriminator be supported very soon, because with upper workaround our api spec is hard to maintain and the rendered ui is not easy to read.

[raderio]

An ETA when it will be supported?

an example how it works in ReDoc
https://github.com/Rebilly/ReDoc/blob/master/docs/images/discriminator-demo.gif
From https://github.com/Rebilly/ReDoc

[webron]

@raderio at the moment, it's not in our immediate plans.

[mikeholler]

It's pretty surprising to me that this isn't supported out of the box (or being prioritized). The way it shows just the "parent" and doesn't give anybody an idea of the other types available in any way is... not great, to put it lightly.

It's going to be very unintuitive for users that want to try our routes that use polymorphic inputs and outputs.

[pschichtel]

Would a pull request be welcome for this?

[elear]

@pschichtel certainly by me. I'd be happy to test.

[KartikSoneji]

Hi, I looked at swagger-ui with the posted spec but I can't see a good place to add a dropdown for animalType for the POST request.
Also, I'm not sure how the optional fields should appear in the GET schema, maybe instead of the Animal schema there should be two different schemas for Dog and Cat?

[YousefHaggy]

Is this on the roadmap in 2024?

[YousefHaggy]

Created a PR for this #10224