[OpenAPI] Add "type" property with value "object" response schema to fix Infragistics AppBuilder tooling

[seantleonard]

Why make this change?

• Closes Support for OpenAPI description in a Infragistics AppBuilder integration use case #2212 which describes how the missing "type":"object" key/value pair on the response child object schema breaks certain client tooling. in this case: Infragistics AppBuilder.

Background

I found a relevant thread that discusses whether type is a required property. Consensus is that type isn't required:

OAI/OpenAPI-Specification#1657
OpenAPI-Specification discussion
PaloAltoNetworks/docusaurus-openapi-docs#430
Example of how different tooling handles type or missing type differently.
Ultimately, different tooling handles the presence of the type property differently. Some may try to guess the type when not present:

The fact that the type isn't required means that https://github.com/microsoft/OpenAPI.NET didn't complain about missing type. An error if type were required would have helped prevent this becoming an issue in the first place.

What is this change?

• Adds "type": "object" to the openapi document for describing the response schema:

                "responses": {
                    "200": {
                        "description": "OK",
                        "content": {
                            "application/json": {
                                "schema": {
                                    "type": "object", // <--- This property/value
                                    "properties": {
                                        "value": {
                                            "type": "array",
                                            "items": {
                                                "$ref": "#/components/schemas/Book"
                                            }
                                        },
                                        "nextLink": {
                                            "type": "string"
                                        }
                                    }
                                }
                            }
                        }
                    }

How was this tested?

• Integration Tests
• Unit Tests

Sample Request(s)

View generated schema at

GET localhost:5001/api/openapi

[abhishekkumams]

Thanks for the change and adding relevant information on the PR description. It was easy to follow.

[abhishekkumams]

/azp run

[Aniruddh25]

LGTM