$ref pointing at the same schema causes a resolver error

Q&A

• OS: macOS
• Browser: chrome
• Version: 79
• Method of installation: npm swagger-ui-react
• Swagger-UI version: 3.24.3
• Swagger/OpenAPI version: OpenAPI 3.0

Content & configuration

I have a $ref that is a causing a resolver error (#/components/schemas/PartsOrderLine/properties/listPrice/allOf/0). The main difference I can see to other working refs is that it is pointing at the same schema, although it does not throw an error if I omit /allof/0.

I have removed as much of the spec as possible, whilst retaining the error in order to simplify the problem.

For now I have ended up manually copying the information from the $ref instead of using a $ref, but that is not ideal.

Example Swagger/OpenAPI definition:

{
  "openapi": "3.0.0",
  "paths": {
    "/parts-orders": {
      "post": {
        "responses": {
          "201": {
            "content": {
              "application/json": {
                "schema": {
                  "$ref": "#/components/schemas/PartsOrder"
                }
              }
            }
          }
        }
      }
    },
    "/parts-orders/{partsOrderId}": {
      "get": {
        "responses": {
          "200": {
            "content": {
              "application/json": {
                "schema": {
                  "$ref": "#/components/schemas/PartsOrder"
                }
              }
            }
          }
        }
      }
    }
  },
  "components": {
    "schemas": {
      "PartsOrder": {
        "type": "object",
        "properties": {
          "parts": {
            "type": "array",
            "items": {
              "$ref": "#/components/schemas/PartsOrderLine"
            }
          }
        }
      },
      "PartsOrderLine": {
        "type": "object",
        "properties": {
          "listPrice": {
            "allOf": [
              {
                "type": "string"
              }
            ]
          },
          "orderPrice": {
            "allOf": [
              {
                "$ref": "#/components/schemas/PartsOrderLine/properties/listPrice/allOf/0"
              }
            ]
          }
        }
      }
    }
  }
}

Swagger-UI configuration options:

import spec from '../../specs/parts-orders.json';
<SwaggerUI spec={spec} />

To reproduce…

Steps to reproduce the behavior:

1. Load this up in Create React App
2. See the resolver error

Expected behavior

The $ref resolves correctly.

[gavmck]

Thanks, that’s very helpful!

I have a call with the spec maintainers tomorrow so I’ll raise that as an issue.

[webron]

Of course. The reason why components exist in the spec is to enable (and encourage) reusability. A reference like $ref: '#/components/schemas/PartsOrderLine/properties/listPrice/allOf/0' suggests to me that the content of #/components/schemas/PartsOrderLine/properties/listPrice/allOf/0 should have been set it its own schema under components and referenced from both locations.

Referencing objects directly under their components section makes sense, but digging in deeper with a ref is something I’d consider a… code smell.