$ref resolution may fail.

[hogegex]

Q&A (please complete the following information)

• OS: Windows 10 22H2
• Browser: Chrome
• Version: 131.0.6778.86
• Method of installation: Docker Image (swaggerapi/swagger-ui:v5.18.2)
• Swagger-UI version: v5.18.2
• Swagger/OpenAPI version: OpenAPI 3.0.3

Content & configuration

Example Swagger/OpenAPI definition:

openapi: 3.0.3
info:
  title: SomeWebAPI
  version: 1.0.0
servers:
  - url: "https://example.com/v1"
paths:
  /endpoint:
    get:
      description: Description
      responses:
        "422":
          description: Error
          content:
            application/json:
              schema:
                $ref: "#/components/responses/SomeResponse/content/application~1json/schema/allOf/0"
    post:
      description: Description
      requestBody:
        description: Description
        content:
          application/json:
            schema:
              $ref: "#/components/schemas/SomeRequest"
      responses:
        "404":
          $ref: "#/components/responses/SomeResponse"
components:
  schemas:
    SomeRequest:
      type: object
  responses:
    SomeResponse:
      description: Description
      content:
        application/json:
          schema:
            allOf:
              - type: object
              - type: object

Swagger-UI configuration options: Docker image default

Describe the bug you're encountering

The following error appears at the top of the Swagger UI page:

Errors
 
Resolver error at paths./endpoint.get.responses.422.content.application/json.schema.$ref
Could not resolve reference: Could not resolve pointer: /components/responses/SomeResponse/content/application~1json/schema/allOf/0 does not exist in document

Also, the schema is not loaded and the path of the reference is displayed instead.

To reproduce...

Steps to reproduce the behavior:

1. Save the above OpenAPI yaml as openapi.yaml.

2. Start Swagger UI with the following command:

   docker run -v <PATH_TO_LOCAL_OPENAPI_YAML>:/openapi.yaml -e SWAGGER_JSON=/openapi.yaml -p 8002:8080 --rm swaggerapi/swagger-ui:v5.18.2

3. Access http://localhost:8002 in your browser.

4. Open the endpoint definitions POST /endpoint -> GET /endpoint.

5. See error

Expected behavior

No errors occur and the schema loads.

Screenshots

N/A

Additional context or thoughts

• If I change the order of opening the endpoint definitions to GET /endpoint -> POST /endpoint, the error does not occur.

  This issue seems to depend on the order of operations in the UI.

• This issue also occurred on https://editor.swagger.io/.