Regression: OAS2 response examples are not displayed if response has no schema

[hkosova]

Issue #5458 reappeared in v. 3.36.2.

Q&A (please complete the following information)

• OS: Windows 10
• Browser: Chrome, Firefox (latest)
• Method of installation: https://editor.swagger.io
• Swagger-UI version: 3.36.2
• Swagger/OpenAPI version: 2.0

Content & configuration

Example Swagger/OpenAPI definition:

swagger: "2.0"
info:
  title: OAS2 response examples
  version: 1.0.0
produces:
  - application/json
paths:
  /foo1:
    get:
      summary: Response without a schema
      responses:
        200:
          description: Successful response
          examples:
            application/json:
              foo: custom value
  /foo2:
    get:
      summary: Response with schema
      responses:
        200:
          description: Successful response
          schema:
            $ref: '#/definitions/Foo'
          examples:
            application/json:
              foo: custom value

definitions:
  Foo:
    type: object
    properties:
      foo:
        type: string
        example: bar

Describe the bug you're encountering

v. 3.36.2 has a regression where OAS2 response examples are not displayed if the response does not have a schema defined. Previous versions of Swagger UI rendered the response examples in this case.

Expected behavior

Both GET ​/foo1 and GET /foo2 should display the same response example:

{
  "foo": "custom value"
}

Actual behavior

GET ​/foo1 does NOT display a response example. But if you add schema: {} to its /foo1's response then the example appears.

Workaround

Add a schema for responses that have examples. Even an empty schema schema: {} will work.

[tim-lai]

@hkosova I am unable to reproduce the issue as described with the provided definition. When loaded into editor.swagger.io, both endpoints display

{
  "foo": "custom value"
}

However, I do observe an issue of updating. If the example in/foo1 (without schema) is updated in the editor, swagger-ui does not re-render and display the updated value. However, the example in /foo2 does display the updated value.

[hkosova]

@tim-lai you're right, it must have happened during editor updates. Is this a UI issue or editor issue then?

Steps to reproduce:

1. Paste this spec into editor:

swagger: "2.0"
info:
  title: OAS2 response examples
  version: 1.0.0
produces:
  - application/json
paths:
  /foo1:
    get:
      summary: Response without a schema
      responses:
        200:
          description: Successful response

  /foo2:
    get:
      summary: Response with schema
      responses:
        200:
          description: Successful response
          schema: {}
          examples:
            application/json:
              foo: custom value

2. In the UI panel, expand both operations.
3. Copy examples (but not schema) from the second operation's response to the first operation's response.

Expected result: First operation should display newly added response example.

Actual result: Newly added example is not displayed.

[tim-lai]

Pretty sure this is a swagger-ui issue.

[tim-lai]

Yup, it's swagger-ui. I can see that the res value doesn't always reflect incoming arguments to memoizedSampleFromSchema.

swagger-ui/src/core/utils.js

Line 570 in 24225e4

const res = memoizedSampleFromSchema(schema, config, exampleOverride)