XML example generator crashes if "example" contains an unknown property name

[hkosova]

Q&A (please complete the following information)

• OS: Windows 10
• Browser: Chrome latest
• Method of installation: dist assets
• Swagger-UI version: 3.39.0
• Swagger/OpenAPI version: OpenAPI 3.0 (I didn't check OAS2 but it may also be affected by this issue)

Content & configuration

Example Swagger/OpenAPI definition:

openapi: 3.0.3
info:
  title: XML examples
  version: 1.0.0
paths:
  /foo:
    get:
      responses:
        '200':
          description: ok
          content:
            application/xml:
              schema:
                $ref: '#/components/schemas/MyObject'
        '201':
          description: ok
          content:
            application/xml:
              schema:
                $ref: '#/components/schemas/MyArray'

components:
  schemas:
    MyObject:
      type: object
      properties:
        id:
          type: integer
        foo:
          type: string
      example:
        id: 5
        foos: value    # <--- "foos" not "foo"

    MyArray:
      type: array
      items:
        type: object
        properties:
          id:
            type: integer
          foo:
            type: object
            properties:
              bar:
                type: string
      example:
        - id: 5
          foo:
            bars: value    # <--- "bars" not "bar"

Describe the bug you're encountering

If a schema-level example contains a property not defined in schema properties (e.g. if the property name is misspelled), then the XML example generator crashes.

Note: An unknown property name in examples is NOT an error. For example, schemas without additionalProperties: false allow arbitrary extra properties.

Expected behavior

XML example generator should not crash.

As for handling unknown properties, either:

• display schema-level examples as is, including unknown properties
  or
• ignore (exclude) unknown properties when generating XML examples

Screenshots

Additional context or thoughts

In v. 3.35.2, XML example generator didn't crash, it ignored unknown properties.