XML rendering for array-level examples uses duplicates of the 1st array item

[hkosova]

Q	A
Bug or feature request?	Bug
Which Swagger/OpenAPI version?	2.0, 3.0
Which Swagger-UI version?	3.4.0
How did you install Swagger-UI?	http://editor.swagger.io
Which browser & version?	Chrome 62
Which operating system?	Windows 7

Demonstration API definition

2.0:

swagger: '2.0'
info:
  title: test
  version: 0.0.0

paths:
  /:
    get:
      produces: 
        - application/xml
        - application/json
      responses:
        200:
          description: OK
          schema:
            $ref: '#/definitions/Users'

definitions:
  Users:
    type: array
    items:
      $ref: '#/definitions/User'
    xml:
      name: users
      wrapped: true
    example:
      - id: 1
        name: Arthur Dent
      - id: 2
        name: Ford Prefect
  User:
    type: object
    properties:
      id:
        type: integer
      name:
        type: string
    xml:
      name: user

3.0:

openapi: 3.0.0
info:
  title: test
  version: 0.0.0

paths:
  /:
    get:
      responses:
        '200':
          description: OK
          content:
            application/xml:
              schema:
                $ref: '#/components/schemas/Users'
            application/json:
              schema:
                $ref: '#/components/schemas/Users'

components:
  schemas:
    Users:
      type: array
      items:
        $ref: '#/components/schemas/User'
      xml:
        name: users
        wrapped: true
      example:
        - id: 1
          name: Arthur Dent
        - id: 2
          name: Ford Prefect
    User:
      type: object
      properties:
        id:
          type: integer
        name:
          type: string
      xml:
        name: user

Expected Behavior

XML response example consists of the items specified in the array example:

<?xml version="1.0" encoding="UTF-8"?>
<users>
	<user>
		<id>1</id>
		<name>Arthur Dent</name>
	</user>
	<user>
		<id>2</id>
		<name>Ford Prefect</name>
	</user>
</users>

Current Behavior

XML response example contains duplicates of the 1st array item:

<?xml version="1.0" encoding="UTF-8"?>
<users>
	<user>
		<id>1</id>
		<name>Arthur Dent</name>
	</user>
	<user>
		<id>1</id>
		<name>Arthur Dent</name>   <!-- Should be id=2, name="Ford Prefect" -->
	</user>
</users>

Context

Array-level examples are rendered correctly in JSON. This issue applies to XML rendering only.

[shockey]

Some notes on this:

sampleXmlFromSchema is getting tripped up... here's what schema is being passed around through the recursive calls to it.

// 1. Top level object, nothing to see here
{ type: 'array',
  items:
   { type: 'object',
     properties: { id: [Object], name: [Object] },
     xml: { name: 'user' } },
  xml: { name: 'users', wrapped: true },
  example:
   [ { id: 1, name: 'Arthur Dent' },
     { id: 2, name: 'Ford Prefect' } ] }


// 2. Correctly drill into the first array item in the example
{ type: 'object',
  properties: { id: { type: 'integer' }, name: { type: 'string' } },
  xml: { name: 'user' },
  example: { id: 1, name: 'Arthur Dent' } }


// 3. Correctly project subschema-level examples onto the property
{ type: 'integer', xml: { name: 'id' }, example: 1 }


// 3. Correctly project subschema-level examples onto the second property
{ type: 'string', xml: { name: 'name' }, example: 'Arthur Dent' }


// 4. Now we're back up at the same level as (2), processing the other array entry
// You can see the problem here: the subschema property-level example projections
// have stuck around.
{ type: 'object',
  properties:
   { id: { type: 'integer', xml: [Object], example: 1 },
     name: { type: 'string', xml: [Object], example: 'Arthur Dent' } },
  xml: { name: 'user' },
  example: { id: 2, name: 'Ford Prefect' } }


// 5. The presence of the property-level examples override the correct subschema-level 
// example you see immediately above.
{ type: 'integer', xml: { name: 'id' }, example: 1 }


// 6. And so on....
{ type: 'string', xml: { name: 'name' }, example: 'Arthur Dent' }