Parser: YAML anchors & aliases depend on declaration order

[rdrey]

Hi

This following example works:

    swagger: '2.0'

    info:
      version: "0.0.1"
      title: API

    definitions:      
      OperationType:
        type: string
        enum: &OperationType
        - registration

    # Describe your paths here
    paths:
      /checker:
        get:
          parameters:
            - name: operations
              in: query
              type: array
              items:
                type: string
                enum: *OperationType
              default: [registration]
          responses:
            200:
              description: OK
              schema:
                $ref: '#/definitions/OperationType'

But if the order of paths: and definitions: is reversed, it results in the following error:

YAML Syntax Error
Unidentified alias "OperationType" at line 17, column 37: enum: *OperationType ^

This is probably an error in the YAML Parsing dependency, but I'm not sure.

Thanks!

[mohsen1]

Yes, in YAML you should define an alias before using it. If you put definitions after paths the OperationType anchor is used before being defined. I recommend defining all of your anchors on top under a free-form swagger extension

swagger: '2.0'

info:
  version: "0.0.1"
  title: API

x-types:
  OperationType: &OperationType
    - registration

# Describe your paths here
paths:
  /checker:
    get:
      parameters:
        - name: operations
          in: query
          type: array
          items:
            type: string
            enum: *OperationType
          default: [registration]
      responses:
        200:
          description: OK
          schema:
            $ref: '#/definitions/OperationType'

definitions:      
  OperationType:
    type: string
    enum: *OperationType

[rdrey]

Ah, thanks! I wasn't aware this was a YAML limitation (even though the examples I've found all declared the anchors first). Will follow your example and declare some lists up top.