Error: "nullable" cannot be used without "type"

[roma0297]

I'm generating the following yaml spec file with openapi 3.0.0 from my kotlin backend:

    Request:
      required:
      - field1
      - field2
      - field3
      type: object
      properties:
        field1:
          type: string
        field2:
          type: string
          format: date-time
        field3:
          type: string
        field4:
          allOf:
          - $ref: '#/components/schemas/RequestVehicleConfiguration'
          - nullable: true

The interesting part here is this field4 which may be a nulllable reference.

After that I try to write a test and mock this API:

  const api = new OpenAPIBackend({ definition: this.spec });
  // Register some handlers
  api.init()

Expected behaviour: Api is initialized

Actual behaviour: Error: "nullable" cannot be used without "type"

What I tried so far:

• Tried to use openapi-backend 4.1.0 and 4.2.0

I tried to replace

      field4:
        allOf:
        - $ref: '#/components/schemas/RequestVehicleConfiguration'
        - nullable: true

with

        vehicleConfiguration:
          $ref: '#/components/schemas/RequestVehicleConfiguration'

And it helps but I don't won't to do it manually, I would like to rely on automatic schema generation. Any ideas what I'm doing wrong? As far as I understand the schema is valid, why I cannot generate an API mock from it?

[jaecktec]

Just dropping this here:

https://github.com/OAI/OpenAPI-Specification/issues/1368

Might be a feature 'support openapi 3.1'

[robogeek]

FWIW - I'm using OpenAPI Backend to implement an application using a spec developed by a standards organization. They recently switched to using nullable: true, for which I'm getting this sort of error:

/Volumes/Evoke/esx-server/server/node_modules/ajv/lib/compile/validate/dataType.ts:26
      throw new Error('"nullable" cannot be used without "type"')
            ^
Error: "nullable" cannot be used without "type"
    at getSchemaTypes (/Volumes/Evoke/esx-server/server/node_modules/ajv/lib/compile/validate/dataType.ts:26:13)
    at typeAndKeywords (/Volumes/Evoke/esx-server/server/node_modules/ajv/lib/compile/validate/index.ts:159:31)
    at subSchemaObjCode (/Volumes/Evoke/esx-server/server/node_modules/ajv/lib/compile/validate/index.ts:147:3)
    at subschemaCode (/Volumes/Evoke/esx-server/server/node_modules/ajv/lib/compile/validate/index.ts:124:7)
    at KeywordCxt.subschema (/Volumes/Evoke/esx-server/server/node_modules/ajv/lib/compile/validate/index.ts:500:5)
    at applyPropertySchema (/Volumes/Evoke/esx-server/server/node_modules/ajv/lib/vocabularies/applicator/properties.ts:45:11)
    at Object.code (/Volumes/Evoke/esx-server/server/node_modules/ajv/lib/vocabularies/applicator/properties.ts:32:9)
    at keywordCode (/Volumes/Evoke/esx-server/server/node_modules/ajv/lib/compile/validate/index.ts:532:9)
    at /Volumes/Evoke/esx-server/server/node_modules/ajv/lib/compile/validate/index.ts:265:9
    at CodeGen.code (/Volumes/Evoke/esx-server/server/node_modules/ajv/lib/compile/codegen/index.ts:525:33)

Commenting out all uses of nullable: true fixed the problem. I see the link provided by @jaecktec but in this case it is not associated with $ref uses.

Some examples:

        x:
          type: number
          format: float
          description: A value on an x axis.
          example: 1.0
          # nullable: true
          default: null

        targets:
          type: array
          description: An list of target objects.
          # nullable: true
          default: null
          items:
            $ref: '#/components/schemas/target'

    userIdentifier:
        oneOf: [
          {type: integer},
          {type: string}
        ]
        description: User generated numeric or string identifier
        example: 99
        # nullable: true
        default: null

        programDescriptions:
          type: array
          description: A list of programDescriptions
          # nullable: true
          default: null
          items:
            required:
              - URL
            properties:
              URL:
                type: string
                # format: uri
                description: a human or machine readable program description
                example: www.myCorporation.com/myProgramDescription

The last one also demonstrates another unrelated issue - that format: uri is not recognized.