additionalProperties==false produces unexpected behavior when used with definitions

[dreftymac]

Problem

• Using additionalProperties seems to omit acceptance of declared properties when those properties are declared in a definitions section

Expected behavior

• The additionalProperties setting should not behave differently depending on whether properties are declared in a definitions section

Actual behavior

• The additionalProperties setting behaves differently depending on whether properties are declared in a definitions section
• In the example below, the schema that avoids the use of definitions behaves as expected when additionalProperties == false
• In the example below, the schema that uses definitions behaves unexpectedly additionalProperties == false ... the error message is Additional properties are not allowed

Example

Sample schema (avoiding use of definitions and YAML-formatted)

  additionalProperties:   false
  type:             object
  required:         ["fname", "lname", "age"]
  properties:
    fname:          { type: string  }
    lname:          { type: string  }
    age:            { type: integer }

Sample schema (using definitions and YAML-formatted)

  additionalProperties:   false
  allOf:
    - {"$ref": "#/definitions/contactinfo_001"}
  definitions:
    contactinfo_001:
      type:             object
      required:         ["fname", "lname", "age"]
      properties:
        fname:          { type: string  }
        lname:          { type: string  }
        age:            { type: integer }

Sample documents

  # ## ********************
  ## NO__WORKY -- age must be integer
  -
    fname:            homer
    lname:            himpson
    age:              '33'

  ## ********************
  ## NO__WORKY -- age is required
  -
    fname:            homer
    lname:            himpson

  ## ********************
  ## YES_WORKY -- all expected properties
  -
    fname:            homer
    lname:            himpson
    age:              33

  ## ********************
  ## additional property 'motto' (affected by additionalProperties)
  -
    fname:            homer
    lname:            himpson
    age:              33
    motto:            i love science

[Julian]

Hi, thanks.

This is the behavior specified by the spec for better or worse.

Many run into this same issue, which I believe is being addressed in part in draft 8, but yeah, nothing really here for this library to do at the minute.

[dreftymac]

Got it. Thanks for the heads-up. Any references or links to the specification greatly appreciated, by anyone who may come across this issue, before it is closed.

Thanks again.

[handrews]

@dreftymac you are looking for draft-08's unevaluatedProperties: json-schema-org/json-schema-spec#656 (although note that there were several other changes laying the groundwork for how that keywords functions, as it's much more complicated than you'd think to make this work).

[Julian]

(thanks for the ref @handrews)