nullable elements handled incorrectly in string arrays

[heinen]

Description

If nullable is used to specifiy that a single string element can be zero, it works. However, if the type is 'array' and nullable is used in the items, None/null is implicitly converted to the string 'None'. With numeric values, everything works fine

Expected behaviour

If single string elements can be nullable, so should be array elements

Actual behaviour

They're not

Steps to reproduce

Using this api.yaml:

openapi: 3.0.0
info:
  description: debug
  version: '1.0'
  title: Debug
servers:
  - url: 'http://127.0.0.1:9191/v1'
paths:
  /predict:
    post:
      operationId: debug.loaded_predict
      responses:
        '200':
          description: OK
      requestBody:
        content:
          application/json:
            schema:
              x-body-name: some_element
              $ref: '#/components/schemas/some_element'
components:
  schemas:
    some_element:
      type: object
      properties:
        some_property:
          type: array
          items:
            type: string
            nullable: true

Now, when

import requests
r = requests.post("http://127.0.0.1:9191/v1/predict", json={'some_property': ['some string', None]})

is used, the value of some_element will be {'some_property': ['some string', 'None']}, which is wrong.

Additional info:

Has also been tested with curl to make sure this isn't a requests problem

Output of the commands:

• python --version: Python 3.6.7 :: Anaconda custom (64-bit)
• pip show connexion | grep "^Version\:": Version 2.2.0

[heinen]

I continued with a workaround but found another, probably correlated, issue: If you have an array of type integer, it seems to be impossible to make them nullable altogether. In the above example, just change the type to integer and try finding any request with nulled elements that goes trough. If numpy.nan is passed as an element in the array (which will be converted to NaN in the request json), the response will be 400 - nan is not of type 'integer'. If None is passed via requests.post (which will be converted to null), the response will be 500 - The server encountered an internal error with the console showing TypeError: int() argument must be a string, a bytes-like object or a number, not 'NoneType'. Do you want me to open another issue for this or do you think that the two problems have the same underlying cause?

[mathi123]

Same problem here. Have you found a workaround for this?

[mathi123]

For future reference, You can define an array of (nullable) integers like this:

          value:
          type: array
          items:
            oneOf:
              - type: string
                nullable: true
              - type: number

Its not 100% perfect, but the api won't block if it encounters a None in the array.

[RobbeSneyders]

This is fixed in version 3.