[BUG][Python] readOnly property inside of allOf causes "The input data was invalid for the allOf schema"

[mfmarche]

Bug Report Checklist

• Have you provided a full/minimal spec to reproduce the issue?
• Have you validated the input using an OpenAPI validator (example)?
• Have you tested with the latest master to confirm the issue still exists?
• Have you searched for related issues/PRs?
• What's the actual output vs expected output?
• [Optional] Sponsorship to speed up the bug fix or feature request (example)

Description

This is related specifically to the python generator.

Here is an example schema:

openapi-generator version

master

OpenAPI declaration file content or url

openapi: 3.0.0
info:
  title: Sample test
  version: '2.0'
paths:
  /v2/projects:
    post:
      operationId: sample_post
      summary: sample
      tags:
        - Samplek
      requestBody:
        required: true
        content:
          application/json:
            schema:
              $ref: '#/components/schemas/parent'
      responses:
        '200':
          description: OK
components:
  schemas:
    parent:
      allOf:
        - $ref: '#/components/schemas/child'
    child:
      type: object
      properties:
        test_readonly:
          type: string
          readOnly: true
          example: 4e1bfbc3

Generation Details

java -jar openapi-generator-cli.jar generate -i test.yaml -g python

Steps to reproduce

from openapi_client.model import parent
parent.Parent._from_openapi_data(test_readonly="foobar")
<snip>
openapi_client.exceptions.ApiValueError: Invalid inputs given to generate an instance of 'Child'. The input data was invalid for the allOf schema 'Child' in the composed schema 'Parent'. Error=`test_readonly` is a read-only attribute. Use `from_openapi_data` to instantiate class with read only attributes.

Related issues/PRs

Suggest a fix

I made a quick fix to model_utils.mustache as follows:

mfmarche@eb28082#diff-5378d085f86e7e92f3e0044670bce659d30efdfe1f0c31a502b5da22ba6e2070R1458

But likely inappropriate since it now always calls from_openapi_data, but rather it should likely use either__init_ or _from_openapi_data depending on the caller.

[spacether]

Yes it should definitely call either __init__ or _from_openapi_data depending on the calling context

[languitar]

Does anyone know when this issue was introduced?

[languitar]

Ah, with 5.2.0. This is a serious blocker for using 5.2.0 when generating Python clients. Any chance to get this fixed?

[mfmarche]

#9735 has a fix for this that should address this issue. That fix is currently in review and fixes are pending.

[spacether]

Fixed per PR