Readonly-required properties are being marked as breaking changes

[gssbzn]

Describe the bug
Oasdiff ignores readOnly: true for required fields marking them as breaking changes when they are not

To Reproduce
Steps to reproduce the behavior:
base example

openapi: 3.0.1
info:  
  version: "1.0"
servers:
- url: https://localhost:9080
paths:
  /api/v1.0/groups:    
    post:     
      operationId: createOneGroup
      requestBody:
        content:
          application/json:
            schema:
              $ref: '#/components/schemas/GroupView'
        description: Creates one project.
        required: true
      responses:
        "200":
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/GroupView'
          description: OK        
      summary: Create One Project
  /api/v1.0/groups/{groupId}:
    get:      
      operationId: returnOneGroup
      parameters:      
      - $ref: '#/components/parameters/groupId'      
      responses:
        "200":
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/GroupView'
          description: OK
      summary: Return One Project
components:
  parameters:
    groupId:      
      in: path
      name: groupId
      required: true
      schema:
        type: string        
  schemas:
    GroupView:
      type: object
      properties:        
        created:
          type: string
          format: date-time          
          readOnly: true
        id:
          type: string          
          readOnly: true        
        name:
          type: string                  
      required:    
      - name

revision example

openapi: 3.0.1
info:  
  version: "1.0"
servers:
- url: https://localhost:9080
paths:
  /api/v1.0/groups:    
    post:     
      operationId: createOneGroup
      requestBody:
        content:
          application/json:
            schema:
              $ref: '#/components/schemas/GroupView'
        description: Creates one project.
        required: true
      responses:
        "200":
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/GroupView'
          description: OK        
      summary: Create One Project
  /api/v1.0/groups/{groupId}:
    get:      
      operationId: returnOneGroup
      parameters:      
      - $ref: '#/components/parameters/groupId'      
      responses:
        "200":
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/GroupView'
          description: OK
      summary: Return One Project
components:
  parameters:
    groupId:      
      in: path
      name: groupId
      required: true
      schema:
        type: string        
  schemas:
    GroupView:
      type: object
      properties:        
        created:
          type: string
          format: date-time          
          readOnly: true
        id:
          type: string          
          readOnly: true        
        name:
          type: string                  
      required:    
      - name
      - created
      - id

1. Run oasdiff -breaking-only -base base.yaml -revision revision.yaml
2. Receive

    modified:
        ?   method: POST
            path: /api/atlas/v1.0/groups
        :   requestBody:
                content:
                    mediaTypeModified:
                        application/json:
                            schema:
                                required:
                                    stringsdiff:
                                        added:
                                            - id
                                            - created

Expected behavior
It should not be a diff for POST, only GET and not a breaking change

Screenshots
redocly safely ignores read_only fields

Desktop (please complete the following information):

• OS: macOS
• Version 1.1.39

Additional context
From the OAS definition

Relevant only for Schema "properties" definitions. Declares the property as "read only". This means that it MAY be sent as part of a response but SHOULD NOT be sent as part of the request. If the property is marked as readOnly being true and is in the required list, the required will take effect on the response only. A property MUST NOT be marked as both readOnly and writeOnly being true. Default value is false.

[gssbzn]

If we agree this is a bug to be fixed I'm happy to take some time to look into possible fixes

[reuvenharrison]

Hi Gustavo,
I agree with your assessment.
Please go ahead with a fix and let me know if you have any questions.
Thanks,
Reuven