[BUG][Python] Reference to schema property produces undefined types

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?
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Description

Given Robocorp API the generated response models contain undefined types coming from pagination_details.PaginationDetails like HasMore and Next.
E.g. list_processes200_response.py:

class ListProcesses200Response(BaseModel):
    """
    ListProcesses200Response
    """
    next: Next = Field(...)
    has_more: HasMore = Field(...)
    data: conlist(ListProcesses200ResponseDataInner) = Field(...)
    __properties = ["next", "has_more", "data"]

where there's no resource created for these Next and HasMore (non existing model classes), and the only reference of them I found in the pagination_details.py model as attributes.

openapi-generator version

7.0.1, 8.0.0-SNAPSHOT, 7.1.0-SNAPSHOT

OpenAPI declaration file content or url

--> https://robocorp.com/api/openapi.json

Generation Details

% openapi-generator-cli generate -g python -i https://robocorp.com/api/openapi.json -c openapiconf.yaml --skip-validate-spec -o src -t templates

openapiconf.yaml:

generateSourceCodeOnly: true
packageName: robocorp.workspace
packageUrl: https://github.com/robocorp/robo/
packageVersion: 0.1.0
projectName: robocorp-workspace

Generated source.

Steps to reproduce

Just run the command above and look into the models using these pagination properties: HasMore, Next.

Related issues/PRs

Couldn't find one.

Suggest a fix

The problem can be solved in multiple ways:

• A. The codegen detects that these properties are coming from a shared resource and the models including them (has_more, next) should include and use the parent resource actually, through pagination_details attribute taking pagination_details.PaginationDetails as type. (maybe it works out of the box if the OpenAPI schema will return such a resource instead of the props alone)
• B. The codegen generates such individual models for properties from PaginationDetails like HasMore and Next so these can be imported and used by the models as they are.
• C. The codegen will simply detect references to schema properties and will just use primitive types as it should. (see structure below)

Property references from a common shared schema:

"properties": {
                                        "next": {
                                            "$ref": "#/components/schemas/paginationDetails/properties/next"
                                        },
                                        "has_more": {
                                            "$ref": "#/components/schemas/paginationDetails/properties/has_more"
                                        },
                                        "data": {
                                            "type": "array",
                                            "items": {
                                                "$ref": "#/components/schemas/WorkerGroupResource"
                                            }
                                        }
                                    }

The schema:

"paginationDetails": {
                "type": "object",
                "required": [
                    "next",
                    "has_more"
                ],
                "properties": {
                    "next": {
                        "type": "string",
                        "description": "The full URL to access the next set of results. Null if there are no next set of results.",
                        "nullable": true,
                        "format": "url"
                    },
                    "has_more": {
                        "type": "boolean",
                        "description": "Whether or not there are more elements available after this set. If false, this set comprises the end of the list."
                    }
                }
            }

Expecting to get something like this in every model referencing them:

class PaginationDetails(BaseModel):
    """
    PaginationDetails
    """
    next: Optional[StrictStr] = Field(description="The full URL to access the next set of results. Null if there are no next set of results.")
    has_more: StrictBool = Field(description="Whether or not there are more elements available after this set. If false, this set comprises the end of the list.")
    __properties: ClassVar[List[str]] = ["next", "has_more"]

Reproduce the issue with the provided openapi-generator-cli command and https://robocorp.com/api/openapi.json. Inspect the generated list_processes200_response.py and pagination_details.py models, focusing on references to paginationDetails/properties/next and has_more. Done means generated Python models use the referenced primitive types instead of undefined Next and HasMore classes.