[BUG] ClassCastException when casting UUIDs to strings

[gitrid]

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

I'm currently working on a project where I need to generate a Python client for the Allegro API. However, I'm encountering a ClassCastException when the generator tries to handle a UUID. It seems like the generator is trying to cast a UUID to a string, but it's failing. I've tried looking for solutions online, but haven't found anything that works yet. However, it is kind of similar to previous issue solved as marked: #15114

Error message:

Exception in thread "main" java.lang.RuntimeException: Could not process operation:
  Tag: class Tag {
    name: Advance Ship Notices
    description: null
    externalDocs: null
}
  Operation: deleteAdvanceShipNotice
  Resource: delete /fulfillment/advance-ship-notices/{id}
  Schemas: {BillingEntries=class ObjectSchema {
    class Schema {
(...)

}}
  Exception: class java.util.UUID cannot be cast to class java.lang.String (java.util.UUID and java.lang.String are in module java.base of loader 'bootstrap')
	at org.openapitools.codegen.DefaultGenerator.processOperation(DefaultGenerator.java:1225)
	at org.openapitools.codegen.DefaultGenerator.processPaths(DefaultGenerator.java:1120)
	at org.openapitools.codegen.DefaultGenerator.generateApis(DefaultGenerator.java:590)
	at org.openapitools.codegen.DefaultGenerator.generate(DefaultGenerator.java:953)
	at org.openapitools.codegen.cmd.Generate.execute(Generate.java:511)
	at org.openapitools.codegen.cmd.OpenApiGeneratorCommand.run(OpenApiGeneratorCommand.java:32)
	at org.openapitools.codegen.OpenAPIGenerator.main(OpenAPIGenerator.java:66)
Caused by: java.lang.ClassCastException: class java.util.UUID cannot be cast to class java.lang.String (java.util.UUID and java.lang.String are in module java.base of loader 'bootstrap')
	at org.openapitools.codegen.languages.AbstractPythonCodegen.toDefaultValue(AbstractPythonCodegen.java:185)
	at org.openapitools.codegen.DefaultCodegen.toDefaultValue(DefaultCodegen.java:2261)
	at org.openapitools.codegen.DefaultCodegen.fromProperty(DefaultCodegen.java:4129)
	at org.openapitools.codegen.DefaultCodegen.fromProperty(DefaultCodegen.java:3841)
	at org.openapitools.codegen.DefaultCodegen.fromParameter(DefaultCodegen.java:5116)
	at org.openapitools.codegen.DefaultCodegen.fromOperation(DefaultCodegen.java:4636)
	at org.openapitools.codegen.DefaultGenerator.processOperation(DefaultGenerator.java:1193)
	... 6 more

openapi-generator version

7.0.0

OpenAPI declaration file content or url

https://developer.allegro.pl/swagger.yaml

Relevant part causing error:

/fulfillment/advance-ship-notices/{id}/labels:
  get:
    summary: 'Get labels for Advance Ship Notice'
    description: 'Use this resource to get labels for Advance Ship Notice after being created with "create labels command".'
    tags:
      - Advance Ship Notices
    operationId: getAdvanceShipNoticeLabels
    parameters:
      - name: id
        in: path
        description: An identifier of the Advance Ship Notice.
        required: true
        schema:
          type: string
          format: uuid
        example: 84529ad2-2265-4e15-b76b-c17025d848f6
      - name: accept
        in: header
        description: Content-type of generated labels
        required: true
        schema:
          type: string
          enum:
            - application/pdf
            - x-application/zpl

Generation Details

openapi-generator-cli generate -g python -i https://developer.allegro.pl/swagger.yaml -o /home/user/client

Steps to reproduce

openapi-generator-cli generate -g python -i https://developer.allegro.pl/swagger.yaml -o /home/user/client

Related issues/PRs

(#15114)

Suggest a fix

[gitrid]

I can confirm that downgrading to 6.6.0 solved the issue.

[wing328]

@gitrid thanks for reporting the issue, which has been fixed via #16432