[BUG][Python] UUID properties with default values trigger ClassCastException

[alexras]

Bug Report Checklist

• Have you provided a full/minimal spec to reproduce the issue?
• Have you validated the input using an OpenAPI validator (example)?
• What's the version of OpenAPI Generator used?
• Have you search for related issues/PRs?
• What's the actual output vs expected output?
• [Optional] Bounty to sponsor the fix (example)

Description

If I define a schema that has a UUID property, and that property has a default value, the Python code generator throws a ClassCastException.

openapi-generator version

4.0.3

OpenAPI declaration file content or url

---
components:
  schemas:
    MyModel:
      properties:
        id:
          default: "00000000-0000-4000-8000-000000000000"
          format: uuid
          type: string
      title: MyModel
      type: object

info:
  title: 'My API'
  version: 0.1.0dev

openapi: 3.0.2

paths: {}

Command line used for generation

docker run --rm -v ${PWD}:/local --env 'PYTHON_POST_PROCESS_FILE="/usr/local/bin/yapf -i"' openapitools/openapi-generator-cli:v4.0.3 generate -i /local/swagger.yml -g python -o /local/build

Steps to reproduce

Run the generator with the above declaration file; it will throw an exception that looks like this:

Exception in thread "main" java.lang.RuntimeException: Could not process model 'MyModel'.Please make sure that your schema is correct!
        at org.openapitools.codegen.DefaultGenerator.generateModels(DefaultGenerator.java:470)
        at org.openapitools.codegen.DefaultGenerator.generate(DefaultGenerator.java:920)
        at org.openapitools.codegen.cmd.Generate.run(Generate.java:396)
        at org.openapitools.codegen.OpenAPIGenerator.main(OpenAPIGenerator.java:60)
Caused by: java.lang.ClassCastException: java.util.UUID cannot be cast to java.lang.String
        at org.openapitools.codegen.languages.PythonClientCodegen.toDefaultValue(PythonClientCodegen.java:643)
        at org.openapitools.codegen.DefaultCodegen.fromProperty(DefaultCodegen.java:1981)
        at org.openapitools.codegen.DefaultCodegen.addVars(DefaultCodegen.java:3627)
        at org.openapitools.codegen.DefaultCodegen.addVars(DefaultCodegen.java:3575)
        at org.openapitools.codegen.DefaultCodegen.fromModel(DefaultCodegen.java:1845)
        at org.openapitools.codegen.DefaultGenerator.processModels(DefaultGenerator.java:1197)
        at org.openapitools.codegen.DefaultGenerator.generateModels(DefaultGenerator.java:465)
        ... 3 more

If you remove the default and run the generator again, code generation will succeed.

Related issues/PRs

#2209 - similar exception, with a different cause.

Suggest a fix

Rather than just casting to a string, perhaps just calling p.getDefault().toString() would work.

[auto-labeler]

👍 Thanks for opening this issue!
🏷 I have applied any labels matching special text in your issue.

The team will review the labels and make any necessary changes.

[Briggybros]

This is not specific to the python generator. I'm seeing the same problem in java, typescript-fetch, and typescript-axios.

[black-snow]

I second this. Trying to generate code for java. Models are being created but then it breaks with

Cause: 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')

/edit: runs fine when I comment all the format: uuid lines

[ccampanale]

This is still an issue with typescript and typescript-axios generators.

[spacether]

We welcome a PR to fix this issue if anyone wants to file it