fix: correct OpenAPI schema for enum constraints (#2812)

[hzhou0]

Pull Request Checklist

• New code has 100% test coverage
• (If applicable) The prose documentation has been updated to reflect the changes introduced by this PR
• (If applicable) The reference documentation has been updated to reflect the changes introduced by this PR
• Pre-Commit Checks were ran and passed
• Tests were ran and passed

Description

• Fixes OpenAPI schema generation when enum constraints are present, such as in python Enums or Literal types.
  • The JSONSchema "type" constraint is now a list of all types present in the enum constraints, which is the specified schema expectation.
• Fixes tests to expect corrected behaviour.

Close Issue(s)

• Closes Bug: Incorrect OpenAPI Generated For Optional Literal Types #2812

[peterschutt]

Thanks for this! I'm out of time to review it for now, but will get to it ASAP, or someone else will. Are those type check failures issues with the way we have the properties typed on the spec models?

[peterschutt]

@all-contributors add @hzhou0 for bug and code

[allcontributors]

@peterschutt

I've put up a pull request to add @hzhou0! 🎉

[hzhou0]

Thanks for this! I'm out of time to review it for now, but will get to it ASAP, or someone else will. Are those type check failures issues with the way we have the properties typed on the spec models?

I fixed most of it, the problem is TYPE_MAP in schema.py. It has Schema values, which have type: OpenAPIType | Sequence[OpenAPIType] | None, however in that map it could be narrowed to type: OpenAPIType. I tried to typeguard, but not sure how to do that against Sequence types.

[cofin]

LGTM. Thanks @hzhou0

[github-actions]

Documentation preview will be available shortly at https://litestar-org.github.io/litestar-docs-preview/2818