fix: enumName is ignored in @Api[Param|Query|Header]

[lucas-gregoire]

PR Checklist

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• The commit message follows our guidelines: https://github.com/nestjs/nest/blob/master/CONTRIBUTING.md
• Tests for the changes have been added (for bug fixes / features)
• Docs have been added / updated (for bug fixes / features)
  => Documentation is already describing the correct expected behavior: https://docs.nestjs.com/openapi/types-and-parameters#enums-schema:

PR Type

What kind of change does this PR introduce?

• Bugfix
• Feature
• Code style update (formatting, local variables)
• Refactoring (no functional changes, no api changes)
• Build related changes
• CI related changes
• Other... Please describe:

What is the current behavior?

Using enumName in @Api[Param|Query|Header] is not making a reference to the enum model in the Openapi specification.

=>

When removing @Param('type') type: LettersEnum, the enum is correctly referenced:

The expected behavior should be like this last screen in both cases (with or without a param in the method).

What is the new behavior?

In SchemaObjectFactory.createFromModel, when we get a primitive type infered from method parameter metadata, it skips the call of createEnumParam which handles enums references via $ref.

Calling it before isPrimitiveType did the job.
BTW, I also improved the implementation of ApiParam to make it look like more like ApiQuery by using addEnumSchema

Does this PR introduce a breaking change?

• Yes
• No

Other information

[lucas-gregoire]

Hello @kamilmysliwiec, would it be possible to merge this PR please ?

[kamilmysliwiec]

LGTM