Regression - OpenAPIGen breaks with String output examples

[russwyte]

Describe the bug
A recent PR #2714 seems to have broken OpenAPIGen when providing output examples for simple String output.

To Reproduce

        val endpoint = Endpoint(Method.GET / "simple/api/v1.0")
          .out[String]
          .examplesOut("a" -> "hello", "b" -> "world")
        val json     = toJsonAst(OpenAPIGen.fromEndpoints("String Endpoint", "1.0", endpoint))

Expected behaviour
This seems to be a regression - it worked before and I would expect it to work.

Screenshots

Desktop (please complete the following information):

• OS: [e.g. iOS]
• Browser [e.g. chrome, safari]
• Version [e.g. 22]

Smartphone (please complete the following information):

• Device: [e.g. iPhone6]
• OS: [e.g. iOS8.1]
• Browser [e.g. stock browser, safari]
• Version [e.g. 22]

Additional context
Add any other context about the problem here.

[russwyte]

If I add an explicit outCodec it seems to work - but this should not be required for a simple string.

        val endpoint = Endpoint(Method.GET / "simple/api/v1.0")
          .outCodec[String](HttpCodec.content(MediaType.text.plain))
          .examplesOut("a" -> "hello", "b" -> "world")

[987Nabil]

I can only assume one default value for the MediaType. And that is Json. We support text plain and protobuf by default as well. But OpenAPI picks Json first. You have to support the explicit MediaType, if you want to only support that one type.
But, this should imho not break the examples.

[russwyte]

That sounds sensible - but as you say - even if the MediaType is application/json those examples should be valid - and in fact they are handled without error up until the breaking commit.

[csgero]

I have the same issue with a scala 3 enum return value. It worked before RC7, but now it causes a similar exception:

java.lang.ClassCastException: class scala.util.Left cannot be cast to class com.ekata.emailInterpreter.domain.EmailAddressParseResult (scala.util.Left and com.ekata.emailInterpreter.domain.EmailAddressParseResult are in unnamed module of loader 'app')

It looks like the example value gets wrapped in a Left somewhere.

[csgero]

I think it's this change that's causing the error:
https://github.com/987Nabil/zio-http/blame/1fedb49fe7801a1a6f55333923a3c22944ad2bff/zio-http/shared/src/main/scala/zio/http/endpoint/Endpoint.scala#L387