codegen: Improve enum support

[hughsimpson]

Various improvements to enum support in codegen:

• Supports enum serdes for zio-json (scala 2.x only)
• Supports inline enum definitions (on both paths and schemas)
• Supports Option[Enum], List[Enum], and Option[List[Enum]]* query params
• Supports a wider range of enum values

* Note that Option[List[T]] is only supported for unexploded params -- for exploded params, there's no distinction betwen an empty list and an absent value; so the required field will be ignored for exploded query params.

Also adds some support for explode on query params; will now default to explode = true (as per the spec), but also supports explode = false. It still only supports arrays in form style for now.

Since the generator runs with scala 2.12 and does not have access to sttp.tapir.model.CommaSeparated I've had to implement case class CommaSeparatedValues and case class ExplodedValues in the generated files, which is a shame, but should be okay...

[hughsimpson]

Bumping sbt fixes sbt scripted on Java 18+

[hughsimpson]

Sorry this pr conflates a few things together, but I didn't have the energy to split it out only to resolve conflicts down the line.. I think it represents a decent improvement, though, and hopefully none of the functionality is really contentious.

[kciesielski]

Impressive! A few nitpick comments so far, I'll finish the review later today or tomorrow.

[hughsimpson]

Thanks for the comments 🙏 all very sensible suggestions (especially around that Seq[(Option[String], Seq[(String, String, Option[String])])] 😬 -- took me a few mins to unpick that myself 😅). Have pushed up some fixes to address them

[hughsimpson]

Test failure seems to be... not sure exactly. It ends with

2024-06-22T14:01:01.9474905Z �[0m[�[0m�[0minfo�[0m] �[0m�[0m�[32mAll tests passed.�[0m�[0m
2024-06-22T14:12:30.0226099Z �[34mclientTestServer�[0m ... killing ...
2024-06-22T14:12:40.0077417Z ##[error]Final attempt failed. Timeout of 900000ms hit

-- clientTestServer seems to be related to reStart / mainClass := Some("sttp.tapir.client.tests.HttpServer"), under clientTestServer in the build file? I don't even know if that's what's actually timing out, but tests pass for me locally.

Anyway I think the tests have generally been less flakey of late and I appreciate that, but I mentioned the observation in case it helped shed some light on what the (presumably timing) issue actually is.

[kciesielski]

@hughsimpson Sorry for the flaky tests, I'm still investigating what's causing these freezes #3827
Don't worry about it, I'll rerun whatever needs rerunning until it succeeds for now.

[kciesielski]

I guess this part of docs can be updated? https://tapir.softwaremill.com/en/latest/generator/sbt-openapi-codegen.html#json-support

Currently, string-like enums in Scala 2 depend upon the enumeratum library ("com.beachape" %% "enumeratum"). For Scala 3 we derive native enums, and depend on "io.github.bishabosha" %% "enum-extensions" for generating query param serdes. Other forms of OpenApi enum are not currently supported.

Particularly "Other forms of OpenApi enum are not currently supported."?

[kciesielski]

@hughsimpson Thanks again, looks good!