[elm] Add toString for all types

[eriktim]

PR checklist

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• Ran the shell script under ./bin/ to update Petstore sample so that CIs can verify the change. (For instance, only need to run ./bin/{LANG}-petstore.sh, ./bin/openapi3/{LANG}-petstore.sh if updating the {LANG} (e.g. php, ruby, python, etc) code generator or {LANG} client's mustache templates). Windows batch files can be found in .\bin\windows\. If contributing template-only or documentation-only changes which will change sample output, be sure to build the project first.
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Description of the PR

Fix #3959 by adding support for any type as a parameter (and exposing a toString for types so each can be serialized)

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[eriktim]

@wing328 please do not approve yet. This adds undesired quotes to string types. Need to fix that first.

[eriktim]

@andys8 can you give this PR a try?

[andys8]

Is this branch published, so it's possible to execute it directly via docker or npm?

[Agraphie]

Hi there,

I tried the PR but I ran into some issues. I attached a minimal sample yaml. Is this possibly a regression? Thanks for your help!

sample.yml

openapi: "3.0.0"
info:
  version: 1.0.0
  title: message-engine
  license:
    name: MIT
servers:
  - url: http://localhost:9090
paths:
  /message/{messageId}:
    get:
      summary: Get current conversation
      operationId: getConversation
      parameters:
        - name: messageId
          in: path
          required: true
          schema:
            type: string
            format: uuid
      responses:
        "200":
          description: Current conversation
          content:
            application/json:
              schema:
                $ref: "#/components/schemas/Message"

components:
  schemas:
    Message:
      type: object
      required:
        - messageType
        - messageId
      discriminator:
        propertyName: messageType
      properties:
        messageId:
          type: string
          format: uuid
        messageType:
          type: string

    MessageStatement:
      allOf:
        - $ref: "#/components/schemas/Message"
        - type: object
          required:
            - text
          properties:
            text:
              type: string

This leads to the following problem in MessageStatement.elm

MessageStatement.elm

module Data.MessageStatement exposing (MessageStatement, decoder, encode, toString)

import Dict exposing (Dict)
import Json.Decode as Decode exposing (Decoder)
import Json.Decode.Pipeline exposing (optional, required)
import Json.Encode as Encode
import Uuid exposing (Uuid)


type alias MessageStatement =
    { messageId : Uuid
    , text : String
    }


decoder : Decoder MessageStatement
decoder =
    Decode.succeed MessageStatement
        |> required "messageId" Uuid.decoder
        |> required "text" Decode.string


encode : String -> MessageStatement -> Encode.Value
encode tag model =
    Encode.object
        [ ( "messageId", Uuid.encode model.messageId )
        , ( "text", Encode.string model.text )
        , ( "messageType", Encode.string tag )
        ]


toString : MessageStatement -> String
toString =
    Encode.encode 0 << encode

And to the following problem in the request file

Default.elm

module Request.Default exposing (getConversation)

import Data.Message as Message exposing (Message)
import Data.Uuid as Uuid exposing (Uuid)
import Dict
import Http
import Json.Decode as Decode
import Url.Builder as Url
import Uuid exposing (Uuid)


getConversation :
    { onSend : Result Http.Error Message -> msg
    , basePath : String
    , messageId : Uuid
    }
    -> Cmd msg
getConversation params =
    Http.request
        { method = "GET"
        , headers = List.filterMap identity []
        , url =
            Url.crossOrigin params.basePath
                [ "message", Uuid.toStringUuid.toString params.messageId ]
                (List.filterMap identity [])
        , body = Http.emptyBody
        , expect = Http.expectJson params.onSend Message.decoder
        , timeout = Just 30000
        , tracker = Nothing
        }

[eriktim]

Is this branch published, so it's possible to execute it directly via docker or npm?

@andys8 Nope it does not get published until it's merged in. If you can build the generator yourself that would be great.

@Agraphie thanks for the detailed report. I'm on it.

[eriktim]

@Agraphie just pushed some fixes. Can you try again?

[Agraphie]

@eriktim looks good to me. I tried it with the minimal example seen above as well as with our project and there aren't any compiler errors. Thanks!

[eriktim]

@wing328 can you have a look at the errors? They seem unrelated to my PR. This should be good to go.

[wing328]

Agreed these errors are not related to your PR (some have been fixed in the master already)

[wing328]

CI failure not related to this PR. (the ruby issue addressed in the master already)

[wing328]

@eriktim thanks for the PR, which has been included in v4.2.0 release: https://twitter.com/oas_generator/status/1189824932345069569