Handle untyped schemas (in some languages)

[gibson042]

Ref swagger-api/swagger-codegen#6898
Ref swagger-api/swagger-codegen#6896

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 and ./bin/security/{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\.
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Description of the PR

Partial copy of swagger-api/swagger-codegen#6898 (for handling untyped schemas, especially as additionalProperties), at the request of @wing328 . This has not yet been tested, nor have tests been updated, nor are all languages covered.

[wing328]

Thanks @gibson042 . We'll run some tests and let you know if we've any feedback/question. Have a nice weekend.

[wing328]

@gibson042 I ran some tests but couldn't repeat the issue with the OpenAPI Generator. Here is what I got from C# client:

        /// <exception cref="Org.OpenAPITools.Client.ApiException">Thrown when fails to make API call</exception>
        /// <returns>Dictionary&lt;string, Object&gt;</returns>
        Dictionary<string, Object> MapOfAnything ();

Spec:

swagger: '2.0'
info:
  title: 'map of arbitrary values'
  version: '1'
produces: ["application/json"]
paths:
  /mapOfAnything:
    get:
      operationId: mapOfAnything
      responses:
        default:
          schema:
            description: 'map of arbitrary values'
            type: object
            additionalProperties:
              description: Any JSON type

I wonder if you can test with OpenAPI Generator and see if it also works for you without the PR.

[gibson042]

I can't get a successful build at the moment, but I can tell you that the issue was originally discovered in Java... what code is produced in that language by each relevant version of OpenAPI Generator?

[wing328]

That's ok. I plan to add better handling of free-form object via #1338. Stay tuned.

[wing328]

@gibson042 #1338 has been merged into master. Please give it another try when you've time.

Closing this PR for the time being.

Happy New Year!