[BUG] [Crystal] Free-Form Object results in "Error: undefined constant AnyType"

[grokify]

Bug Report Checklist

• Have you provided a full/minimal spec to reproduce the issue?
• Have you validated the input using an OpenAPI validator (example)?
• Have you tested with the latest master to confirm the issue still exists?
• Have you searched for related issues/PRs?
• What's the actual output vs expected output?
• [Optional] Sponsorship to speed up the bug fix or feature request (example)

Description

Generation of Crystal client using Free-Form object results in compile time error Error: undefined constant AnyType.

Free-form objects are described here: https://swagger.io/docs/specification/data-models/dictionaries/#free-form

Free-Form Objects

If the dictionary values can be of any type (aka free-form object), use additionalProperties: true:

type: object
additionalProperties: true

This is equivalent to:

type: object
additionalProperties: {}

Running crystal spec results in the following:

% crystal spec
Showing last frame. Use --error-trace for full trace.

In src/addlprops/models/pet.cr:27:34

 27 | property info : Hash(String, AnyType)?
                                   ^------
Error: undefined constant AnyType

This is due to the following generated code:

    # Optional properties
    @[JSON::Field(key: "info", type: Hash(String, AnyType)?, nillable: true, emit_null: false)]
    property info : Hash(String, AnyType)?

Ref: https://github.com/grokify/crystal-addlprops/blob/a07dab7def7d699cb52b30cd354cfd181e9cd6a4/src/addlprops/models/pet.cr#L25-L27

openapi-generator version

The following versions have been tested:

• 6.2.0
• openapi-generator-cli-7.0.0-20221012.083708-4.jar

OpenAPI declaration file content or url

The entire spec is here:

https://github.com/grokify/crystal-addlprops/blob/a07dab7def7d699cb52b30cd354cfd181e9cd6a4/spec_addlprop_oas3.yaml

The definition causing the issue is here:

        info:
          type: object
          additionalProperties: {}

The same result occurs for:

        info:
          type: object
          additionalProperties: true

Ref: https://github.com/grokify/crystal-addlprops/blob/a07dab7def7d699cb52b30cd354cfd181e9cd6a4/spec_addlprop_oas3.yaml#L42-L44

Generation Details

The generation command is here:

java -jar openapi-generator-cli.jar generate -i addlprop_spec.json -g crystal -o addlprops --additional-properties=shardName=addlprops,moduleName=Addlprops,shardLicense=MIT,shardVersion=0.1.0,shardAuthors=grokify,shardDescription=Additional\ Properties\ demo

Ref: https://github.com/grokify/crystal-addlprops/blob/d504e1da60eb1790f0972231d88f99871ec3a93a/generator.sh#L1

Steps to reproduce

1. Run generator command to create the API client
2. cd addlprops
3. Patch src/addlprops/configuration.cr for issue Error: for empty hashes use '{} of KeyType => ValueType' by turning {} to Hash(String, String).new as seen here: https://github.com/grokify/crystal-addlprops/blob/d504e1da60eb1790f0972231d88f99871ec3a93a/src/addlprops/configuration.cr#L218-L221
4. shards install
5. crystal spec

Related issues/PRs

None

Suggest a fix

I was able to compile the client by changing Hash(String, AnyType) to Hash(String, Object).

[cyangle]

@grokify You can override the type mappings with command line option --type-mappings=AnyType=JSON::Any.

The double colons in JSON::Any are missing in the generated files and this issue is fixed in #13736