[BUG][cpp-restsdk] key-type of a map is hardcoded to utility::string_t

Bug Report Checklist

• Have you provided a full/minimal spec to reproduce the issue?
• Have you validated the input using an OpenAPI validator?
• 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

The cpp-restsdk generator always uses utility::string_t as the type of the key in an std::map, even if a different type-mapping is given.

openapi-generator version

v7.20.0

OpenAPI declaration file content or url

openapi: 3.1.0
info:
  title: Example
  description: Example
  version: 1.0.0

components:
  schemas:
    Pet:
      type: object
      properties:
        name:
          type: string
        age:
          type: integer
      required: [ name, age ]

    PetCollection:
      type: object
      properties:
        collectionName:
          type: string
        owners:
          type: array
          items:
            type: string
        pets:
          type: object
          additionalProperties:
            $ref: "#/components/schemas/Pet"
      required: [collectionName, owners, pets]

Generation Details

java -jar openapi-generator-cli-7.20.0.jar generate -i openapi.yaml -g cpp-restsdk -o petstore --type-mappings string=std::string

Steps to reproduce

1. Generate C++ code as described above
2. Check type of m_Pets in PetCollection.h

The current result is
std::map<utility::string_t, std::shared_ptr<Pet>> m_Pets;
while the expected outcome is
std::map<std::string, std::shared_ptr<Pet>> m_Pets;

Note that the type-mapping for m_CollectionName and m_Owners is correct and uses the provided std::string.

Related issues/PRs

-

Suggest a fix

It looks like utility::string_t is hardcoded in https://github.com/OpenAPITools/openapi-generator/blob/master/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/CppRestSdkClientCodegen.java#L466

Probably utility::string_t on this line has to be changed to getSchemaType("string")

Open modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/CppRestSdkClientCodegen.java around line 466, then run the provided Java generation command with the sample OpenAPI YAML. Check PetCollection.h and confirm the map key follows the supplied string type mapping while the existing property mappings remain correct.