[BUG][C++][cpp-restsdk] Error compiling c++ client library with enums

[animesh-bhadouria]

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?
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Description

I defined a schema object type enum in yaml file as per the reusable enum samples docs/data-models/enums and generated the cpprestsdk API client library. Getting a compilation error while upon compiling the API client library.

openapi-generator version

openapi-generator-cli 5.3.0-SNAPSHOT
  commit : 0c7ec41
  built  : 2021-08-31T18:02:21-07:00
  source : https://github.com/openapitools/openapi-generator
  docs   : https://openapi-generator.tech/

OpenAPI declaration file content or url

openapi: 3.0.0
info:
  title: Open API Sample
  version: 1.0.0
servers:
  - url: http://localhost:8000
paths:
  /products:
    get:
      parameters:
      - in: query
        name: color
        required: true
        schema:
          $ref: '#/components/schemas/Color'
      responses:
        '200':
          description: OK
components:
  schemas:
    Color:
      type: string
      enum:
        - black
        - white
        - red
        - green
        - blue

Generation Details

java -jar ./openapi-generator/modules/openapi-generator-cli/target/openapi-generator-cli.jar generate -g cpp-restsdk -i test.yaml -o ./test/

Steps to reproduce

• Create a test.yaml file with the provided (above) sample configuration. (validated)

java -jar ./openapi-generator/modules/openapi-generator-cli/target/openapi-generator-cli.jar validate -i test.yaml
Validating spec (test.yaml)
No validation issues detected.

• Generate the Client API library.

java -jar ./openapi-generator/modules/openapi-generator-cli/target/openapi-generator-cli.jar generate -g cpp-restsdk -i test.yaml -o ./test/

• Compile the C++ Client API library.

cd test
cmake -DCPPREST_ROOT=/usr -DCMAKE_CXX_FLAGS="-I/usr/local/opt/openssl/include" -DCMAKE_MODULE_LINKER_FLAGS="-L/usr/local/opt/openssl/lib"
make

Error Log

The generated client code cannot match the template parameterToString() conversion for enums.

In file included from /test/api/DefaultApi.cpp:13:
In file included from /test/api/DefaultApi.h:22:
/test/api/../ApiClient.h:104:12: error: use of undeclared identifier 'parameterToString'
    return parameterToString(*value.get());
           ^
/test/api/DefaultApi.cpp:86:86: note: in instantiation of function template specialization
      'org::openapitools::client::api::ApiClient::parameterToString<org::openapitools::client::model::Color>' requested here
        localVarQueryParams[utility::conversions::to_string_t("color")] = ApiClient::parameterToString(color);
                                                                                     ^
/test/api/../ApiClient.h:59:30: note: must qualify identifier to find this declaration in dependent base class
    static utility::string_t parameterToString(utility::string_t value);
                             ^
/test/api/../ApiClient.h:60:30: note: must qualify identifier to find this declaration in dependent base class
    static utility::string_t parameterToString(int32_t value);
                             ^
/test/api/../ApiClient.h:61:30: note: must qualify identifier to find this declaration in dependent base class
    static utility::string_t parameterToString(int64_t value);
                             ^
/test/api/../ApiClient.h:62:30: note: must qualify identifier to find this declaration in dependent base class
    static utility::string_t parameterToString(float value);
                             ^
/test/api/../ApiClient.h:63:30: note: must qualify identifier to find this declaration in dependent base class
    static utility::string_t parameterToString(double value);
                             ^
/test/api/../ApiClient.h:64:30: note: must qualify identifier to find this declaration in dependent base class
    static utility::string_t parameterToString(const utility::datetime &value);
                             ^
/test/api/../ApiClient.h:88:30: note: must qualify identifier to find this declaration in dependent base class
utility::string_t ApiClient::parameterToString(const std::vector<T>& value)
                             ^
/test/api/../ApiClient.h:102:30: note: must qualify identifier to find this declaration in dependent base class
utility::string_t ApiClient::parameterToString(const std::shared_ptr<T>& value)
                             ^
/test/api/../ApiClient.h:104:12: error: no matching function for call to 'parameterToString'
    return parameterToString(*value.get());
           ^~~~~~~~~~~~~~~~~
/test/api/../ApiClient.h:59:30: note: candidate function not viable: no known conversion from
      'std::__1::shared_ptr<org::openapitools::client::model::Color>::element_type' (aka 'org::openapitools::client::model::Color') to 'utility::string_t' (aka
      'basic_string<char, char_traits<char>, allocator<char> >') for 1st argument
    static utility::string_t parameterToString(utility::string_t value);
                             ^
/test/api/../ApiClient.h:60:30: note: candidate function not viable: no known conversion from
      'std::__1::shared_ptr<org::openapitools::client::model::Color>::element_type' (aka 'org::openapitools::client::model::Color') to 'int32_t' (aka 'int') for 1st argument
    static utility::string_t parameterToString(int32_t value);
                             ^
/test/api/../ApiClient.h:61:30: note: candidate function not viable: no known conversion from
      'std::__1::shared_ptr<org::openapitools::client::model::Color>::element_type' (aka 'org::openapitools::client::model::Color') to 'int64_t' (aka 'long long') for 1st argument
    static utility::string_t parameterToString(int64_t value);
                             ^
/test/api/../ApiClient.h:62:30: note: candidate function not viable: no known conversion from
      'std::__1::shared_ptr<org::openapitools::client::model::Color>::element_type' (aka 'org::openapitools::client::model::Color') to 'float' for 1st argument
    static utility::string_t parameterToString(float value);
                             ^
/test/api/../ApiClient.h:63:30: note: candidate function not viable: no known conversion from
      'std::__1::shared_ptr<org::openapitools::client::model::Color>::element_type' (aka 'org::openapitools::client::model::Color') to 'double' for 1st argument
    static utility::string_t parameterToString(double value);
                             ^
/test/api/../ApiClient.h:64:30: note: candidate function not viable: no known conversion from
      'std::__1::shared_ptr<org::openapitools::client::model::Color>::element_type' (aka 'org::openapitools::client::model::Color') to 'const utility::datetime' for 1st argument
    static utility::string_t parameterToString(const utility::datetime &value);
                             ^
/test/api/../ApiClient.h:88:30: note: candidate template ignored: could not match 'vector<type-parameter-0-0, allocator<type-parameter-0-0> >'
      against 'org::openapitools::client::model::Color'
utility::string_t ApiClient::parameterToString(const std::vector<T>& value)
                             ^
/test/api/../ApiClient.h:102:30: note: candidate template ignored: could not match 'shared_ptr<type-parameter-0-0>' against
      'org::openapitools::client::model::Color'
utility::string_t ApiClient::parameterToString(const std::shared_ptr<T>& value)
                             ^
/test/api/../ApiClient.h:104:12: error: no matching function for call to 'parameterToString'
    return parameterToString(*value.get());
           ^~~~~~~~~~~~~~~~~
/test/api/../ApiClient.h:59:30: note: candidate function not viable: no known conversion from
      'std::__1::shared_ptr<org::openapitools::client::model::Color>::element_type' (aka 'org::openapitools::client::model::Color') to 'utility::string_t' (aka
      'basic_string<char, char_traits<char>, allocator<char> >') for 1st argument
    static utility::string_t parameterToString(utility::string_t value);
                             ^
/test/api/../ApiClient.h:60:30: note: candidate function not viable: no known conversion from
      'std::__1::shared_ptr<org::openapitools::client::model::Color>::element_type' (aka 'org::openapitools::client::model::Color') to 'int32_t' (aka 'int') for 1st argument
    static utility::string_t parameterToString(int32_t value);
                             ^
/test/api/../ApiClient.h:61:30: note: candidate function not viable: no known conversion from
      'std::__1::shared_ptr<org::openapitools::client::model::Color>::element_type' (aka 'org::openapitools::client::model::Color') to 'int64_t' (aka 'long long') for 1st argument
    static utility::string_t parameterToString(int64_t value);
                             ^
/test/api/../ApiClient.h:62:30: note: candidate function not viable: no known conversion from
      'std::__1::shared_ptr<org::openapitools::client::model::Color>::element_type' (aka 'org::openapitools::client::model::Color') to 'float' for 1st argument
    static utility::string_t parameterToString(float value);
                             ^
/test/api/../ApiClient.h:63:30: note: candidate function not viable: no known conversion from
      'std::__1::shared_ptr<org::openapitools::client::model::Color>::element_type' (aka 'org::openapitools::client::model::Color') to 'double' for 1st argument
    static utility::string_t parameterToString(double value);
                             ^
/test/api/../ApiClient.h:64:30: note: candidate function not viable: no known conversion from
      'std::__1::shared_ptr<org::openapitools::client::model::Color>::element_type' (aka 'org::openapitools::client::model::Color') to 'const utility::datetime' for 1st argument
    static utility::string_t parameterToString(const utility::datetime &value);
                             ^
/test/api/../ApiClient.h:88:30: note: candidate template ignored: could not match 'vector<type-parameter-0-0, allocator<type-parameter-0-0> >'
      against 'org::openapitools::client::model::Color'
utility::string_t ApiClient::parameterToString(const std::vector<T>& value)
                             ^
/test/api/../ApiClient.h:102:30: note: candidate template ignored: could not match 'shared_ptr<type-parameter-0-0>' against
      'org::openapitools::client::model::Color'
utility::string_t ApiClient::parameterToString(const std::shared_ptr<T>& value)
                             ^
1 warning and 3 errors generated.
make[2]: *** [CMakeFiles/CppRestOpenAPIClient.dir/api/DefaultApi.cpp.o] Error 1
make[1]: *** [CMakeFiles/CppRestOpenAPIClient.dir/all] Error 2
make: *** [all] Error 2

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