[BUG][resttemplate] Object with additionalProperties (HashMap) does not generate a model

[Na3blis]

Description

I am trying to generate a HashMap class, but no class is generated and a plain Java Map is used where the class ContextHeaders should be used.

  @JsonProperty("contextHeaders")

  private Map contextHeaders = null;

openapi-generator version

4.0.3

OpenAPI declaration file content or url

swagger.json
swagger-client-config.json

Command line used for generation

curl -s -o ./codegen.jar http://central.maven.org/maven2/org/openapitools/openapi-generator-cli/4.0.3/openapi-generator-cli-4.0.3.jar
java -jar ./codegen.jar generate -c ./swagger-client-config.json -i ./swagger.json -g java -o generated-client/

Steps to reproduce

Run the codegen 4.0.3 against the swagger.json file with the config swagger-client-config.json. Notice there is no com.example.authrules.v1.client.model.ContextHeaders class, and com.example.authrules.v1.client.model.RulesUser references a plain Java Map instead of a class

[auto-labeler]

👍 Thanks for opening this issue!
🏷 I have applied any labels matching special text in your issue.

The team will review the labels and make any necessary changes.

[jmini]

Can you please switch to a newer version of OpenAPI generator?

Can you provide a small OpenAPI-Spec that show what is not working for you?

[Na3blis]

@jmini I just tried with 4.1.0 same results, as well as with the 4.2 snapshot.

Here is what I'm referring to. Currently I'm using a 2.0 spec, and swagger-codegen 2.3.1 and it generates ContextHeaders.java.
And in the model that references that, it has:

  @JsonProperty("contextHeaders")
  private ContextHeaders contextHeaders = null;

However, when using the 3.0 spec, it still creates a HashMap<String, List>, the problem is that it's not it's own Model Object as before, where it's referenced it shows up now as

  public static final String JSON_PROPERTY_CONTEXT_HEADERS = "contextHeaders";
  @JsonProperty(JSON_PROPERTY_CONTEXT_HEADERS)
  private Map<String, List<String>> contextHeaders = new HashMap<String, List<String>>();

[jmini]

I think that with generateAliasAsModel you get the Swagger-Codegen behavior where models (ContextHeaders extends Map<String, List<String>>) are created .

See: #472

[Na3blis]

Thanks, that does look like the solution! However it does not create the object correctly when referenced,
[ERROR] /Users/tim/dev/authorization-rules-service/generated-client/src/main/java/com/example/authrules/v1/client/model/RulesUser.java:[146,43] incompatible types: java.util.HashMap<java.lang.String,java.util.List<java.lang.String>> cannot be converted to com.example.authrules.v1.client.model.ContextHeaders

And in the RulesUser class it has:

public static final String JSON_PROPERTY_CONTEXT_HEADERS = "contextHeaders";
  @JsonProperty(JSON_PROPERTY_CONTEXT_HEADERS)
  private ContextHeaders contextHeaders = new HashMap<String, List<String>>();

So it's trying to instantiate it as a HashMap instead of as a new ContextHeaders object.

[bodograumann]

We have just encountered the same behaviour as @Na3blis. The problem is that, while DefaultGenerator does generate the model definition file in the generateModels method, DefaultCodegen does not reference them in the fromRequestBody method.

I'll try to fix it.

[Praveen2518]

@Na3blis did you get the answer why ContextHeaders object created with HashMap and how can we fix this

[Na3blis]

@Na3blis did you get the answer why ContextHeaders object created with HashMap and how can we fix this

Unfortunately not. I think I ended up having to change the api to work around this