[BUG][JAVA] Not specifying additionalProperties should generate the Map

[ncelerier]

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

Hello,

Regarding additionalProperties and the specification here: https://json-schema.org/understanding-json-schema/reference/object#additionalproperties, I think there might be a bug in the Java spring generator.

I'm not specifying the additionalProperties property and in this case, because of the specification mentioning:

By default any additional properties are allowed.

I would expect the JsonWebKey generated class to contain the Map<String, Object> additionalProperties (and get/put methods) to be generated. But it is not !

It seems the only way to generate this map is to use either:

additionalProperties: true

Or:

additionalProperties:
  type: string

Which I would like to avoid and shouldn't be necessary.

Am I missing something ?

Thank you for your help !

openapi-generator version

7.10.0 (current latest)
7.11.0-SNAPSHOT (2b891f6)

OpenAPI declaration file content or url

My src/main/resources/swagger/swagger.yaml file:

swagger: '2.0'
info:
  version: '1.0'
  title: FooBar
paths:
  /jwks:
    get:
      operationId: getJwks
      responses:
        200:
          description: "Success"
          schema:
            type: "array"
            items:
              $ref: "#/definitions/JsonWebKey"
definitions:
  JsonWebKey:
    title: JSON Web Key
    type: object
    properties:
      kid:
        type: string
    # No additionalProperties specified

Generation Details

I'm using this pom.xml:
https://gist.github.com/ncelerier/1729b37b6f9d37aefc8af33926fed07b

Steps to reproduce

Running mvn clean install, then looking at the generated file if the Map is generated or not:
target/generated-sources/openapi-server/src/main/java/com/example/models/JsonWebKey.java

Related issues/PRs

Suggest a fix

I can suggest something but I would like to know first if this is really a bug or if I am missing something.

[wing328]

did you try setting disallowAdditionalPropertiesIfNotPresent to false? (e.g. --additional-properties disallowAdditionalPropertiesIfNotPresent=false in CLI)

https://openapi-generator.tech/docs/generators/java/

[ncelerier]

Hi @wing328, I have this property in the pom.xml :

<configOptions>
  <disallowAdditionalPropertiesIfNotPresent>false</disallowAdditionalPropertiesIfNotPresent>
</configOptions>

Could it be that it is not taken into account ?

[wing328]

I think there might be a bug in the Java spring generator.

Ah. I can only assure this option works for java client generator (jersey2, jersey3, okhttp-gson) but not the spring generator. Sorry.

One way to check is to remove the option or set the option to true to see if there's any change in the output

[ncelerier]

For the java client generator, I tried with this and indeed the Map is generated:

<generatorName>java</generatorName>
<configOptions>
  <disallowAdditionalPropertiesIfNotPresent>false</disallowAdditionalPropertiesIfNotPresent>
</configOptions>

However, if I set additionalProperties: false in my schema, the Map is still generated whereas it shouldn't.

[DavidGrath]

@ncelerier Please can you help confirm if this is the case for the default library and the java generator?

[ncelerier]

Hello, sorry for this late response.

Forget what I said about the java client generator and additionalProperties: false : the Map is not generated which is the expected behaviour. Sorry, I think I mixed things up.

Here is a recap of the current behaviour using version 7.11.0 :

generatorName	additionalProperties value	additionalProperties field/methods present	Result
spring	Not specified	No	❌ Should be present
spring	additionalProperties: false	No	✔️
spring	additionalProperties: true	Yes, Map<String, Object>	✔️
spring	additionalProperties: type: string	Yes, Map<String, String>	✔️
java	Not specified	Yes, Map<String, Object>	✔️
java	additionalProperties: false	No	✔️
java	additionalProperties: true	Yes, Map<String, Object> additionalProperties	✔️
java	additionalProperties: type: string	Yes, Map<String, Object> additionalProperties	❌ Should be Map<String, String> additionalProperties, as with the spring generator

[DavidGrath]

Hey, @wing328, sorry for taking so long, but I think I see the cause of the issue:

openapi-generator/modules/openapi-generator/src/main/java/org/openapitools/codegen/DefaultCodegen.java

Line 2868 in de310f6

if (ModelUtils.isMapSchema(schema)) {

isDisallowAdditionalPropertiesIfNotPresent is not taken into account at this point, so addAdditionPropertiesToCodeGenModel is never called, which means CodegenModel.additionalPropertiesType is never set here:

openapi-generator/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/AbstractJavaCodegen.java

Line 2333 in de310f6

codegenModel.additionalPropertiesType = getSchemaType(s);

My idea is to add another if-else branch to this block with isDisallowAdditionalPropertiesIfNotPresent, but since DefaultGenerator is such a fundamental class, I want to know if simply adding a test case like givenAdditionalPropertiesNotDefinedAndIsDisallowAdditionalPropertiesIfNotPresentIsFalseWhenGenerateModelThenAdditionalPropertiesTypeIsObject is enough, or if there's more involved.
Also, for the next part of this issue:

❌ Should be Map<String, String> additionalProperties, as with the spring generator

I see that this is because Object is hardcoded for okhttp-gson which is the default, and it seems to be that way because of the custom adapter:

openapi-generator/modules/openapi-generator/src/main/resources/Java/libraries/okhttp-gson/pojo.mustache

Line 538 in de310f6

for (Map.Entry<String, JsonElement> entry : jsonObj.entrySet()) {

Does this mean that not much can be done without a complete rewrite? I'm not sure if it's worth changing if that's the case

[DavidGrath]

@wing328 @martin-mfg , please what are your thoughts?