ModelUtils.getUnusedSchemas reports simple model from array types as unused

[jimschubert]

Description

Found in #251

openapi-generator version

3.0.0

OpenAPI declaration file content or url

https://github.com/OAI/OpenAPI-Specification/blob/master/examples/v3.0/petstore.yaml

Command line used for generation

n/a (not a generation bug)

Steps to reproduce

Discovered while testing #251.

On that branch:

mvn clean install
cd modules/openapi-generator-gradle-plugin/
./gradlew assemble publishToMavenLocal
./gradlew --build-file=samples/local-spec/build.gradle generateGoWithInvalidSpec

Related issues/PRs

• Validate spec on generation by default #251

Suggest a fix/enhancement

ModelUtils.getUnusedSchemas calls into visitOpenAPI, and visitOpenAPI needs to account for multiple levels of nested arrays, enums, map structures, and polymorphic types.

[jmini]

Thank you a lot!

ModelUtils.getUnusedSchemas calls into visitOpenAPI, and visitOpenAPI needs to account for multiple levels of nested arrays, enums, map structures, and polymorphic types.

This is absolutely correct, and we also needs to ensure that we do not create infinite loops

[jmini]

I have started something to fix it: #253

[jmini]

ModelUtils.getUnusedSchemas calls into visitOpenAPI, and visitOpenAPI needs to account for multiple levels of nested arrays, enums, map structures, and polymorphic types.

@jimschubert : what have you in mind with "enums"? I have looked at the spec, but I did not find where you can use/reference a Schema.

[jimschubert]

@jmini here's an example of an OpenAPI 2.0 spec with a top-level enum of weekdays. https://github.com/OpenAPITools/openapi-generator/blob/master/modules/openapi-generator/src/test/resources/integrationtests/csharp/general/enum-support-spec.json#L35

I only skimmed ModelUtils.getUnusedSchemas for a few seconds to present the list of what I felt might be missing. I noticed it was inspecting items, but it didn't look like it was evaluating nested children which might refer to top-level enums. Similar to logic that is there, I think it would have to be done for inputs, outputs, and other response models (like errors).

[jmini]

@jimschubert thank you a lot for your reply.

Enum models are exactly like other models in the definitions section (or schema and components/schema section in the OAS3 terminology), I have already an example in the Unit test:

openapi-generator/modules/openapi-generator/src/test/resources/3_0/unusedSchemas.yaml

Lines 251 to 256 in ebaa702

	SomeObj11:
	type: string
	enum:
	- v1
	- v2
	default: v1

I am glad you gave this precision, because I was afraid to miss something.

Let me finish #253 and I hope I will have all cases.