OpenAPITools / OpenAPITools/openapi-generator

[BUG][Java] duplicate @JsonTypeName annotation

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Issue: Bug
Dominant language
Java
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Description

Bug Report Checklist
Description

If a Spec uses inheritance, and a Schema is considered to be sanitised (isClassnameSanitized is true) the java generator will generate a duplicate @JsonTypeName("Model_Name")annotation.

See Java/pojo.mustache and Java/typeInfoAnnotation.mustache.

openapi-generator version

5.4.0

Suggest a fix

I'm happy to provide PR with a fix, but would like to discuss prior with the core team and / or Java technical committee wether to unconditionally include @JsonTypeName or use the isClassnameSanitized condition.

{{#isClassnameSanitized}}
@JsonTypeName("{{name}}")
{{/isClassnameSanitized}}

Contributor guide

Open the contributing guide

First steps

  1. Read the whole issue, then the project's contributing guide.
  2. Comment on the issue to say you are picking it up — it saves two people doing the same work.
  3. Fork the repository and make your change on a branch.
  4. Open a pull request that references the issue number.

Research direction

Start by comparing Java/pojo.mustache with Java/typeInfoAnnotation.mustache, focusing on how isClassnameSanitized controls @JsonTypeName for inherited schemas. Reproduce the Java generation case described in the issue and verify that a sanitized model produces only one @JsonTypeName annotation. The annotation policy remains open for discussion.

Written by the indexing model from the issue text.

Assessment

Tech stack
java
Domain
tooling
Issue type
Bug
Difficulty
3/5
Estimated time
1-2 days
Activity status
Stale
Clarity
Mostly clear
Newbie friendliness
35/100

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