Normalizer: new rule LOOSE_NULL_DEFINITIONS to allow more null definitions in 3.0 spec.

[wing328]

Normalizer: new rule LOOSE_NULL_DEFINITIONS to allow more null definitions in 3.0 spec

When set to true, {type: object, nullable: true} (in 3.0 spec) is considered as null type in 3.1 spec.

based on #23621 by @ericdriggs

e.g. in CLI

java -jar modules/openapi-generator-cli/target/openapi-generator-cli.jar generate -g java -i modules/openapi-generator/src/test/resources/bugs/issue_anyof_bare_nullable_object.yaml -o /tmp/java-okhttp/ --openapi-normalizer LOOSE_NULL_DEFINITIONS=true

PR checklist

• Read the contribution guidelines.
• Run the following to build the project and update samples:

  ./mvnw clean package || exit
  ./bin/generate-samples.sh ./bin/configs/*.yaml || exit
  ./bin/utils/export_docs_generators.sh || exit
  

  (For Windows users, please run the script in WSL)
  Commit all changed files.
  This is important, as CI jobs will verify all generator outputs of your HEAD commit as it would merge with master.
  These must match the expectations made by your contribution.
  You may regenerate an individual generator by passing the relevant config(s) as an argument to the script, for example ./bin/generate-samples.sh bin/configs/java*.
  IMPORTANT: Do NOT purge/delete any folders/files (e.g. tests) when regenerating the samples as manually written tests may be removed.
• If your PR is targeting a particular programming language, @mention the technical committee members, so they are more likely to review the pull request.

---

Summary by cubic

Fixes null-type detection in OpenAPI 3.0.x for {type: object, nullable: true} so anyOf/oneOf patterns like $ref | null simplify to typed nullable fields, not Object or wrapper classes. Adds the LOOSE_NULL_DEFINITIONS normalizer option to enable this behavior.

• New Features

  • Adds LOOSE_NULL_DEFINITIONS to OpenAPINormalizer; enabling it sets ModelUtils.looseNullDefinitions = true.
  • Updates docs with a CLI example using modules/openapi-generator/src/test/resources/bugs/issue_anyof_bare_nullable_object.yaml.

• Bug Fixes

  • Updates ModelUtils.isNullTypeSchema to treat a bare nullable object (no $ref, no additionalProperties) as null in 3.0.x when the rule is enabled; 3.1 remains unchanged.
  • Ensures SIMPLIFY_ONEOF_ANYOF collapses $ref | {type: object, nullable: true} into a typed nullable field; adds tests for 3.0 and 3.1 and guards objects with properties or additionalProperties from being treated as null.

^{Written for commit 0e501ef. Summary will update on new commits.}

[cubic-dev-ai]

3 issues found across 8 files

<sub>Reply with feedback, questions, or to request a fix.

Re-trigger cubic</sub>