[core] Resolve primitive aliases for the oneOf discriminator property type

CM
16d ago
+347-0

fix #25226

When the discriminator property of all the subtypes mapped by a oneOf is a $ref to the same alias of a primitive type (e.g. ShapeKind: {type: string}), DefaultCodegen#getCommonSchemaType (added by #24812) returns the name of the alias schema as the type of the getter of the generated oneOf interface. No model is generated for such an alias, so the generated code does not compile, while the subtypes use String:

public interface Shape {
    public ShapeKind getKind();   // error: cannot find symbol, class ShapeKind (7.25.0: public String getKind();)
}

The schema is now unaliased first, like getSingleSchemaType does for the property type of the subtypes. A $ref that is still present afterwards (enum, object, composed schema, schemaMappings target) is still used as a model name, so the behavior added by #24812 for enums is unchanged. Aliases of primitive types resolve to the aliased type (String, Integer, UUID, ...).

Tests

  • New spec oneOf_issue_25226.yaml with one oneOf per case: shared string alias, integer alias, format: uuid alias, alias of an alias, alias of an enum, direct $ref to an enum, one alias per subtype, alias inherited through allOf.
  • DefaultCodegenTest#testOneOfDiscriminatorPropertyIsRefToPrimitiveAlias (discriminator property type) and SpringCodegenTest#issue_25226 (generated interfaces and models). Both fail without the change (e.g. Shape ==> expected: <String> but was: <ShapeKind>) and pass with it.
  • ./mvnw -pl modules/openapi-generator -am test: 5361 tests, 0 failures (14 skipped, @Ignored upstream).
  • ./bin/generate-samples.sh ./bin/configs/*.yaml (all 827 configs) and ./bin/utils/export_docs_generators.sh: no change under samples/ or docs/.

PR checklist

  • Read the contribution guidelines.
  • Run the following to build the project and update samples (the CLI was built with ./mvnw -pl modules/openapi-generator-cli -am package -DskipTests, and the tests of modules/openapi-generator were run as above): 
    ./mvnw clean package || exit
./bin/generate-samples.sh ./bin/configs/*.yaml || exit
./bin/utils/export_docs_generators.sh || exit
    No file needed to be updated.
  • If your PR is targeting a particular programming language, @mention the technical committee members, so they are more likely to review the pull request. (This is a core change that affects the generators with oneOf interfaces, i.e. the Java family) cc @jpfinne @Mattias-Sehlstedt (#24812), @wing328 @cbornet

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Summary by cubic

Fixes #25226. When all subtypes of a oneOf use a $ref to the same alias of a primitive type as the discriminator property, the generated oneOf interface now uses the aliased type (e.g. String) instead of the missing alias schema name, which previously broke compilation. The change unaliases the schema in DefaultCodegen#getCommonSchemaType; aliases to enums and composed schemas still resolve to model names, preserving the behavior introduced in #24812.