[BUG] array schemas with single non-object allOf entry aren't resolved

[RomiRand]

Description

When an array schema contains an allOf definition with just a single element (that is not an object), it is not resolved, even though this can safely be unwrapped. This leads to type resolution errors in generated code. Other composed schemas such as oneOf are handled correctly.

openapi-generator version

v7.22.0

OpenAPI declaration file content or url

openapi: 3.0.0
info:
  title: Test
  version: 1.0.0
paths: {}
components:
  schemas:
    Data:
      type: object
      properties:
        outer:
          type: array
          items:
            allOf:
              - type: array
                items:
                  type: string

Generation Details

It happens with all generated outputs, many languages can't compile the generated code. E.g. go:

// Data struct for Data
type Data struct {
	Outer []Array `json:"outer,omitempty"`
}

Steps to reproduce

run openapi-generator with:
openapi-generator generate -i modules/openapi-generator/src/test/resources/3_0/array_allof_single_type.yaml -o out/ -g <anything>

Related issues/PRs

#23838

Suggest a fix

Basically needs analog handling to the object case:

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

Lines 328 to 335 in 0b1ac88

	} else if (ModelUtils.isComposedSchema(prop)) {
	if (prop.getAllOf() != null && prop.getAllOf().size() == 1 &&
	!(((Schema) prop.getAllOf().get(0)).getType() == null ||
	"object".equals(((Schema) prop.getAllOf().get(0)).getType()))) {
	// allOf with only 1 type (non-model)
	LOGGER.info("allOf schema used by the property `{}` replaced by its only item (a type)", propName);
	props.put(propName, (Schema) prop.getAllOf().get(0));
	}

I'll open a PR