[BUG] [Spring] allOf conversion issue

[giuseppe-pagliaro]

Bug Report Checklist

• Have you provided a full/minimal spec to reproduce the issue?
• Have you validated the input using an OpenAPI validator?
• [] Have you tested with the latest master to confirm the issue still exists?
• Have you searched for related issues/PRs?
• What's the actual output vs expected output?
• [Optional] Sponsorship to speed up the bug fix or feature request (example)

Description

When a schema is extended, using allOf, and some constraints are applied to the properties of the original object, but the constraints are inserted above the reference to the original schema; the constraints are not applied in the generated code. Whereas, the swagger UI seems to render the schemas correctly.

openapi-generator version

version "7.12.0"

OpenAPI declaration file content or url

# Base Schema

    PlantOfferEditRequest:
      type: object
      properties:
        name:
          type: string
        imageURL:
          type: string
        averageDaysToHarvest:
          type: integer
        price:
          $ref: '#/components/schemas/Price'

# Not Working Schema

PlantOfferCreateRequest:
      allOf:
        - type: object
          properties:
            gardenId:
              type: integer
              format: int64
          required:
            - gardenId
            - name
            - imageURL
            - averageDaysToHarvest
            - price
        - $ref: '#/components/schemas/PlantOfferEditRequest'

# Working Schema

PlantOfferCreateRequest:
      allOf:
        - type: object
          properties:
            gardenId:
              type: integer
              format: int64
          required:
            - gardenId
        - $ref: '#/components/schemas/PlantOfferEditRequest'
        - type: object
          required:
            - name
            - imageURL
            - averageDaysToHarvest
            - price

Expected vs Actual Output

Expected:

public class PlantOfferCreateRequest {

private String name;

private String imageURL;

private Integer averageDaysToHarvest;

private Price price;

private Long gardenId;
}

Actual:

public class PlantOfferCreateRequest {

private @nullable String name;

private @nullable String imageURL;

private @nullable Integer averageDaysToHarvest;

private @nullable Price price;

private Long gardenId;
}

Generation Details

The gradle plugin configuration:

openApiGenerate {
    generatorName.set("spring")
    inputSpec.set("$projectDir/src/main/resources/openapi.yaml")
    outputDir.set("$buildDir/generated")
    apiPackage.set("com.myname.prjname.api")
    modelPackage.set("com.myname.prjname.model")
    configOptions.set(
        mapOf(
            "library" to "spring-boot",
            "useSpringBoot3" to "true",
            "language" to "Kotlin",
            "interfaceOnly" to "true",
            "useTags" to "true",
        	"useOperationId" to "true"
        )
    )
	typeMappings.set(
		mapOf(
			"Page" to "org.springframework.data.domain.Page",
			"Pageable" to "org.springframework.data.domain.Pageable",
			"Sort" to "org.springframework.data.domain.Sort",
			"PageGardenInfo" to "org.springframework.data.domain.Page<com.myname.prjname.model.GardenInfo>",
			"PagePlantOffer" to "org.springframework.data.domain.Page<com.myname.prjname.model.PlantOffer>",
			"PagePlantedPlant" to "org.springframework.data.domain.Page<com.myname.prjname.model.PlantedPlant>",
			"PageGardener" to "org.springframework.data.domain.Page<com.myname.prjname.model.Gardener>"
		)
	)
}

Steps to reproduce

1 - Create a schema with some non-required properties.
2 - Create another schema, using the allOf construct, that extends the first one.
3 - Add some constraints to the properties from the previous schema, listing above the reference to the previous schema.

Suggest a fix

Instead of iterating over the schemas and applying the constraints as they come, store them in a secondary location and apply them all at the end.