[BUG][TYPESCRIPT] Inconsistent handling of required property by $ref

Description

When generating the TypeScript models from the following OpenAPI spec, the type property of CriterionGenericConjunction is marked as optional (type?), even though it is defined as required in the referenced CriterionResidenceCriteriaHandmadeEnumResidenceCriteriaFieldEnum schema.

This causes a TypeScript error because the type property should be required, not optional.

Error :

openapi-generator version

"@openapitools/openapi-generator-cli": "^2.13.13",

OpenAPI declaration file content or url

"CriterionGenericConjunction": {
  "type": "object",
  "allOf": [
    {
      "$ref": "#/components/schemas/CriterionResidenceCriteriaHandmadeEnumResidenceCriteriaFieldEnum"
    },
    {
      "type": "object",
      "properties": {
        "type": {
          "type": "string",
          "enum": [
            "AND",
            "CONTAINS",
            "ENDS_WITH",
            "EQUALS",
            "GREATER_THAN",
            "GREATER_THAN_OR_EQUALS",
            "IN",
            "IS_NOT_NULL",
            "IS_NULL",
            "LESS_THAN",
            "LESS_THAN_OR_EQUALS",
            "LIKES",
            "NOT",
            "NOT_EQUALS",
            "OR",
            "STARTS_WITH"
          ]
        },
        "criteria": {
          "type": "array",
          "items": {
            "$ref": "#/components/schemas/CriterionCriteriaHandmadeEnumCriteriaFieldEnum"
          }
        }
      }
    }
  ]
},
"CriterionResidenceCriteriaHandmadeEnumResidenceCriteriaFieldEnum": {
  "required": [
    "type"
  ],
  "type": "object",
  "properties": {
    "type": {
      "type": "string"
    }
  },
  "discriminator": {
    "propertyName": "type"
  }
}

Generation Details

openapi-generator-cli generate -i http://localhost:5000/api/v3/api-docs/Aic -g typescript-fetch -o ./src/api/generated --skip-validate-spec --additional-properties=supportsES6=true,typescriptThreePlus=true

Related issues/PRs

Not found

Suggest a fix

Ensure that the type property in CriterionGenericConjunction is generated as required (type: string) based on the $ref to CriterionResidenceCriteriaHandmadeEnumResidenceCriteriaFieldEnum, which defines type as required.

Reproduce the issue with the provided OpenAPI declaration and the openapi-generator-cli typescript-fetch command. Inspect how the TypeScript generator handles required properties across allOf and $ref, then add or update a regression test if the relevant test area is found. Done means CriterionGenericConjunction generates type as required rather than type?.