[BUG] No more inheritance for components generated by version 5.0.0

[antonio-petricca]

Description

No schema inheritance.

openapi-generator version

5.0.0

OpenAPI declaration file content or url

schemas:
  UserDTO:
      type: object
      properties:
        id:
          type: string
          minLength: 1
          maxLength: 20

  QueryUserResponseDTO:
      type: object
      allOf:
        - $ref: '#/components/schemas/UserDTO'

Generation Details

The above YAML produces:

public class QueryUserResponseDTO   {
   private @Valid String id;
}

Instead as for the 4.3.1:

public class QueryUserResponseDTO extends UserDTO   {
}

Suggest a fix

Does exist a configuration parameter to enforce the DTO inheritance generation? Or it is a bug?

[Msurrow]

Just to confirm. I updated from 4.3.1 -> 5.0.0 and I'm seeing the same issue (with dotnet-core generator) and AllOf inheritance.
For us, this makes vers 5.0.0 unusable.

If any help, here is a git diff of 4.3.1 generated class and 5.0.0 generated class which shows the issue:

• superclass gone form class signature
• base construtor not called
• superclass properties added to subclass

namespace FOOBAR.Model
 {
@@ -29,7 +29,7 @@ namespace FOOBAR.Model
     /// ProductBankLoan
     /// </summary>
     [DataContract(Name = "ProductBankLoan")]
-    public partial class ProductBankLoan : Product, IEquatable<ProductBankLoan>
+    public partial class ProductBankLoan : IEquatable<ProductBankLoan>, IValidatableObject
     {
         /// <summary>
         /// Initializes a new instance of the <see cref="ProductBankLoan" /> class.
@@ -38,9 +38,12 @@ namespace FOOBAR.Model
         /// <param name="productID">productID.</param>
         /// <param name="debtors">debtors.</param>
         /// <param name="collaterals">collaterals.</param>
-        public ProductBankLoan(double balance = default(double), int productID = default(int), List<Debtor> debtors = default(List<Debtor>), List<Collateral> collaterals = default(List<Collateral>)) : base(productID, debtors, collaterals)
+        public ProductBankLoan(double balance = default(double), int productID = default(int), List<Debtor> debtors = default(List<Debtor>), List<Collateral> collaterals = default(List<Collateral>))
         {
             this.Balance = balance;
+            this.ProductID = productID;
+            this.Debtors = debtors;
+            this.Collaterals = collaterals;
         }

[antonio-petricca]

I am going to revert to 4.3.1. :(

[Msurrow]

@antonio-petricca I'm getting this from the log when running the generator:

[main] INFO  o.o.codegen.utils.ModelUtils - [deprecated] inheritance without use of 'discriminator.propertyName' has been deprecated in the 5.x release. Composed schema name: null. Title: null
[main] INFO  o.o.codegen.utils.ModelUtils - [deprecated] inheritance without use of 'discriminator.propertyName' has been deprecated in the 5.x release. Composed schema name: null. Title: null

I havn't had time to dive into it fully yet (we've reverted to 4.3.1 for now) but from what I can gather it seems that my swagger.json doesnt have the discriminator field on the supertype. However I'm using asp.net swashbuckle to generate the swagger.json/.yaml which is setup to OAS3. So what I havn't figured out yet is if the problem really is the yaml not being generated correctly by swashbuckle (i.e. missing the discriminator field). I cant seem to get it to generate the discriminator field. (yet - working on it when I have time)

[felschr]

This happened to me after upgrading from 5.0.0-beta3 to 5.0.0.
The generated code using the typescript-fetch & dotnet generators is missing the inheritance.
Our openapi schema hasn't changed.

UPDATE:
Like @Msurrow we're using Swasbuckle and we disabled the oneOf & discriminator generation because we were previously hitting some other issues with the resulting unions that openapi-generator is creating (#7367).
Using allOf inheritance with a discriminator instead doesn't seem to be currently supported by Swashbuckle, see domaindrivendev/Swashbuckle.AspNetCore/issues/1973.

[adsanche]

I have the same problem from 5.x.x.

Actually, the following warning doesn't make sense :

[INFO] [deprecated] inheritance without use of 'discriminator.propertyName' has been deprecated in the 5.x release. Composed schema name: null. Title: null

As I have a propertyName placed on the discriminator on the parent object :

DeliveryDateApi:
      description: 'Delivery date information.'
      oneOf:
        - $ref: '#/components/schemas/RangeDeliveryDateApi'
        - $ref: '#/components/schemas/FixedDeliveryDateApi'
      discriminator:
        propertyName: type
        mapping:
          RANGE: '#/components/schemas/RangeDeliveryDateApi'
          FIXED: '#/components/schemas/FixedDeliveryDateApi'

Are there any update on this that could avoid rollbacking to 4.3.1?

[antonio-petricca]

I reverted to 4.3.1.

[tamershahin]

I have the same problems with kotlin-spring generator.
is this independent from the generator?

[Blackclaws]

This might be a bug in how ambiguousness of inheritance is being determined. I'm on it

[tamershahin]

This might be a bug in how ambiguousness of inheritance is being determined. I'm on it

I don't know if it's related to this bug, but I documented what worked for me here:
#8687

[Blackclaws]

So right now the issue is the following:

The spec itself says that allOf by itself does not imply a hierarchic relationship between the components. Therefore even if there is only a single reference in allOf this means that generating an inheritance relationship between them is not per se wrong (as the spec does not forbid it) but it also goes further than the spec and infers something that some people might not want to have.

I've opened an issue on the OpenAPI Spec itself to maybe get some clarification into the spec as to whether treating a single allOf ref as inheritance might make sense.

For now the solution is to simply add a discriminator property to the base object in order to get inheritance.

[Msurrow]

For now the solution is to simply add a discriminator property to the base object in order to get inheritance.

@Blackclaws
Its some time since I've looked at this, but for me part of the problem is that the spec generated by Swashbuckle doesn't include a discriminator on the base object.

You can see a code example in my post above, and a snippet of the generated spec is shown below. Perhaps this is the wrong place for this question (but you mentioned discriminators), but am I doing something wrong here?

      "Product": {
        "type": "object",
        "properties": {
          "productId": {
            "type": "integer",
            "format": "int32"
          },
          "debtors": {
            "type": "array",
            "items": {
              "$ref": "#/components/schemas/Debtor"
            },
            "nullable": true
          },
          "collaterals": {
            "type": "array",
            "items": {
              "$ref": "#/components/schemas/Collateral"
            },
            "nullable": true
          }
        },
        "additionalProperties": false
      },
      "ProductBankLoan": {
        "type": "object",
        "allOf": [
          {
            "$ref": "#/components/schemas/Product"
          }
        ],
        "properties": {
          "balance": {
            "type": "number",
            "format": "double"
          }
        },
        "additionalProperties": false
      }

This is using the configuraton:

Services.AddSwaggerGen(c =>
            {
                // Add discrimitators to swagger generator to handle inheritance types e.g. Product
                c.UseAllOfForInheritance();
              
                c.SwaggerDoc("v1", new OpenApiInfo { Title = "FOOBARApi", Version = "v1" });
            });