[BUG] @SuperBuilder with a class with generic types

[cjp0tter]

Describe the bug
I'm running into an issue attempting to use the @SuperBuilder annotation with a class with generic types.

To Reproduce

Works .. Allows me to provide my own customized constructor.

Sample Code...

@SuperBuilder
@Getter
public abstract class ShapeClass {
   private final String name;
   protected ShapeClass(ShapeClassBuilder<?, ?> b) {
      this.name = b.name;
      validate();
   }
   private void validate() {
      if (name == null || name.isEmpty()) {
         throw new IllegalArgumentException("Name must not be empty");
      }
   }
}

@SuperBuilder
@Getter
public class RectangleClass extends ShapeClass {
   private final int width;
   private final int height;
   protected RectangleClass(RectangleClassBuilder<?, ?> b) {
      super(b);
      this.width = b.width;
      this.height = b.height;
      validate();
   }
   private void validate() {
      if (width <= 0 || height <= 0) {
         throw new IllegalArgumentException("Width and height must be positive integers");
      }
   }
}

Fails (The constructor was taken from de-lomboked code). Error message is...

 "/Users/potterc/vcs/nexus/couchbase-core/src/main/java/com/vu/core/couchbase/context/RectangleClass.java:8: error: constructor RectangleClass(RectangleClassBuilder<T,?,?>) is already defined in class RectangleClass
@SuperBuilder
^
  where T is a type-variable:
    T extends Serializable declared in class RectangleClass
1 error".

Sample Code...

@SuperBuilder
@Getter
public abstract class ShapeClass<T extends Serializable> {
   private final String name;
   protected ShapeClass(ShapeClassBuilder<T, ?, ?> b) {
      this.name = b.name;
      validate();
   }
   private void validate() {
      if (name == null || name.isEmpty()) {
         throw new IllegalArgumentException("Name must not be empty");
      }
   }
}

@SuperBuilder
@Getter
public class RectangleClass<T extends Serializable> extends ShapeClass<T> {
   private final int width;
   private final int height;
   protected RectangleClass(RectangleClassBuilder<T, ?, ?> b) {
      super(b);
      this.width = b.width;
      this.height = b.height;
      validate();
   }
   private void validate() {
      if (width <= 0 || height <= 0) {
         throw new IllegalArgumentException("Width and height must be positive integers");
      }
   }
}

Version info (please complete the following information):

• version 1.18.32
• javac 11.0.7

[aforslow-cubist]

I noticed this bug yesterday as well and made an SO post on it: https://stackoverflow.com/q/78264233/8353218. Basically, the default constructor works for regular classes, but not generic classes.

Works:

@SuperBuilder
public class MyRegularSuperObject {
    private final String someString;
    
    protected MyRegularSuperObject(MyRegularSuperObject.MyRegularSuperObjectBuilder<?,?> b) {
        someString = b.someString;
    }
}

Does not work:

@SuperBuilder
public class MyGenericSuperObject<T> {
    private final String someString;
    
    protected MyGenericSuperObject(MyGenericSuperObjectBuilder<T,?,?> b) {
        someString = b.someString;
    }
}

The following error is thrown:

error: constructor MyGenericSuperObject(MyGenericSuperObjectBuilder<T,?,?>) is already defined in class MyGenericSuperObject @SuperBuilder ^ where T is a type-variable: T extends Object declared in class MyGenericSuperObject

Hope someone takes a look at this, as this is a very important use case for me and probably many others. Right now, I have to delombok in order to get this working, but it creates so much boiler plate and makes the code so much harder to understand...

[janrieke]

There is already a PR in the works: #3646

[cjp0tter]

This is great news. Thanks.