@injectable() in abstract class doesn't work with protected constructor

[AmirBazanov]

Decorator function return type 'abstract new (...args: never) => unknown' is not assignable to type 'void | typeof BaseController'.
  Types of construct signatures are incompatible.
    Type 'abstract new (...args: never) => unknown' is not assignable to type 'abstract new (logger: ILogger) => BaseController'.
      Type 'unknown' is not assignable to type 'BaseController'.ts(1270)
Argument of type 'typeof BaseController' is not assignable to parameter of type 'abstract new (...args: never) => unknown'.
  Cannot assign a 'protected' constructor type to a 'public' constructor type.ts(2345)

This error rise when I make constructor protected, I'm trying to find answer in Inversify docs but where is nothing about

Example of my code

@injectable()
export abstract class BaseController {
    private readonly _router: Router

    protected constructor(@inject(TYPES.ILogger) private logger: ILogger) {
        this._router = Router();
    }
    //some code
}

Why should it be public?

[simaosoares]

I have the same issue. I tried to remove the decorator @injectable() but it fails later on running the services, saying the decorator is missing 🤷‍♂️

[notaphplover]

Hey @AmirBazanov, you're right, @injectable is not only targeted by non abstract classes since you might be interested in provide child classes of BaseController. Therefore, it makes a lot of sense to allow using this decorator in classes with a protected constructor as long as the child class has a public constructor.

We have plans to update inject and injectable decorators to rely on ClassDecorator, MethodDecorator and PropertyDecorator as proposed on #1591. Once we go for it this issue should be solved.