Renaming a public class in a shipped library

Question

I have a library which has shipped (internally, but still shipped), and I would like to rename a public class within the library.

What I would like is a way to make sure that

• client code keeps on working

• client code gets a deprecation warning on compilation on use of the class name

• Is there any way to alias the class in some way, which will exhibit the above properties?

• Is there any way to avoid this problem in the future (other than making sure classes are named and spelled properly?) Note that I would like to keep a public constructor, so working with interfaces will not fix all my problems.

Answer 1

You can' provide any public alias name to the class, but you can forward all public properties, methods, etc. to a private instance of the renamed class and decorate the class with the obsolete attribute:

[Obsolete("Please use LatestGreatest instead.")]
public class OldSchool
{
    private LatestGreatest _Target;

    public OldSchool()
    {
        _Target = new LatestGreatest();
    }

    public void DoSomething()
    {
        _Target.DoSomething();
    }

    [Obsolete("Please use LatestGreatest.DoItInSomeOtherWay()")]
    public void DoTheOldWay()
    {
        _Target.DoItInSomeOtherWay();
    }
}

public class LatestGreatest
{
    public void DoSomething()
    {
        Console.WriteLine("I'm so fresh and cool.");
    }

    public void DoItInSomeOtherWay()
    {
        Console.WriteLine("Let's do it...");
    }
}

Depending on the size of the public side of your old class this work can be quite tedious, but there is nothing else you can do.