Using .Net default value is trouble especially for APIs

Though there are features, they are not meant to be used. JavaScript atleast has a book named "JavaScript: The good parts" but others don't have one. Lets see one scenario in C# .Net.

Long long ago there was an API exposed to clients.

---

        class MyAPI
        {
            public void APIMethod(string s, int i = 10)
            {
                Console.WriteLine($"Inside foo with i = {i}");
            }
        }

internal void Test()
        {
            MyAPI apiClient = new MyAPI();
            apiClient.APIMethod("hi");
        }

---

Clients were happy using it. Later someone got added to the API team and he overloaded the method as follows thinking that keeping the same name will help the clients discover the API.

---

        class MyAPI
        {
            public void APIMethod(string s, int i = 10)
            {
                Console.WriteLine($"Inside APIMethod with i = {i}");
            }
            public void APIMethod(string s)
            {
                Console.WriteLine($"Inside APIMethod");
            }
        }

---

Clients happily adopted the new version of API. But soon they started feeling their calls are not working as expected. They escalated the issue and developers spent hours and days and finally they figured what went wrong. They corrected the code as follows.

---

        class MyAPI
        {
            public void APIMethod(string s, int i = 10)
            {
                Console.WriteLine($"Inside APIMethod with i = {i}");
            }
            public void NewAPIMethod(string s)
            {
                Console.WriteLine($"Inside NewAPIMethod");
            }
        }

---

Moral of the story

Do not use a feature only because it is available.