> But the truth is, all you need is the array holding the important values and all you need to do is document the function appropriately. "Don't modify the retu

> But the truth is, all you need is the array holding the important values and all you need to do is document the function appropriately. "Don't modify the returned list" would be a good start. I agree that over-engineering is both common and unhelpful in software development. On the other hand, I think you are too quick to dismiss encapsulation techniques. The sort of defensive programming tools you mentioned aren't there because dumb programmers don't know any better. They are there because smart programmers know that sometimes they will still make mistakes anyway. See also: failing to free dynamically allocated memory, failing to check return codes or handle exceptions, failing to exit a loop under the correct conditions, creating deadlocks in multithreaded code, etc.