What is the name of the throw-an-exception on invalid inputs pattern?

Question

In some .NET libraries, there's a pattern of two alternative ways to call a function.

int i = x.GetValue(k); /* Might throw. */
if (x.TryGetValue(k, out int i) { /*...*/ } else { /* ... */ }

I don't like the names of these two functions as the not-Try variant presents itself the "normal" way to call a function. TryX, having the added word in the name, feels like a specialist form. For my new library that doesn't have to worry about existing users, I'd like to switch that around.

If I rename TryGetValue to just GetValue, what do I call the original GetValue that will throw an exception if it can't complete my request?

Is there a standard name for this pattern? (I'm hoping the industry has an established pattern rather than coining a new word in the comments, but you're welcome to do so if you wish.)

EDIT: I could be persuaded that TryGetValue is the correct name, but I'd still like to change the name of GetValue that throws an exception, leaving no function called just GetValue.

Answer 1

The TryX is a C# convention to indicate that the caller must check for errors explicitly and manually: failure is to be expected as part of normal program execution, so there won't be an exception.

Eliding this prefix is likely to lead to buggy code. Don't try to save these three characters, just stick to the convention.

In other languages, the compiler can enforce that the return value is checked, e.g. via [[nodiscard]] in C++ or #[must_use] in Rust. C# has no comparable feature.