[default-kramer]

How many people actually write exhaustive tests for everything that could possibly be null? No one I've ever met in my mostly-C# career.

I can confirm that at least 30% of the prod alerts I've seen come from NullReferenceExceptions. I insist on writing new C# code with null-checking enabled which mostly solves the problem, but there's still plenty of code in the wild crashing on null bugs all the time.

[9rx]

> How many people actually write exhaustive tests for everything that could possibly be null?

Of those who are concerned about type theory? 99%. With a delusional 1% thinking that a gimped type system (read: insufficient for formal proofs) is some kind of magic that negates the need to write tests, somehow not noticing that many of the lessons on how to write good tests come from those language ecosystems (e.g. Haskell).

> I can confirm that at least 30% of the prod alerts I've seen come from NullReferenceExceptions.

I don't think I've ever seen a null exception (or closest language analog) occur in production, and I spent a lot of years involved in projects that used dynamically typed languages even. I'd still love for someone to show actual code and associated tests to see how they ended up in that situation. The other commenter, despite being adamant, has become avoidant when it comes down to it.

[mdaniel]

> to see how they ended up in that situation

The "how" is almost always lack of discipline (or as I sometimes couch it, "imagination") but usually shit like https://github.com/microsoft/SynapseML/issues/405#:~:text=cl...

I've had to learn in my career not to open other people's projects in a real IDE because of all the screaming it does about "value can be null"