[OT] my experience with nullable types (C#)

[Dadoum]

On Wednesday, 30 April 2025 at 07:17:37 UTC, Kagamin wrote:
> Finally I had my chance to cope with nullable types in one of 
> our C# codebases, and the experience wasn't nice.
>
> I had a prejudice that nullable types give some kind of promise 
> that you will have only a few of them, but now that I think 
> about it I can't remember anyone making this promise, and 
> reality is quick to shatter this prejudice in a very ugly way.
> If you have a nullable type, all code now sees it as nullable, 
> and you must insert null checks everywhere, even if you know 
> it's not null by that point, and the volume of this null check 
> spam is uncomfortably large.

I don't really understand, why is your type nullable if you know 
for sure it's not null at this point ? If it's a function 
parameter, you'll have to think and ask yourself: "Does my 
function have any point on a null object?" If not, just remove 
the nullable type there.

If your type has a nullable field, ask yourself: "When will this 
be null?" If you know that after some action this can no longer 
be null, just create a new type to encode this knowledge. Just 
keep in mind that basically, having a nullable field means that 
the object is in valid state even when the field is null. An 
example of bad design is when a lot of functions dealing with 
that object type have guards/asserts at the beginning. It means 
probably that the object doesn't provide enough guarantees about 
what it's storing.