Edge Case Poisoning (2020)

Weaken the type system, reduce the automated test coverage, and you are likely to find that edge cases are addressed on more of a "who's currently yelling at us about what feature isn't working" basis, which will ultimately mean that fewer edge cases get addressed or are more likely to persist as undetected bugs, which could be either desirable or undesirable, depending on your domain.

It's fine to handle an explicit subset of a problem. What's not fine is not making this clear. Real software can generally have a well-defined domain and range, which this article muddies with its example.

> This works but is quitter talk.

It's a valid solution. Expressing weird recipes as lists of normal recipes is perfectly fine.

> If we want to include recipe expansion as a feature of our model, we need to make the algorithm more complicated to handle the single edge case of fondant.

Yes, it turns out writing correct software sometimes requires this, even for a small amount of overall cases. That's no argument against not handling all cases.

To the parent poster:

I expect someone incapable of writing perfect software to claim it to be impossible, yes. I'd upload an article I've written proving my point, but it's about correct software, so it would just get ignored here.

Software is mathematics, and mathematics can be perfect.

> This is why I laugh at talk of "bug free" software. The best you can do is zero reported bugs. Temporarily.

No, this is the best the incompetent can do, but I won't let them drag me down to their level.

As several people pointed out, I never said what my context for encoding recipes was, so here's a bit more about what inspired this example. I throw a lot of dinner parties, and a lot of my friends have dietary restrictions. I always try to pick a menu where everybody can eat at least one entree and at least one side.¹ I want to be able to query my recipes for "vegan-friendly" or "peanut-free". But also a lot of recipes have substitutions: if a pork ingredient can be replaced by tofu, does that dish count as "vegetarian"? Maybe, maybe not, but it'd be nice to have the option to choose.

(The other menu constraint is the cooking process: I can't make two dishes that both take the slow cooker, but I can do two that both take skillets.)

I occasionally look for recipe apps but I never find any that are good for this use case. For now I still print out recipes and put them in a binder and figure out the menus on a whiteboard. So ultimately it's more an interesting example than a problem I'm trying to solve.

¹ I love them to death but I also a breath a sigh of relief when none of my vegan friends can make it