NGL, writing pure functions in Rust is fantastic. Writing responsible code that handles all the error conditions turns the “happy path” into hamburger. Even with the ergonomics of Result, Option, and even ?, code just sprawls and becomes a readability tradeoff. I’m only a few months into Rust at this point, and I have a lot to learn, but it’s tempting to just .unwrap() and .expect() where I think it’s unlikely to fail.

At times that shit is pretty much the opposite of what should be done.

Fail Fast is generally a much better way to handle certain risks, especially those around parts of the code which have certain expectations and the code upstream calling it (or even other systems sending it data) gets changed and breaks those expectations: it’s much better to just get “BAAM, error + stack trace” the first time you run the code with those upstream changes than have stuff silently fail to work properly and you only find out about it when the database in Production starts getting junk stored in certain fields or some other high impact problem.

You don’t want to silently suppress error reporting unless the errors are expected and properly dealt with as part of the process (say, network errors), you want to actually have the code validate early certain things coming in from the outside (be it other code or, even more importantly, other systems) for meeting certain expectations (say, check that a list of things which should never be empty is in fact not empty) and immediatly complain about it.

I’ve lost count how many times following this strategy has saved me from a small stupid bug (sometimes not even in my system) snowballing into something much worse because of the code silently ignoring that something is not as it’s supposed to be.

I’ve seen a lot worse where they just gobble the original error and throw a new one with 0 of the original context included making it 100x more difficult to debug.