This can happen regardless of language.

The actual issue is that they should be canarying changes. Push them to a small percentage of servers, and ensure nothing bad happens before pushing them more broadly. At my workplace, config changes are automatically tested on one server, then an entire rack, then an entire cluster, before fully rolling out. The rollout process watches the core logs for things like elevated HTTP 5xx errors.

honestly this was a coding cock-up. there's a code snippet in the article that unwraps on a Result which you don't do unless you're fine with that part of the code crashing

i think they are turning linters back to max and rooting through all their rust code as we speak

I hope you're joking. If anything, Rust makes error handling easier by returning them as values using the Result monad. As someone else pointed out, they literally used unwrap in their code, which basically means "panic if this ever returns error". You don't do this unless it's impossible to handle the error inside the program, or if panicking is the behavior you want due to e.g. security reasons.

Even as an absolute amateur, whenever I post any Rust to the public, the first thing I do is get rid of unwrap as much as possible, unless I intentionally want the application to crash. Even then, I use expect instead of unwrap to have some logging. This is definitely the work of some underpaid intern.

Also, Python is sloooowwww.