> Well Rust won't save you from the usual programming mistake
This is not a Rust problem. Someone consciously chose to NOT handle an error, possibly thinking "this will never happen". Then someone else conconciouly reviewed (I hope so) a PR with an unwrap() and let it slide.
And people doing testing failed to ignore their excuse of this never happening and still testing it. With this kind of systems you need the separate group that just ignores any "this will never happen" and still checks what happens if it does.
Now it might be that it was tested, but then ignored or deprioritised by management...
This is not a Rust problem. Someone consciously chose to NOT handle an error, possibly thinking "this will never happen". Then someone else conconciouly reviewed (I hope so) a PR with an unwrap() and let it slide.