What UB? This has nothing to do with UB; it'd be well-defined in any language. It's equivalent to this python snippet:
config = load_config()
if !config.valid():
sys.exit(1) # config is corrupt. restart pod
Did Python do something wrong by letting users call `sys.exit`? No. This is a deliberate crash. Under other circumstances, crashing might have been a valid strategy, but here it turned out to be a bad choice, since Cloudflare's infrastructure was restarting the service with the same bad config every time.
Sys exit does not crash. It raises a SystemExit exception, which can be caught on any layer above it. Given that python uses exceptions for trivial things like loop termination this can be considered normal flow control.
Yeah, and in Rust you can catch the panic from `unwrap()` with panic::catch_unwind. You just don't, for the same reason you don't catch SystemExits. If a SystemExit is being thrown, it's because you want to crash; if you don't wan to crash, don't throw a SystemExit.
