Steven D'Aprano <steve+comp.lang.pyt...@pearwood.info> writes: >> But there's no way to know what that minimum is. Python libraries throw >> all sorts of exceptions that their documentation doesn't mention. > > Yes, you're absolutely correct. But it's also irrelevant. Most of those > exceptions should not be caught, even if you know what they are, because > they represent either bugs that should be fixed, or bad data which should > raise an exception. A bare except, or except Exception, is hardly ever the > right approach.
I'm not sure what to do instead. The exceptions I'm currently dealing with happen when certain network operations go wrong (e.g. network or remote host is down, connection fails, etc.) The remedy in each case is to catch the exception, log the error, and try the operation again later. But there's no guaranteed-to-be-complete list in the Python docs of all the exceptions that can be thrown. A new and surprising mode of network failure can lead to an unhandled exception, unless you catch everything. The Erlang approach is tempting. Don't catch the exception at all--just let the process crash, and restart it. But that's a more heavyweight operation in Python. > After all, unless you're writing > software for a nuclear reactor, or an aeroplane's autopilot, chances are > that *bugs don't really matter*. That is to say, if you release software > with a hidden bug, the consequences generally aren't very important. It's a retail application that would cause some business disruption and a pissed off customer if the program went down. Also it's in an embedded box on a customer site. It's not in Antarctica or anything like that, but it's a few towns over, and someone would have to drive there (probably through heavy traffic) if something went wrong that power cycling the box couldn't fix. > It took me a long time to realise that the world won't end if I write a > piece of software with a bug. It's not the end of the world if I get run over a truck, but such an event would be of enough consequence to me personally that I find it worth going to some trouble to avoid it. -- http://mail.python.org/mailman/listinfo/python-list
