When is bare except: justified?

John J. Lee jjl at pobox.com
Fri Dec 5 21:38:01 CET 2003


"Dave Brueck" <dave at pythonapocrypha.com> writes:

> > When *is* it justified to use except:, then?
[...]
> The rule of thumb I use is that a bare except is bad if it hides the fact that
> an exception occurred. So, for example, using a bare except in code like this
> is okay:
> 
> for worker in workers:
>   try:
>     worker.process()
>   except:
>     LogException()
> 
> It's considered "okay" because even though the code prevents the exception from
> propagating, it doesn't lose record of the fact that something went wrong.
[...]

Now that you say that, it's obvious :-) In fact, IIRC just the other
day I fixed code to work that way in the same package I discussed in
my post:

        try:
            __import__(module_name)
        except ImportError:
+           traceback.print_exc()
            sys.exit("Import of test module failed -- Couldn't find tests?")

(this is in a hack to import all tests from a bunch of test_foo.py files)


I guess I can keep the bare except:s I discussed in the first part of
my post after all, but just make sure I emit a warning (with the
warnings module in 2.3, I suppose).

Thanks!


John




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