[Python-Dev] Adding NetworkIOError for bug 1706815

[Gregory P. Smith]

On Wed, Jul 04, 2007 at 11:03:42AM +0200, Guido van Rossum wrote:
> Why not simply inherit socket.error from EnvironmentError?

True, that would be simpler; is it enough?  If we avoid adding the new
exception, I really think it should inherit from IOError, not
EnviromnentError because sockets are I/O.  urllib2.URLError was
already a child of IOError; doing the same to to socket.error makes
sense.

The patch makes URLError a child of NetworkIOError instead of IOError.
Does that make sense?  URLs as an abstract concept may or may not
imply network I/O behind the scenes though network i/o is the most
common use.  I could take that argument further and suggest they don't
necessarily even imply actual I/O if you've provided your own protocol
handlers.

The question then becomes if there are any use cases for "except
NetworkIOError:" that code wouldn't want to just use "except IOError:"
for that using "except socket.error:" or "except urllib2.URLError:"
are insufficient for.  My intuition is telling me: probably not.
urllib2 code should catch socket.error everywhere internally and turn
it into a URLError (the code appears to do this in many places though
i haven't audited that it does everywhere).

-greg

PS for the person complaining that the url didn't work.  blame
   sourceforge and go look the bug up by id yourself.  nothing i can
   do about that.

> On 7/4/07, Gregory P. Smith <greg at electricrain.com> wrote:
> >In response to bug 1706815 and seeing messy code to catch errors in
> >network apps I've implemented most of the ideas in the bug and added a
> >NetworkIOError exception (child of IOError).  With this, socket.error
> >would now inherit from NetworkIOError instead of being its own thing
> >(the old one didn't even declare a parent!).
> >
> >Complete patch attached to the bug.  All unit tests pass.
> >Documentation updates included.
> >
> > http://sourceforge.net/tracker/index.php?func=detail&aid=1706816&group_id=5470&atid=105470
> >
> >Any thoughts?  I'm happy with it and would like to commit it if folks
> >agree.