Inconsistent socket.gethostbyname exceptions

[Donn Cave]

Quoth Ronald Hiller <ron at graburn.com>:
| I've noticed that the socket.gethostbyname function doesn't return the
| same format of exceptions as other socket operations (like connect).
| For example, a failed get hostbyname returns a simple string 'host not
| found' whereas a failed connect returns a list (146, 'Connection
| refused').
|
| I've looked at socketmodule.c and noticed that gethostbyname puts
| together it's own exception while connect calls PySocket_Err to pack up
| errno with the string into a tuple.
|
| Now, I understand that there is no errno value for 'host not found' and
| synthesizing something may be a "bad thing".  However, testing
| exceptions is somewhat tricky since the format apparently differs
| between operations.  Now, if these are the only two cases, I guess it's
| not so bad, but I worry (I admit to not having searched the source) that
| there could be more cases with different formats.
|
| Is this a bug, or am I getting excited about nothing?

Somewhere in between the two, I think.  It's a good question, too good
for me or apparently anyone else to have a good answer!  If it's not a
bug, certainly it's not a strong point of the runtime either.

I hope in some future version of Python, the exception will have more
reliable attributes.  I have no specific idea how that would actually
look, what attributes precisely I'm looking for, but I think if the
socket module ever gets the 1.5 OO exception treatment, like the posix
module did, that will probably help.  I wouldn't be surprised if this
is on the list of things to do, but there also might be room for someone
to contribute that change.

	Donn Cave, donn at oz.net