Re: How to except the unexpected?

>Yes, and that's the Right Thing(tm) to do. Source code don't lie. Source > code don't get out of sync. So source code *is* the best documentation >(or at least the most accurate). I could not disagree more strongly with this. Not just no, but hell no! >Yes, and that's the Right Thing(tm) to do

Re: How to except the unexpected?

Rene Pijlman wrote: > Steven D'Aprano: >> The OP is doing it because catching all exceptions masks bugs. There are >> certain exceptions which should be allowed through, as they indicate a bug >> in the OP's code. Normally the tactic is to catch only the exceptions you >> are interested in, and let

Re: How to except the unexpected?

Steven D'Aprano: >The OP is doing it because catching all exceptions masks bugs. There are >certain exceptions which should be allowed through, as they indicate a bug >in the OP's code. Normally the tactic is to catch only the exceptions you >are interested in, and let everything else through, but

Re: How to except the unexpected?

On Sat, 04 Mar 2006 13:19:29 -0800, James Stroud wrote: > Why catch an error only to re-raise it? As a general tactic, you may want to catch an exception, print extra debugging information, then raise the exception again, like this: try: x = somedata() y = someotherdata() z = process

Re: How to except the unexpected?

James Stroud <[EMAIL PROTECTED]> writes: > My suggestion was to use some common sense about the source code and > apply it. The common sense to apply is that if the source code says one thing and the documentation says another, then one of them is wrong and should be updated. Usually it's the sou

Re: How to except the unexpected?

Paul Rubin wrote: > James Stroud <[EMAIL PROTECTED]> writes: > >>>approach. Basically this is reverse engineering the interface from the >>>source at the time of writing the app. >> >>This is using the source as documentation, there is no law against >>that. > > That's completely bogus. Undocume

Re: How to except the unexpected?

James Stroud <[EMAIL PROTECTED]> writes: > > approach. Basically this is reverse engineering the interface from the > > source at the time of writing the app. > > This is using the source as documentation, there is no law against > that. That's completely bogus. Undocumented interfaces in the li

Re: How to except the unexpected?

Rene Pijlman wrote: > James Stroud: > >>Which suggests that "try: except HTTPException:" will be specific enough >>as a catchall for this module. >> >>The following, then, should catch everything you mentioned except the >>socket timeout: > > > Your conclusion may be (almost) right in this cas

Re: How to except the unexpected?

James Stroud <[EMAIL PROTECTED]> writes: > > try: > > process_things() > > except Reraise: > > raise > > except: > > log_error() > > > > Why catch an error only to re-raise it? > > This falls under http://c2.com/cgi/wiki?YouReallyArentGonnaNeedThis No, without the reraise, the bare "

Re: How to except the unexpected?

James Stroud <[EMAIL PROTECTED]> wrote: > > Reraise = (LookupError, ArithmeticError, AssertionError) # And then some > > > > try: > > process_things() > > except Reraise: > > raise > > except: > > log_error() > > > > Why catch an error only to re-raise it? To avoid the following ha

Re: How to except the unexpected?

Rene Pijlman wrote: > Steven D'Aprano: > >>ExpectedErrors = (URLError, IOError) >>ErrorsThatCantHappen = >> >>try: >> process_things() >>except ExpectedErrors: >> recover_from_error_gracefully() >>except ErrorsThatCantHappen: >> print "Congratulations! You have found a program bug!" >> pri

Re: How to except the unexpected?

Rene Pijlman a écrit : > Jorge Godoy: > >>Rene Pijlman: >> >>>my app was surprised by an >>>httplib.InvalidURL since I hadn't noticed this could be raised by >>>robotparser (this is undocumented). >> >>It isn't undocumented in my module. From 'pydoc httplib': > > > That's cheating: pydoc is rea

Re: How to except the unexpected?

Rene Pijlman wrote: > Paul Rubin : > >>We have to get Knuth using Python. > > > Perhaps a MIX emulator and running TeXDoctest on his books will convince > him.. Or maybe Python written for MIX... -Roman -- http://mail.python.org/mailman/listinfo/python-list

Re: How to except the unexpected?

In article <[EMAIL PROTECTED]>, Rene Pijlman <[EMAIL PROTECTED]> wrote: > Roy Smith: > >In theory, all exceptions which represent problems with the external > >environment (rather than programming mistakes) should derive from > >Exception, but not from StandardError. > > Are you sure? > > """

Re: How to except the unexpected?

Roy Smith: >In theory, all exceptions which represent problems with the external >environment (rather than programming mistakes) should derive from >Exception, but not from StandardError. Are you sure? """ The class hierarchy for built-in exceptions is: Exception +-- StandardError

Re: How to except the unexpected?

Jorge Godoy: >Rene Pijlman: >> my app was surprised by an >> httplib.InvalidURL since I hadn't noticed this could be raised by >> robotparser (this is undocumented). > >It isn't undocumented in my module. From 'pydoc httplib': That's cheating: pydoc is reading the source :-) What I meant was, I'

Re: How to except the unexpected?

Rene Pijlman <[EMAIL PROTECTED]> wrote: > A catchall seems like a bad idea, since it also catches AttributeErrors > and other bugs in the program. All of the things like AttributeError are subclasses of StandardError. You can catch those first, and then catch everything else. In theory, all e

Re: How to except the unexpected?

Rene Pijlman <[EMAIL PROTECTED]> writes: > With low coverage, yes. But unit testing isn't the answer for this > particular problem. For example, yesterday my app was surprised by an > httplib.InvalidURL since I hadn't noticed this could be raised by > robotparser (this is undocumented). If that fa

Re: How to except the unexpected?

Steven D'Aprano: >ExpectedErrors = (URLError, IOError) >ErrorsThatCantHappen = > >try: >process_things() >except ExpectedErrors: >recover_from_error_gracefully() >except ErrorsThatCantHappen: >print "Congratulations! You have found a program bug!" >print "For a $327.68 reward, pleas

Re: How to except the unexpected?

Paul Rubin : >We have to get Knuth using Python. Perhaps a MIX emulator and running TeXDoctest on his books will convince him.. -- René Pijlman -- http://mail.python.org/mailman/listinfo/python-list

Re: How to except the unexpected?

Peter Hansen: >Good code should probably have a very small set of real exception >handling cases, and one or two catchalls at a higher level to avoid >barfing a traceback at the user. Good point. >> A catchall seems like a bad idea, since it also catches AttributeErrors >> and other bugs in the

Re: How to except the unexpected?

James Stroud: >Which suggests that "try: except HTTPException:" will be specific enough >as a catchall for this module. > >The following, then, should catch everything you mentioned except the >socket timeout: Your conclusion may be (almost) right in this case. I just don't like this approach. B

Re: How to except the unexpected?

Roy Smith: >I like to create a top-level exception class to encompass all the >possible errors in a given module, then subclass that. This way, if you >want to catch anything to goes wrong in a call, you can catch the top-level >exception class without having to enumerate them all. What do you

Re: How to except the unexpected?

Steven D'Aprano <[EMAIL PROTECTED]> writes: > The way to deal with it is to add another except clause to deal with the > KeyboardInterrupt, or to have recover_from_error_gracefully() deal with > it. I think adding another except clause for KeyboardInterrupt isn't good because maybe in Python 2.6

Re: How to except the unexpected?

On Fri, 03 Mar 2006 21:10:22 -0800, Paul Rubin wrote: > Steven D'Aprano <[EMAIL PROTECTED]> writes: >> try: >> process_things() >> except ExpectedErrors: >> recover_from_error_gracefully() >> except ErrorsThatCantHappen: >> print "Congratulations! You have found a program bug!" >>

Re: How to except the unexpected?

Steven D'Aprano <[EMAIL PROTECTED]> writes: > try: > process_things() > except ExpectedErrors: > recover_from_error_gracefully() > except ErrorsThatCantHappen: > print "Congratulations! You have found a program bug!" > print "For a $327.68 reward, please send the following " \ >

Re: How to except the unexpected?

On Sat, 04 Mar 2006 00:10:17 +0100, Rene Pijlman wrote: > I've writen an application that uses urllib2, urlparse, robotparser and > some other modules in the battery pack. One day my app failed with an > urllib2.HTTPError. So I catch that. But then I get a urllib2.URLError, so > I catch that too.

Re: How to except the unexpected?

Rene Pijlman wrote: > One of the things I dislike about Java is the need to declare exceptions > as part of an interface or class definition. But perhaps Java got this > right... > > I've writen an application that uses urllib2, urlparse, robotparser and > some other modules in the battery pack. O

Re: How to except the unexpected?

In article <[EMAIL PROTECTED]>, Ben Caradoc-Davies <[EMAIL PROTECTED]> wrote: > James Stroud wrote: > > except URLError, HTTPException: > > Aieee! This catches only URLError and binds the name HTTPException to > the detail of that error. You must write > > except (URLError, HTTPException): >

Re: How to except the unexpected?

Ben Caradoc-Davies wrote: > James Stroud wrote: > >> except URLError, HTTPException: > > > Aieee! This catches only URLError and binds the name HTTPException to > the detail of that error. You must write > > except (URLError, HTTPException): > > to catch both. > Oops. -- http://mail.python

Re: How to except the unexpected?

James Stroud wrote: > except URLError, HTTPException: Aieee! This catches only URLError and binds the name HTTPException to the detail of that error. You must write except (URLError, HTTPException): to catch both. -- Ben Caradoc-Davies <[EMAIL PROTECTED]> http://wintersun.org/ "Those who deny

Re: How to except the unexpected?

Rene Pijlman wrote: > One of the things I dislike about Java is the need to declare exceptions > as part of an interface or class definition. But perhaps Java got this > right... > > I've writen an application that uses urllib2, urlparse, robotparser and > some other modules in the battery pack. O

How to except the unexpected?

One of the things I dislike about Java is the need to declare exceptions as part of an interface or class definition. But perhaps Java got this right... I've writen an application that uses urllib2, urlparse, robotparser and some other modules in the battery pack. One day my app failed with an url