[Python-3000] [Python-Dev] warnings.showwarning (was Re: Reminder: last alphas next Wednesday 07-May-2008) (original) (raw)

Brett Cannon brett at python.org
Fri May 2 23:27:48 CEST 2008

On Fri, May 2, 2008 at 6:47 AM, Jean-Paul Calderone <exarkun at divmod.com> wrote: [SNIP]

> Hi Brett, > > I'm still seeing some strange behavior from the warnings module, This > can be observed on the community buildbot for Twisted, for example: > > http://python.org/dev/buildbot/community/trunk/x86%20Ubuntu%20Hardy%20trunk/builds/171 /step-Twisted.zope.stable/0 > > The log ends with basically all of the warning-related tests in Twisted > failing, reporting that no warnings happened. >

Just to follow up on this part, the failures are due to the tests expecting to be able to override a different function in the warnings module, not showwarning (warnexplicit). We used warnexplicit because there's no way to clear way to disable the filtering that gets applied to showwarning. warnexplicit doesn't claim to be a public hook, so I guess I won't complain about this. :)

Yeah, you guys are being naughty by replacing that and expecting stuff still to work. =)

The below behavior still seems wrong to me, though.

> There is also some strange behavior that can be easily observed in the REPL: > > exarkun at boson:~/Projects/python/trunk$ ./python /home/exarkun/Projects/Divmod/trunk/Combinator/combinator/xsite.py:7: DeprecationWarning: the sets module is deprecated > from sets import Set > Python 2.6a2+ (trunk:62636M, May 2 2008, 09:19:41) [GCC 4.1.3 20070929 (prerelease) (Ubuntu 4.1.2-16ubuntu2)] on linux2 > Type "help", "copyright", "credits" or "license" for more information. > >>> import warnings > >>> warnings.warn("foo") > :1: UserWarning: foo # Where'd the module name go? > >>> def f(*a): > ... print a > ... > >>> warnings.showwarning = f > >>> warnings.warn("foo") > >>> # Where'd the warning go? > > Any ideas on this?

If you run this in a stock 2.5 interpreter I get something similar except the missing 'main'. If I run it with PYTHONSTARTUP set it actually uses that module for some reason as the source.

I created issue2743 to fix the output at the interpreter, but I made it a critical bug since it is only at the interpreter (and thus breaking people's code will be small), but it should still be fixed since 'warnings' is a core piece of infrastructure.

-Brett

-Brett

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