[Mailman-Developers] re: advice needed: shunt problems with MM2.1 and 2.1.2 only on one list out of many

[Chris Dagdigian]

Hello,

I'm following up my own message because we seem to have resolved our 
issue with MM2.1.2 shunting messages with a "TypeError: iterable 
argument required" traceback.

We re-created our list and got email flowing again which was our main 
concern. Andrew Dalke then had the time to check out the traceback 
errors and the messages that remaind in the shunt/ directory.

He is suggesting a patch or a possible fix so I'm enclosing his entire 
message here:

Our server is an ancient Alpha box running RedHat Linux 6.2 with a clean 
build of python 2.3.

Mailman is 2.1.2 but since we've been using MM for years and 
upgrade-installing into the same directory I can't promise that our 
problems were not caused entirely by old cruft laying around....


-Chris

Here are the notes from Andrew:

> Actually, I didn't get your email about the shunt problem, I got it
> about the archive problem.  So I'm sending this to you to let
> you forward to mailman developers in the proper context
> 
> Here's the traceback
> 
> Traceback (most recent call last):
>   File "/home/mailman/Mailman/Queue/Runner.py", line 105, in _oneloop
>     self._onefile(msg, msgdata)
>   File "/home/mailman/Mailman/Queue/Runner.py", line 155, in _onefile
>     keepqueued = self._dispose(mlist, msg, msgdata)
>   File "/home/mailman/Mailman/Queue/IncomingRunner.py", line 130, in _dispose
>     more = self._dopipeline(mlist, msg, msgdata, pipeline)
>   File "/home/mailman/Mailman/Queue/IncomingRunner.py", line 153, in _dopipeline
>     sys.modules[modname].process(mlist, msg, msgdata)
>   File "/home/mailman/Mailman/Handlers/ToDigest.py", line 89, in process
>     send_digests(mlist, mboxfp)
>   File "/home/mailman/Mailman/Handlers/ToDigest.py", line 130, in send_digests
>     send_i18n_digests(mlist, mboxfp)
>   File "/home/mailman/Mailman/Handlers/ToDigest.py", line 303, in send_i18n_digests
>     msg = scrubber(mlist, msg)
>   File "/home/mailman/Mailman/Handlers/Scrubber.py", line 257, in process
>     url = save_attachment(mlist, part, dir)
>   File "/home/mailman/Mailman/Handlers/Scrubber.py", line 349, in save_attachment
>     ext = guess_extension(ctype, fnext)
>   File "/home/mailman/Mailman/Handlers/Scrubber.py", line 80, in guess_extension
>     if ext in all:
> TypeError: iterable argument required
> 
> It occurs when Scrubber.guess_extension .  The code does
> 
>     all = guess_all_extensions(ctype, strict=0)
>     if ext in all:
>         return ext
>     return all and all[0]
> 
> The function 'guess_all_extensions' comes from the top of the
> files from the section
> 
> try:
>     from mimetypes import guess_all_extensions
> except ImportError:
>     import mimetypes
>     def guess_all_extensions(ctype, strict=1):
>         # BAW: sigh, guess_all_extensions() is new in Python 2.3
> 
> We're running Python 2.3, which means we're using the
> one from mimetypes.  That function's docstring says
> 
>         guess_type().  If no extension can be guessed for `type', None
>         is returned.
> 
> So if no extension can be guessed, then Scrubber.guess_extension
> try to iterate over None, which fails
> 
> Our fix to get things working again is
> 
>     all = guess_all_extensions(ctype, strict=0)
>     if all is None: all = []
>     if ext in all:
>         return ext
>     return all and all[0]
> 
> However, another possibility is that the guess_all_extensions
> in Python 2.3's mimetypes should return [] when it cannot
> guess, rather than a None.  I would be happier with that
> solution than this patch, but will leave it up to the Mailman
> and Python people to decide on the appropriate solution.
> 
>                     Andrew Dalke
>                     dalke at dalkescientific.com