Author paul.j3
Recipients Robert, bethard, chris.jerdonek, paul.j3
Date 2013-04-25.04:51:28
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Message-id <1366865488.78.0.830036964604.issue16970@psf.upfronthosting.co.za>
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Content
http://bugs.python.org/issue9849
also deals with nargs values.  However there the focus is on string values like '1', not whether an integer value can be 0 or <0.

I submitted a patch that moves the nargs testing to a ArgumentParser._check_argument() method.  It still depends on _format_args to do the actual testing of nargs.  I also make sure that group.add_argument() does this test.

Regarding this issue, can nargs=0 or <0?  _Store_action objects to 0, not because it causes runtime errors, but because it does not make sense.  Code with nargs=-1 runs without error, not consuming a string and returning [], just as a nargs=0 would.  

In http://bugs.python.org/issue14191 I found it useful to temporarily set nargs=0 to 'turn off' a positional.

I would vote for leaving this error message as is:

"ValueError: nargs for store actions must be > 0; if you have nothing to store, actions such as store true or store const may be more appropriate"

even though the test is actually nargs==0.  For normal use the recommendation that nargs>0 makes sense.
History
Date User Action Args
2013-04-25 04:51:28paul.j3setrecipients: + paul.j3, bethard, chris.jerdonek, Robert
2013-04-25 04:51:28paul.j3setmessageid: <1366865488.78.0.830036964604.issue16970@psf.upfronthosting.co.za>
2013-04-25 04:51:28paul.j3linkissue16970 messages
2013-04-25 04:51:28paul.j3create