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python and gpl

Steve Holden steve at holdenweb.com
Mon Jan 31 15:35:57 EST 2005 
Scott Robinson wrote:

> On 30 Jan 2005 21:59:25 -0800, Paul Rubin
> <http://phr.cx@NOSPAM.invalid> wrote:
> 
> 
>>John Hunter <jdhunter at ace.bsd.uchicago.edu> writes:
>>
>>>The question is: does shipping a backend which imports a module that
>>>links with GPL code make some or all of the library GPL.
>>
>>Literally speaking, no, not automatically, any more than driving a car
>>makes you into a licensed driver if you weren't one already.  But if
>>you weren't licensed, then you've broken the law by driving the car.
>>So your question should be: 1) is shipping that backend one of the
>>things you need the GPL to license you to legally do, and 2) if so,
>>does the GPL in fact give you that license?
>>
>>If you're asking in terms of legal enforcement, the answer is 1) maybe
>>and 2) almost certainly not.  I think it's better to ask in terms of
>>the GPL's spirit.  I would say that it's not in the GPL's spirit and
>>that GPL die-hards would consider that use objectionable, though they
>>might make exceptions for specific cases (so it doesn't hurt to ask).
>>Some authors who use the GPL are less strict about how they interpret
>>it, so again, the friendly thing to do is ask the author.
>>
>> * If a backend module somebackend does
>>
>>    import somelib
>>
>>   where somelib is a python wrapper of GPL code, is somebackend GPLd?
>>
>>It's GPL'd if you GPL it.  If you don't GPL it, then distributing it
>>it may be a GPL violation that could get you taken to court.  I
>>believe the FSF's view is that it is fact a violation; however, the
>>courts have not yet established this.  The law doesn't have a
>>black-and-white boundary.  It's more like a fractal.  The only way to
>>find out what a court will decide is to actually try a case there.
>>
>>Rather than try to probe how closely you can dance around the
>>boundaries of the GPL, you might just ask the author of the GPL'd
>>library whether what you want to do is ok with him or her.  If s/he
>>says no and you do it anyway, you're both inviting trouble over the
>>possible infringement, and also inviting people to try to use your
>>code in ways you don't like.  Since the free software movement depends
>>on a spirit of cooperation, I think it's best to avoid trying to press
>>too hard against the boundaries of anyone's licenses.
>>
>>http://www.gnu.org/licenses/gpl-faq.html
> 
> 
> If you read the GPL, it claims everything it can (any "work" created
> using GPLed "work").  My guess is that anything that calls the code in
> a way not specifically allowed by the author is going to get you into
> trouble.  IANAL, but from what I can remember about earlier licensing
> issues, any code specific for a GPLed library (especially "import")
> will get you into to trouble.  Having a non-free library with an
> identical API and issuing 
> 	exec("import "+sys.argv[1])
> where the user can supply sys.argv as the name of the gpl'ed library
> will work (I think there is a free/non-free library out there that is
> never run, but exists for exactly this condition).
> 
> Scott Robinson
> 
I presume the appropriate way to answer this question is to ask the Gnu, 
since under these circumstances the Python zen would advise "refuse the 
temptation to guess". So I am Cc'ing gnu at gnu.org with a request for an 
answer to the (apparently relatively simple) question:

If a Python program imports a module licensed under the GPL, in your 
opinion does the Python program become a derivative work of the GPL'd 
software?

regards
  Steve
-- 
Steve Holden               http://www.holdenweb.com/
Python Web Programming  http://pydish.holdenweb.com/
Holden Web LLC      +1 703 861 4237  +1 800 494 3119
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