[AstroPy] Healpy

Mon Oct 5 13:29:17 EDT 2015

That doesn’t say quite that. It says “GPL-compatible” and 3-clause BSD is GPL compatible. A contrasting example is if you released software that had a GPL incompatible license (e.g., as SOFA did), you just can’t use GPL code at all, period, in any release.

This FAQ item is more relevant: http://www.gnu.org/licenses/gpl-faq.html#NFUseGPLPlugins

Note the third paragraph. “Borderline” :-)

In any case, if even the current usage was prohibited, then one just designs the library to use a generic plug-in feature, and all the GPL-dependent plug-ins are released under the GPL separately somewhere else.

So long as there is no essential functionality needed in the plugin (e.g., there is no usefulness to the package without using the GPL software) then that probably skirts the issue effectively.

Cheers, Perry

On Oct 5, 2015, at 1:20 PM, Peter Williams <peter at newton.cx> wrote:

> The last paragraph in this FAQ entry:
> 
> http://www.gnu.org/licenses/gpl-faq.html#IfInterpreterIsGPL
> 
> seems, to me, to make it clear that using a GPL'd module inside an
> interpreted program/library (e.g. astropy) obliges you to make it
> available under GPL-compatible terms. I am generally positive about the
> GPL but I find this to be unfortunate.
> 
> I think the best solution in these cases is to provide extension hooks
> in the core (BSD/MIT-type-licensed) module so that you can load up an
> optional GPL-licensed module so that GPL-only features can be used in a
> relatively convenient way through the core module's API.
> 
> Peter
> 
> On Mon, 2015-10-05 at 12:32 -0400, Perry Greenfield wrote:
>> Not if the functionality is essential to the package (at least from
>> what I understand). I’ll see if I can dig that aspect of the license
>> that specifically mentions it (or legal discussion around it).
>> 
>> Cheers, Perry
>> 
>> On Oct 5, 2015, at 12:30 PM, Wolfgang Kerzendorf <
>> wkerzendorf at gmail.com> wrote:
>> 
>>> This is very off topic:
>>> 
>>> I thought you just can’t ship a non-GPL package with GPL libraries.
>>> BUT: If Microsoft makes Word relying on some GPLed library (core
>>> -functionality), then they can ship a closed source copy of Word as
>>> long as the user needs to download the GPL library from some other
>>> source? 
>>> 
>>> Isn’t that right?
>>> 
>>> Cheers, 
>>>  Wolfgang
>>>> On Oct 5, 2015, at 18:20, Perry Greenfield <stsci.perry at gmail.com
>>>>> wrote:
>>>> 
>>>> If that were the case then Python would have to be licensed as
>>>> GPL since it uses readline optionally. But it isn’t and I know
>>>> that they have looked at that issue carefully. From what I
>>>> understand, if the functionality is not core to the package, and
>>>> it isn’t bundled with the package, it doesn’t force the licensing
>>>> of it. There probably are subtleties here since one might argue
>>>> that readline is doesn’t add functionality to Python (but
>>>> obviously it does), and healpy does. 
>>>> 
>>>> In this case I’m inclined to worry unless someone wants to make a
>>>> legal issue of it, and in that even about the most that would
>>>> happen is a cease-and-desist order. They aren’t going to make a
>>>> lot of money suing Astropy (well, given the current checking
>>>> account, they are bound to lose a lot of money in legal fees).
>>>> 
>>>> Perry
>>>> 
>>>> On Oct 5, 2015, at 12:07 PM, Nathan Goldbaum <
>>>> nathan12343 at gmail.com> wrote:
>>>> 
>>>>> 
>>>>> 
>>>>> On Sat, Oct 3, 2015 at 2:46 AM, Thomas Robitaille <
>>>>> thomas.robitaille at gmail.com> wrote:
>>>>> Hi Emil,
>>>>> 
>>>>> The 'reproject' Astropy-affiliated package provides a way to
>>>>> easily
>>>>> reproject images using Healpy in addition to astropy.wcs:
>>>>> 
>>>>> http://reproject.readthedocs.org/en/stable/
>>>>> 
>>>>> The functionality with Healpy is optional, so the package is
>>>>> normally
>>>>> BSD-licensed, but if you do install Healpy, then as indicated
>>>>> here:
>>>>> 
>>>>> http://reproject.readthedocs.org/en/stable/healpix.html
>>>>> 
>>>>> you have to abide by the GPL license instead.
>>>>> 
>>>>> Hi Tom,
>>>>> 
>>>>> I don't want to stir up any problems for you, but I don't
>>>>> understand how this works legally.
>>>>> 
>>>>> You're distributing code that imports healpy. Even if it's
>>>>> "optional" functionality, the code that imports healpy is being
>>>>> distributed under a BSD license. As far as I understand it, the
>>>>> intent of the user doesn't matter for the licensing, all that
>>>>> matters is the license the code is distributed under.
>>>>> 
>>>>> I'd strongly urge you to contact e.g. debian-legal or the
>>>>> software freedom conservancy about this to get an opinion from
>>>>> an expert. I suspect your only legal recourses here are either
>>>>> to no longer import healpy in the reproject package or
>>>>> relicense reproject under a GPLv2 compatible license.
>>>>> 
>>>>> -Nathan
>>>>> 
>>>>> 
>>>>> Cheers,
>>>>> Tom
>>>>> 
>>>>> Emil Lenc wrote:
>>>>>> Hi All,
>>>>>> 
>>>>>> I was wondering if there were any plans to incorporate healpy
>>>>>> (the python interface to the HEALPIX library) into astropy? I
>>>>>> often work between HEALPIX and FITS format images and it
>>>>>> would be really convenient to have these two common formats
>>>>>> available within the same package.
>>>>>> 
>>>>>> Cheers,
>>>>>> 
>>>>>> Emil.
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