[Haskell-cafe] Dual-licensing the package on Hackage

David Sorokin david.sorokin at gmail.com
Tue Jul 30 13:02:01 CEST 2013

This is already another question what license to use :)

On 30.07.2013 14:56, Vo Minh Thu wrote:
> Again I haven't seen a reason to do what you propose: virtually every
> single GPL library author would gladly accept money for their work to
> be used in a closed source setting, no need to use OtherLicense to
> reach that effect.
> On the other hand, you will stop people interested in open source to
> look further into your project if they see OtherLicense instead of a
> well-known open-source license.
> 2013/7/30 David Sorokin <david.sorokin at gmail.com>:
>> I am inclined to use value OtherLicense but state in the description that
>> the package is available either under GPL or a commercial license. The
>> latter must be requested to me. Then there would be no required additional
>> steps to use the package under GPL. Only the LICENSE file must be
>> appropriate. Probably, I will need two files LICENSE and LICENSE-GPLv3. In
>> the former I will have add my copyright and write in a simple form that the
>> license is dual and everyone is free to use the library under GPLv3 (which
>> is the main use case) according the terms provided in the corresponded
>> second file.
>> Thanks,
>> David
>> On 30.07.2013 13:57, Vo Minh Thu wrote:
>>> Unless you want to provide multiple open source licenses, I don't see the
>>> point:
>>> Anybody that needs a commercial license (and has some money) will
>>> simply ask for such a commercial license when seeing that the code is
>>> available under GPL.
>>> Another reason it is pointless is that you will certainly not want to
>>> list all the commercial licenses you have used/will use with different
>>> clients (there are virtually infinite commercial licenses that you can
>>> invent as needs arise: per seat, per core, per year, and so on
>>> depending on the clients/projects).
>>> I.e. you don't need to state upfront that commercial licences exist
>>> (although I understand that you think it is better to advertise your
>>> willingness to provide such commercial license, but a comment is
>>> enough, the fact is that license is not provided through Hackage).
>>> 2013/7/30 Krzysztof Skrzętnicki <gtener at gmail.com>:
>>>> Perhaps it would be best if .cabal allowed to have more than one license
>>>> listed.
>>>> Another solution would be to use custom field, for example:
>>>> License: GPL
>>>> x-Other-License: Commercial, see License-Commercial.txt
>>>> All best,
>>>> Krzysztof Skrzętnicki
>>>> On Tue, Jul 30, 2013 at 11:44 AM, David Sorokin <david.sorokin at gmail.com>
>>>> wrote:
>>>>> Thanks Thu,
>>>>> I agree with you. Just I don't know what to write in the license field
>>>>> of
>>>>> the .cabal file: GPL or OtherLicense. The both choices seem correct to
>>>>> me
>>>>> and misleading at the same time.
>>>>> Cheers,
>>>>> David
>>>>> 30.07.2013, в 12:53, Vo Minh Thu написал(а):
>>>>>> 2013/7/30 David Sorokin <david.sorokin at gmail.com>:
>>>>>>> Hi, Cafe!
>>>>>>> Probably, it was asked before but I could not find an answer with help
>>>>>>> of Google.
>>>>>>> I have a library which is hosted on Hackage. The library is licensed
>>>>>>> under BSD3. It is a very specialized library for a small target group.
>>>>>>> Now
>>>>>>> I'm going to relicense it and release a new version already under the
>>>>>>> dual-license: GPLv3 and commercial. In most cases GPL will be
>>>>>>> sufficient as
>>>>>>> this is not a library in common sense.
>>>>>>> Can I specify the GPL license in the .cabal file, or should I write
>>>>>>> OtherLicense?
>>>>>>> I'm going to add the information about dual-licensing in the
>>>>>>> description section of the .cabal file, though.
>>>>>> Although you can indeed license your software under different
>>>>>> licences, in the case of your question it doesn't seem to be a concern
>>>>>> with Hackage:
>>>>>> The license displayed on Hackage is the one for the corresponding
>>>>>> .cabal file (or at least I think it is). So you issue your new version
>>>>>> with the changed license, the new version is available with the new
>>>>>> license, the old versions are still available with the old license.
>>>>>> Everything is fine.
>>>>>> Now about the dual licensing. It seems it is again not a problem with
>>>>>> Hackage: you are not granting through Hackage such a commercial
>>>>>> license. I guess you provide it upon request (for some money). I.e.
>>>>>> when I download your library from Hackage, I receive it under the
>>>>>> terms of the BSD (or GPL) license you have chosen, not under a
>>>>>> commercial license that I would have to receive through other means.
>>>>>> Otherwise the semantic of the license field on Hackage would mean the
>>>>>> library is available under such and such licenses, which are not
>>>>>> granted to you when you download the library on Hackage. Only when you
>>>>>> download the package you can actually find the licensing terms (e.g.
>>>>>> in the LICENSE file). But this seems unlikely to me.
>>>>>> Cheers,
>>>>>> Thu
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