[Xapian-discuss] Re: [Swig-devel] license issue

Sam Liddicott sam at liddicott.com
Tue Aug 21 20:51:32 BST 2007

-----Original Message-----
From: "Alexander Lind" <malte at webstay.org>
To: "Sam Liddicott" <sam at liddicott.com>
Cc: "Xapian Discussion" <xapian-discuss at lists.xapian.org>
Sent: 21/08/07 19:57
Subject: Re: [Xapian-discuss] Re: [Swig-devel] license issue

>As long as you freely publish the source code of whatever 
>you release that derives from GPL:ed code, do you really 
>have to ask anyones permission?

As long as you abide by the requirements  of the GPL you can distribute GPL software.  The license is the permission. It permits you to distribute under the terms of that license. It grants certain permissions on the work and on derived works, and places certain constraints on those who distribute and the manner of distribution.

Merely publishing the source does not fulfil the GPL. Nor does the GPL permit you to add extra constraints or remove GPL constraints or remove GPL permissions.  I believe the PHP license makes extra constraints. The GPL which is your conditional permission to distribute forbids you to add the extra constraints of the PHP license to those you distribute to. The PHP license does not permit you to remove those extra constraints.

Thus, according to the licenses (pre-existing permissions) you may be forbidden to distribute works derived from both PHP (or Zend) and GPL code.

Fortunately we can (check with a lawer) a specification or instructions for producing such a derived work if those instructions are also not such a derived work.

(This is all based on copyright).

Luckily the swig definition file for the xapian bindings are such instructions.

But as existing licenses do not both simultaneously permit distribution of dual derived works we cannot distribute such dual-derived works so we can either: get permission from all the copyright holders of the deriving portion of one of the works for extra permission (sometimes called a gpl exception), or write our own middle layer that we can grant this extra permission on, or distribute automatic systems for creating a dual-derived work on-the-fly which itself cannot be distributed (because copyright law says we need permissionnd we don't have it).

So.... It's not based on niceness or common sense, but law. And I'm not a lawer or a judge or the judge (if there is one) deciding a case on xapian and php.



Sam Liddicott wrote:
> The PHP bindings derive from PHP, swig and also derive from Xapians swig definitions which derive from Xapian.
> It would require discovering those contributors whose work the swig definitions derive from and getting their permission.
> Sam
> -----Original Message-----
> From: "Alexander Lind" <malte at webstay.org>
> To: "Xapian Discussion" <xapian-discuss at lists.xapian.org>
> Sent: 21/08/07 16:35
> Subject: [Xapian-discuss] Re: [Swig-devel] license issue
> Would it be possible to build Xapian PHP bindings against this 
> alternative PHP implementation?
> I take it this would be quite different from building them using SWIG.
> Alec
> Marijn Schouten (hkBst) wrote:
>> Hash: SHA1
>> Alexander Lind wrote:
>>> Apparently the PHP license does not play nice with the standard GPL
>>> license,
>> There is a GPL/LGPL licensed alternative PHP implementation:
>> <http://code.roadsend.com/pcc>
>> - --
>> Marijn Schouten (hkBst), Gentoo Lisp project
>> <http://www.gentoo.org/proj/en/lisp/>, #gentoo-lisp
>> Version: GnuPG v2.0.6 (GNU/Linux)
>> Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org
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>> =rThH
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