Xapian discuss - Jul 2019 - Revisiting the PHP binding license issues

Hello,

I would like to see Xapian used more widely in the PHP community. The major
obstacle is that binaries of the PHP extension cannot be distributed. I've
been reading earlier discussions on this and wonder if there's now an
option.

My starting points were
https://trac.xapian.org/wiki/FAQ/PHP%20Bindings%20Package and the
discussion at https://trac.xapian.org/ticket/191.

One comment int he discussion is:
> So the PHP bindings don't link in any PHP licensed code, but they do
> compile against PHP licensed headers. I'm not a lawyer, but I think
this is
> the only remaining potential problem.

The GPL FAQ says at
https://www.gnu.org/licenses/gpl-faq.html#GPLIncompatibleLibs that there is
scope for adding exceptions when building against incompatible libraries.

Given that only the PHP bindings compile against the PHP licensed headers,
can the PHP bindings alone:
a) be relicensed under GPLv3, and grant an additional permission under
section 7?
b) remain GPLv2 and add a specific exception?

If so, this would allow Xapian to remain GPLv2+ licenced, and yet the PHP
bindings to be distributed pre-compiled.

I've searched the Debian legal archives for precedence one way or the
other, but (ironically) the search isn't great at returning relevant
results.

Peter

Other references:
https://xapian.org/docs/bindings/php7/
https://lists.debian.org/debian-legal/2009/04/msg00101.html

On Fri, Jul 26, 2019 at 02:01:35PM +0100, Peter Bowyer
wrote:
> The GPL FAQ says at
> https://www.gnu.org/licenses/gpl-faq.html#GPLIncompatibleLibs that there is
> scope for adding exceptions when building against incompatible libraries.
> 
> Given that only the PHP bindings compile against the PHP licensed headers,
> can the PHP bindings alone:
> a) be relicensed under GPLv3, and grant an additional permission under
> section 7?
> b) remain GPLv2 and add a specific exception?
There are two early copyright holders who aren't interested in
relicensing (nor in adding exceptions to the licence which is
effectively the same thing), so we can't do either of those (if we could
we probably would have years ago).

I'm hoping this will get resolved in the foreseeable future - we're
now at a point where a lot of that old code has been replaced, and git
master can be configured to give a build where libxapian and the
bindings only contain code which we could relicense.  Currently you
don't get a backend that supports writing in that build though, which
limits its usefulness in practice - it uses the new "honey" backend
which currently requires you to build a glass database and convert it
(and the glass backend contains code we couldn't relicense).

So some more code needs to be written.  We're also waiting for the
Software Freedom Conservancy to deal with the legal side of the
relicensing.

I don't currently have a timeline, but I'm hopeful the next release
series will support a configuration which would support shippable binary
packages of the PHP bindings.  It won't help for 1.4.x though.

[Aside: I don't really understand why the PHP developers are so keen on
the problematic clause.  It doesn't achieve what they want because it
only restricts naming of products *derived from PHP* - for example,
"CakePHP" and "PHP-Nuke" can use those names because they
aren't derived
from PHP.  A trademark would give them the control over use of the
name "PHP" which they actually seem to want, while allowing people to
use GPLed libraries from PHP more easily.]

Cheers,
    Olly

Le vendredi 26 juillet 2019 à 14:01 +0100, Peter Bowyer a écrit
:
> Hello,
> 
> I would like to see Xapian used more widely in the PHP community.
I would like that too. We recently removed a Xapian searching feature
from our Free Software because it required a process too complex for
most of our users to install it (and update it) on their servers.

[...]
> The GPL FAQ says at
> https://www.gnu.org/licenses/gpl-faq.html#GPLIncompatibleLibs that
> there is scope for adding exceptions when building against
> incompatible libraries.
> 
> Given that only the PHP bindings compile against the PHP licensed
> headers, can the PHP bindings alone:
> a) be relicensed under GPLv3, and grant an additional permission
> under section 7?
> b) remain GPLv2 and add a specific exception?
> 
> If so, this would allow Xapian to remain GPLv2+ licenced, and yet the
> PHP bindings to be distributed pre-compiled.
My 2 cents: I think it would make sense for Olly (the project
founder/leader/maintainer) to ask the Free Software Foundation
directly, if that wasn't done before. They are the top experts on the
subject and have legal advisors for that.

Your explanation seems to sum it up quite well, and contact information
about licensing is here: https://www.fsf.org/licensing/contact
(although it seems more focused on finding licensing violations, I'm pretty
sure this is the best contact point).

Cheers,

Yannick

On Mon, Jul 29, 2019 at 06:01:51PM +0200, Yannick Warnier
wrote:
> My 2 cents: I think it would make sense for Olly (the project
> founder/leader/maintainer) to ask the Free Software Foundation
> directly, if that wasn't done before. They are the top experts on the
> subject and have legal advisors for that.
The FSF's take on this is already clearly stated on their website:

    "It is incompatible with the GNU GPL because it includes strong
    restrictions on the use of “PHP” in the name of derived products."

https://www.gnu.org/licenses/license-list.html#PHP-3.01

As I wrote in my earlier reply, we're working towards a solution to
this which will hopefully allow redistributing binary packages of
Xapian's PHP bindings for the next release series, provided you
configure xapian-core suitably.

If that answer isn't a fast enough solution for you, all I can really
suggest is persuading the PHP developers to drop the problematic clause
from their licence, or at least adding some sort of exception to it to
allow GPL compatibility.  That would fix the problem once and for all
for all GPL software.

Cheers,
    Olly