Revisiting the PHP binding license issues

[Olly Betts]

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