[wp-hackers] Plugin licenses

[Otto]

On Sat, Oct 25, 2008 at 9:08 AM, Daniele Muscetta <muscetta at gmail.com> wrote:
> If you release the plugin as GPL, you would automatically make the
> embedded library GPL as well... and the owner of that library will
> come and get you... :-)

You can't relicense code that you don't own. So that library is NOT
GPL, no matter what you try to do. You are violating the GPL in such a
circumstance, by distributing non-free code.

However, if you write a plugin that interfaces some GPL code and a
non-GPL library together, and the plugin is GPL, what exactly has been
violated here? Look at it from all pieces:
1. GPL code requires derivative work to be GPL. The plugin is
derivative. The library is probably not derivative, because is an
identifiably separate and unrelated work.
2. The non-GPL library has its own terms. Obviously, you need to abide
by whatever those are.
3. Your plugin is GPL because you said so. You wrote it, and you can't
violate your own copyright.

I am aware that the FSF disagrees with this analysis. But you know
what? The FSF can go suck eggs as far as I am concerned, because they
are flat-out wrong on this point. I've read the GPLv2, and I
understand it, and whether they like it or not, nothing in the above
scenario violates it.

> I think a lot of people till today simply assumed that they COULD do
> something like this, release their plugin under a NON-GPL license...
> as long as they would not claim any right to have the plugin
> distributed/hosted on WP.org they were OK.
> But apparently they are not.... :-(

True. 99% of plugins need to be GPL to be distributed legally.