EPL, GPL and plugins

[Antoine Pitrou]

Peter Arrenbrecht <peter.arrenbrecht <at> gmail.com> writes:
> >
> > Copyright and the GPL both talk about protection of original and
> > "derived works". If your work is a derived work in the view of copyright
> > law, then it is covered by the GPL. Precisely what does and does not
> > constitute a derived work in software is something that currently can
> > only be answered in a court of law. One possible test is: if Alice's
> > code can't work in any useful sense without Bob's code, then Alice's
> > code is probably a derived work of Bob's.
> 
> So, regardless of the interfacing technique, an Eclipse plugin for Hg
> has to be GPL. But also EPL. Question is, can it be both? It seems to
> me that:

It doesn't have to be under the EPL, unless the EPL is a very bad license
(remember, it's not copyleft).
Actually I don't think it has to be under the GPL either.

Matt's test is just a hint, not a hard rule; if you take it too literally it
means that every software relying on non-standard features of the Linux kernel
should be GPL'd too, which is probably a bit far-fetched :-)

The most reasonable solution is to ask authors of respective software (Eclipse,
Mercurial). Ask them whether they accept the existence of plugins under a
different open-source license than the one they chose for their software. It's
enough if one of both projects says "yes". And since the EPL is not copyleft
it's hard to imagine the Eclipse authors would disagree.

Regards

Antoine.