[Xapian-discuss] commercial license

[Olly Betts]

On Fri, Dec 05, 2008 at 11:26:12AM +0000, James Aylett wrote:
> Alternatively, you might want to consider a client-server arrangement,
> where the server would be GPL but the client (and hence any part of
> your code that used the client code) could be under any license you
> chose (if you wrote it yourself; if you adopted someone else's, then
> whatever license they had chosen).

I think you need to be careful with this approach.

Although much discussion about the GPL seems to focus on "linking", the
licence text for GPL v2 doesn't actually mention the term "link" (except
once in the addendum "How to Apply These Terms to Your New Programs"
which doesn't form part of the licence terms).  The key is what forms
a derivative work under copyright law, since that's what the GPL is
built upon.

This is just a layman's view, but if you create a client/server split
for the sole purpose of avoiding having the GPL licence on code in the
server apply to the client, it seems to me that there's a strong
argument that the client and server form a single work, which is derived
from the GPL code, and so the GPL applies to the client.  (And it's
morally bankrupt even if it's legal!)

Taking the client-server split towards the other extreme, if I use
Apache as an HTTP server and Firefox to fetch web pages from it, we have
two components developed independently and using a standard protocol
developed largely by independent entities, and either component can be
replaced with many alternative implementations.  I think you'd really
struggle to argue that either is a derivative work of the other.

Cheers,
    Olly