Are two programs installed by the same Setup package still an aggregate under GPL?

Question

Let's say I have two applications: one is the "server" application and licensed under GPLv3 and the other is the "client" application and is licensed under a non-GPL compatible license. The server runs as a Windows service, and the client is a normal windows application, and they communicate only via TCP/IP and XML (no linking at all).

I know that I could distribute both of these on the same media, or together in a zip file, as an "aggregate" as far as the GPL is concerned.

However, can I write an installation program that installs both the server and the client in one process, just to be user friendly?

Answer 1

I believe you can write an installation program that launches two separate installation programs for each piece of software. Make sure you alert the user that his is going to happen, and in order to make it more obvious you might give them a custom option that permits them to install only one or the other (even if one can't work without the other).

But you'll still catch flak if you're doing this primarily to avoid GPL licensing the closed source software. They may not be able to do anything about it legally, but you may find some open source competition quickly if you irritate enough people.

Answer 2

I presume the installer doesn't link to what it's installing, so it looks to me like three separate programs in one aggregate, one of which is GPLv3. In any case, I don't see that kicking off different installer processes will do anything: either this is an aggregate, or it's a single derived work.

Of course, this depends on the definition of a derivative work, which as far as I know is an undecided legal issue. However, I'd go ahead with the single installer, and make sure that some prominent documentation mentioned the different licenses.

Answer 3

As long as

"The only condition is that you cannot release the aggregate under a license that prohibits users from exercising rights that each program's individual license would grant them."

http://www.gnu.org/licenses/gpl-faq.html#MereAggregation

then you should be ok with the installer program. It is not necessary to provide click-throughs, etc. as other posters mention:

http://www.gnu.org/licenses/gpl-faq.html#ClickThrough

The main issue, however, is not installation but whether what you are doing is a derived work (it is not as simple as linking or not linking):

[..]pipes, sockets and command-line arguments are communication mechanisms normally used between two separate programs. [...] But if the semantics of the communication are intimate enough, exchanging complex internal data structures, that too could be a basis to consider the two parts as combined into a larger program.

http://www.gnu.org/licenses/gpl-faq.html#MereAggregation