GPL code in a proprietary program by putting it in a separate standalone program, but shipping in same installer together with proprietary program?

Question

this question is an extension of the following question:

Is it legal to use GPL code in a proprietary, closed-source program by putting it in a separate, standalone program?

It has been more or less concluded that such practice is legal.

However, in my case, I plan to put the separate GPL program together with the proprietary program under the same windows installer. This gives my users a seamless experience while installing the suite. The installer will install two separate programs. They communicate with each other optionally via HTTP (Resftful) Web API.

There is also a downloadable stand alone installer JUST for the GPL software. And this GPL software is really stand alone by nature i.e. I'm not trying to beat the bush by doing this.

Would this violate the GPL?

Answer 1

If they are separate programs, putting GPL and non-GPL together into a single installer is fine. The GPL calls this “aggregation”.

You do still have to comply with the GPL for the GPL-covered program in the installer, in particular you must not limit end user's rights for that software. Ideally, the GPL-covered program can be extracted or installed independently, and is not not gated behind some EULA that users would have to agree to first. It should be possible for end users to modify the GPL components.

The tricky question is when two programs are separate. Just because you have two separate executables does not guarantee that these are separate creative works in the sense of copyright law. (Neither, for that matter, is it clear that combining components into a single program would create a single creative work). The FSF argues that two programs are separate if they do not share an address space and they do not share intimate data structures.

• That your programs communicate via some REST API is a strong indication that they are truly separate.
• More to the point, that the GPL software is standalone and can be installed separately is a very clear indication that they are completely separate programs.