[development] Modules that integrate non-GPL PHP apps violate the GPL.

[Jeff Eaton]

On Sep 2, 2007, at 9:43 AM, Darren Oh wrote:

> So far this whole discussion seems to be a case of ask the wrong  
> question, get the wrong answer. I have seen no evidence to suggest  
> that one cannot write some code that depends on non-free software,  
> release it under the GPL, and have the GPL apply to that code. What  
> would be against the spirit of the GPL would be to write code that  
> depends on GPL software and to release only a compatibility layer  
> under the GPL, keeping the main functionality non-free. Since 1)  
> the third-party apps that are being integrated do not depend on  
> Drupal and 2) the module authors do not own the rights to the code  
> in the third-party apps, this issue is irrelevant to the situation  
> under discussion.

I used to take this position as well, but it's apparent after quite a  
bit of research that this is based on loose use of the phrase  
"depends on" to define the terms of the discussion. The GPL doesn't  
use those words. It doesn't recognize a difference between a piece of  
software that *uses* a library, and the library that *is used by*  
another program. It simply sees those two programs being combined to  
form a single work if they interoperate in certain ways.

As such, if they do not share compatible licenses, they can't be  
distributed together. And if one component is clearly designed to  
work *only in the presence of the other component* it is an implicit  
violation of the GPL. (According to the FSF).

That's their official interpretation.

--Jeff