> The license must not place restrictions on other software that is distributed along with the licensed software.

When I base software on GPL software, then my software is distributed along with that GPL software. According to this phrase, GPL might not place restrictions on my software. Yet it does.

There is a profound misunderstanding here somewhere. I suspect it is coming from the use of the phrase 'base on'. If you modify GPL licensed software, your software is restricted because it qualifies as a derivative work under copyright law, and it must comply with GPL. But if you zip up a GPL program with your non-GPL program and distribute the bundle, the GPL does nothing to restrict your non-GPL program. If there's linking involved, it gets more complicated, but that's unrelated to this discussion.

> If there's linking involved, it gets more complicated, but that's unrelated to this discussion.

I think it is very much related. If my linker cannot link GPLed software because of the license of this software, then this software is restricting my linker. As per the definition of opensource.org, GPLed software is not open source.

Again,

> 9. License Must Not Restrict Other Software

Other software (distributed alongside, "mere aggregation") != Software based on a work (derivative).

GPL obligations apply in the latter case, OSI definition talks about the first case.

If your view of the definition were true, then the OSI definition would have been more clear about the distinction.

Further, as an example, software running on Linux is clearly different than the Linux kernel. Nobody would say that an application and the OS kernel is the same software. OSI doesn't make a distinction between library calls and kernel calls.

OSI specifically lists the GPL as an open source approved license.

https://opensource.org/licenses/GPL-2.0 https://opensource.org/licenses/GPL-3.0

Even AGPL is approved. https://opensource.org/licenses/AGPL-3.0