I am not a lawyer, but what I understand from that is, if Apple authorizes use of bash under GPLv3, and then Apple decides it has a patent on something and bash is infringing on that patent, Apple can't go sue their customers for patent infringement because they are using bash. I'm 99% sure that's the intent of the clause. Lawyers are famously pessimistic and so I can see why they wouldn't want to test that, but seriously, what. are. the. chances.
Like seriously, maybe Oracle comes and sues Apple for patent infringement, and Apples only defense is to counter sue Oracle for using bash on their Macbooks?? They lost that defense when they stopped distributing bash, why not just distribute it under GPLv3 anyway?
As I understand it, it's more difficult than that... though I'm not a lawyer.
Let's say {some company} and Apple have a cross patent licensing for some set of patents.
Apple releases some softer under GPLv3. {Some company} sues someone else for a patent in bash. Since Apple licenses that patent and distributes bash, Apple is now obligated ("must act to shield") the distribution of bash that includes that patent.
If you distribute a covered work knowingly relying on a patent license, you must act to shield downstream users against the possible patent infringement claims from which your license protects you.
That wording of "knowingly relying on a patient license" and "must act to shield downstream users" are things that lawyers don't want to touch with a 10 foot pole. Would it mean that Apple would be required to defend the company that its patent partner is suing? Not a spot that lawyers want to be in. Furthermore, if you distribute GPLv3 software, it may mean that doing the cross patent licensing is more perilous... again, not a situation that lawyers or large companies want to be in.
There's Apple's bash distribution. If this was the GPLv3 version of bash and apple distributed a version that {some company} decided was infringing, and {some company} sued you - "I got it from Apple. Apple Legal, help me."
That's a helpful explanation, thank you. As a consumer of free software, that sounds great! I agree that it sounds pretty messy for big companies and all their patent deals. Sucks to be them, I guess
Like seriously, maybe Oracle comes and sues Apple for patent infringement, and Apples only defense is to counter sue Oracle for using bash on their Macbooks?? They lost that defense when they stopped distributing bash, why not just distribute it under GPLv3 anyway?