I've been going over the Apache CLA recently, and while I am a layman here I see one point of concern that hopefully someone can clarify.
Specifically, it seems on first reading that section 3
You hereby grant to the Foundation and to recipients of software distributed by the Foundation a perpetual, worldwide, non-exclusive, no-charge, royalty-free, irrevocable ... where such license applies only to those patent claims licensable by You that are necessarily infringed by Your Contribution(s) alone or by combination of Your Contribution(s) with the Work to which such Contribution(s) were submitted.
"combination of Your Contribution(s) with the Work to which such Contribution(s) were submitted" would on its face mean that if, for instance, there was existing infringement of Foo Corp's patents buried deep within the Apache sources that Foo Corp was not aware of, and Foo Corp signed the CLA then submitted a trivial patch completely unrelated to the infringing code, that Foo Corp just gave a patent license for all existing infringing code without even knowing it existed.
Is this a correct reading, and if not, what am I missing? Note that I understand patent licenses can only be granted if Foo Corp is legally allowed to do so, the question is more on the interplay between a systems patent and the CLA as detailed below.
To add an interesting twist: the real world issue being considered here is not one of software-only patents (which I generally consider a bad idea anyway), but one of patents that claim certain functionality relying on both specific software and specific hardware components working together. As I understand it, attempting to claim infringement against the software component alone would be near suicide as the existing grants back to Foo Corp would terminate, but it should still be possible to claim infringement against any commercial packaged system products (hardware + software) that infringe without invoking the Apache revocation clause.
What is not clear to me is whether a.) the grant is as I assume above and b.) whether this would then affect the ability to claim infringement against a competitor of Foo Corp that is selling infringing systems (hardware + software) that include the Apache licensed software.