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I am beginning to learn about open source software licenses. I am especially interested in how open source licenses interact with patents. I've seen the term "patent-granting" used several times to describe some licenses (e.g. here and here), but I can't find a clear definition. What does "patent-granting" mean, and what are its implications? Are "patent-granting" licenses supposed to grant users the right to use/modify/distribute not only the software but also any patents related to the software? If so, is there an opposite, i.e. an open source license that gives license to the code but not any related patents?

I would appreciate any examples.

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Suppose Alice writes a piece of code that (in the immortal words of GPLv2) "makes passes at compilers". It uses a novel technique that makes passes at n lines of code in O(sqrt(n)) time. Alice applies for a patent on this, and let's say for the sake of argument the patent is granted. She also publishes the code under, let's say, the MIT licence.

Bob takes this code and uses it as the core of his new proprietary compiler-passer, taking care to preserve Alice's copyright notices and the text of the MIT licence. From a copyright standpoint, this is completely lawful, because he has a copyright licence to do this, and has satisfied the conditions thereof. But Alice then sues him for patent infringement. From a free-software perspective, this is undesirable.

A patent-granting copyright licence is one that, in addition to copyright, also licences any patents held by the licensor and embodied in the code so licensed; examples include Apache2, in section 3, and GPLv3, in section 11. In both cases, those licences contain a grant for any patents that are licensable by the copyright licensor and which are embodied in the licensed code. Bob can use that code, subject to the terms of the copyright licence thereon, without fear that Alice will sue him for patent infringement.

If so, is there an opposite, i.e. an open source license that gives license to the code but not any related patents?

Yes; CC0 is one such example, in section 4a:

No trademark or patent rights held by Affirmer are waived, abandoned, surrendered, licensed or otherwise affected by this document.

See this question for more details about that.

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  • Do you think GPL v2 counts as patent-granting? In s7, that license seems not to explicitly give a patent grant, but it might imply this outcome in a reversed logical way (i.e. if you can't give a patent license, then you can't distribute the code at all). The preamble of GPLv2 might act as implying a patent grant, but I'm not sure if that would be binding in the kind of dispute you mentioned (if Alice releases under GPLv2 and then tries to sue for violation of her own patent). In any case the GPL v3 wording seems much clearer on this point.
    – Brandin
    Sep 28, 2023 at 9:24
  • @Brandin I think I follow the argument, but am unpersuaded by it. If I accept it, then it seems to me I must also regard GPLv2 as a unilateral offer to buy everyone a computer, because without that they can't redistribute the software I have just conveyed to them. As you say, it's much safer for everyone to explicitly grant the patent licence by using GPLv3.
    – MadHatter
    Sep 28, 2023 at 9:45

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