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Comment by Null-Set | Hacker News Reader

How is twitter intending to use libsignal? I doubt it would be via the primary AGPL license[1], forcing them to publish the source code of their backend service. Does signal sell private licenses?

[1] https://github.com/signalapp/libsignal/blob/main/LICENSE

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Signal requires all contributors to license their work to the company [1]

So they are able to offer Twitter a non-APGL license. Usually for a sizeable fee.

[1] https://signal.org/cla/

What are people’s thoughts on dual licensing in this manner? Is it compatible with foss or no?

It's not compatible with FOSS from a dogmatic point of view, but I think it's a pragmatic way forward given how AWS and other actors act. I dual license my company's products in this manner.

Even Stallman isn't completely opposed to selling exceptions to copyleft licences.

https://www.fsf.org/blogs/rms/selling-exceptions

Oh wow, I retract my statement then. I wasn't aware of this. I thought for sure RMS wouldn't approve.

It is compatible. The people who have a say are the people who write the code. If you are not comfortable with dual licensing, don't contribute upstream.

You can fork such dual licensed project, add your own contributions and then Signal cannot use your code in anything they license to third-parties under non-AGPL. The fork becomes AGPL-only.

Example of where this has happened: MySQL was forked to MariaDB, so developments to MariaDB cannot be used by Oracle in their proprietary licensing of MySQL.

I don't think it's compatible with the sprit of FOSS.

You're giving the company (in this case Signal) an open-ended license for your contributions whilst they don't return the favour. And so whilst they can offer a proprietary version e.g. Signal Pro with a friendlier license e.g. BSD you can't.

And what kind of underpins all of this is that many companies especially in the enterprise will not touch anything that is GPL or AGPL.

Huh? This is like saying that the AGPL isn't compatible with FOSS. I've heard stories that there was a window of time where RMS was advocating for the AGPL terms to be incorporated into GPL3. If your definition of FOSS excludes the GPL --- as your last sentence suggests --- your definition is... unusual.

FOSS is a very big umbrella that incorporates a wide variety of licenses.

But for me AGPL is not in the spirit of FOSS. It's like you're an unpaid employee of some company who is happy to take your work as long as you don't compete with them.

I understand why AGPL was invented i.e. to prevent AWS ripping your project off but I don't think it's a particularly fair license for individual contributors.

At the point where you've defined the FSF out of FOSS, you've departed the ordinary definition of the term.

Interestingly the FSF also requires copyright assignment for contributions to GCC, Emacs and some other GNU software.

The FSF does appear to prefer copyright assignment over DCOs[1], but as of last year GCC contributions only require a DCO[2].

[1] https://www.fsf.org/blogs/licensing/FSF-copyright-handling [2] https://lwn.net/Articles/857791/

That is good news, thank you! And I apologize for spreading incorrect information.

agpl was definitely not invented to prevent AWS stealing your project.

Affero predates AWS by a lot. It was invented because FSF wants users to be able to see software they are using, but they cannot if it’s a remote server.

It has been used recently as magic anti-AWS wand, but it wasn’t built for that

edit: I am wrong in my dating! Affero is 2007, AWS was launched 2006. But yeah it was never meant as anti-AWS magic wand.

I think you are being pedantic.

Aws , TiVo , whatever . Lots of orgs exploited the contractual logic gap in gpl v2. Aws is the latest in a long list of freeloaders .

I license all my / my startups code under AGPL v3. I don’t offer anyone proprietary license and I don’t ask anyone for CLA.

Defense against freeloaders and also tyrant. My operating agreement for my LLC has language about this stuff. It’s that core to our DNA.

Aren't you talking about copyright assignments rather than AGPL? You can definitely compete using AGPL, you just have to publish your changes (without necessarily assigning the copyrights), just like the company you're competing with has to if they start using your changes and you haven't assigned your copyrights to them.

The key of the comment you're responding to is signing away copyright, not AGPL/GPL.

With BSD, you're giving every company the right to take your code and use it without returning any favour at all.

With the CLA it's the same. But at least Signal give back by still providing libsignal as free software.

It depends on your motivations for contributing. If you don't like the CLA or any other things, you can still fork. Even if it may not be compatible with your own motivations, it is still in the spirit of free software.

It is compatible if one of the licenses offered is actually a real open source license that is available to all. The AGPL is really an open source license. Licenses which restrict based on type of use or characteristics of user are not.

I believe they already have a license (it may have expired):

> "agreement to license Signal protocol was reached"

https://mobile.twitter.com/bhcarpenter/status/15966919162503...

IANAL but my understanding is that agpl requires you to publish server code if that code uses code under agpl, because consuming an api is equivalent to distributing the code.Aka that "calling an api which uses agpl code" is equivalent to using the code itself ( which means you should, as an api consumer, have access to the source eventhough you actually downloaded no binary).

e2e means server never does any encryption or decryption so i don't think they'll have any signal code running on their server.

They will however be required to open source their application code.

Edit : and i think open sourcing twitter app would be a stunning move, that elon is totally capable of.

There seems to be a bunch of code in the Twitter app that's licensed from other third parties, so unless they're fine with their code being re-licensed under AGPL it's not possible to release the app under those terms.

> "calling an api which uses agpl code" is equivalent to using the code itself

No, not at all. If a server is AGPL-licensed, clients may have whatever license they want. If a client is AGPL-licensed, servers may have whatever license they want. What the AGPL does is provide that if code under the AGPL is used to provide network services, then clients of those servers are entitled to the server source code. You may read the terms here: https://www.gnu.org/licenses/agpl-3.0.en.html

There is no copyright mechanism by which the AGPL could apply to clients of an AGPL server.

I don’t think we understood each other. I’m saying twitter should have to release their client code *if their client code uses libsignal*.

What i’m saying about server code is the logic of agpl. GPL is about providing the means for users to obtain source code of the binary they’re running. There was a gap with api, where a given library feature could be exposed through network services and since no binary were downloaded then the code wouldn’t required to be open sourced. AGPL fixes that.

But we both agree that client code and server code are independent relative to their licensing terms.

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