It can also be evidence that HN posters have a poor understanding of GPL licenses. Pretty much all these questions are answered in the FAQ [0]. Your guess is as good as mine as to why people continually post random, uninformed, needlessly conservative takes on them instead of just doing a small amount of reading.
The FAQ is not at all clear about this question. #GPLInProprietarySystem says that you unconditionally cannot "incorporate GPL-covered software in a proprietary system", although it might be OK to ship a proprietary system that integrates with and depends on GPL software so long as "the two programs remain well separated". How do I know whether a particular API usage qualifies as well separated or not? The only standard described is "like the compiler and the kernel, or like an editor and a shell".
> How do I know whether a particular API usage qualifies as well separated or not?
The two paragraphs above what you quoted are:
"However, in many cases you can distribute the GPL-covered software alongside your proprietary system. To do this validly, you must make sure that the free and nonfree programs communicate at arms length, that they are not combined in a way that would make them effectively a single program."
"The difference between this and 'incorporating' the GPL-covered software is partly a matter of substance and partly form. The substantive part is this: if the two programs are combined so that they become effectively two parts of one program, then you can't treat them as two separate programs. So the GPL has to cover the whole thing."
Two programs communicating over a socket aren't incorporated. They're two programs.
Again, the FAQ says otherwise. #MereAggregation says that this is "normally" the case, but "if the semantics of the communication are intimate enough" two binaries communicating over a socket may still be one program. Whether they are one program is explicitly left as a question for judges to decide.
Here's how that section starts: "An “aggregate” consists of a number of separate programs, distributed together on the same CD-ROM or other media.". Are you distributing a lot of apps on CD-ROMs? Have you heard of Linux distributions? Seems like things are fine!
I'm not super interested in fielding more thin gotchas based on out of context quotes. There's a big difference between a license that's difficult to understand and a license that somehow summons people from the ether who find endless ways to deliberately misunderstand it.
Sorry but what does "arms length" mean? My software doesn't have arms. Using metaphors full of imagery is cute but essentially meaningless.
> Two programs communicating over a socket aren't incorporated. They're two programs.
Aren't they? So, if I want to use a GPL library, all I need to do is write a little wrapper program that does RPC over a socket, and boom, I can use a GPL library in my closed source program? Obviously not.
> Aren't they? So, if I want to use a GPL library, all I need to do is write a little wrapper program that does RPC over a socket, and boom, I can use a GPL library in my closed source program?
What about when running a wasm component in an AGPL host? Can the compiled wasm file be proprietary? They share the same memory space, but the wasm component is not compiled with the host.
That's the GNU project's interpretation of the license. I don't see how a court couldn't reach a different agreement on what the often discussed "derivative works" section means.
The FAQ also has interesting takes, where depending on the jurisdiction you're in, I'm sure such views would differ:
Q: In an object-oriented language such as Java, if I use a class that is GPLed without modifying, and subclass it, in what way does the GPL affect the larger program? (#OOPLang)
A: Subclassing is creating a derivative work. Therefore, the terms of the GPL affect the whole program where you create a subclass of a GPLed class.
Thats... a really weird and technically inept take on an issue that is not broadly applicable to all object oriented languges, but going with this argument, I'd argue that "subclassing" essentially constitutes just using an interface (in the general sense, not in the Java sense) to some existing software, so in Minio's case, using their API would constitute a similar usage pattern -> my "derivative" work must now be GPL licensed.
I know a lot of this stuff is legally pretty new (though AGPLv3 is almost 17 years old now) and there's not a huge body of case law around it. But--and I'm earnestly asking here--is there case law where courts reach in and modify licenses separate from the authors' explicit intent? It's hard for me to imagine a court doing that, especially with all the reliance interests involved (I use AGPLv3 with the understanding that subclassing requires release, court says no, now my business model is toast).
> I'd argue that "subclassing" essentially constitutes just using an interface (in the general sense, not in the Java sense) to some existing software, so in Minio's case, using their API would constitute a similar usage pattern -> my "derivative" work must now be GPL licensed.
No, again the difference is incorporation. In order to subclass something you have to incorporate it into your code.
> is there case law where courts reach in and modify licenses separate from the authors' explicit intent
What are you on about? The explicit purpose of a license is that it's users do not have to worry about anyone else's "explicit intent". A license needs to be unambigious about it's terms, else it's just not a good license, hence see the discussion in this thread about the meaning of derivative works.
It may very well be that the FSF/RMS/GNU Project had some intent on it's use when creating the GPL/AGPL v3, but a court in another jurisdiction will not care. I have no idea how to get a hold of the FSF when I'm being sued for license violations in europe and even if so, I doubt a court would care about the FSF's interpretation, given that they're likely not a party to the proceedings.
I'm surprised that people on an US centric site believe that intent in US jurisprudence matters, because in a legal system largely based on precedence, it really does not.
> No, again the difference is incorporation. In order to subclass something you have to incorporate it into your code.
You have to do the same thing in order to use API's. I'm sorry, unless I don't understand something here, this doesn't make sense.
> What are you on about? The explicit purpose of a license is that it's users do not have to worry about anyone else's "explicit intent". A license needs to be unambigious about it's terms, else it's just not a good license, hence see the discussion in this thread about the meaning of derivative works.
Even the most carefully written license has ambiguity, and that's for two reasons. First, we want to cover situations without exhaustively enumerating and
describing them in great detail. Statutes and the Constitution run into this all the time, but no one's like "don't start a business in the US, their Constitution is ambiguous and courts have to clarify and interpret it all the time" because courts (except for this one, I'll admit) do things like take reliance interests into account when adjudicating cases. It works well enough in contract law that we've built the most advanced economy in history, so I wouldn't poo-poo it.
Second, and I'll echo Dijkstra here [0] our languages aren't precise. They're bad at the thing you want them to do. Your argument argues against all contracts and licenses everywhere, even laws themselves.
Finally, (A)GPLv3 don't refer to derivative works. That's a GPLv2 thing.
> I'm surprised that people on an US centric site believe that intent in US jurisprudence matters, because in a legal system largely based on precedence, it really does not.
Again, happy to read any case law you can find on this.
> You have to do the same thing in order to use API's. I'm sorry, unless I don't understand something here, this doesn't make sense.
I'm starting to believe people here don't know what linking and incorporate mean. Linking is using a linker--like ld--to build an executable or library. It's not some abstract idea of linkage. Incorporate means pulling the source code into your own. It's not some abstract idea of building a larger system. You don't pull the source code to Minio into your code to use its API.
[0]: https://www.gnu.org/licenses/gpl-faq.html