IANAL, but I guess the file format itself is not covered by the GPL 3, only the reference implementation.
They specifically say that "FLIF is completely royalty-free and it is not encumbered by software patents". So, I suppose people will be allowed to develop their own libraries with another license.
True, but the only complete documentation of the file format I found was the source code of the reference implementation. So the only way to write a new implementation is to study the reference implementation, which will make your new implementation "tainted".
Studying GPL'ed source code does not "taint" anything. You're absolutely allowed to do that. If you're really concerned about subconsciously copying elements of the original into your implementation, you could let somebody else study the original and write a spec.
Guess how many court cases has been about developers tainted from reading code.
1000? 1? 0?
Zero. You are about as likely to be tainted from reading GPL code as to be tainted by reading HN, the news paper, or driving around in silicon valley and looking at building with programmers in them.
They also go on to say. That might be a clear indication that this is in fact GPL v3.
FLIF is Free Software. It is released under the GNU General Public License (GPL) version 3 or any later version. That means you get the “four freedoms”:
The freedom to run the program, for any purpose.
The freedom to study how the program works, and adapt it to your needs.
The freedom to redistribute copies.
The freedom to improve the program, and release your improvements to the public, so that the whole community benefits.
No documented format (actually an explicit acknowledgement that the format will likely change). The implementation is the spec, the implementation is GPLv3, so many companies lawyers will prevent engineers even looking at it to write a clean-room implementation.
>so many companies lawyers will prevent engineers even looking at it to write a clean-room implementation.
Maybe you should look up what 'clean-room' reverse engineering is. One person looks at the code, writes down how what it does, then gives that description to another person who writes CLEAN-ROOM code based upon the description.
There's no difference in doing a clean-room implementation of GPLv3 code than of any other code license.
The difference is that the lawyers for some companies will not sign off on employees even looking at GPLv3 sources. Rightly or wrongly, this really does make a clean-room implementation impossible.
One can reasonably argue that this is stupid and not the fault of the GPL. However, it's also reality, and a real block to adoption of technologies like image formats.
Clean-room implementation has been around for ages, I've done it professionally myself, both from source code and disassembly.
Also not every company has clueless lawyers, nor does a clean-room re-implementation of this format need to come from a company, I'd say it's more likely not.
Seriously this sounds more like GPLv3 scaremongering than anything else, I've never seen anything like this in my professional life as a developer.
edit: as for my personal preference, I think GPL is a great license for full application/solution style software, but for libraries/frameworks, I prefer permissive licensing.
+1 for the "full app/solution" vs. library/framework applicability for GPL vs. permissive: That is exactly my opinion too. When I see GPL'ed libraries, I think "try before you buy"-style open source code, and these invariably also comes with an option to buy a commercial license.
The code won't but the spec/format can. What you do is have a third party look at the code. They need to identify a high-level description of what it does, what inputs the format takes, what outputs it uses, the storage format, and so on. Precise enough for someone else to implement it from scratch with likely compatibility. Yet, not copying the code itself and maybe not even copying the implementation strategy. Should avoid GPL tainting.
Even if someone wants to sue over it, I'd say that legal battle is worth fighting because this is similar to how FOSS makes stuff compatible with proprietary software/protocols: reverse engineering their function to make a separate, compatible implementation. Knowing how important that is, I doubt even the zealots would sue someone using above methodology knowing it could set a precedent which might be used against them.
