Re-writing the code using the original source as a guide means it is a derivative work if you want to get picky. Changing the programming language doesn't make it non-derivative.
If you want a non-derivative work you need to do something like a clean room implementation where the one writing the code doesn't have access to the code of the existing implementation: https://en.wikipedia.org/wiki/Clean_room_design
BTW this guy can not stop derivative works once he has released it as BSD.
Clean room design is a sufficient but not necessary condition to establish that something is non-derivative. It's possible that enough changes to the source make it non-derivative under copyright law.
As the Wikipedia link you gave says:
> Clean room design is usually employed as best practice, but not strictly required by law. In NEC Corp. v Intel Corp. (1990), NEC sought declaratory judgment against Intel's charges that NEC's engineers simply copied the microcode of the 8086 processor in their NEC V20 clone. A US judge ruled that while the early, internal revisions of NEC's microcode were indeed a copyright violation, the later one, which actually went into NEC's product, although derived from the former, were sufficiently different that they could be considered free of copyright violations.
As another example, BSD Unix evolved sufficiently away from AT&T Unix that only a couple of files needed to be replace to get away from AT&T's copyright.
Both derive from someone else's works, but that's a different sense of "derivative" than what copyright law cares about.
> BTW this guy can not stop derivative works once he has released it as BSD.
could he just remove the BSD license from all subsequent commits to the code base? The existing code base will still continue to be BSD licensed of course.
Provided no one else has ever contributed yes he can. In fact this is not unique to the BSD, you can do that with any license. Even proprietary licenses do not force the author to continue using the same license since they own the original copyright.
How would the enforcement of that work? What if I have cloned the version of the repo that was BSD, and I'm working on a yet-unrelated derivative work when the author changes the license? The answer that seems reasonable to me (not that I expect any correlation between that and the actual law) is that any version of the code that was released with a given license is perpetually under that license.
I'm presuming what you are referring to, and which is likely to confuse a predominantly English speaking audience is that a number of countries with legal systems typically based in Germanic or Napoleonic legal systems, copyright consists of the combination of moral rights on one side and economic rights on the other hand.
Moral rights are generally impossible to forfeit and assign. Economic rights usually (I don't know of any jurisdictions where assigning economic rights to the project maintainer would be impossible - are you?) are possible to assign.
In common law systems, the two are usually traditionally much more closely tied, and when we talk about copyright in English, it is usually the economic rights we're referring to.
While there aren't any software licenses that do that, many projects do it as a condition of accepting contributions. As an example here is GCC's contributor documentation: https://gcc.gnu.org/contribute.html
The short version is assign FSF copyright, or put it in the public domain.
Thanks for this. I would be interested to know if, in practice (in a court of law), attempt to show something is derivative work when it's not is a more common instance than when it actually is. How easy (or hard) is it to prove something is a derivative work? (i am especially thinking of 2 pieces of code doing basically the same thing with the same algorithm, no patents)
The other answers to your question are not correct. In some countries, authors' "moral rights" can include the right to withdraw the software, saying "I don't want you to continue distributing the software", which is similar to retroactively revoking the license. For the situation in France, see:
The GPL actually has a clause agaisnt revocation in section 2:
All rights granted under this License are granted for the
term of copyright on the Program, and are irrevocable
provided the stated conditions are met.
Doesn't this make it illegal to distribute GPL software in France under clause 12?
If conditions are imposed on you (whether by court order, agreement or
otherwise) that contradict the conditions of this License, they do not
excuse you from the conditions of this License. If you cannot convey a
covered work so as to satisfy simultaneously your obligations under this
License and any other pertinent obligations, then as a consequence you may
not convey it at all.
Since allowing the licensor to revoke the licence would be an extra condition.
It doesn't make the distribution illegal per-se, but it does make the license invalid and thus the software unlicensed. Same as "public domain" licensing.
I happen to know about this "France problem" because for a while it affected the OCaml distribution (it has now been resolved by some French-specific legal wrangle).
I don't know how this affects the GPL specifically, but you can be pretty sure that if the GPL doesn't contain France-specific French-language legalese to work around it, then it's likely to be revokable whatever the license says. Of course this only affects you if you're in France or have French contributors.
Unless I'm misreading it, that section specifically says that the author may not withdraw distribution rights for software:
> Nevertheless, the Intellectual Property Code provides some specific rules regarding moral rights over software. It provides that the author may not oppose modifications of the software, in as far as such modifications do not affect his honor or reputation, and exercise his right of withdrawal.
The entirety of the license is the text of the license. If there is no revocation clause specifying how revocation would happen, the answer is no, it can't be revoked.
Assuming he holds the copyright for the entirety of the program, he could change the license for all future versions, and he also could stop distributing old versions under the old license (putting a new license on it, or simply discontinuing distribution). But, the old license has already granted thousands, or millions, of people, the right to distribute it under those terms.
This is an interesting question. I was at a talk at this years's GsoC summit where this was discussed and indeed, the language of the BSD license does not issue an `irrevocable` license as the language of a lot of other licenses does. Nobody has every tried revoking an MIT or BSD license before, but it would be an interesting legal argument to see if the courts would allow it.
For future modifications, yes, but you can not retroactively revoke a license. Although I am sure if you get a lawyer involved he can likely try to come p with reasons why it couldn't have legitimately been released as BSD in the first place, thus declare the first BSD licensing of the code as invalid.
Huh? Where does the law say this? It is my impression that the copyright owner has all rights unless he explicitly relaxes them. A license by definition cannot create more rights, it can only relax them.
A license doesn't "relax" rights, it grants rights to others (and sometimes/in some jurisdictions also can limit how the copyright owner can make use of his rights)
If you give someone the right to do something and don't specify how you can take it away, you can't take it away again. Without termination clauses a license is a contract thats valid indefinitely.
And why can't you take it away? If I give someone a permit to cross my bridge, I can revoke it at any time. Usually when something is perpetual, you have to write in it: "perpetual" for it to actually be so.
Let's keep it with software. The bridge metaphor is more applicable to a service offering where you maintain infrastructure and adjust pricing based on the cost of maintaining it.
In software, the license is what you sell. I don't buy MS Windows or Photoshop, I buy a license for it. If you sell me a 3-seat license of software v1.0 allowing me to install it on up to 3 computers, you can't come back 2 years later and change the terms to only 1 computer. Now, in 2 years, you might have v2.0 and require a new license for that. But the license you sold me for v1.0 remains in place.
By releasing the software under the BSD license, he basically sold us a license (price immaterial) granting permission to redistribute and alter the code, provided that new code includes the BSD license.
I understand that wasn't his intention. Another commenter pointed out that the author gave permission to another project which was being released under the BSD license. Now anyone that was "sold" the software with that license has been granted those redistribution rights.
I did think of this, but surely a transaction between two parties is not the same as simply posting a license on a website?
If I pay money in return for a license to use Photoshop, there is a reasonable expectation that I can use that indefinitely. I give then money, they give me permission.
If I simply download a piece of open source software from the internet, that isn't the same thing. There's no transaction. There's no anything. If the author subsequently tells me "I hereby revoke all previous licenses", I don't see how that wouldn't have legal weight.
"If I pay money in return for a license to use Photoshop, there is a reasonable expectation that I can use that indefinitely. I give then money, they give me permission."
Money has nothing to do with it, all reproduction of bits is automatically covered by copyright law, and has a legal presumption of "all rights reserved" unless explicitly delineated in a license.
Even when paying money, it isn't a reasonable expectation to expect to be able to use it forever for all software. With shrink-wrap or click-through agreements, perhaps, by convention, but plenty of software is sold on subscription for example, or may have revocation clause without refund which is common with MMO games for example.
Some software also may naturally break some day due to incompatibility or disinterest by the author. Other than limited warranty protections by law, there's not much a buyer can do about it. This is of course subject to local laws which may allow moral revocation (France) or stricter warranties.
With regards to downloading a piece of open source, the downloader is consenting to the copyright license it is offered under: it's the same as a click through.
If there is no license, you technically have no right to use or redistribute the software (all rights are reserved).
If there is a license, usually that will explain the author's intentions for fees, redistribution rights, and rights of revocability.
The OSI exists to approve licenses as "open source" when they (among other clauses) explicitly denounce revocability. The only recourse is that an author can refuse to OSI license future modifications or releases of the software (basically making a private fork).
If you just tell someone you can use the bridge then you can probably revoke it. But if you keep letting them use it and they build a house on the other side of the bridge or something then you've probably granted an implied easement[1] and can't, in fact, suddenly stop letting them use the bridge. But in this case there's actually a legal document saying that anybody can use the bridge so that would be analogous to an express easement.
We are not talking about permits (which are typically temporary as per whatever conditions they have). We are talking about software licenses, which often do not allow the copyright holder to revoke.
These licenses are explicit about what they do/do not grant. p
If you want a non-derivative work you need to do something like a clean room implementation where the one writing the code doesn't have access to the code of the existing implementation: https://en.wikipedia.org/wiki/Clean_room_design
BTW this guy can not stop derivative works once he has released it as BSD.