Here is the scenario:

As a researcher you are making a modification to some GPL3-licensed software, and thus if you were to distribute the code, you would need to do this using the GPL (or a compatible license, but I'll just stick to GPL to simplify).

Now imagine you submit an article to a scientific journal, and the reviewers, as part of the review process, request your code. From what I understand, you would need then to share this code under a GPL license. Until here, no issues. The problem that I see is that most scientific journals have strict (and ethical) restrictions on what a review can do with the content they are reviewing, i.e., not being able to share the content in public.

So wouldn't this create an incompatibility with GPL license? I mean, according to the license, the reviewer should be entitled to share it as they like, as long as the license is maintained and so on... Meanwhile, the journal review guidelines would act as a limitation on the GPL.

So the big question is if this would indeed constitute a breach of the GPL license. Or would it mean that you can't submit your article to that journal, since their requirements could impose a limitation on the license itself?

Or could you make a case that you are not distributing the software when you distribute it to the reviewer in the first place (I know that for personal use or to use internally you don't need to make your code use GPL even if you are using/changing GPL software).

  • A simple, practical solution is to publish the source code prior to the article being reviewed.
    – jpa
    Dec 14, 2022 at 16:24

6 Answers 6


You certainly are distributing the GPL-licensed work to the reviewer. "Internal" non-distribution conveyance only occurs between agents of the same legal corporation (persona ficta) because it doesn't leave the possession of the corporate person. That does not occur here.

In the simplest case, you are not forbidden to tell the reviewer, "I must tell you: I cannot and will not forbid you from distributing this software." And the reviewer will surely say in reply, "Thanks, if early release of this software is worth forever destroying my academic career, I'll think about employing that option." And there is no GPL violation: the reviewers badly want to ensure that they do not share your software, for the safety of their own careers.

The legal specifics of more complex cases will probably come down to what specific contracts are enacted between the parties involved (you, the reviewer, and the journal publisher).

In the event that you give your code directly to a reviewer, and that reviewer has a separate contract with the publisher not to share reviewed material, I don't see a GPL violation here, because no distributor of GPL'd work is attempting to impose restrictions on redistribution. If the publisher acts as a proxy between you and the reviewer and gives the work to the reviewer themselves, and such a contract is in effect, then they probably commit a GPL violation.

It's possible that you give the work directly to the reviewer, and there exists a legal contract between you and the publisher asserting that you will not grant reviewers the rights to redistribute the software. This would put you in the position of either violating the upstream author's GPL grant or violating your contract with the publisher.

One possible exception to this last case: the GPLv3 does handle this case for contractors hired to make modifications and for remote code-hosting/execution platforms (e.g., Amazon Web Services):

You may convey covered works to others for the sole purpose of having them make modifications exclusively for you, or provide you with facilities for running those works, provided that you comply with the terms of this License in conveying all material for which you do not control copyright. Those thus making or running the covered works for you must do so exclusively on your behalf, under your direction and control, on terms that prohibit them from making any copies of your copyrighted material outside their relationship with you.

If we can say that reviewers fall under the broad category of parties who receive your code for "the sole purpose of having them make modifications exclusively for you" then the GPLv3 would allow this particular restriction. (The GPLv2 would not.) Whether or not reviewer feedback on software constitutes "making modifications" under this provision isn't clearly settled for me, but I can surely see a strong argument in favor of it (e.g., they might indeed offer improvements, and there isn't an expectation they'd want to redistribute the work further, much like a contractor).

  • 5
    I'm a bit confused. Who are you saying would be violating the GPL in that scenario? The publisher? Why would the publisher be bound by the GPL? Dec 14, 2022 at 8:17
  • 2
    I echo David's confusion. In the scenario that "there exists a legal contract between the reviewer and the publisher forbidding the reviewer from releasing the code," you say that "there is a GPL violation," but who is violating the GPL? What are they doing that's a violation of the GPL and what part of the GPL prohibits that action? Dec 14, 2022 at 11:29
  • 2
    @DavidSchwartz I was envisioning in particular that the author gives the work to the publisher to forward to the reviewers, under an NDA. I can absolutely see how my answer was unclear, so I have more clearly differentiated these cases.
    – apsillers
    Dec 14, 2022 at 12:10
  • 2
    @Tanner-reinstateLGBTpeople I had imagined that the author gives the work to the publisher to forward to the reviewers (as occurs in some academic environments), so I have clarified and differentiated a few different cases. (In that case, the publisher commits a violation.)
    – apsillers
    Dec 14, 2022 at 12:24
  • Thank you @apsillers, I think I see now your point, and I didn't now that exception on the GPLv3, at first it would seem like an exaggeration, but your last phrase makes a very compelling point on it (on not having the expectation for the redistribution). And from my understanding, the publisher indeed usually acts as a proxy, at least in most journals I've seen.
    – Arruda
    Dec 14, 2022 at 18:49

Isn't this a direct application of section 12 of GPL?

  1. No Surrender of Others' Freedom.

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. For example, if you agree to terms that obligate you to collect a royalty for further conveying from those to whom you convey the Program, the only way you could satisfy both those terms and this License would be to refrain entirely from conveying the Program.

You have send the program to the reviewer under GPL license. But the reviewer has other obligations, namely the journal requires the reviewer not to share the content in any way. So the reviewer must comply with both requirements, which means that they can not share the program at all.

Note that the GPL does not require a reviewer to share program. Anybody can obtain a GPL-licensed program and choose not to share it further. And if one has other obligations that forbid sharing program further, then the only choice left is not to share at all.

UPD, based on the comments: the above refers to the situation for the reviewer. They will be in no problem, because GPL does not require them to be able to distribute the software.

Also, it tangentially explains why you are not in any violation of GPL. You are not placing any limitations on the reviewer, and the fact that the reviewer has any other limitations does not affect your actions. After all, these limitations are resolved by this section 12.

A more tricky situation may be for the editor, in case when they forward your program to the reviewers (usually you do not interact with the reviewers directly), because the editor will then have to send the program to the reviewer and require a non-disclosure.

However, I believe that this can be easily solved if you do not sent a full program to the editor, but only a link where the program can be obtained (a link to a repository, Google Drive archive, etc.) The editor will then forward the link to the reviewer, and this will not constitute "conveying" according to the definition of the GPL (because "conveying" is a special case of "propagation", which requires "[doing something that] would make you directly or secondarily liable for infringement under applicable copyright law", and simply sending a link would not constitute any infringement).

(Although the latter paragraph poses an interesting question per se, I've posted a separate question regarding it: Does sending a link to software constitute "conveying" according to GPL? )

  • 1
    I don't think this is what Section 12 is about.
    – wizzwizz4
    Dec 15, 2022 at 3:31
  • 1
    If the reviewers were to find themselves in the position of having a GPL grant to the work they are reviewing and also under restrictions on distributing the work, section 12 tells the reviewer what they can do. The OP is not the reviewer, they are concerned whether the GPL allows them to distribute the work to the reviewer in the first place if it will put the reviewer in this position. Section 12 doesn't address that.
    – Ben
    Dec 15, 2022 at 5:43
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    @Ben "they are concerned whether the GPL allows them to distribute the work to the reviewer in the first place if it will put the reviewer in this position." But if I meet a random Mr. A on the street, I am definitely allowed to give him a printout of a GPL-licensed source code, with a GPL license. I don't have to ask whether Mr. Smith might be forbidden from doing something with it by a court order, agreement or otherwise. I don't see how it would make any difference if I know Mr. A has such an agreement with someone. Is the case any different if I replace "Mr. A" with "Referee 2"?
    – JiK
    Dec 15, 2022 at 22:27
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    The use of Section 12 in this case is that it gives me the peace of mind that I didn't force Mr. A to a legal contradiction and thus they will honor their agreements if they had some. Section 12 doesn't have to say anything about whether what I did was legal because of course it was. (Or in case of Referee 2, I know that I haven't forced Referee 2 to do anything they aren't allowed to do.)
    – JiK
    Dec 15, 2022 at 22:34
  • 1
    (But I do agree with the comments, I don't think Section 12 is the answer to OP's question but I think it addresses a part of it.)
    – JiK
    Dec 15, 2022 at 22:37

No, that would not be a breach of the GPL.

So wouldn't this create an incompatibility with GPL license? I mean, according to the license, the reviewer should be entitled to share it as they like, as long as the license is maintained and so on.

That's not true. The license merely states that if I, the researcher, convey a copy of my software to the reviewers, then I must (among other requirements) release my software under the GPL. (That's in section 5, "Conveying Modified Source Versions.") The license doesn't say that the reviewers must actually be able, all things considered, to share it as they like.

In other words, if I give the reviewers my permission to redistribute the code, then I've satisfied the requirement that the GPL imposes on me, and so I'm not violating the license. The fact that other people are forbidding the reviewers from distributing the code doesn't mean that I'm somehow violating the license. Those other people aren't violating the license either, because they're not distributing the software, so the license doesn't apply to them.

  • And be careful to give the journalist the application together with source code. If you distribute the application (to the journalist) then anyone in the world, for example me, can request the source code from you. Except if you gave the journalist application and source code, then you have no obligations against third parties.
    – gnasher729
    Dec 15, 2022 at 11:52

You're essentially looking at the same situation as "Does the GPL allow me to develop a modified version under a nondisclosure agreement?" from the GPL FAQ:

  • Your code is still licensed under the GPL (without any further restrictions) and the reviewer could distribute it without a breach of the copyright license they have received.
  • Due to a separate agreement, the reviewer is almost certainly going to choose not to distribute your code, because doing so would likely irreparably ruin their relationship with the journal.
  • Although very close, this seems more like the previous one in their FAQs, the one on distribution under NDA, not development.
    – Arruda
    Dec 14, 2022 at 18:53

So the big question is if this would indeed constitute a breach of the GPL license. Or would it mean that you can't submit your article to that journal, since their requirements could impose a limitation on the license itself?

I'm having a hard time figuring out who is supposedly trying to impose a restriction here. The 'ethical' restrictions on redistributing code sent to reviewers are, I assume, an attempt to protect the rights of the person submitting the paper and therefore the code to the reviewer. If you are submitting binaries of code someone licensed to you under the GPL to anyone, you have the responsibility to afford them the same rights of redistribution of the source code. If you are trying to 'protect' your modifications to this code by relying on the agreement between a journal and the reviewers to keep your code secret, after benefiting from the work done by the authors of the code you are licensed to use under the GPL, you are acting highly unethically.

If there is some agreement between you and the journal that the code can be copied and distributed to the reviewers, but then the reviewers are denied the rights to modify and redistribute the code, then again you are acting highly unethically.

  • I think it's a bit different, in my view. The way I was seen was that if you (the author) made some changes to a GPL software, and made a paper about that, then is not that you are sharing someone else work... or... actually, now that I think more about it, it is a bit like that, right? so yeah, maybe this could be seen as an unethical research practice since in some scenarios (see @apsillers answer) you could be the one limiting liberties the GPL license from the original software that you used as a base.
    – Arruda
    Dec 21, 2022 at 19:15

The biggest problem I see is not with sharing, but with attribution.

The journal will have strict anonymity requirements, while GPL3 art 5.a forbids exactly that:

a) The work must carry prominent notices stating that you modified
it, and giving a relevant date.
  • That's another good point to look into... Even if not all journals have a double-blind review process.
    – Arruda
    Jan 13, 2023 at 17:03

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