We've created, appointed, or otherwise identified certain question/answer pairs that are the canonical answer for certain problems. These are answers where the community has said all it is going to say on a class of subject, because although everyone's particular problems in that class are somewhat different, to the extent that they are interesting they aren't different, and to the extent that they're different they aren't interesting (to anyone save the questioner). So we write one answer that's designed to be the last word on the subject, and say no more.

A list of these problems is given in the (soon-to-be) accepted answer below.


  • Post an answer (to this question) to nominate a question for inclusion. Questions explicitly posted for the meta-approved purpose of creating a canonical Question/Answer can skip this. Consensus seems to have evolved that a score of +4 is enough to approve canonicalisation.

  • Delete answers nominating questions that have been merged into the official list. Try to keep this post neat and tidy.


4 Answers 4


Proposed canonical question: How can a "crayon" license be a problem?

Bruce Perens (co-founder of OSI) has coined the term "crayon license":

I've been calling these "crayon licenses", taking a line from an old Monty Python sketch about a dog license with the word "dog" crossed out and "cat" written in, in crayon.

The licenses referenced are typical well-intended free software licenses that have been written by programmers in simple, easy-to-understand, non-legalese language. Some typical examples are the WTFPL and the somewhat more elaborate Artistic License 1.0.

Perens seems to imply that such licenses may pose a problem for developers using them, or for the open source community.

How can these licenses be a problem?

Or is Perens wrong about them being a problem?


Proposed canonical question: So the GPL doesn't restrict the creator of the software in any way?

In the interest of full disclosure, I'm the author of the accepted answer.

I'm honestly not a huge fan of the question's structure -- being four closely-related questions in one -- but it does allow the Q&A to cover a lot of conceptual ground, making its concerns a superset of many other questions. I'd be interested in discussing whether to use it as-is (possibly cleaned up first), or make a new differently-structured question to fill this canonical niche.

  • 2
    I'd probably change the word "GPL" in the title to "licence" (or "license" :), because part 3 of your answer makes it clear that it's not GPL-specific. But other than that I'd be happy with the question as it appears.
    – MadHatter Mod
    May 19, 2020 at 15:26

Proposed canonical question: How can a project be relicensed?

I've found out that the license I picked for my project does not quite do what I wanted it do (bad research).

Now I want to change the license. Is it as simple as changing the LICENSE.txt in the root?

  • 1
    I think a canonical question on this might be a good idea, but I wouldn't pick that particular question. The answers all fail to distinguish between relicensing away from a strong copyleft licence, and relicensing away from a permissive free licence, and they're not the same question.
    – MadHatter Mod
    May 19, 2020 at 11:52
  • 1
    @MadHatter I don't see how, if you're the sole copyright owner or you have the consent of all contributors you can relicense to anything (as long as your project doesn't depend on copyleft libraries.) May 19, 2020 at 11:59
  • 1
    Do you mean "unless you're the sole copyright owner"? Forgive me, but I don't quite understand the point.
    – MadHatter Mod
    May 19, 2020 at 12:06
  • 1
    I meant I didn't see how they're different questions. I don't think the project's old license matters. May 19, 2020 at 12:08
  • 1
    I do, as you can read here if you want. I won't reiterate the arguments here, but I do hold that there is a big difference in relicensing process depending on whether the original licence which permitted redistribution forbade changing the licensing terms when so doing (as well as on other factors like the existence of multiple rightsholders). I may well be wrong, but I'm far from the only person to hold this position, and it should be reflected in some of the answers to any canonical question on the subject. Perhaps propose a fresh question?
    – MadHatter Mod
    May 19, 2020 at 12:12
  • 1
    @MadHatter Oohhhh, that's sublicensing someone else's project, whereas this question is specifically about the original author of a project changing the license. They definitely need to be handled separately. May 19, 2020 at 12:21
  • Problem is, there's overlap: what if I start a project under free license X and receive contributions on those terms, with no CLA in place? Then relicensing is a sublicensing question (as you would have it), and this depends on whether X is permissive or strong copyleft. I do agree the proposed canonical is unaffected by the issue I raise provided the original author is the sole rightsholder - but surely a canonical question on this subject should deal also with the more complex, and common, case?
    – MadHatter Mod
    May 19, 2020 at 12:23
  • @MadHatter I think the answers cover that adequately enough. If you can get permission from all contributors, the relicensing is actually just like dual-licensing, you can start from a clean slate. If you can't get their permission, then as the answers say, you can only switch to a compatible license. But let's see what other people think. May 19, 2020 at 12:29
  • 1
    Actually, re-reading, I think I agree with you. Let's, as you say, wait and see what others think.
    – MadHatter Mod
    May 19, 2020 at 13:10

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