Section 6 states:

(6) You may Distribute a Modified Version in Compiled form without the Source, provided that you comply with Section 4 with respect to the Source of the Modified Version.

But if you look at Section 4:

Distribution of Modified Versions of the Package as Source

(4) You may Distribute your Modified Version as Source (either gratis or for a Distributor Fee, and with or without a Compiled form of the Modified Version) provided that you clearly document how it differs from the Standard Version, including, but not limited to, documenting any non-standard features, executables, or modules, and provided that you do at least ONE of the following:

(a) make the Modified Version available to the Copyright Holder of the Standard Version, under the Original License, so that the Copyright Holder may include your modifications in the Standard Version.

(b) ensure that installation of your Modified Version does not prevent the user installing or running the Standard Version. In addition, the Modified Version must bear a name that is different from the name of the Standard Version.

(c) allow anyone who receives a copy of the Modified Version to make the Source form of the Modified Version available to others under (i) the Original License or (ii) a license that permits the licensee to freely copy, modify and redistribute the Modified Version using the same licensing terms that apply to the copy that the licensee received, and requires that the Source form of the Modified Version, and of any works derived from it, be made freely available in that license fees are prohibited but Distributor Fees are allowed.

The wording at the beginning is "You may Distribute" - does not distributing the source of the Modifed version also mean that you are complying with Section 4?

Or does the wording in Section 6 imply that you must distribute the source of the Modified Version, and that distribution should comply with Section 4?


The Artistic License has two goals:

  1. Ensure that the original author has some control over the further development of their work.
  2. Be an extremely permissive license.

It is commonly used in the Perl ecosystem. It is not generally recommended outside of that context.

You have correctly noted that it is allowed to distribute modified versions in compiled form without distributing the source forms of the modified version. In this respect, the license is very permissive, and allows such software to be embedded into proprietary systems.

The license is somewhat unclear on whether (4) and especially (4.b) also applies to compiled modified versions, i.e. the requirement that installation of the modified version must not prevent use of the standard version and use a different name.

I interpret the license so that distributing modified versions in compiled form under (6) requires you to to also satisfy the requirements under (4). The sub-points of (4) are choices, and you only need to comply with one of these options. If you do not wish to distribute the source under (4.a) or (4.c) this only leaves (4.b) for compliance: you need not distribute the source if you're not interfering with the standard version.

This wording of paragraph (6) was also flagged as unclear during the OSI license review process. One of the license's authors (Allison Randal) responded:

It means what it says: you can distribute compiled forms as long as your distribution (or lack of distribution) of the source code complies with Section 4.

– Allison Randal, in an email to the license-discuss list (permalink)

Under section 6, all binary versions (compiled versions, etc) must comply with section 4. And under section 4 you must either contribute your changes (as source) back to the original project, change the name, or release your source code under the Artistic License or a copy-left license. Distribution is distribution, whether it's binary or source.

– Allison Randal, in an email to the license-discuss list (permalink)

This fits my above interpretation.

Note that quite a lot of software is distributed only in source form, e.g. scripts and most Perl modules. But even running a minifier over the source would be a compiled form in the sense of the Artistic License.

  • I agree with you about what the AL was trying to require. I have to disagree with you about what it actually requires, I'm afraid, because there is other language the AL could have used (including, but not limited to, the example I gave) which would ensure their desired outcome. For me, it's a clear-cut case of why you shouldn't write your own license, especially not if your primary motivation appears to be wordplay. +1 from me, though, for digging up the original material on the author's intentions - great stuff!
    – MadHatter
    Dec 10 '17 at 16:14
  • @MadHatter The original Artistic License was indeed an unusable crayon license as you suggest, but the AL2 is a serious rewrite that was actually co-written by lawyers – a decent license aside from this very confusing clause. I think this clause is unclear, but not fatal to the license. Instead, the primary reason not to use it is to avoid license proliferation (although AL2 has excellent GPL compatibility).
    – amon
    Dec 10 '17 at 16:41
  • AL2's GPL compatibility, as the FSF notes, is due entirely to the relicensing option which allows you to get rid of the AL; I'm not sure that's the most ringing endorsement I've ever heard. I agree that AL2 is not as bad as AL1 but poor phrasing choices like s6 (vide this whole question) do not make me love it.
    – MadHatter
    Dec 10 '17 at 20:42

IANAL/IANYL. That said, as I read it, s6 requires that if you choose to distribute the modified version binary-only, you must comply with s4. As you have observed, s4 does not require anything of you unless you distribute your modified version in source form. The net effect as I read it is that you may distribute your modified version binary-only, and you have no further obligations if you do so.

It's as if I sell you a beat-up car with a contract that says

a) You will pay me for my car, and obey paragraph b, then it's yours.

b) If you later crash it, you have to fix it up like new.

If I see the car later and you haven't crashed it, should I expect you to have fixed it up? I think not: paragraph a obliged you to honour paragraph b, but paragraph b's requirements didn't cut in unless a certain thing happened, and it hasn't.

Now for the suppositious bit: what I suspect the authors to have intended was a s6 that read

(6) You may distribute a modified version in compiled form without the source, provided that you comply with at least one of the provisions 4a, 4b and 4c with respect to the source of the modified version.

But that's only guesswork. If I were writing a little project that depended on a third party's artistically-licensed code I'd assume reading two, honour 4.ii.c, release the whole thing under GPL3, and make the world a more-free place. If I were betting a company on it, I'd assume reading one - but I'd also get qualified legal advice, and not rely on random internet postings.

Really, the whole thing makes me angry with Yet Another Bloody Crayon Licence. What is the point? If you want strong copyleft, use GPL3+ (unless you're Linus, in which case carry on with GPL2). If you want weak copyleft use 3-clause BSD, or Apache 2.0 if you care about patent treachery. Anything else even vaguely copylefty you're trying to achieve is probably so close to one of those outcomes that the distinction is not worth the hassle of uncertainty.

  • 1
    If I were betting a company on it, I would reject the use of artistically-licensed code on the grounds that the license is unclear and a potential legal minefield. Dec 10 '17 at 9:06
  • "If you want strong copyleft, use GPL3+", wanting source to be distributed does not imply wanting copyleft (you can have a relicensing clause). However, it seems that today, there is no other option. Dec 10 '17 at 14:53
  • @theindigamer I'm not sure I see your point. Suppose you're distributing something in source form. If you don't care whether people who modify it redistribute their sources along with their modified versions, go weak copyleft (see above). If you want modified versions to be equally fully-available, go strong copyleft. What other meaningful outcomes for modified sources are there?
    – MadHatter
    Dec 10 '17 at 16:10
  • 1
    @MadHatter, as I understand it, copyleft means you literally need to use the same license. Wanting source to be distributed does not imply wanting copyleft; you have the room to allow relicensing to other licenses with the same requirement of "you must distribute the source". Dec 10 '17 at 16:17
  • 1
    Not at all. Most weak copyleft licences don't prevent you from including their code in a proprietary product, which will be distributed under a very different licence. Only strong copyleft licences, the ones that specify what licence must apply to modified versions, clearly prevent this.
    – MadHatter
    Dec 10 '17 at 16:22

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