April 25, 2006

Perl's Artistic License undergoing update

Author: Joe 'Zonker' Brockmeier

The GPL isn't the only license being revised this year. The Perl Foundation has published its drafts of the Artistic License 2.0 and Contributor License Agreement for public comment.

The work toward a new license has been going on since 2000, at about the same time work began on Perl 6. Perl users developed a first draft of the Artistic License 2.0 on the Perl6-licenses mailing list, then sent it out for review by legal counsel and organizations that use Perl. Now the license is available for public comment.

The 2.0 draft includes several new provisions, and is somewhat longer than the Artistic License 1.0. However, according to Perl Foundation board member Allison Randal, the basic terms of the license are the same. "Most of the changes we made were clarifying and simplifying the language of the license so it would be easier for average human beings to understand, and so the legal implications of some of the terms are more immediately obvious.

"We removed some anachronisms, particularly the explicit references to posting modifications on 'Usenet' or 'uunet.uu.net' or compiling via 'undump' or 'unexec.' And, we intentionally avoided future anachronisms, so Artistic 2 has no references to 'CD' or 'DVD' distribution, or compiling with 'gcc' etc."

Randal says the new draft should also clear up relicensing issues. Right now, Perl and many Perl modules are dual-licensed under the GNU General Public License (GPL) and the Artistic License, allowing developers to distribute modified versions under one or both licenses. A change in 2.0 would allow a broader range of free software licenses, says Randal.

"One significant change to the terms is in clause 4(c)(ii). We call this the 'relicensing' clause, and it allows people to redistribute a Modified Version of an Artistic License package under one of the so called 'copy-left' licenses. This alleviates the downstream licensing compatibility problems that so many licenses have. If you want to include an Artistic licensed package in an Apache licensed package, for example, you just relicense the Artistic package under the Apache license. It also means we can eliminate the complexity of dual licensing Perl as Artistic and GPL. We can release Perl under the Artistic license only, and anyone who needs it under the GPL can simply relicense it."

The new license also addresses patent issues, which were not a major issue when the first version of the Artistic License was drafted. Randal says that software patents haven't been a problem for Perl yet, but "given the general legal environment around open source software these days it's a wise form of insurance have. Some large companies involved in the review were very pleased to see the patent language going in."

In addition to the draft license, the Perl Foundation has also put forth a Contributor License Agreement, which would be signed by contributors to document contributions and explicitly grant rights to the Perl Foundation.

At present, Randal says that there isn't a specific procedure in place for handling contributions, but the Perl Foundation plans to put one in place this year. "It will be relatively lightweight to avoid disrupting the development process too much, and will feel familiar to anyone who has worked with the Apache process."

Randal notes that contributors will be keeping their copyright, rather than assigning it to the Perl Foundation. "They are only granting the Perl Foundation a license to use and redistribute their contributions. Every contributor retains the copyright on their individual pieces of code. The Perl Foundation owns the copyright on the compilation, that is, on the entire collection of everyone's contributions."

The plan is to apply the Artistic License 2.0 to not only Perl 6 and Parrot, which are not yet finished, but also to Perl 5, according to Randal. "We plan to eventually also update Perl 5, but only after we have signed contribution agreements from all the Perl 5 developers with commit access to the repository and other significant contributors."

If all goes according to plan, the new license should be approved by the end of the year. Randal says that the Foundation expects to approve it "within the next couple of months," but it could go longer if the public review raises any questions that need to be resolved.


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