Version 3 of the GPL or any later version

[van-de-bugger]

gnu.org recommends to use "Version 3 of the GPL or any later version", and have some rationale for it: https://www.gnu.org/licenses/gpl-faq.html#VersionThreeOrLater

How to express "GPL 3 or later" in meta? License "gpl_3+" is not in the list of valid licenses.

[dagolden]

You can specify it as "open_source", which is a catch-all for anything that isn't a specific, known license. The same thing applies to dual license situations, where a user has a choice of licenses. (Except, for historical reasons, the terms of Perl which is a joint Artistic/GPL license)

I'll leave this open and mark it as a wishlist item, though a more general approach for this would be better than adding "gpl3+" only.

[van-de-bugger]

More general approach could be adding suffix "+" to any known license name to denote "or any later version" clause. However, I am not sure if such approach is applicable to non-GNU licenses.

[dagolden]

A subtle point to consider is that while I understand the FSF's interest in people licensing things as "3 or later", that exposes developers to anything the FSF puts into a subsequent license. I think developers would be prudent to be explicit, and I think that's what our META should require.

[van-de-bugger]

Err... Look: CPAN::Meta::Spec defines perl_5 license (I guess it is the mostly used license for Perl modules published on CPAN), which is Artistic or GPL 1 or any later. Thus, implicit using GPL 1 or any later is allowed, but explicit using GPL 3 or any later is not? Why? The door is already open.

At the same time, I understand that implementing this may be non-trivial, require efforts, there is no (large) demand for it, etc. Such reasoning is quite acceptable.

[dagolden]

This is still on the table when the next version of the META spec is released, but there are no immediately plans to do so.