Hi,

I guess this post might be better to go ruby-core.

In message "Re: [ruby-dev:39167] [Bug #2000] Change the license to "GPLv2+ or Ruby's original"."
    on Wed, 26 Aug 2009 23:47:10 +0900, Mamoru Tasaka <redmine / ruby-lang.org> writes:

|Recently readline 6.0 was released and its license was changed from
|GPLv2+ (GPL version 2 and any later) to GPLv3+ [1][2]
|Unfortunately Ruby's license is still under GPLv2 and Ruby's original license [3],
|which is incompatible with GPLv3 [4]. So unless Ruby's license is changed
|to "GPLv2+ or Ruby's original license" or so , Ruby's readline module cannot be shipped
|any more. Note that "Ruby's original license" is regarded as incompatible with
|GPL [5].
|
|So please change the Ruby's license to GPLv3 (and GPLv2) compat.

I am not sure how Fedra project think, but there's no such thing as
Ruby's license independent from GPL.  It's always dual licensed, so as
a whole it's always GPL compatible (at least to GPLv2).  It's already
known to FSF, see the compatibility note from them (I don't remember
the URL right now).

For license compatibility issue, I think we are still able to ship
readline extension without changing Ruby's license as a whole, since
the older version of readline library is always available.  But to
avoid the potential problem, we should either, a) note that it's
incompatible with GPLv3 version of libreadline, or b) note that
readline extension can be distributed by GPLv3 as well (triple
license).

I recommend the latter.

Compatibility issues between free software licenses suck.

							matz.