Rewrite pasted paragraph with historical context.

This change perhaps is somewhat controversial, but reflects honest
reality of this history of additional requirements on GPL.  The
additional requirements that GPLv3 permits mostly represent historically
known situations where GPLv2 permitted license compatibility with Free
Software licenses containing such requirements.

Orthodox compatibility theory demands that such additional requirements
have explicit codification in a copyleft license, which hints at why
GPLv3 needed to include this section.

However, historical copyright holder toleration of these sorts of
requirements placed on GPLv2 works is well-documented, and failure to
mention it here is a disservice to the reader.
This commit is contained in:
Bradley M. Kuhn 2014-11-13 07:41:08 -05:00
parent f03369c7ed
commit ea8cab561d

View file

@ -3382,12 +3382,11 @@ asymmetrical, because they do not raise the same interpretive
issues; in particular, additional requirements, if allowed without careful
limitation, could transform a GPL'd program into a non-free one.
% FIXME-URGENT: integrate
While GPLv2 does not allow for any additional restrictive terms, GPLv3 allows
for some specific limited variations, thus varying the strict copyleft of
GPLv2 in the interest of broader compatibility with other licenses.
% FIXME-URGENT: end
Due to the latter fear, historically, GPLv2 did not permit any additional
requirements. However, over time,
many copyright holders generally tolerated certain types of benign additional requirements
merely through a ``failure to enforce'' estoppelesque scenario. Therefore, GPLv3 allows
for some specific limited requirement variations that GPLv2 technically prohibits.
With these principles in the background, GPLv3~\S7 answers the following
questions: