Re: GPLv3 comedy unfolding -- "possibly self-contradictory" stuff belongs to GNU!

[Alexander Terekhov]

Man oh man.

------
Opinion on Additional Terms

Introduction

The wording of section 7 in Draft 1 proved difficult for many readers to
understand. In Draft 2 section 7 has been entirely rewritten and bears a
new title that more accurately reflects its scope. The new section 7 is longer
than the first version, but it is no less concise; it now explicitly addresses
certain issues regarding the presence and validity of additional terms that
were not covered in the first version. It is meant to be clear, comprehensible,
and comprehensive. Because most of the comments we received on section 7
were, in effect, questions about its meaning and interpretation, we use this
opinion to explain how section 7 provides a framework for the analysis and
treatment of additional terms under the GPL.

The GPL is a statement of permissions, some of which have conditions.
Additional terms, terms that supplement those of the GPL, may come to
be placed on, or removed from, GPL-covered code in certain common ways.
We consider those added terms “additional permissions” if they grant exceptions
from the conditions of the GPL, and “additional requirements” if they
add conditions to the basic permissions of the GPL. The treatment of additional
permissions and additional requirements under GPLv3 is necessarily
asymmetrical, because they do not raise the same ethical and interpretive
issues; in particular, additional requirements, if allowed without careful 
limitation,
could transform a GPL’d program into a non-free one. With these
principles in the background, section 7 answers the following questions: (1)
How do the presence of additional terms on all or part of a GPL’d program
affect users’ rights? (2) When and how may a licensee add terms to code being
distributed under the GPL? (3) When may a licensee remove additional
terms?

Additional Permissions

Additional permissions present the easier case. We have licensed some of
our own software under GPLv2 with permissive exceptions that allow combination
with non-free code, and that allow removal of those permissions
by downstream recipients; similarly, LGPLv2.1 is in essence a permissive
variant of GPLv2, and it permits relicensing under the GPL. We have generalized
these practices in section 7. A licensee may remove any additional
permission from a covered work, whether it was placed by the original author
or by an upstream distributor. A licensee may also add any kind of
additional permission to any part of a work for which the licensee has, or
can give, appropriate copyright permission. For example, if the licensee
has written that part, the licensee is the copyright holder for that part and
can therefore give additional permissions that are applicable to it. 
Alternatively,
the part may have been written by someone else and licensed, with
the additional permissions, to that licensee. Any additional permissions on
that part are, in turn, removable by downstream recipients. As subsection
7a explains, the effect of an additional permission depends on whether the
permission applies to the whole work or a part.

We have drafted version 3 of the GNU LGPL, which we have released
with Draft 2 of GPLv3, as a simple list of additional permissions supplementing
the terms of GPLv3. Section 7 has thus provided the basis for
recasting a formally complex license as an elegant set of added terms, without
changing any of the fundamental features of the existing LGPL. We
offer this draft of LGPLv3 as as a model for developers wishing to license
their works under the GPL with permissive exceptions. The removability of
additional permissions under section 7 does not alter any existing behavior
of the LGPL; the LGPL has always allowed relicensing under the ordinary
GPL.

Additional Requirements and License Compatibility

We broadened the title of section 7 because license compatibility, as it is
conventionally understood, is only one of several facets of the placement of
additional terms on GPL’d code. The license compatibility issue arises for
three reasons. First, the GPL is a strong copyleft license, requiring modified
versions to be distributed under the GPL. Second, the GPL states that no
further restrictions may be placed on the rights of recipients. Third, all other
free software licenses in common use contain certain requirements, many of
which are not conditions made by the GPL. Thus, when GPL’d code is
modified by combination with code covered by another formal license that
specifies other requirements, and that modified code is then distributed to
others, the freedom of recipients may be burdened by additional requirements
in violation of the GPL. It can be seen that additional permissions in
other licenses do not raise any problems of license compatibility.

Section 7 relaxes the prohibition on further restrictions slightly by 
enumerating,
in subsection 7b, a limited list of categories of additional requirements
that may be placed on code without violating GPLv3. The list includes
the items that were listed in Draft 1, though rewritten for clarity.
It also includes a new catchall category for terms that might not obviously
fall within one of the other categories but which are precisely equivalent
to GPLv3 conditions, or which deny permission for activities clearly not
permitted by GPLv3. We have carefully considered but rejected proposals
to expand this list further. We have also rejected suggestions, made
by some discussion committee members, that the Affero clause requirement
(7d in Draft 1 and 7b4 in Draft 2) be removed, though we have revised it
in response to certain comments. We are unwavering in our view that the
Affero requirement is a legitimate one, and we are committed to achieving
compatibility of the Affero GPL with GPLv3.

A GPL licensee may place an additional requirement on code for which
the licensee has or can give appropriate copyright permission, but only if
that requirement falls within the list given in subsection 7b. Placement of
any other kind of additional requirement continues to be a violation of the
license. Additional requirements that are in the 7b list may not be removed,
but if a user receives GPL’d code that purports to include an additional 
requirement
not in the 7b list, the user may remove that requirement. Here we
were particularly concerned to address the problem of program authors who
purport to license their works in a misleading and possibly self-contradictory
fashion, using the GPL together with unacceptable added restrictions that
would make those works non-free software.

Section 7 points out that GPLv3 itself makes no assertion that an additional
requirement is enforceable by the copyright holder. However, section
7 makes clear that enforcement of such requirements is expected to be by
the termination procedure given in section 8 of GPLv3.

Conclusion

Some have questioned whether section 7 is needed, and some have suggested
that it creates complexity that did not previously exist. We point out to
those readers that there is already GPLv2-licensed code that carries additional
terms. One of the objectives of section 7 is to rationalize existing
practices of program authors and modifiers by setting clear guidelines regarding
the removal and addition of such terms. With its carefully limited
list of allowed additional requirements, section 7 accomplishes additional
objectives, permitting the expansion of the base of code available for GPL
developers, while also encouraging useful experimentation with requirements
we do not include in the GPL itself.
------

regards,
alexander.