On 7 Oct 2009, at 22:14, David Schwartz wrote:
Can copyright can be added to modified files or new files be
contributed
under a different (but compatible) license?
Thanks,
-Mark
I don't specifically know the policy of the OpenSSL project, but I
strongly
recommend simply adding them under the project's existing license if
the
licenses are compatible. If the code's existing license makes
additional
requirements that make this difficult or impossible, the code
probably won't
be (and shouldn't be) accepted.
The reason is that having code under different licenses complicates
maintenance. Someone who, say, cuts/pastes code from one file to
another and
then modifies it has to decide whether that change requires moving the
licenses around, and that can make programmers do lots of irritating
lawyering.
The classic example is a project with some GPL code and some BSD
code. If a
programmer who only wishes to license his code under the GPL license
modifies a BSD file (or a programmer who wishes to make his code
available
under the BSD license cuts/pastes some code from the GPL-licensed
section
into a BSD-licensed file), he has to put his lawyer hat on to decide
how to
modify the licenses. Programmers don't like to wear laywering hats,
nor do
they typically do it very well. (Especially in this area which is
tricky
even for IP lawyers.)
Most projects will (and should) make exceptions for self-contained
modules,
especially if any adaptation code can be made available under the
project's
license. This allows the project to continue to take advantage of
development of that self-contained module under its native license.
A good
example might be an implementation of a network protocol dual-licensed
BSD/GPL with a BSD-licensed adaptation layer for the FreeBSD kernel
and a
GPL-licensed adaptation layer for the Linux kernel. Nobody wants to
have to
fix bugs twice.
The problem scenario is tightly integrated code under multiple
licenses. In
that case, the code has to be valuable enough that the inconvenience
is
worth it. For example, OpenSSL contains software under two different
licenses (the SSLeay code). While this is very slightly
inconvenient, since
the code is critical to the project, it's worth it. (And only very
slightly,
since the licenses are almost identical, just with different
advertising
clauses if memory serves me.)
I pretty much agree with everything you've said :) Thanks for the
insightful response.
-M
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