[cc-licenses] input requested: GPL/BY-SA compatibility - source

Sarah Pearson sarah at creativecommons.org
Thu Feb 5 11:32:54 EST 2015

This is the first of several discussion prompts we will be sending about
one-way compatibility from BY-SA 4.0 to GPLv3. *This particular email
addresses the source requirement in GPL and how it would work if one-way
compatibility is declared.*

As many have pointed out on this list over the last several days, the GPL
requires that works be distributed with source or that source be made
available (with “source” being the preferred form for making modifications
to the work).

BY-SA does not impose a similar requirement. Instead, BY-SA licensors are
free to distribute their works in any format, whether or not modifiable.

If one-way compatibility is declared, this will not change.  No new
obligations would be imposed under the BY-SA license, either upon the
original licensor or any downstream adapter who wishes to license their
contributions under the GPL instead of BY-SA. This is the BY-SA side of the

On the GPL side, those who adapt BY-SA works and choose to license their
contributions under the GPL would, however, still have to comply with the
GPL obligation to distribute or make available the work in the preferred
form for making modifications. If a particular adapter cannot do this
because she never received modifiable format from the BY-SA licensor and/or
cannot convert the content to modifiable format, then that person would not
be able to take advantage of the one-way compatibility declaration and use
the GPL. This is our understanding of how one-way compatibility will
operate from the GPL side of the equation, though it is ultimately a matter
for FSF to opine on formally as GPL's steward.

Assuming this is the right interpretation, the next question is what
actually constitutes the preferred form for making modifications for works
other than software (musical recordings, text, photos, etc.). This is not
as simple of a question for content as it is for software. The answer will
ultimately depend once again on FSF's interpretation as steward.

We have been in touch with FSF about obtaining a formal pronouncement on
these issues, and we look forward to hearing from them during this process
on this list. In the meantime, we look forward to hearing more from all of
you about how you think these issues might play out in practice.

CC Legal
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