Re: Cygwin Python Distribution GPL Licensing Issue?

[DJ Delorie <dj at delorie dot com>]

> License clarifications sure are wordy <wink/sigh>.

Yup.

> Python is not licensed under the GPL.  Its license has been certified as Open
> Source by the OSI, and called a "GPL-Incompatible, Free Software License" by
> the FSF (although the lawyers who worked on the license disagree with the FSF
> that it's incompatible with the GPL).

OK, I can short-cut the rest of this, then.  Building a Python binary
with Cygwin is OK, provided there are no *other* things you link in
that cause problems.  The Cygwin exception is specifically designed to
allow GPL-incompatible yet otherwise open source projects be built
with Cygwin.

> Lawyers disagree over whether that's possible in this case.  You think the
> FSF's opinion doesn't matter here, but I don't buy that:  try *saying* the
> Cygwin Python is under the GPL, and distribute an app linking it with GNU
> readline.

If you add yet another third party library (the FSF being the third
party in this case) the rules change.  I wasn't even going to touch
that.

> I don't know what Jason did here, so that's for him to address.

I assume Jason simply built a python.exe using Cygwin.

> The Python authors (of which I am one) are incompetent to interpret the GPL.
> The Python license doesn't care whether Cygwin is or is not a standard part
> of anything -- it's a "do whatever the heck you want, just don't sue us" kind
> of license.

If Python is not GPL, this is irrelevent anyway.  You don't need to
interpret a license you don't use - it's the people who combine works
who need to worry about multiple licenses.  In our case (Red Hat), we
must intepret the GPL wrt our products (Cygwin) so we can help people
understand what's allowed and what's not.

> Again, Jason is in no danger of running afoul of the Python license.  I
> believe he's asking you to clarify the Cygwin half of this.  That the FSF
> does not consider the Python license to be GPL-compatible may or may not be
> relevant to you, depending on how *you* see things.  It sounds like it isn't
> relevant to you, and, if so, cut Jason a break and just say "Ah!  Right you
> are, fine" <wink>.  Everything he's doing is fine with us.

Right.  The Cygwin exception is basically us (Red Hat) saying "Yes,
but as long as it's *any* kind of open source, you're basically ok."

> to himself, he could have released Cygwin Python as a derivative work, and
> then the Python license allows him to set any licensing terms he wants on the

OK, if the license allows it, that's different.

> and the Python license does not require derivative works to be
> released as open source.

It *allows* it, yes?  Then people who build python with Cygwin are not
affected by Cygwin's GPL (insofar as libcygwin.a is used to build
python.exe), as long as they continue to distribute as open source.

> Since the Python license allows closed derivatives, you had better make that
> very clear in your own license maze.

Nothing is clear when it comes to licensing.

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