Re: RFC: proposed GPLv3 license exception draft

[Ralf Wildenhues]

* Russ Allbery wrote on Wed, Apr 22, 2009 at 03:21:43AM CEST:
> > You have permission to propagate output of Autoconf, even if such
> > propagation would otherwise violate the terms of GPLv3.
> 
> Is there something that defines "propagate" to include creation and
> distribution of derivative works?

Yes, "propagate" is defined in the GPLv3 text in `0. Definitions.':

    To "propagate" a work means to do anything with it that, without
  permission, would make you directly or secondarily liable for
  infringement under applicable copyright law, except executing it on a
  computer or modifying a private copy.  Propagation includes copying,
  distribution (with or without modification), making available to the
  public, and in some countries other activities as well.

IIRC the move away from the term "derivative work" was taken as a
step to make the language less dependent on U.S. law.

> The current exception permits
> configure scripts to be patched and redistributed in patched form.  It's
> not a great idea, but it's sometimes a useful workaround.

It's definitely very useful, and allowing it is definitely one of the
goals of the Exception.

> On a technical side, does this mean that the output of Autoconf can be
> covered under some other license, or is it still under the GPL v3?

It is supposed to be possible that configure scripts are covered under
some other license.

Really, the intent is that you can do what you like with the "normal"
output of Autoconf, e.g., configure and testsuite scripts and so on.

However, the input files from the Autoconf package still fall under the
GPL.  Now, one can probably do the following: change Autoconf a little,
and then use the tracing interface to let the input files from the
Autoconf package appear as output, likely in a reusable form, or even
identical to the input.  So just allowing all kinds of output to be
all-permissive could in effect subvert the GPL on the input files.

That's the reason for balancing the language between "you can do what
you like with autoconf output" and "you should not use autoconf only
to provide you with those input files from its package merely to have
them in a more permissive license".

> If
> it's under the GPL v3, that's rather annoying, since it would require
> shipping a copy of the GPL v3 with packages that use Autoconf scripts
> but which don't otherwise have any GPL material.

Right.

> My ideal would be to be able to include somehow in my configure.ac the
> license text that I want to write into the configure script, together
> with whatever boilerplate Autoconf itself needs to add.  I would
> strongly prefer to not have to include additional long licenses in
> packages that don't otherwise use them.

The technical answer to this is to use AC_COPYRIGHT: it emits its
argument as shell comment near the top of the configure script, after
the all-permissive Autoconf boiler.  Likewise, the text appears in
`configure --version' output after the Autoconf statement.

Cheers,
Ralf