Bug#694657: closed by Reinhard Tartler <siretart at tauware.de> (Bug#694657: fixed in libav 6:9.1-1)

Francesco Poli invernomuto at paranoici.org
Wed Jan 9 22:56:22 UTC 2013

On Wed, 09 Jan 2013 23:27:44 +0100 Jonas Smedegaard wrote:

> Quoting Francesco Poli (2013-01-09 22:07:30)
> > Moreover, the comment states that Apache-2.0 is incompatible with 
> > LGPL: I think this is incorrect and misleading.
> Ah, yes - I agree there is a typo in the comment:  s/LGPL/GPL-2/

Good, this is one of the most misleading parts of the comment.

> > > So even if you cannot find a single GPL-3+ licensed piece anywhere 
> > > in this project, the very purpose of libavcodec-extra-* (as compared 
> > > to libavcodec-*) is to link against GPL-licensed parts.
> > 
> > This is the part that's not clear.
> > Where is this stated?
> As I wrote earlier as well: In the long description of that binary 
> package.

I read:

| Because this package links against libraries that are licensed under
| Apache License 2.0, the resulting binaries are distributed under the
| GPL version 3 or later.

If I am not missing anything else, this seems to be very similar to the
comment we are talking about.
It does _not_ point out that the package also links with libraries under

So, once again: if one is not aware of the GPL-2+ libraries (maybe
because he/she has not reviewed the debian/copyright files of _all_ the
dependencies!), he/she may look at the debian/copyright file of the
package and see that the corresponding source files are under LGPL-2.1+.
At that point, it would _not_ be clear how linking with libraries under
Apache-2.0 causes the binary package to be effectively under GPL-3+.

I really think that the libraries under GPL-2+ should be mentioned, or
otherwise very few people will understand what's going on...

> > The comment does clarifies this subtlety.
> Apparently that comment confuses more than it helps.  I suspect that is 
> because that comment relates to licensing of _binary_ package which is 
> not really the purpose of debian/copyright file.

I think it is confusing because it does not mention that the binary
package also links with libraries under GPL-2+.

> > And I cannot see it documented in the binary package description,
> > either: http://packages.debian.org/experimental/libavcodec-extra-54
> Uhm, look for the keywords Apache and GPL on that page.

As I said, I cannot see where the long description points out that the
binary package also links with libraries under GPL-2+.

> > Unless I start digging into the debian/copyright files of all the
> > dependencies, and find out that
> > 
> >   * libx264-123 is under GPL-2+
> >   * libxvidcore4 is also under GPL-2+
> >   * a small part of libmp3lame0 is under GPL-1+
> > 
> > Is this (together with the linking with Apache-2.0 libraries) the
> > reason why the _binary_ package libavcodec-extra-* is effectively under
> > GPL-3+, rather than "GPL-3+ or LGPL-2.1+ (excluding GPL-2)" ?
> Yes.

As I said, I think that this should be explicitly documented.

> > If this is the case, then I think the comment should be clarified (and
> > also the binary package description).
> Instead of trying to improve it, I suggest we *remove* that comment!

I disagree: it is a useful warning for people who look at the
debian/copyright file in order to determine the license compatibility
status of the package.
It basically says: "watch out! source is mostly LGPL-2.1+, but one
binary package is effectively GPL-3+"
It just should be clearer when it explains the reasons why!

> > > > If this is really the case, then, although it's true that 
> > > > Apache-2.0 is not compatible with GPL-2, I don't think it's 
> > > > accurate to say that Apache-2.0 is not compatible with LGPL...
> > > 
> > > Correct.  One need to check the long description and 
> > > build-dependencies of libavcodec-extra-* to get an epiphany here.
> > 
> > If one has to dig into all the dependencies anyway, then the comment 
> > does not seem to be too useful...
> What is wrong with "check the long description"?

The long description is not really clearer.
As I said, it does not mention the GPL-2+ libraries, either.

> > Anyway, let's see whether you think that the following re-formulation
> > is accurate:
> > 
> > | Comment:
> > |  Because the libavcodec-extra-* package links against libraries
> > |  licensed under GPL-2+ and (since libavcodec-extra-54) against libraries
> > |  under Apache-2.0 (compatible with GPL-3, but not with GPL-2), effective
> > |  license of that package and libav-dbg is GPL-3+ (rather than LGPL-2.1+).
> Your rewrite introduce new confusions.  I would prefer we drop the 
> comment instead.

I think that my rewrite explains the actual reasons why the binary
package is effectively under GPL-3+ (rather than LGPL-2.1+).

> > A similar clarification may be applied to the description of the
> > libavcodec-extra-* binary package.
> I fail to see what is wrong with current wording in long description of 
> libavcodec-extra-* binary package.

See above: it fails to mention the GPL-2+ libraries.

 New GnuPG key, see the transition document!
..................................................... Francesco Poli .
 GnuPG key fpr == CA01 1147 9CD2 EFDF FB82  3925 3E1C 27E1 1F69 BFFE
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