[pulseaudio-discuss] PulseAudio LICENSE file is wrong or misleading about GPL/LGPL

[Arun Raghavan]

On Sun, 2011-10-16 at 15:07 -0500, Brian Cameron wrote:
> Maarten:
> 
> > Do I conclude correctly from the bug that in pulse 1.0 it isn't true
> > anymore that the library dependencies are:
> > libpulse ->  libpulsecommon
> > libpulsecore ->  libpulsecommon
> 
> I am not familiar enough with PulseAudio to be able to describe the
> library dependencies.  I just know that programs which use libpulse
> fail to compile unless you link in libpulsecore.  It seems that
> libpulse or libpulsecommon uses symbols in libpulsecore.

At least on my system, this is not the case:

$ readelf -d /usr/lib/libpulse.so | grep pulse
 0x0000000000000001 (NEEDED)             Shared library: [libpulsecommon-1.98.so]
 0x000000000000000e (SONAME)             Library soname: [libpulse.so.0]

readelf -d /usr/lib/libpulsecommon-1.98.so | grep pulse
 0x000000000000000e (SONAME)             Library soname: [libpulsecommon-1.98.so]

Are you sure this isn't some Solaris linker weirdness?

> > I do remember some stuff about circular dependencies. But as only
> > libpulsecore links to libsamplerate, the above dependency chain would
> > be the best to have, because libpulse is always LGPL, regardless of
> > pulse is build with libsamplerate support.
> 
> I think it may be ambiguous if libpulse is LGPL if it links in
> libpulsecore built with GPL libsamplerate.

It does not, *but*, I see one bug that I've fixed now [1] -- during a
Makefile.am cleanup, a bunch of extra dependencies got added to
libpulsecommon, including libsamplerate. This will get fixed in the next
release which shouldn't be too far away.

[1]: http://cgit.freedesktop.org/pulseaudio/pulseaudio/commit/?id=bb4b8f896e63559df2b53617ff205d8a4024178c

[...]
> > And I'm a bit confused about why you would
> > have a GPL library installed, but don't want pulse to use it in order
> > to keep it LGPL. (and of course for these kind of use cases you can
> > easily override the autodetection)
> 
> To me, it seems more "safe" to avoid linking a GPL library into a
> LGPL program by default.  This is the sort of licensing concern that
> would be better for people to make a conscious decision about rather
> than having a configure script make a decision for you.  Personally I
> think this is especially a concern if the LICENSING file is not
> well maintained, or contains incorrect or misleading information.

It is well-maintained, insofar that when things with different licenses
are pulled in, the file is updated. I'm assuming that people who care
keen about the GPL/LGPL division would also be careful about how the PA
server is compiled. I'm not completely against making libsamplerate an
off-by-default choice if others feel this is more prudent, though.

-- Arun