Re: [gentoo-dev] Re: Re: Implicit system dependencies

[Mike Frysinger]

On Sunday, August 28, 2011 14:38:31 Michael wrote:
> Mike Frysinger wrote:
> > like Nathan said, only if the package directly uses/links against the X11
> > API/libs in question.  if the package only uses gtk+ funcs, then it
> > should not be declaring a dependency on the X11 libs.
>
> Just to confirm (as I've had one such bug marked WONTFIX), should a package
> that depends on say, qt-gui (which in turn depends on qt-core), list an
> explicit dependency on qt-core if it uses symbols from it?
>
> tinderbox ~ # readelf -d /usr/bin/lfhex | grep Qt
>  0x0000000000000001 (NEEDED)             Shared library: [libQtGui.so.4]
>  0x0000000000000001 (NEEDED)             Shared library: [libQtCore.so.4]
>
> tinderbox ~ # equery g lfhex | grep qt
>  [  1]  x11-libs/qt-gui-4.7.3-r1

i cant speak to this exact case, but the qt libs are a bit special.  upstream, 
it's really one package, but in Gentoo we've split them up into sep ones to 
make fixing/upgrading in the sub-libs easier/faster.  so by depending on any 
of the qt sublibs, they're hard bound to the qt-core as well.

also, your readelf doesnt exactly say that ifhex is using the qt-core API 
directly.  it could only be using qt-gui, but end up pulling in the others 
implicitly via the qt-gui APIs.  so in this specific case, qt-gui requirement 
only is OK.
-mike