Bug#819779: gdk-pixbuf: libgdk-pixbuf2.0-dev depends on libpng-dev but gdk-pixbuf2.0.pc requires libpng12-dev

[Tanguy Ortolo]

Package: libgdk-pixbuf2.0-dev
Version: 2.32.3-1.2
Severity: grave
Justification: renders package unusable

Hello,


While trying to build a new version of my package latexila for
experimental, I noticed it was failing because of libgtk-pixbuf2.0-dev.
Indeed, that package, in unstable and in experimental as well:

* ships a gdk-pixbuf2.0.pc that requires libpng12.pc;
* depends on libpng-dev which:
  - on experimental, is a real package that does not ship libpng12.pc
    but only libpng16.pc and libpng.pc;
  - on unstable, is provided by libpng12-dev which does provide
    libpng12.pc, but that situation should change to that of
    experimental whenever the new libpng-dev real package is uploaded to
    it.


Basically, when requiring libpng12.pc, it does not seem right to depend
on a package, either virtual or real, that is not guaranteed to provide
it. In my opinion, in its current state, libgdk-pixbuf2.0-dev should
depend on libpng12-dev as this is what it uses, and not on libpng-dev
which may or may not provide what it currently needs.


Since there is a transition to make to libpng-dev, one solution would be
to rebuild gdk-pixbuf for experimental, but doing it in an environment
with libpng12-dev not installed and libpng-dev installed from
experimental. That way, its configure script (l. 18507) would just pick
libpng16 and the resulting gdk-pixbuf2.0.pc would require the
libpng16.pc it provides:

>for l in libpng16 libpng15 libpng14 libpng12 libpng13 libpng10; do
>  […]


In the longer term, it could be better to have the configure script
check for libpng before libpng16 or libpng12:

>for l in libpng libpng16 libpng15 libpng14 libpng12 libpng13 libpng10; do
>  […]


That way, it would not even need to be adapted for future versions of
libpng.


Regards,

-- 
Tanguy