[arch-general] pacman's "Depends On"

[Ralf Mardorf]

Hi :)

if a dedicated version of a dependency is needed, some packages
mention it, others don't.

Firefox does not explicitly mention a version of libvpx

$ pacman -Si firefox | grep On
Depends On     : [snip] libvpx [snip]

but it needs a dedicated version

$ firefox
XPCOMGlueLoad error for file /usr/lib/firefox/libxul.so:
libvpx.so.2: cannot open shared object file: No such file or directory
Couldn't load XPCOM.

ffmpeg does mentions that a dedicated version is needed

$ pacman -Si ffmpeg | grep On
Depends On     : [snip] libvpx.so=2-64 [snip]

IMO official packages should mention dedicated versions, since for
users of a rolling release, there sometimes are good reasons to
downgrade.

I tried to build Firefox from ABS against the outdated version of libvpx
that is needed and installed on my system, but that's another issue.

Perhaps other packages are broken too and I get aware of it, at an
inconvenient time.

How can I figure out what packages depend on a dedicated version of
another package?

Regards,
Ralf