It seems that some packages in the official package repository have a new dependency which is not in the official repos:
$ sudo pacman --sync --refresh --refresh --sysupgrade :: Synchronising package databases... core 122.3 KiB 284K/s 00:00 [###] 100% extra 1773.8 KiB 2.45M/s 00:01 [###] 100% community 3.4 MiB 2.64M/s 00:01 [###] 100% multilib 163.1 KiB 426K/s 00:00 [###] 100% :: Starting full system upgrade... resolving dependencies... warning: cannot resolve "ffmpeg2.8", a dependency of "firefox" warning: cannot resolve "ffmpeg2.8", a dependency of "gst-libav" warning: cannot resolve "ffmpeg2.8", a dependency of "vlc" :: The following packages cannot be upgraded due to unresolvable dependencies: firefox gst-libav vlc
I suspect the issue might be that the mirror hasn't updated properly, so how do I figure out which one I've downloaded from?
This is not about how to resolve the issue once the mirror is up to date. Another refresh fixed that just fine. But this is the first time this has happened, and I'd like to avoid mirrors which get updated only partially.