pacman -Syu barfs error: XYZ: signature is unknown trust

Things kept getting better and better. Following the recent pacman upgrade, I was now facing issues with regards to package signatures. I had already successfully completed the keyring initialisation and I was a bit stumbled as to what exactly I was doing wrong.

You remember all those /etc/config saved as /etc/ messages. Yes, as it turns out these are important. Given you haven’t modified your pacman configuration (perhaps added to the HoldPkg list recently?), you can safely accept the new values:

$ [sudo] mv /etc/pacman.conf /etc/pacman.conf.pacprev
$ [sudo] mv /etc/pacman.conf.pacnew /etc/pacman.conf

Re-run [sudo] pacman -Syu and you are on your way.