Font rendering broken as of pango 1.56.0

Description:

GTK apps are completely broken in latest ArchLinux testing branch. (Both GTK3 and GTK4 apps and desktops are affected)

I would usually have used IRC to contact the ArchLinux testing team to figure out which exact package is causing the issue, but due to my IRC client using GTK I'm currently unable to do that, and due to the severity and emergency of the issue, I'm opening an issue here.

While I'll try to get an IRC client that doesn't use GTK, configuring it might take me precious time, if you can, please contact the ArchLinux testing team ASAP!

A bug like this must not make it's way into the regular ArchLinux repos if it's not already too late.
(I only run ArchLinux with testing repos since I'm a ArchLinux tester)

I update my system daily, I updated my system yesterday before going to bed, so it's a recent breakage.

Steps to reproduce:

Just open any GTK apps, attached is a screenshot of polari (IRC client I currently cannot use to contact ArchLinux testing team).

GTK Desktop like Cinnamon crash too with weird visual artifacts.

Qt apps/desktops like KDE and it's apps are working fine.