I'm on archlinux. When upgrading to pulseaudio 12, my setup with pulse running as system daemon and outputting to a fifo pipe stopped working.
The setup is:
mpd -> pulseaudio (system) -> fifo -> snapserver (part of snapcast)
Pulseaudio is running in system mode because it's a headless server broadcasting the audio over the network through snapcast.
I traced the problem back to the change in umask setting in pulseaudio 12.
This causes the pipe to be created by pulseaudio with only read and write permissions for the pulse user, where before it was also allowing read permissions for the pulse group.
Creating the sink pipe with only permissions for the pulse user is completely useless, since any program that's reading the pipe will very likely be running under a different user.
This basically renders the sink pipe useless in system mode, and will probably also have consequences or side-effects in user mode.
This is my very first ticket here, so please let me know if additional information is needed.
Thanks for reporting!
I think we should make a bugfix release (12.1) soon with a fix for this regression, but I'll anyway mark this as a 13.0 blocker.
I submitted a patch:
The fix is now in master.