ag does not work on tmpfs/cgroup filesystem

[jirib]

the_silver_searcher-2.2.0-3.5.x86_64 (OpenSUSE TW - update 20231003) seems not to work correctly with tmpfs/cgroup filesystem:

$ findmnt /sys/fs/cgroup
TARGET         SOURCE  FSTYPE  OPTIONS
/sys/fs/cgroup cgroup2 cgroup2 rw,nosuid,nodev,noexec,relatime,nsdelegate,memory_recursiveprot

An example: searching for a file containing '5055' pattern, in fact a PID number.

$ ag -D 5055 /sys/fs/cgroup/user.slice/user-1000.slice/ 2>&1 | grep -P 'cgroup.procs: file is empty'
DEBUG: Skipping /sys/fs/cgroup/user.slice/user-1000.slice/[email protected]/cgroup.procs: file is empty.
DEBUG: Skipping /sys/fs/cgroup/user.slice/user-1000.slice/cgroup.procs: file is empty.
DEBUG: Skipping /sys/fs/cgroup/user.slice/user-1000.slice/[email protected]/session.slice/gvfs-goa-volume-monitor.service/cgroup.procs: file is empty.
DEBUG: Skipping /sys/fs/cgroup/user.slice/user-1000.slice/[email protected]/session.slice/cgroup.procs: file is empty.
DEBUG: Skipping /sys/fs/cgroup/user.slice/user-1000.slice/[email protected]/session.slice/xdg-permission-store.service/cgroup.procs: file is empty.
DEBUG: Skipping /sys/fs/cgroup/user.slice/user-1000.slice/[email protected]/session.slice/xdg-document-portal.service/cgroup.procs: file is empty.
DEBUG: Skipping /sys/fs/cgroup/user.slice/user-1000.slice/[email protected]/session.slice/xdg-desktop-portal.service/cgroup.procs: file is empty.
DEBUG: Skipping /sys/fs/cgroup/user.slice/user-1000.slice/[email protected]/session.slice/pipewire-pulse.service/cgroup.procs: file is empty.
DEBUG: Skipping /sys/fs/cgroup/user.slice/user-1000.slice/[email protected]/session.slice/wireplumber.service/cgroup.procs: file is empty.
DEBUG: Skipping /sys/fs/cgroup/user.slice/user-1000.slice/[email protected]/session.slice/gvfs-daemon.service/cgroup.procs: file is empty.
DEBUG: Skipping /sys/fs/cgroup/user.slice/user-1000.slice/[email protected]/session.slice/gvfs-udisks2-volume-monitor.service/cgroup.procs: file is empty.
DEBUG: Skipping /sys/fs/cgroup/user.slice/user-1000.slice/[email protected]/session.slice/gvfs-gphoto2-volume-monitor.service/cgroup.procs: file is empty.
DEBUG: Skipping /sys/fs/cgroup/user.slice/user-1000.slice/[email protected]/session.slice/at-spi-dbus-bus.service/cgroup.procs: file is empty.
DEBUG: Skipping /sys/fs/cgroup/user.slice/user-1000.slice/[email protected]/session.slice/gvfs-metadata.service/cgroup.procs: file is empty.
DEBUG: Skipping /sys/fs/cgroup/user.slice/user-1000.slice/[email protected]/session.slice/pipewire.service/cgroup.procs: file is empty.
DEBUG: Skipping /sys/fs/cgroup/user.slice/user-1000.slice/[email protected]/session.slice/dbus.service/cgroup.procs: file is empty.
DEBUG: Skipping /sys/fs/cgroup/user.slice/user-1000.slice/[email protected]/session.slice/gvfs-mtp-volume-monitor.service/cgroup.procs: file is empty.
DEBUG: Skipping /sys/fs/cgroup/user.slice/user-1000.slice/[email protected]/session.slice/gvfs-afc-volume-monitor.service/cgroup.procs: file is empty.
DEBUG: Skipping /sys/fs/cgroup/user.slice/user-1000.slice/[email protected]/background.slice/cgroup.procs: file is empty.
DEBUG: Skipping /sys/fs/cgroup/user.slice/user-1000.slice/[email protected]/background.slice/tracker-miner-fs-3.service/cgroup.procs: file is empty.
DEBUG: Skipping /sys/fs/cgroup/user.slice/user-1000.slice/[email protected]/app.slice/cgroup.procs: file is empty.
DEBUG: Skipping /sys/fs/cgroup/user.slice/user-1000.slice/[email protected]/app.slice/syncthing.service/cgroup.procs: file is empty.
DEBUG: Skipping /sys/fs/cgroup/user.slice/user-1000.slice/[email protected]/app.slice/dconf.service/cgroup.procs: file is empty.
DEBUG: Skipping /sys/fs/cgroup/user.slice/user-1000.slice/[email protected]/app.slice/dbus.socket/cgroup.procs: file is empty.
DEBUG: Skipping /sys/fs/cgroup/user.slice/user-1000.slice/[email protected]/app.slice/obex.service/cgroup.procs: file is empty.
DEBUG: Skipping /sys/fs/cgroup/user.slice/user-1000.slice/[email protected]/init.scope/cgroup.procs: file is empty.
DEBUG: Skipping /sys/fs/cgroup/user.slice/user-1000.slice/session-3.scope/cgroup.procs: file is empty.

# checking the file containing '5055' pattern
$  ls -l /sys/fs/cgroup/user.slice/user-1000.slice/[email protected]/session.slice/xdg-document-portal.service/cgroup.procs
-rw-r--r-- 1 jiri users 0 Oct  3 18:10 /sys/fs/cgroup/user.slice/user-1000.slice/[email protected]/session.slice/xdg-document-portal.service/cgroup.procs

$ grep -H '' /sys/fs/cgroup/user.slice/user-1000.slice/[email protected]/session.slice/xdg-document-portal.service/cgroup.procs
/sys/fs/cgroup/user.slice/user-1000.slice/[email protected]/session.slice/xdg-document-portal.service/cgroup.procs:5055
/sys/fs/cgroup/user.slice/user-1000.slice/[email protected]/session.slice/xdg-document-portal.service/cgroup.procs:5066