zfs-import-cache.service fails after 7da8f8d81bf1fadc2d9dff10f0435fe601e919fa

[WoefulDerelict]

System information

Type	Version/Name
Distribution Name	Arch Linux
Distribution Version	Rolling
Linux Kernel	4.14.15
Architecture	x86-64
ZFS Version	cd0a89d
SPL Version	23602fd

Describe the problem you're observing

The zfs-import-cache.service fails after the introduction of ExecStartPost=/bin/bash -c "/usr/bin/systemctl set-environment BOOTFS=$(@sbindir@/zpool list -H -o bootfs)" in 7da8f8d81bf1fadc2d9dff10f0435fe601e919fa

The local output of /usr/bin/zpool list -H -o bootfs is

-
rpool/ROOT/default

The failure can be mitigated via ExecStartPost=/bin/bash -c "/usr/bin/systemctl set-environment BOOTFS=$(@sbindir@/zpool list -H -o bootfs)" | grep -ve '^\-$'

I don't have a reference for the output of /usr/bin/zpool list -H -o bootfs from earlier versions of the Linux kernel and thus am unsure if this output is expected or a result of 7082

Describe how to reproduce the problem

1. Install ZFS from any point after 7da8f8d81bf1fadc2d9dff10f0435fe601e919fa
2. Boot the machine.

Include any warning/errors/backtraces from the system logs

systemd[1]: Starting Import ZFS pools by cache file...
systemd[1]: Starting Mount ZFS filesystems...
zpool[2517]: no pools available to import
bash[2524]: Failed to set environment: Invalid environment assignments
systemd[1]: zfs-import-cache.service: Control process exited, code=exited status=1
systemd[1]: zfs-import-cache.service: Failed with result 'exit-code'.
systemd[1]: Failed to start Import ZFS pools by cache file.

[behlendorf]

@prometheanfire can you look in to this.