System state with 'space' in name prevent update-grub to create menu entries in grub.cfg

Describe the bug I did create few days ago a System state with a 'space' in the name : "pool/ROOT/ubuntu_u7dn3s@Stable Plex"

server:~$ zsysctl show 
Name:           rpool/ROOT/ubuntu_u7dn3s
ZSys:           true
Last Used:      current
History:        
  - Name:       rpool/ROOT/ubuntu_u7dn3s@autozsys_ceqh6a
    Created on: 2020-10-16 06:49:59
  - Name:       rpool/ROOT/ubuntu_u7dn3s@autozsys_ahzb7l
    Created on: 2020-10-15 06:40:13
  - Name:       rpool/ROOT/ubuntu_u7dn3s@autozsys_a00j2k
    Created on: 2020-10-08 06:46:34
   - Name:       rpool/ROOT/ubuntu_u7dn3s@autozsys_b7t6lj
     Created on: 2020-10-07 06:20:00
   - Name:       rpool/ROOT/ubuntu_u7dn3s@Stable Plex
     Created on: 2020-10-03 19:18:18
   - Name:       rpool/ROOT/ubuntu_u7dn3s@autozsys_a81mbp
     Created on: 2020-10-03 17:58:19
(truncated)...

I found myself in the impossibility to boot the server few days after as the Grub menu had only the UEFI entry in it. No more entries for current kernel or zsys history.

server:~$ cat /boot/grub/grub.cfg 
...(truncated)
### END /etc/grub.d/20_linux_xen ###

### BEGIN /etc/grub.d/30_os-prober ###
### END /etc/grub.d/30_os-prober ###

### BEGIN /etc/grub.d/30_uefi-firmware ###
menuentry 'UEFI Firmware Settings' $menuentry_id_option 'uefi-firmware' {
    fwsetup
}
### END /etc/grub.d/30_uefi-firmware ###

### BEGIN /etc/grub.d/40_custom ###
# This file provides an easy way to add custom menu entries.  Simply type the
# menu entries you want to add after this comment.  Be careful not to change
# the 'exec tail' line above.
### END /etc/grub.d/40_custom ###
(truncated)...

After chrooting into the server, I tried to rebuild the menu with update-grub and got a weird error message on ignoring datasets:

server:~$ update-grub
Sourcing file `/etc/default/grub'
Sourcing file `/etc/default/grub.d/init-select.cfg'
Generating grub configuration file ...
Found linux image: vmlinuz-5.4.0-48-generic in rpool/ROOT/ubuntu_25bi0j
Found initrd image: initrd.img-5.4.0-48-generic in rpool/ROOT/ubuntu_25bi0j
Found linux image: vmlinuz-5.4.0-42-generic in rpool/ROOT/ubuntu_25bi0j
Found initrd image: initrd.img-5.4.0-42-generic in rpool/ROOT/ubuntu_25bi0j
...(truncated)...
Found initrd image: initrd.img-5.4.0-42-generic in rpool/ROOT/ubuntu_u7dn3s@autozsys_a81mbp
Warning: Failed to find a valid directory 'etc' for dataset 'rpool/ROOT/ubuntu_u7dn3s@Stable'. Ignoring
Warning: Ignoring rpool/ROOT/ubuntu_u7dn3s@Stable
filesystem 'Plex' cannot be mounted, unable to open the dataset
Adding boot menu entry for UEFI Firmware Settings
done

As a result the grub.cfg file was letf with only the UEFI entry.

To solve this issue, I had to delete the problematic state and reran update-grub. I then was back to normal.

server:~$ zsysctl state remove 'Stable Plex' --system
ZSys is adding automatic system snapshot to GRUB menu

server:~$ update-grub
...(truncated)...

server:~$ cat /boot/grub/grub.cfg 
...(truncated)
    menuentry '* Ubuntu 20.04.1 LTS, with Linux 5.4.0-48-generic (recovery mode)' --class ubuntu --class gnu-linux --class gnu --class os ${menuentry_id_option} 'gnulinux-rpool/ROOT/ubuntu_u7dn3s-5.4.0-48-generic' {
        recordfail
        load_video
        insmod gzio
        if [ "${grub_platform}" = xen ]; then insmod xzio; insmod lzopio; fi
        insmod part_gpt
        insmod zfs
        if [ x$feature_platform_search_hint = xy ]; then
          search --no-floppy --fs-uuid --set=root  9976c549b4d44f87
        else
          search --no-floppy --fs-uuid --set=root 9976c549b4d44f87
        fi
        echo Loading Linux 5.4.0-48-generic ...
        linux   /BOOT/ubuntu_u7dn3s@/vmlinuz-5.4.0-48-generic root=ZFS=rpool/ROOT/ubuntu_u7dn3s ro recovery nomodeset dis_ucode_ldr  
        echo 'Loading initial ramdisk ...'
        initrd  /BOOT/ubuntu_u7dn3s@/initrd.img-5.4.0-48-generic
    }
}
submenu 'History for Ubuntu 20.04.1 LTS' ${menuentry_id_option} 'gnulinux-history-rpool/ROOT/ubuntu_u7dn3s' {
    submenu 'Revert to 10/16/2020 @ 06:49' ${menuentry_id_option} 'gnulinux-history-rpool/ROOT/ubuntu_u7dn3s@autozsys_ceqh6a' {
(truncated)...

To Reproduce

Create a system state with a 'space' in the name
Run update-grub and check the warning message at the end of the process
Check /boot/grub/grub.cfg file for missing Grub menu entries

Expected behavior A grub.cfg file with all necessary menu entries. zsysctl should forbid to create state with space in name or zsys update-grub helper should be able to handle states' names with spaces in it.

For ubuntu users, please run and copy the following:

ubuntu-bug zsys --save=/tmp/report

Copy paste below /tmp/report content:

File is too big. Will put it in comment.

Installed versions:

OS: (/etc/os-release)

NAME="Ubuntu"
VERSION="20.04.1 LTS (Focal Fossa)"
ID=ubuntu
ID_LIKE=debian
PRETTY_NAME="Ubuntu 20.04.1 LTS"
VERSION_ID="20.04"
HOME_URL="https://www.ubuntu.com/"
SUPPORT_URL="https://help.ubuntu.com/"
BUG_REPORT_URL="https://bugs.launchpad.net/ubuntu/"
PRIVACY_POLICY_URL="https://www.ubuntu.com/legal/terms-and-policies/privacy-policy"
VERSION_CODENAME=focal
UBUNTU_CODENAME=focal

Zsysd running version: (zsysctl version output)
```
zsysctl 0.4.7
zsysd   0.4.7
```

Additional context It's a Ubuntu Server flavor, booting on ZFS with Zsys and installed with the following procedure: https://openzfs.github.io

ubuntu / zsys

System state with 'space' in name prevent update-grub to create menu entries in grub.cfg #169