Fix the ZFS hook to support datasets with a "canmount" property of "noauto" (#1269).

NEWS

@@ -3,6 +3,7 @@
    handy for fetching borgmatic configuration from external scripts. See the documentation for more
    information:
    https://torsion.org/borgmatic/reference/command-line/actions/config-show/
+ * #1269: Fix the ZFS hook to support datasets with a "canmount" property of "noauto".
 
 2.1.2
  * #1231: If a source file is deleted during a "spot" check, consider the file as non-matching

borgmatic/hooks/data_source/zfs.py

@@ -71,7 +71,7 @@ def get_datasets_to_backup(zfs_command, patterns):
                 )
                 # Skip datasets that are marked "canmount=off", because mounting their snapshots will
                 # result in completely empty mount points—thereby preventing us from backing them up.
-                if can_mount == 'on'
+                if can_mount != 'off'
             ),
             key=lambda dataset: dataset.mount_point,
             reverse=True,

tests/end-to-end/commands/fake_zfs.py

@@ -35,7 +35,7 @@ BUILTIN_DATASETS = (
         'used': '256K',
         'avail': '23.7M',
         'refer': '25K',
-        'canmount': 'on',
+        'canmount': 'noauto',
         'mountpoint': '/e2e/pool/dataset',
     },
 )