Fix for potential data loss (data not getting backed up) when borgmatic omitted configured source directories in certain situations (#333).

NEWS

@@ -1,4 +1,8 @@
 1.5.7.dev0
+ * #333: Fix for potential data loss (data not getting backed up) when borgmatic omitted configured
+   source directories in certain situations. Specifically, this occurred when two source directories
+   on different filesystems were related by parentage (e.g. "/foo" and "/foo/bar/baz") and the
+   one_file_system option was enabled.
  * Update documentation code fragments theme to better match the rest of the page.
  * Improve configuration reference documentation readability via more aggressive word-wrapping in
    configuration schema descriptions.

borgmatic/borg/create.py

@@ -44,10 +44,24 @@ def _expand_home_directories(directories):
     return tuple(os.path.expanduser(directory) for directory in directories)
 
 
-def deduplicate_directories(directories):
+def map_directories_to_devices(directories):  # pragma: no cover
     '''
-    Given a sequence of directories, return them as a sorted tuple with all duplicate child
-    directories removed. For instance, if paths is ('/foo', '/foo/bar'), return just: ('/foo',)
+    Given a sequence of directories, return a map from directory to an identifier for the device on
+    which that directory resides. This is handy for determining whether two different directories
+    are on the same filesystem (have the same device identifier).
+    '''
+    return {directory: os.stat(directory).st_dev for directory in directories}
+
+
+def deduplicate_directories(directory_devices):
+    '''
+    Given a map from directory to the identifier for the device on which that directory resides,
+    return the directories as a sorted tuple with all duplicate child directories removed. For
+    instance, if paths is ('/foo', '/foo/bar'), return just: ('/foo',)
+
+    The one exception to this rule is if two paths are on different filesystems (devices). In that
+    case, they won't get de-duplicated in case they both need to be passed to Borg (e.g. the
+    location.one_file_system option is true).
 
     The idea is that if Borg is given a parent directory, then it doesn't also need to be given
     child directories, because it will naturally spider the contents of the parent directory. And
@@ -56,19 +70,23 @@ def deduplicate_directories(directories):
     Borg.
     '''
     deduplicated = set()
-
-    for directory in sorted(directories):
-        # If the directory is "/", that contains all child directories, so we can early out.
-        if directory == os.path.sep:
-            return (os.path.sep,)
-
-        # If no other directories are parents of current directory (even n levels up), then the
-        # current directory isn't a duplicate.
-        if not any(
-            pathlib.PurePath(other_directory) in pathlib.PurePath(directory).parents
-            for other_directory in directories
-        ):
-            deduplicated.add(directory)
+    directories = sorted(directory_devices.keys())
+
+    for directory in directories:
+        deduplicated.add(directory)
+        parents = pathlib.PurePath(directory).parents
+
+        # If another directory in the given list is a parent of current directory (even n levels
+        # up) and both are on the same filesystem, then the current directory is a duplicate.
+        for other_directory in directories:
+            for parent in parents:
+                if (
+                    pathlib.PurePath(other_directory) == parent
+                    and directory_devices[other_directory] == directory_devices[directory]
+                ):
+                    if directory in deduplicated:
+                        deduplicated.remove(directory)
+                    break
 
     return tuple(sorted(deduplicated))
 
@@ -179,9 +197,11 @@ def create_archive(
     create command while also triggering the given processes to produce output.
     '''
     sources = deduplicate_directories(
-        _expand_directories(
-            location_config['source_directories']
-            + borgmatic_source_directories(location_config.get('borgmatic_source_directory'))
+        map_directories_to_devices(
+            _expand_directories(
+                location_config['source_directories']
+                + borgmatic_source_directories(location_config.get('borgmatic_source_directory'))
+            )
         )
     )
 

tests/unit/borg/test_create.py

@@ -63,20 +63,25 @@ def test_expand_home_directories_considers_none_as_no_directories():
 @pytest.mark.parametrize(
     'directories,expected_directories',
     (
-        (('/', '/root'), ('/',)),
-        (('/', '/root/'), ('/',)),
-        (('/root', '/'), ('/',)),
-        (('/root', '/root/foo'), ('/root',)),
-        (('/root/', '/root/foo'), ('/root/',)),
-        (('/root', '/root/foo/'), ('/root',)),
-        (('/root/foo', '/root'), ('/root',)),
-        (('/root', '/etc', '/root/foo/bar'), ('/etc', '/root')),
-        (('/root', '/root/foo', '/root/foo/bar'), ('/root',)),
-        (('/dup', '/dup'), ('/dup',)),
-        (('/foo', '/bar'), ('/bar', '/foo')),
+        ({'/': 1, '/root': 1}, ('/',)),
+        ({'/': 1, '/root/': 1}, ('/',)),
+        ({'/': 1, '/root': 2}, ('/', '/root')),
+        ({'/root': 1, '/': 1}, ('/',)),
+        ({'/root': 1, '/root/foo': 1}, ('/root',)),
+        ({'/root/': 1, '/root/foo': 1}, ('/root/',)),
+        ({'/root': 1, '/root/foo/': 1}, ('/root',)),
+        ({'/root': 1, '/root/foo': 2}, ('/root', '/root/foo')),
+        ({'/root/foo': 1, '/root': 1}, ('/root',)),
+        ({'/root': 1, '/etc': 1, '/root/foo/bar': 1}, ('/etc', '/root')),
+        ({'/root': 1, '/root/foo': 1, '/root/foo/bar': 1}, ('/root',)),
+        ({'/dup': 1, '/dup': 1}, ('/dup',)),
+        ({'/foo': 1, '/bar': 1}, ('/bar', '/foo')),
+        ({'/foo': 1, '/bar': 2}, ('/bar', '/foo')),
     ),
 )
-def test_deduplicate_directories_removes_child_paths(directories, expected_directories):
+def test_deduplicate_directories_removes_child_paths_on_the_same_filesystem(
+    directories, expected_directories
+):
     assert module.deduplicate_directories(directories) == expected_directories
 
 
@@ -235,6 +240,7 @@ ARCHIVE_WITH_PATHS = ('repo::{}'.format(DEFAULT_ARCHIVE_NAME), 'foo', 'bar')
 def test_create_archive_calls_borg_with_parameters():
     flexmock(module).should_receive('borgmatic_source_directories').and_return([])
     flexmock(module).should_receive('deduplicate_directories').and_return(('foo', 'bar'))
+    flexmock(module).should_receive('map_directories_to_devices').and_return({})
     flexmock(module).should_receive('_expand_directories').and_return(())
     flexmock(module).should_receive('_expand_home_directories').and_return(())
     flexmock(module).should_receive('_write_pattern_file').and_return(None)
@@ -263,6 +269,7 @@ def test_create_archive_with_patterns_calls_borg_with_patterns():
     pattern_flags = ('--patterns-from', 'patterns')
     flexmock(module).should_receive('borgmatic_source_directories').and_return([])
     flexmock(module).should_receive('deduplicate_directories').and_return(('foo', 'bar'))
+    flexmock(module).should_receive('map_directories_to_devices').and_return({})
     flexmock(module).should_receive('_expand_directories').and_return(())
     flexmock(module).should_receive('_expand_home_directories').and_return(())
     flexmock(module).should_receive('_write_pattern_file').and_return(
@@ -293,6 +300,7 @@ def test_create_archive_with_exclude_patterns_calls_borg_with_excludes():
     exclude_flags = ('--exclude-from', 'excludes')
     flexmock(module).should_receive('borgmatic_source_directories').and_return([])
     flexmock(module).should_receive('deduplicate_directories').and_return(('foo', 'bar'))
+    flexmock(module).should_receive('map_directories_to_devices').and_return({})
     flexmock(module).should_receive('_expand_directories').and_return(())
     flexmock(module).should_receive('_expand_home_directories').and_return(('exclude',))
     flexmock(module).should_receive('_write_pattern_file').and_return(None).and_return(
@@ -322,6 +330,7 @@ def test_create_archive_with_exclude_patterns_calls_borg_with_excludes():
 def test_create_archive_with_log_info_calls_borg_with_info_parameter():
     flexmock(module).should_receive('borgmatic_source_directories').and_return([])
     flexmock(module).should_receive('deduplicate_directories').and_return(('foo', 'bar'))
+    flexmock(module).should_receive('map_directories_to_devices').and_return({})
     flexmock(module).should_receive('_expand_directories').and_return(())
     flexmock(module).should_receive('_expand_home_directories').and_return(())
     flexmock(module).should_receive('_write_pattern_file').and_return(None)
@@ -351,6 +360,7 @@ def test_create_archive_with_log_info_calls_borg_with_info_parameter():
 def test_create_archive_with_log_info_and_json_suppresses_most_borg_output():
     flexmock(module).should_receive('borgmatic_source_directories').and_return([])
     flexmock(module).should_receive('deduplicate_directories').and_return(('foo', 'bar'))
+    flexmock(module).should_receive('map_directories_to_devices').and_return({})
     flexmock(module).should_receive('_expand_directories').and_return(())
     flexmock(module).should_receive('_expand_home_directories').and_return(())
     flexmock(module).should_receive('_write_pattern_file').and_return(None)
@@ -381,6 +391,7 @@ def test_create_archive_with_log_info_and_json_suppresses_most_borg_output():
 def test_create_archive_with_log_debug_calls_borg_with_debug_parameter():
     flexmock(module).should_receive('borgmatic_source_directories').and_return([])
     flexmock(module).should_receive('deduplicate_directories').and_return(('foo', 'bar'))
+    flexmock(module).should_receive('map_directories_to_devices').and_return({})
     flexmock(module).should_receive('_expand_directories').and_return(())
     flexmock(module).should_receive('_expand_home_directories').and_return(())
     flexmock(module).should_receive('_write_pattern_file').and_return(None)
@@ -409,6 +420,7 @@ def test_create_archive_with_log_debug_calls_borg_with_debug_parameter():
 def test_create_archive_with_log_debug_and_json_suppresses_most_borg_output():
     flexmock(module).should_receive('borgmatic_source_directories').and_return([])
     flexmock(module).should_receive('deduplicate_directories').and_return(('foo', 'bar'))
+    flexmock(module).should_receive('map_directories_to_devices').and_return({})
     flexmock(module).should_receive('_expand_directories').and_return(())
     flexmock(module).should_receive('_expand_home_directories').and_return(())
     flexmock(module).should_receive('_write_pattern_file').and_return(None)
@@ -438,6 +450,7 @@ def test_create_archive_with_log_debug_and_json_suppresses_most_borg_output():
 def test_create_archive_with_dry_run_calls_borg_with_dry_run_parameter():
     flexmock(module).should_receive('borgmatic_source_directories').and_return([])
     flexmock(module).should_receive('deduplicate_directories').and_return(('foo', 'bar'))
+    flexmock(module).should_receive('map_directories_to_devices').and_return({})
     flexmock(module).should_receive('_expand_directories').and_return(())
     flexmock(module).should_receive('_expand_home_directories').and_return(())
     flexmock(module).should_receive('_write_pattern_file').and_return(None)
@@ -468,6 +481,7 @@ def test_create_archive_with_stats_and_dry_run_calls_borg_without_stats_paramete
     # https://borgbackup.readthedocs.io/en/stable/usage/create.html#description
     flexmock(module).should_receive('borgmatic_source_directories').and_return([])
     flexmock(module).should_receive('deduplicate_directories').and_return(('foo', 'bar'))
+    flexmock(module).should_receive('map_directories_to_devices').and_return({})
     flexmock(module).should_receive('_expand_directories').and_return(())
     flexmock(module).should_receive('_expand_home_directories').and_return(())
     flexmock(module).should_receive('_write_pattern_file').and_return(None)
@@ -498,6 +512,7 @@ def test_create_archive_with_stats_and_dry_run_calls_borg_without_stats_paramete
 def test_create_archive_with_checkpoint_interval_calls_borg_with_checkpoint_interval_parameters():
     flexmock(module).should_receive('borgmatic_source_directories').and_return([])
     flexmock(module).should_receive('deduplicate_directories').and_return(('foo', 'bar'))
+    flexmock(module).should_receive('map_directories_to_devices').and_return({})
     flexmock(module).should_receive('_expand_directories').and_return(())
     flexmock(module).should_receive('_expand_home_directories').and_return(())
     flexmock(module).should_receive('_write_pattern_file').and_return(None)
@@ -525,6 +540,7 @@ def test_create_archive_with_checkpoint_interval_calls_borg_with_checkpoint_inte
 def test_create_archive_with_chunker_params_calls_borg_with_chunker_params_parameters():
     flexmock(module).should_receive('borgmatic_source_directories').and_return([])
     flexmock(module).should_receive('deduplicate_directories').and_return(('foo', 'bar'))
+    flexmock(module).should_receive('map_directories_to_devices').and_return({})
     flexmock(module).should_receive('_expand_directories').and_return(())
     flexmock(module).should_receive('_expand_home_directories').and_return(())
     flexmock(module).should_receive('_write_pattern_file').and_return(None)
@@ -552,6 +568,7 @@ def test_create_archive_with_chunker_params_calls_borg_with_chunker_params_param
 def test_create_archive_with_compression_calls_borg_with_compression_parameters():
     flexmock(module).should_receive('borgmatic_source_directories').and_return([])
     flexmock(module).should_receive('deduplicate_directories').and_return(('foo', 'bar'))
+    flexmock(module).should_receive('map_directories_to_devices').and_return({})
     flexmock(module).should_receive('_expand_directories').and_return(())
     flexmock(module).should_receive('_expand_home_directories').and_return(())
     flexmock(module).should_receive('_write_pattern_file').and_return(None)
@@ -579,6 +596,7 @@ def test_create_archive_with_compression_calls_borg_with_compression_parameters(
 def test_create_archive_with_remote_rate_limit_calls_borg_with_remote_ratelimit_parameters():
     flexmock(module).should_receive('borgmatic_source_directories').and_return([])
     flexmock(module).should_receive('deduplicate_directories').and_return(('foo', 'bar'))
+    flexmock(module).should_receive('map_directories_to_devices').and_return({})
     flexmock(module).should_receive('_expand_directories').and_return(())
     flexmock(module).should_receive('_expand_home_directories').and_return(())
     flexmock(module).should_receive('_write_pattern_file').and_return(None)
@@ -606,6 +624,7 @@ def test_create_archive_with_remote_rate_limit_calls_borg_with_remote_ratelimit_
 def test_create_archive_with_one_file_system_calls_borg_with_one_file_system_parameter():
     flexmock(module).should_receive('borgmatic_source_directories').and_return([])
     flexmock(module).should_receive('deduplicate_directories').and_return(('foo', 'bar'))
+    flexmock(module).should_receive('map_directories_to_devices').and_return({})
     flexmock(module).should_receive('_expand_directories').and_return(())
     flexmock(module).should_receive('_expand_home_directories').and_return(())
     flexmock(module).should_receive('_write_pattern_file').and_return(None)
@@ -634,6 +653,7 @@ def test_create_archive_with_one_file_system_calls_borg_with_one_file_system_par
 def test_create_archive_with_numeric_owner_calls_borg_with_numeric_owner_parameter():
     flexmock(module).should_receive('borgmatic_source_directories').and_return([])
     flexmock(module).should_receive('deduplicate_directories').and_return(('foo', 'bar'))
+    flexmock(module).should_receive('map_directories_to_devices').and_return({})
     flexmock(module).should_receive('_expand_directories').and_return(())
     flexmock(module).should_receive('_expand_home_directories').and_return(())
     flexmock(module).should_receive('_write_pattern_file').and_return(None)
@@ -662,6 +682,7 @@ def test_create_archive_with_numeric_owner_calls_borg_with_numeric_owner_paramet
 def test_create_archive_with_read_special_calls_borg_with_read_special_parameter():
     flexmock(module).should_receive('borgmatic_source_directories').and_return([])
     flexmock(module).should_receive('deduplicate_directories').and_return(('foo', 'bar'))
+    flexmock(module).should_receive('map_directories_to_devices').and_return({})
     flexmock(module).should_receive('_expand_directories').and_return(())
     flexmock(module).should_receive('_expand_home_directories').and_return(())
     flexmock(module).should_receive('_write_pattern_file').and_return(None)
@@ -691,6 +712,7 @@ def test_create_archive_with_read_special_calls_borg_with_read_special_parameter
 def test_create_archive_with_option_true_calls_borg_without_corresponding_parameter(option_name):
     flexmock(module).should_receive('borgmatic_source_directories').and_return([])
     flexmock(module).should_receive('deduplicate_directories').and_return(('foo', 'bar'))
+    flexmock(module).should_receive('map_directories_to_devices').and_return({})
     flexmock(module).should_receive('_expand_directories').and_return(())
     flexmock(module).should_receive('_expand_home_directories').and_return(())
     flexmock(module).should_receive('_write_pattern_file').and_return(None)
@@ -720,6 +742,7 @@ def test_create_archive_with_option_true_calls_borg_without_corresponding_parame
 def test_create_archive_with_option_false_calls_borg_with_corresponding_parameter(option_name):
     flexmock(module).should_receive('borgmatic_source_directories').and_return([])
     flexmock(module).should_receive('deduplicate_directories').and_return(('foo', 'bar'))
+    flexmock(module).should_receive('map_directories_to_devices').and_return({})
     flexmock(module).should_receive('_expand_directories').and_return(())
     flexmock(module).should_receive('_expand_home_directories').and_return(())
     flexmock(module).should_receive('_write_pattern_file').and_return(None)
@@ -748,6 +771,7 @@ def test_create_archive_with_option_false_calls_borg_with_corresponding_paramete
 def test_create_archive_with_files_cache_calls_borg_with_files_cache_parameters():
     flexmock(module).should_receive('borgmatic_source_directories').and_return([])
     flexmock(module).should_receive('deduplicate_directories').and_return(('foo', 'bar'))
+    flexmock(module).should_receive('map_directories_to_devices').and_return({})
     flexmock(module).should_receive('_expand_directories').and_return(())
     flexmock(module).should_receive('_expand_home_directories').and_return(())
     flexmock(module).should_receive('_write_pattern_file').and_return(None)
@@ -776,6 +800,7 @@ def test_create_archive_with_files_cache_calls_borg_with_files_cache_parameters(
 def test_create_archive_with_local_path_calls_borg_via_local_path():
     flexmock(module).should_receive('borgmatic_source_directories').and_return([])
     flexmock(module).should_receive('deduplicate_directories').and_return(('foo', 'bar'))
+    flexmock(module).should_receive('map_directories_to_devices').and_return({})
     flexmock(module).should_receive('_expand_directories').and_return(())
     flexmock(module).should_receive('_expand_home_directories').and_return(())
     flexmock(module).should_receive('_write_pattern_file').and_return(None)
@@ -804,6 +829,7 @@ def test_create_archive_with_local_path_calls_borg_via_local_path():
 def test_create_archive_with_remote_path_calls_borg_with_remote_path_parameters():
     flexmock(module).should_receive('borgmatic_source_directories').and_return([])
     flexmock(module).should_receive('deduplicate_directories').and_return(('foo', 'bar'))
+    flexmock(module).should_receive('map_directories_to_devices').and_return({})
     flexmock(module).should_receive('_expand_directories').and_return(())
     flexmock(module).should_receive('_expand_home_directories').and_return(())
     flexmock(module).should_receive('_write_pattern_file').and_return(None)
@@ -832,6 +858,7 @@ def test_create_archive_with_remote_path_calls_borg_with_remote_path_parameters(
 def test_create_archive_with_umask_calls_borg_with_umask_parameters():
     flexmock(module).should_receive('borgmatic_source_directories').and_return([])
     flexmock(module).should_receive('deduplicate_directories').and_return(('foo', 'bar'))
+    flexmock(module).should_receive('map_directories_to_devices').and_return({})
     flexmock(module).should_receive('_expand_directories').and_return(())
     flexmock(module).should_receive('_expand_home_directories').and_return(())
     flexmock(module).should_receive('_write_pattern_file').and_return(None)
@@ -859,6 +886,7 @@ def test_create_archive_with_umask_calls_borg_with_umask_parameters():
 def test_create_archive_with_lock_wait_calls_borg_with_lock_wait_parameters():
     flexmock(module).should_receive('borgmatic_source_directories').and_return([])
     flexmock(module).should_receive('deduplicate_directories').and_return(('foo', 'bar'))
+    flexmock(module).should_receive('map_directories_to_devices').and_return({})
     flexmock(module).should_receive('_expand_directories').and_return(())
     flexmock(module).should_receive('_expand_home_directories').and_return(())
     flexmock(module).should_receive('_write_pattern_file').and_return(None)
@@ -886,6 +914,7 @@ def test_create_archive_with_lock_wait_calls_borg_with_lock_wait_parameters():
 def test_create_archive_with_stats_calls_borg_with_stats_parameter_and_warning_output_log_level():
     flexmock(module).should_receive('borgmatic_source_directories').and_return([])
     flexmock(module).should_receive('deduplicate_directories').and_return(('foo', 'bar'))
+    flexmock(module).should_receive('map_directories_to_devices').and_return({})
     flexmock(module).should_receive('_expand_directories').and_return(())
     flexmock(module).should_receive('_expand_home_directories').and_return(())
     flexmock(module).should_receive('_write_pattern_file').and_return(None)
@@ -914,6 +943,7 @@ def test_create_archive_with_stats_calls_borg_with_stats_parameter_and_warning_o
 def test_create_archive_with_stats_and_log_info_calls_borg_with_stats_parameter_and_info_output_log_level():
     flexmock(module).should_receive('borgmatic_source_directories').and_return([])
     flexmock(module).should_receive('deduplicate_directories').and_return(('foo', 'bar'))
+    flexmock(module).should_receive('map_directories_to_devices').and_return({})
     flexmock(module).should_receive('_expand_directories').and_return(())
     flexmock(module).should_receive('_expand_home_directories').and_return(())
     flexmock(module).should_receive('_write_pattern_file').and_return(None)
@@ -943,6 +973,7 @@ def test_create_archive_with_stats_and_log_info_calls_borg_with_stats_parameter_
 def test_create_archive_with_files_calls_borg_with_list_parameter_and_warning_output_log_level():
     flexmock(module).should_receive('borgmatic_source_directories').and_return([])
     flexmock(module).should_receive('deduplicate_directories').and_return(('foo', 'bar'))
+    flexmock(module).should_receive('map_directories_to_devices').and_return({})
     flexmock(module).should_receive('_expand_directories').and_return(())
     flexmock(module).should_receive('_expand_home_directories').and_return(())
     flexmock(module).should_receive('_write_pattern_file').and_return(None)
@@ -971,6 +1002,7 @@ def test_create_archive_with_files_calls_borg_with_list_parameter_and_warning_ou
 def test_create_archive_with_files_and_log_info_calls_borg_with_list_parameter_and_info_output_log_level():
     flexmock(module).should_receive('borgmatic_source_directories').and_return([])
     flexmock(module).should_receive('deduplicate_directories').and_return(('foo', 'bar'))
+    flexmock(module).should_receive('map_directories_to_devices').and_return({})
     flexmock(module).should_receive('_expand_directories').and_return(())
     flexmock(module).should_receive('_expand_home_directories').and_return(())
     flexmock(module).should_receive('_write_pattern_file').and_return(None)
@@ -1000,6 +1032,7 @@ def test_create_archive_with_files_and_log_info_calls_borg_with_list_parameter_a
 def test_create_archive_with_progress_and_log_info_calls_borg_with_progress_parameter_and_no_list():
     flexmock(module).should_receive('borgmatic_source_directories').and_return([])
     flexmock(module).should_receive('deduplicate_directories').and_return(('foo', 'bar'))
+    flexmock(module).should_receive('map_directories_to_devices').and_return({})
     flexmock(module).should_receive('_expand_directories').and_return(())
     flexmock(module).should_receive('_expand_home_directories').and_return(())
     flexmock(module).should_receive('_write_pattern_file').and_return(None)
@@ -1029,6 +1062,7 @@ def test_create_archive_with_progress_and_log_info_calls_borg_with_progress_para
 def test_create_archive_with_progress_calls_borg_with_progress_parameter():
     flexmock(module).should_receive('borgmatic_source_directories').and_return([])
     flexmock(module).should_receive('deduplicate_directories').and_return(('foo', 'bar'))
+    flexmock(module).should_receive('map_directories_to_devices').and_return({})
     flexmock(module).should_receive('_expand_directories').and_return(())
     flexmock(module).should_receive('_expand_home_directories').and_return(())
     flexmock(module).should_receive('_write_pattern_file').and_return(None)
@@ -1058,6 +1092,7 @@ def test_create_archive_with_progress_and_stream_processes_calls_borg_with_progr
     processes = flexmock()
     flexmock(module).should_receive('borgmatic_source_directories').and_return([])
     flexmock(module).should_receive('deduplicate_directories').and_return(('foo', 'bar'))
+    flexmock(module).should_receive('map_directories_to_devices').and_return({})
     flexmock(module).should_receive('_expand_directories').and_return(())
     flexmock(module).should_receive('_expand_home_directories').and_return(())
     flexmock(module).should_receive('_write_pattern_file').and_return(None)
@@ -1089,6 +1124,7 @@ def test_create_archive_with_progress_and_stream_processes_calls_borg_with_progr
 def test_create_archive_with_json_calls_borg_with_json_parameter():
     flexmock(module).should_receive('borgmatic_source_directories').and_return([])
     flexmock(module).should_receive('deduplicate_directories').and_return(('foo', 'bar'))
+    flexmock(module).should_receive('map_directories_to_devices').and_return({})
     flexmock(module).should_receive('_expand_directories').and_return(())
     flexmock(module).should_receive('_expand_home_directories').and_return(())
     flexmock(module).should_receive('_write_pattern_file').and_return(None)
@@ -1119,6 +1155,7 @@ def test_create_archive_with_json_calls_borg_with_json_parameter():
 def test_create_archive_with_stats_and_json_calls_borg_without_stats_parameter():
     flexmock(module).should_receive('borgmatic_source_directories').and_return([])
     flexmock(module).should_receive('deduplicate_directories').and_return(('foo', 'bar'))
+    flexmock(module).should_receive('map_directories_to_devices').and_return({})
     flexmock(module).should_receive('_expand_directories').and_return(())
     flexmock(module).should_receive('_expand_home_directories').and_return(())
     flexmock(module).should_receive('_write_pattern_file').and_return(None)
@@ -1150,6 +1187,7 @@ def test_create_archive_with_stats_and_json_calls_borg_without_stats_parameter()
 def test_create_archive_with_source_directories_glob_expands():
     flexmock(module).should_receive('borgmatic_source_directories').and_return([])
     flexmock(module).should_receive('deduplicate_directories').and_return(('foo', 'food'))
+    flexmock(module).should_receive('map_directories_to_devices').and_return({})
     flexmock(module).should_receive('_expand_directories').and_return(())
     flexmock(module).should_receive('_expand_home_directories').and_return(())
     flexmock(module).should_receive('_write_pattern_file').and_return(None)
@@ -1178,6 +1216,7 @@ def test_create_archive_with_source_directories_glob_expands():
 def test_create_archive_with_non_matching_source_directories_glob_passes_through():
     flexmock(module).should_receive('borgmatic_source_directories').and_return([])
     flexmock(module).should_receive('deduplicate_directories').and_return(('foo*',))
+    flexmock(module).should_receive('map_directories_to_devices').and_return({})
     flexmock(module).should_receive('_expand_directories').and_return(())
     flexmock(module).should_receive('_expand_home_directories').and_return(())
     flexmock(module).should_receive('_write_pattern_file').and_return(None)
@@ -1206,6 +1245,7 @@ def test_create_archive_with_non_matching_source_directories_glob_passes_through
 def test_create_archive_with_glob_calls_borg_with_expanded_directories():
     flexmock(module).should_receive('borgmatic_source_directories').and_return([])
     flexmock(module).should_receive('deduplicate_directories').and_return(('foo', 'food'))
+    flexmock(module).should_receive('map_directories_to_devices').and_return({})
     flexmock(module).should_receive('_expand_directories').and_return(())
     flexmock(module).should_receive('_expand_home_directories').and_return(())
     flexmock(module).should_receive('_write_pattern_file').and_return(None)
@@ -1233,6 +1273,7 @@ def test_create_archive_with_glob_calls_borg_with_expanded_directories():
 def test_create_archive_with_archive_name_format_calls_borg_with_archive_name():
     flexmock(module).should_receive('borgmatic_source_directories').and_return([])
     flexmock(module).should_receive('deduplicate_directories').and_return(('foo', 'bar'))
+    flexmock(module).should_receive('map_directories_to_devices').and_return({})
     flexmock(module).should_receive('_expand_directories').and_return(())
     flexmock(module).should_receive('_expand_home_directories').and_return(())
     flexmock(module).should_receive('_write_pattern_file').and_return(None)
@@ -1260,6 +1301,7 @@ def test_create_archive_with_archive_name_format_calls_borg_with_archive_name():
 def test_create_archive_with_archive_name_format_accepts_borg_placeholders():
     flexmock(module).should_receive('borgmatic_source_directories').and_return([])
     flexmock(module).should_receive('deduplicate_directories').and_return(('foo', 'bar'))
+    flexmock(module).should_receive('map_directories_to_devices').and_return({})
     flexmock(module).should_receive('_expand_directories').and_return(())
     flexmock(module).should_receive('_expand_home_directories').and_return(())
     flexmock(module).should_receive('_write_pattern_file').and_return(None)
@@ -1287,6 +1329,7 @@ def test_create_archive_with_archive_name_format_accepts_borg_placeholders():
 def test_create_archive_with_extra_borg_options_calls_borg_with_extra_options():
     flexmock(module).should_receive('borgmatic_source_directories').and_return([])
     flexmock(module).should_receive('deduplicate_directories').and_return(('foo', 'bar'))
+    flexmock(module).should_receive('map_directories_to_devices').and_return({})
     flexmock(module).should_receive('_expand_directories').and_return(())
     flexmock(module).should_receive('_expand_home_directories').and_return(())
     flexmock(module).should_receive('_write_pattern_file').and_return(None)
@@ -1315,6 +1358,7 @@ def test_create_archive_with_stream_processes_calls_borg_with_processes():
     processes = flexmock()
     flexmock(module).should_receive('borgmatic_source_directories').and_return([])
     flexmock(module).should_receive('deduplicate_directories').and_return(('foo', 'bar'))
+    flexmock(module).should_receive('map_directories_to_devices').and_return({})
     flexmock(module).should_receive('_expand_directories').and_return(())
     flexmock(module).should_receive('_expand_home_directories').and_return(())
     flexmock(module).should_receive('_write_pattern_file').and_return(None)