Factor out deprecated config parsing

tests/test_cli.py

@@ -76,14 +76,14 @@ def test_parse_pairs_args():
         'one': ('two', 'three', {'collections': 'a,b,c'}, {}),
         'eins': ('zwei', 'drei', {'ha': True}, {})
     }
-    assert list(
+    assert sorted(
         cli.parse_pairs_args(['foo/foocoll', 'one', 'eins'], pairs)
     ) == [
+        ('eins', None),
         ('foo', 'foocoll'),
         ('one', 'a'),
         ('one', 'b'),
-        ('one', 'c'),
+        ('one', 'c')
-        ('eins', None)
     ]
 
 

vdirsyncer/cli.py

@@ -59,6 +59,19 @@ def validate_section_name(name, section_type):
                                                 SECTION_NAME_CHARS))
 
 
+def _parse_old_config_list_value(d, key):
+    value = d.get(key, [])
+    if isinstance(value, str):
+        # XXX: Deprecation
+        old_form = value
+        value = list(filter(bool, (x.strip() for x in value.split(','))))
+        cli_logger.warning(
+            '{!r} is deprecated, please use:\n{} = {}\n'
+            'The old form will be removed in 0.4.0.'
+            .format(old_form, key, json.dumps(value)))
+    return value
+
+
 def get_status_name(pair, collection):
     if collection is None:
         return pair
@@ -231,16 +244,10 @@ def parse_pairs_args(pairs_args, all_pairs):
                            .format(pair, list(all_pairs)))
 
         if collection is None:
-            collections = pair_options.get('collections', [None])
+            collections = set(
-            if isinstance(collections, str):
+                _parse_old_config_list_value(pair_options, 'collections')
-                # XXX: Deprecation
+                or [None]
-                orig_collections = collections
+            )
-                collections = [x.strip() or None
-                               for x in collections.split(',')]
-                cli_logger.warning(
-                    '{!r} is deprecated, please use:\ncollections = {}\n'
-                    'The old form will be removed in 0.4.0.'
-                    .format(orig_collections, json.dumps(collections)))
         else:
             collections = [collection]