Merge remote-tracking branch 'origin/pr/137' into pr137

2 files changed, 20 insertions, 7 deletions

diff --git a/lib/sqlalchemy/orm/util.py b/lib/sqlalchemy/orm/util.py
index 8d40ae21c..ad610a4ac 100644
--- a/lib/sqlalchemy/orm/util.py
+++ b/lib/sqlalchemy/orm/util.py
@@ -30,13 +30,10 @@ class CascadeOptions(frozenset):
         'all', 'none', 'delete-orphan'])
     _allowed_cascades = all_cascades
 
-    def __new__(cls, arg):
-        values = set([
-            c for c
-            in re.split('\s*,\s*', arg or "")
-            if c
-        ])
-
+    def __new__(cls, value_list):
+        if isinstance(value_list, str) or value_list is None:
+            return cls.from_string(value_list)
+        values = set(value_list)
         if values.difference(cls._allowed_cascades):
             raise sa_exc.ArgumentError(
                 "Invalid cascade option(s): %s" %
@@ -70,6 +67,14 @@ class CascadeOptions(frozenset):
             ",".join([x for x in sorted(self)])
         )
 
+    @classmethod
+    def from_string(cls, arg):
+        values = [
+            c for c
+            in re.split('\s*,\s*', arg or "")
+            if c
+        ]
+        return cls(values)
 
 def _validator_events(
         desc, key, validator, include_removes, include_backrefs):
diff --git a/test/orm/test_cascade.py b/test/orm/test_cascade.py
index bd6a17286..e39911d0f 100644
--- a/test/orm/test_cascade.py
+++ b/test/orm/test_cascade.py
@@ -1,3 +1,4 @@
+import copy
 
 from sqlalchemy.testing import assert_raises, assert_raises_message
 from sqlalchemy import Integer, String, ForeignKey, Sequence, \
@@ -13,6 +14,7 @@ from sqlalchemy.testing import eq_
 from sqlalchemy.testing import fixtures
 from test.orm import _fixtures
 
+
 class CascadeArgTest(fixtures.MappedTest):
     run_inserts = None
     run_create_tables = None
@@ -85,6 +87,12 @@ class CascadeArgTest(fixtures.MappedTest):
             orm_util.CascadeOptions("all, delete-orphan"),
             frozenset)
 
+    def test_cascade_deepcopy(self):
+        old = orm_util.CascadeOptions("all, delete-orphan")
+        new = copy.deepcopy(old)
+        eq_(old, new)
+
+
     def test_cascade_assignable(self):
         User, Address = self.classes.User, self.classes.Address
         users, addresses = self.tables.users, self.tables.addresses