Ensure deepcopy clones using the correct type - PYTHON-459

bson/__init__.py

@@ -32,7 +32,7 @@ from bson.max_key import MaxKey
 from bson.min_key import MinKey
 from bson.objectid import ObjectId
 from bson.py3compat import b, binary_type
-from bson.son import SON
+from bson.son import SON, RE_TYPE
 from bson.timestamp import Timestamp
 from bson.tz_util import utc
 
@@ -52,9 +52,6 @@ except ImportError:
 PY3 = sys.version_info[0] == 3
 
 
-# This sort of sucks, but seems to be as good as it gets...
-RE_TYPE = type(re.compile(""))
-
 MAX_INT32 = 2147483647
 MIN_INT32 = -2147483648
 MAX_INT64 = 9223372036854775807

bson/son.py

@@ -19,6 +19,10 @@ of keys is important. A SON object can be used just like a normal Python
 dictionary."""
 
 import copy
+import re
+
+# This sort of sucks, but seems to be as good as it gets...
+RE_TYPE = type(re.compile(""))
 
 
 class SON(dict):
@@ -227,6 +231,12 @@ class SON(dict):
 
     def __deepcopy__(self, memo):
         out = SON()
+        val_id = id(self)
+        if val_id in memo:
+            return memo.get(val_id)
+        memo[val_id] = out
         for k, v in self.iteritems():
-            out[k] = copy.deepcopy(v, memo)
+            if not isinstance(v, RE_TYPE):
+                v = copy.deepcopy(v, memo)
+            out[k] = v
         return out

pymongo/cursor.py

@@ -854,7 +854,7 @@ class Cursor(object):
             return memo.get(val_id)
         memo[val_id] = y
         for key, value in x.iteritems():
-            if isinstance(value, dict):
+            if isinstance(value, dict) and not isinstance(value, SON):
                 value = self.__deepcopy(value, memo)
             elif not isinstance(value, RE_TYPE):
                 value = copy.deepcopy(value, memo)

test/test_cursor.py

@@ -24,6 +24,7 @@ sys.path[0:0] = [""]
 from nose.plugins.skip import SkipTest
 
 from bson.code import Code
+from bson.son import SON
 from pymongo import (ASCENDING,
                      DESCENDING)
 from pymongo.database import Database
@@ -522,6 +523,12 @@ class TestCursor(unittest.TestCase):
                          id(cursor2._Cursor__spec))
         self.assertEqual(len(cursor2._Cursor__spec), 2)
 
+        # Ensure hints are cloned as the correct type
+        cursor = self.db.test.find().hint([('z', 1), ("a", 1)])
+        cursor2 = copy.deepcopy(cursor)
+        self.assertTrue(isinstance(cursor2._Cursor__hint, SON))
+        self.assertEqual(cursor._Cursor__hint, cursor2._Cursor__hint)
+
     def test_add_remove_option(self):
         cursor = self.db.test.find()
         self.assertEqual(0, cursor._Cursor__query_options())

test/test_son.py

@@ -14,9 +14,11 @@
 
 """Tests for the son module."""
 
-import unittest
-import sys
+import copy
 import pickle
+import re
+import sys
+import unittest
 sys.path[0:0] = [""]
 
 from nose.plugins.skip import SkipTest
@@ -111,5 +113,40 @@ class TestSON(unittest.TestCase):
         son_2_1_1 = pickle.loads(pickled_with_2_1_1)
         self.assertEqual(son_2_1_1, SON([]))
 
+    def test_copying(self):
+        simple_son = SON([])
+        complex_son = SON([('son', simple_son),
+                           ('list', [simple_son, simple_son])])
+        regex_son = SON([("x", re.compile("^hello.*"))])
+        reflexive_son = SON([('son', simple_son)])
+        reflexive_son["reflexive"] = reflexive_son
+
+        simple_son1 = copy.copy(simple_son)
+        self.assertEqual(simple_son, simple_son1)
+
+        complex_son1 = copy.copy(complex_son)
+        self.assertEqual(complex_son, complex_son1)
+
+        regex_son1 = copy.copy(regex_son)
+        self.assertEqual(regex_son, regex_son1)
+
+        reflexive_son1 = copy.copy(reflexive_son)
+        self.assertEqual(reflexive_son, reflexive_son1)
+
+        # Test deepcopying
+        simple_son1 = copy.deepcopy(simple_son)
+        self.assertEqual(simple_son, simple_son1)
+
+        regex_son1 = copy.deepcopy(regex_son)
+        self.assertEqual(regex_son, regex_son1)
+
+        complex_son1 = copy.deepcopy(complex_son)
+        self.assertEqual(complex_son, complex_son1)
+
+        reflexive_son1 = copy.deepcopy(reflexive_son)
+        self.assertEqual(reflexive_son.keys(), reflexive_son1.keys())
+        self.assertEqual(id(reflexive_son1), id(reflexive_son1["reflexive"]))
+
+
 if __name__ == "__main__":
     unittest.main()