bpo-27141: Fix collections.UserList and UserDict shallow copy. (GH-4094)
diff --git a/Lib/collections/__init__.py b/Lib/collections/__init__.py
index 706907a..960d82a 100644
--- a/Lib/collections/__init__.py
+++ b/Lib/collections/__init__.py
@@ -1038,6 +1038,13 @@
# Now, add the methods in dicts but not in MutableMapping
def __repr__(self): return repr(self.data)
+ def __copy__(self):
+ inst = self.__class__.__new__(self.__class__)
+ inst.__dict__.update(self.__dict__)
+ # Create a copy and avoid triggering descriptors
+ inst.__dict__["data"] = self.__dict__["data"].copy()
+ return inst
+
def copy(self):
if self.__class__ is UserDict:
return UserDict(self.data.copy())
@@ -1050,6 +1057,7 @@
self.data = data
c.update(self)
return c
+
@classmethod
def fromkeys(cls, iterable, value=None):
d = cls()
@@ -1118,6 +1126,12 @@
def __imul__(self, n):
self.data *= n
return self
+ def __copy__(self):
+ inst = self.__class__.__new__(self.__class__)
+ inst.__dict__.update(self.__dict__)
+ # Create a copy and avoid triggering descriptors
+ inst.__dict__["data"] = self.__dict__["data"][:]
+ return inst
def append(self, item): self.data.append(item)
def insert(self, i, item): self.data.insert(i, item)
def pop(self, i=-1): return self.data.pop(i)
diff --git a/Lib/test/test_collections.py b/Lib/test/test_collections.py
index 1f619bc..e2d04d5 100644
--- a/Lib/test/test_collections.py
+++ b/Lib/test/test_collections.py
@@ -37,6 +37,20 @@
b=b.__name__,
),
)
+
+ def _copy_test(self, obj):
+ # Test internal copy
+ obj_copy = obj.copy()
+ self.assertIsNot(obj.data, obj_copy.data)
+ self.assertEqual(obj.data, obj_copy.data)
+
+ # Test copy.copy
+ obj.test = [1234] # Make sure instance vars are also copied.
+ obj_copy = copy.copy(obj)
+ self.assertIsNot(obj.data, obj_copy.data)
+ self.assertEqual(obj.data, obj_copy.data)
+ self.assertIs(obj.test, obj_copy.test)
+
def test_str_protocol(self):
self._superset_test(UserString, str)
@@ -46,6 +60,16 @@
def test_dict_protocol(self):
self._superset_test(UserDict, dict)
+ def test_list_copy(self):
+ obj = UserList()
+ obj.append(123)
+ self._copy_test(obj)
+
+ def test_dict_copy(self):
+ obj = UserDict()
+ obj[123] = "abc"
+ self._copy_test(obj)
+
################################################################################
### ChainMap (helper class for configparser and the string module)