[Python-checkins] bpo-27141: Fix collections.UserList and UserDict shallow copy. (GH-4094)
Serhiy Storchaka
webhook-mailer at python.org
Sun May 19 09:57:20 EDT 2019
https://github.com/python/cpython/commit/f4e1babf44792bdeb0c01da96821ba0800a51fd8
commit: f4e1babf44792bdeb0c01da96821ba0800a51fd8
branch: master
author: Bar Harel <bzvi7919 at gmail.com>
committer: Serhiy Storchaka <storchaka at gmail.com>
date: 2019-05-19T16:57:13+03:00
summary:
bpo-27141: Fix collections.UserList and UserDict shallow copy. (GH-4094)
files:
A Misc/NEWS.d/next/Library/2017-10-24-00-42-14.bpo-27141.zbAgSs.rst
M Lib/collections/__init__.py
M Lib/test/test_collections.py
diff --git a/Lib/collections/__init__.py b/Lib/collections/__init__.py
index 706907ad4a28..960d82a5dcfb 100644
--- a/Lib/collections/__init__.py
+++ b/Lib/collections/__init__.py
@@ -1038,6 +1038,13 @@ def __contains__(self, key):
# 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 @@ def copy(self):
self.data = data
c.update(self)
return c
+
@classmethod
def fromkeys(cls, iterable, value=None):
d = cls()
@@ -1118,6 +1126,12 @@ def __mul__(self, n):
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 1f619bcdac92..e2d04d5b4761 100644
--- a/Lib/test/test_collections.py
+++ b/Lib/test/test_collections.py
@@ -37,6 +37,20 @@ def _superset_test(self, a, b):
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_list_protocol(self):
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)
diff --git a/Misc/NEWS.d/next/Library/2017-10-24-00-42-14.bpo-27141.zbAgSs.rst b/Misc/NEWS.d/next/Library/2017-10-24-00-42-14.bpo-27141.zbAgSs.rst
new file mode 100644
index 000000000000..76c2abbf82d6
--- /dev/null
+++ b/Misc/NEWS.d/next/Library/2017-10-24-00-42-14.bpo-27141.zbAgSs.rst
@@ -0,0 +1,3 @@
+Added a ``__copy__()`` to ``collections.UserList`` and
+``collections.UserDict`` in order to correctly implement shallow copying of
+the objects. Patch by Bar Harel.
More information about the Python-checkins
mailing list