Commit 13023ba8 authored by Ben Kraft's avatar Ben Kraft Committed by Tim Graham
Browse files

Fixed #26122 -- Fixed copying a LazyObject 

Shallow copying of `django.utils.functional.LazyObject` or its subclasses has
been broken in a couple of different ways in the past, most recently due to
35355a4f.
parent cfda1fa3

django/utils/functional.py

+20 −0
Original line number Diff line number Diff line
@@ -249,6 +249,8 @@ class LazyObject(object): 
    _wrapped = None



    def __init__(self):

        # Note: if a subclass overrides __init__(), it will likely need to

        # override __copy__() and __deepcopy__() as well.

        self._wrapped = empty



    __getattr__ = new_method_proxy(getattr)
@@ -301,6 +303,15 @@ class LazyObject(object): 
    def __getstate__(self):

        return {}



    def __copy__(self):

        if self._wrapped is empty:

            # If uninitialized, copy the wrapper. Use type(self), not

            # self.__class__, because the latter is proxied.

            return type(self)()

        else:

            # If initialized, return a copy of the wrapped object.

            return copy.copy(self._wrapped)



    def __deepcopy__(self, memo):

        if self._wrapped is empty:

            # We have to use type(self), not self.__class__, because the
@@ -377,6 +388,15 @@ class SimpleLazyObject(LazyObject): 
            repr_attr = self._wrapped

        return '<%s: %r>' % (type(self).__name__, repr_attr)



    def __copy__(self):

        if self._wrapped is empty:

            # If uninitialized, copy the wrapper. Use SimpleLazyObject, not

            # self.__class__, because the latter is proxied.

            return SimpleLazyObject(self._setupfunc)

        else:

            # If initialized, return a copy of the wrapped object.

            return copy.copy(self._wrapped)



    def __deepcopy__(self, memo):

        if self._wrapped is empty:

            # We have to use SimpleLazyObject, not self.__class__, because the

docs/releases/1.8.9.txt

+3 −0
Original line number Diff line number Diff line
@@ -31,3 +31,6 @@ Bugfixes 


* Fixed a crash when using a reverse ``OneToOneField`` in

  ``ModelAdmin.readonly_fields`` (:ticket:`26060`).



* Fixed a regression in Django 1.8.5 that broke copying a ``SimpleLazyObject``

  with ``copy.copy()`` (:ticket:`26122`).

docs/releases/1.9.2.txt

+3 −0
Original line number Diff line number Diff line
@@ -82,3 +82,6 @@ Bugfixes 
  origin from the node via ``Node.token.source[0]``. This was an undocumented,

  private API. The origin is now available directly on each node using the

  ``Node.origin`` attribute (:ticket:`25848`).



* Fixed a regression in Django 1.8.5 that broke copying a ``SimpleLazyObject``

  with ``copy.copy()`` (:ticket:`26122`).

tests/utils_tests/test_lazyobject.py

+78 −7
Original line number Diff line number Diff line
@@ -194,28 +194,99 @@ class LazyObjectTestCase(TestCase): 
        self.assertEqual(unpickled, obj)

        self.assertEqual(unpickled.foo, obj.foo)



    def test_deepcopy(self):

        # Check that we *can* do deep copy, and that it returns the right

        # objects.

    # Test copying lazy objects wrapping both builtin types and user-defined

    # classes since a lot of the relevant code does __dict__ manipulation and

    # builtin types don't have __dict__.



    def test_copy_list(self):

        # Copying a list works and returns the correct objects.

        l = [1, 2, 3]



        obj = self.lazy_wrap(l)

        len(l)  # forces evaluation

        obj2 = copy.deepcopy(obj)

        obj2 = copy.copy(obj)



        self.assertIsNot(obj, obj2)

        self.assertIsInstance(obj2, list)

        self.assertEqual(obj2, [1, 2, 3])



    def test_deepcopy_no_evaluation(self):

        # copying doesn't force evaluation

    def test_copy_list_no_evaluation(self):

        # Copying a list doesn't force evaluation.

        l = [1, 2, 3]



        obj = self.lazy_wrap(l)

        obj2 = copy.copy(obj)



        self.assertIsNot(obj, obj2)

        self.assertIs(obj._wrapped, empty)

        self.assertIs(obj2._wrapped, empty)



    def test_copy_class(self):

        # Copying a class works and returns the correct objects.

        foo = Foo()



        obj = self.lazy_wrap(foo)

        str(foo)  # forces evaluation

        obj2 = copy.copy(obj)



        self.assertIsNot(obj, obj2)

        self.assertIsInstance(obj2, Foo)

        self.assertEqual(obj2, Foo())



    def test_copy_class_no_evaluation(self):

        # Copying a class doesn't force evaluation.

        foo = Foo()



        obj = self.lazy_wrap(foo)

        obj2 = copy.copy(obj)



        self.assertIsNot(obj, obj2)

        self.assertIs(obj._wrapped, empty)

        self.assertIs(obj2._wrapped, empty)



    def test_deepcopy_list(self):

        # Deep copying a list works and returns the correct objects.

        l = [1, 2, 3]



        obj = self.lazy_wrap(l)

        len(l)  # forces evaluation

        obj2 = copy.deepcopy(obj)



        self.assertIsNot(obj, obj2)

        self.assertIsInstance(obj2, list)

        self.assertEqual(obj2, [1, 2, 3])



    def test_deepcopy_list_no_evaluation(self):

        # Deep copying doesn't force evaluation.

        l = [1, 2, 3]



        obj = self.lazy_wrap(l)

        obj2 = copy.deepcopy(obj)



        # Copying shouldn't force evaluation

        self.assertIsNot(obj, obj2)

        self.assertIs(obj._wrapped, empty)

        self.assertIs(obj2._wrapped, empty)



    def test_deepcopy_class(self):

        # Deep copying a class works and returns the correct objects.

        foo = Foo()



        obj = self.lazy_wrap(foo)

        str(foo)  # forces evaluation

        obj2 = copy.deepcopy(obj)



        self.assertIsNot(obj, obj2)

        self.assertIsInstance(obj2, Foo)

        self.assertEqual(obj2, Foo())



    def test_deepcopy_class_no_evaluation(self):

        # Deep copying doesn't force evaluation.

        foo = Foo()



        obj = self.lazy_wrap(foo)

        obj2 = copy.deepcopy(obj)



        self.assertIsNot(obj, obj2)

        self.assertIs(obj._wrapped, empty)

        self.assertIs(obj2._wrapped, empty)