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
35355a4.

tests/utils_tests/test_lazyobject.py

@@ -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.copy(obj)
+
+        self.assertIsNot(obj, obj2)
+        self.assertIsInstance(obj2, list)
+        self.assertEqual(obj2, [1, 2, 3])
+
+    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_no_evaluation(self):
-        # copying doesn't force evaluation
-
+    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)