Fixed #23688 -- Updated cached_property to preserve docstring of original function

django/utils/functional.py

@@ -51,6 +51,7 @@ class cached_property(object):
     """
     def __init__(self, func, name=None):
         self.func = func
+        self.__doc__ = getattr(func, '__doc__')
         self.name = name or func.__name__
 
     def __get__(self, instance, type=None):

tests/utils_tests/test_functional.py

@@ -50,6 +50,7 @@ class FunctionalTestCase(unittest.TestCase):
 
             @cached_property
             def value(self):
+                """Here is the docstring..."""
                 return 1, object()
 
             def other_value(self):
@@ -57,6 +58,9 @@ class FunctionalTestCase(unittest.TestCase):
 
             other = cached_property(other_value, name='other')
 
+        # docstring should be preserved
+        self.assertEqual(A.value.__doc__, "Here is the docstring...")
+
         a = A()
 
         # check that it is cached