Proxy decorator_target.__get__ in TFDecorator

Prior to this change TFDecorator.__get__ mimicked the behaviour of functions
via partial(self.__call__, instance). This is no needed as calling
__get__ on a function would have a ~similar effect; and in fact incorrect
if target implements a custom __get__ method.

PiperOrigin-RevId: 234957239

tensorflow/python/util/tf_decorator.py

@@ -59,7 +59,6 @@ from __future__ import absolute_import
 from __future__ import division
 from __future__ import print_function
 
-import functools as _functools
 import traceback as _traceback
 
 
@@ -212,8 +211,8 @@ class TFDecorator(object):
     else:
       self.__doc__ = ''
 
-  def __get__(self, obj, objtype):
-    return _functools.partial(self.__call__, obj)
+  def __get__(self, instance, owner):
+    return self._decorated_target.__get__(instance, owner)
 
   def __call__(self, *args, **kwargs):
     return self._decorated_target(*args, **kwargs)

tensorflow/python/util/tf_decorator_test.py

@@ -170,6 +170,17 @@ class TfDecoratorTest(test.TestCase):
     self.assertEqual('Return parameters.',
                      TestDecoratedClass().return_params.__doc__)
 
+  def testTarget__get__IsProxied(self):
+    class Descr(object):
+
+      def __get__(self, instance, owner):
+        return self
+
+    class Foo(object):
+      foo = tf_decorator.TFDecorator('Descr', Descr())
+
+    self.assertIsInstance(Foo.foo, Descr)
+
 
 def test_wrapper(*args, **kwargs):
   return test_function(*args, **kwargs)