Remove the instance check of _UnreadVariable (private tf api) in Keras.

PiperOrigin-RevId: 351194027
Change-Id: I373b1fe4df9f68d0ceb019f22222f05496a57375

tensorflow/python/keras/engine/base_layer.py

@@ -73,7 +73,6 @@
 from tensorflow.python.module import module
 from tensorflow.python.ops import array_ops
 from tensorflow.python.ops import math_ops
-from tensorflow.python.ops import resource_variable_ops
 from tensorflow.python.ops import variables as tf_variables
 from tensorflow.python.ops.numpy_ops import np_arrays
 from tensorflow.python.ops.ragged import ragged_tensor
@@ -2877,12 +2876,8 @@ def __setattr__(self, name, value):
     # TODO(b/125122625): This won't pick up on any variables added to a
     # list/dict after creation.
     for val in nest.flatten(value, expand_composites=True):
-      # TODO(b/126450014): Remove `_UnreadVariable` check here when assign ops
-      # no longer return True for isinstance Variable checks.
       if not isinstance(val, tf_variables.Variable):
         continue
-      if isinstance(val, resource_variable_ops._UnreadVariable):  # pylint: disable=protected-access
-        continue
 
       # Users may add extra weights/variables
       # simply by assigning them to attributes (invalid for graph networks)

tensorflow/python/keras/engine/base_layer_test.py

@@ -1139,19 +1139,6 @@ def test_attribute_reassignment(self):
     del l.a
     self.assertEqual([], l._self_tracked_trackables)
 
-  def test_assign_op_not_tracked_as_variable(self):
-
-    class LayerWithAssignAttr(base_layer.Layer):
-
-      def build(self, input_shape):
-        self.v = variables.Variable(1.)
-        self.v_assign = self.v.assign_add(2.)
-
-    layer = LayerWithAssignAttr()
-    layer.build((10, 10))
-
-    self.assertEqual([layer.v], layer.variables)
-
   def test_layer_class_not_tracked_as_sublayer(self):
     # See https://github.com/tensorflow/tensorflow/issues/27431 for details.
 

tensorflow/python/keras/engine/base_layer_v1.py

@@ -61,7 +61,6 @@
 from tensorflow.python.module import module
 from tensorflow.python.ops import array_ops
 from tensorflow.python.ops import math_ops
-from tensorflow.python.ops import resource_variable_ops
 from tensorflow.python.ops import variables as tf_variables
 from tensorflow.python.ops.ragged import ragged_tensor
 from tensorflow.python.platform import tf_logging
@@ -2240,12 +2239,8 @@ def __setattr__(self, name, value):
     # TODO(b/125122625): This won't pick up on any variables added to a
     # list/dict after creation.
     for val in nest.flatten(value):
-      # TODO(b/126450014): Remove `_UnreadVariable` check here when assign ops
-      # no longer return True for isinstance Variable checks.
       if not isinstance(val, tf_variables.Variable):
         continue
-      if isinstance(val, resource_variable_ops._UnreadVariable):  # pylint: disable=protected-access
-        continue
 
       # Users may add extra weights/variables
       # simply by assigning them to attributes (invalid for graph networks)