Do not cache reads for ResourceVariables.

Change: 147487962

tensorflow/python/ops/resource_variable_ops.py

@@ -196,18 +196,14 @@ class ResourceVariable(object):
             self._initialize_op = gen_resource_variable_ops.assign_variable_op(
                 self._handle, self._initial_value, name=n)
         with ops.name_scope("Read"), ops.colocate_with(self._handle):
-          self._value = gen_resource_variable_ops.read_variable_op(
+          value = gen_resource_variable_ops.read_variable_op(
               self._handle, dtype=self._dtype)
+          self._graph_element = value
           if caching_device is not None:
             with ops.device(caching_device):
-              self._cached_value = array_ops.identity(self._value)
+              self._cached_value = array_ops.identity(value)
           else:
-            with ops.colocate_with(self._handle.op):
-              self._cached_value = array_ops.identity(self._value)
-          # TODO(apassos) this is terrible monkey-patching required to make
-          # initialize_all_variables work. Replace self._value with an explicit
-          # class instead of monkey-patching.
-          self._value.initializer = self._initialize_op
+            self._cached_value = None
           ops.add_to_collections(collections, self)
           ops.add_to_collections([ops.GraphKeys.RESOURCES], self)
 
@@ -225,10 +221,12 @@ class ResourceVariable(object):
     self._initialize_op = g.as_graph_element(
         ops.prepend_name_scope(variable_def.initializer_name,
                                import_scope=import_scope))
-    self._cached_value = g.as_graph_element(
-        ops.prepend_name_scope(variable_def.snapshot_name,
-                               import_scope=import_scope))
-    self._value = self._cached_value
+    if variable_def.snapshot_name:
+      self._cached_value = g.as_graph_element(
+          ops.prepend_name_scope(variable_def.snapshot_name,
+                                 import_scope=import_scope))
+    else:
+      self._cached_value = None
     if variable_def.HasField("save_slice_info_def"):
       self._save_slice_info = variables.Variable.SaveSliceInfo(
           save_slice_info_def=variable_def.save_slice_info_def)
@@ -254,7 +252,7 @@ class ResourceVariable(object):
 
   def get_shape(self):
     """The shape of this variable."""
-    return self._value.get_shape()
+    return tensor_shape.TensorShape(self._handle.op.get_attr("shape"))
 
   @property
   def create(self):
@@ -268,11 +266,14 @@ class ResourceVariable(object):
 
   def value(self):
     """A cached operation which reads the value of this variable."""
-    return self._cached_value
+    if self._cached_value is not None:
+      return self._cached_value
+    return gen_resource_variable_ops.read_variable_op(
+        self._handle, dtype=self._dtype)
 
   def _as_graph_element(self):
     """Conversion function for Graph.as_graph_element()."""
-    return self._value
+    return self._graph_element
 
   @property
   def initializer(self):
@@ -286,7 +287,7 @@ class ResourceVariable(object):
 
   def eval(self, session=None):
     """Evaluates and returns the value of this variable."""
-    return self._value.eval(session=session)
+    return self._graph_element.eval(session=session)
 
   def _set_save_slice_info(self, save_slice_info):
     """Sets the slice info for this `ResourceVariable`.
@@ -339,8 +340,9 @@ class ResourceVariable(object):
           self.handle.name, export_scope)
       var_def.initializer_name = ops.strip_name_scope(
           self.initializer.name, export_scope)
-      var_def.snapshot_name = ops.strip_name_scope(
-          self.value().name, export_scope)
+      if self._cached_value is not None:
+        var_def.snapshot_name = ops.strip_name_scope(
+            self._cached_value.name, export_scope)
       var_def.is_resource = True
       if self._save_slice_info:
         var_def.save_slice_info_def.MergeFrom(self._save_slice_info.to_proto(
@@ -420,9 +422,7 @@ def _dense_var_to_tensor(var, dtype=None, name=None, as_ref=False):
   if dtype is not None and dtype != var.value().dtype:
     print("trying to switch the dtype to ", dtype, " from ", var.value().dtype)
     return NotImplemented
-  if as_ref:
-    return var._value
-  return var._cached_value
+  return var.value()
 # pylint: enable=unused-argument,protected-access
 
 # Register a conversion function which reads the value of the variable,