Bugfixes to TensorArray and functional ops:

- TensorArray shape inference now works correctly for scalar elements
- TensorArrays each now get a unique name at runtime, per step.  This means
  that they can be used in nested functional ops (e.g. tf.scan(tf.scan(...)))

Change: 125110643

6 files changed, 53 insertions, 18 deletions

diff --git a/tensorflow/core/kernels/tensor_array.cc b/tensorflow/core/kernels/tensor_array.cc
index 85f1299038..dc1b14ec36 100644
--- a/tensorflow/core/kernels/tensor_array.cc
+++ b/tensorflow/core/kernels/tensor_array.cc
@@ -75,6 +75,8 @@ TF_CALL_GPU_NUMBER_TYPES(TENSOR_ARRAY_SET_ZERO_GPU);
 
 }  // namespace tensor_array
 
+std::atomic<int64> TensorArray::tensor_array_counter{0};
+
 Status TensorArray::CopyShapesFrom(TensorArray* rhs) {
   mutex_lock l(mu_);
   mutex_lock l_rhs(*rhs->mu());
diff --git a/tensorflow/core/kernels/tensor_array.h b/tensorflow/core/kernels/tensor_array.h
index b993f0dfe2..35f199be91 100644
--- a/tensorflow/core/kernels/tensor_array.h
+++ b/tensorflow/core/kernels/tensor_array.h
@@ -124,6 +124,8 @@ TF_CALL_GPU_NUMBER_TYPES(TENSOR_ARRAY_SET_ZERO_GPU);
 //
 class TensorArray : public ResourceBase {
  public:
+  static std::atomic<int64> tensor_array_counter;
+
   // Construct a TensorArray for holding Tensors of type 'dtype' with
   // 'N' elements.  While the underlying storage is a std::vector and
   // can hold more than MAX_INT entries, in practice we do not expect
diff --git a/tensorflow/core/kernels/tensor_array_ops.cc b/tensorflow/core/kernels/tensor_array_ops.cc
index eafd28639d..95734dbae2 100644
--- a/tensorflow/core/kernels/tensor_array_ops.cc
+++ b/tensorflow/core/kernels/tensor_array_ops.cc
@@ -147,14 +147,18 @@ class TensorArrayOp : public TensorArrayCreationOp {
     const int32 size = tensor_size->scalar<int32>()();
 
     auto handle = tensor_array_output_handle->flat<string>();
+    string unique_tensor_array_name =
+        strings::StrCat(tensor_array_name_, "_",
+                        TensorArray::tensor_array_counter.fetch_add(1));
     handle(0) = "_tensor_arrays";
-    handle(1) = tensor_array_name_;
+    handle(1) = unique_tensor_array_name;
 
     TensorArray* tensor_array = new TensorArray(
         dtype_, *tensor_array_output_handle, size, dynamic_size_,
         false /* multiple_writes_aggregate */, clear_after_read_);
 
-    TF_RETURN_IF_ERROR(rm->Create(handle(0), tensor_array_name_, tensor_array));
+    TF_RETURN_IF_ERROR(
+        rm->Create(handle(0), unique_tensor_array_name, tensor_array));
 
     *output_tensor_array = tensor_array;
 
diff --git a/tensorflow/python/kernel_tests/functional_ops_test.py b/tensorflow/python/kernel_tests/functional_ops_test.py
index d0fc17c059..7a59b07bce 100644
--- a/tensorflow/python/kernel_tests/functional_ops_test.py
+++ b/tensorflow/python/kernel_tests/functional_ops_test.py
@@ -180,6 +180,28 @@ class FunctionalOpsTest(tf.test.TestCase):
         results = np.array([6, 16, 38, 84, 178, 368])
         self.assertAllEqual(results, r.eval())
 
+  def testScanFoldl_Nested(self):
+    with self.test_session():
+      elems = tf.constant([1.0, 2.0, 3.0, 4.0], name="data")
+      inner_elems = tf.constant([0.5, 0.5], name="data")
+
+      def r_inner(a, x):
+        return tf.foldl(lambda b, y: b * y * x, inner_elems, initializer=a)
+
+      r = tf.scan(r_inner, elems)
+
+      # t == 0 (returns 1)
+      # t == 1, a == 1, x == 2 (returns 1)
+      #   t_0 == 0, b == a == 1, y == 0.5, returns b * y * x = 1
+      #   t_1 == 1, b == 1,      y == 0.5, returns b * y * x = 1
+      # t == 2, a == 1, x == 3 (returns 1.5*1.5 == 2.25)
+      #   t_0 == 0, b == a == 1, y == 0.5, returns b * y * x = 1.5
+      #   t_1 == 1, b == 1.5,    y == 0.5, returns b * y * x = 1.5*1.5
+      # t == 3, a == 2.25, x == 4 (returns 9)
+      #   t_0 == 0, b == a == 2.25, y == 0.5, returns b * y * x = 4.5
+      #   t_1 == 1, b == 4.5,       y == 0.5, returns b * y * x = 9
+      self.assertAllClose([1., 1., 2.25, 9.], r.eval())
+
   def testScan_Control(self):
     with self.test_session() as sess:
       s = tf.placeholder(tf.float32, shape=[None])
diff --git a/tensorflow/python/kernel_tests/tensor_array_ops_test.py b/tensorflow/python/kernel_tests/tensor_array_ops_test.py
index 25f582eb2c..6038d8993f 100644
--- a/tensorflow/python/kernel_tests/tensor_array_ops_test.py
+++ b/tensorflow/python/kernel_tests/tensor_array_ops_test.py
@@ -22,7 +22,6 @@ from __future__ import print_function
 import numpy as np
 import tensorflow as tf
 
-from tensorflow.python.framework import errors
 from tensorflow.python.framework import tensor_shape
 from tensorflow.python.ops import gen_data_flow_ops
 from tensorflow.python.ops import tensor_array_grad
@@ -462,7 +461,7 @@ class TensorArrayCPUTest(tf.test.TestCase):
       # Assert that if multiple_writes_aggregate is not enabled,
       # multiple writes raise an exception.
       with self.assertRaisesOpError(
-          r"TensorArray foo: Could not write to TensorArray index 2 because "
+          r"TensorArray foo_.*: Could not write to TensorArray index 2 because "
           r"it has already been written to."):
         w1.flow.eval()
 
@@ -495,7 +494,7 @@ class TensorArrayCPUTest(tf.test.TestCase):
       r = r1 + r2
       self.assertAllClose(9.0, r.eval())
 
-  def testDuplicateTensorArrayFails(self):
+  def testDuplicateTensorArrayHasDifferentName(self):
     with self.test_session(use_gpu=self._use_gpu) as session:
       h1 = tensor_array_ops.TensorArray(
           size=1, dtype=tf.float32, tensor_array_name="foo")
@@ -503,8 +502,14 @@ class TensorArrayCPUTest(tf.test.TestCase):
       h2 = tensor_array_ops.TensorArray(
           size=1, dtype=tf.float32, tensor_array_name="foo")
       c2 = h2.write(0, 5.0)
-      with self.assertRaises(errors.AlreadyExistsError):
-        session.run([c1.flow, c2.flow])
+      _, _, c1h, c2h = session.run([c1.flow, c2.flow, c1.handle, c2.handle])
+      c1h = [x.decode("ascii") for x in c1h]
+      c2h = [x.decode("ascii") for x in c2h]
+      self.assertEqual(c1h[0], "_tensor_arrays")
+      self.assertEqual(c2h[0], "_tensor_arrays")
+      self.assertTrue(c1h[1].startswith("foo_"))
+      self.assertTrue(c2h[1].startswith("foo_"))
+      self.assertNotEqual(c1h[1], c2h[1])
 
   def _testTensorArrayGradientWriteReadType(self, dtype):
     with self.test_session(use_gpu=self._use_gpu) as session:
@@ -692,13 +697,6 @@ class TensorArrayCPUTest(tf.test.TestCase):
       w1 = w0.write(1, [3.0])
       w1.close().run()  # Expected to run without problems
 
-      ta = tensor_array_ops.TensorArray(
-          dtype=tf.float32, tensor_array_name="foo", size=3)
-      with self.assertRaisesOpError(
-          r"TensorArray foo has already been closed."):
-        with tf.control_dependencies([w1.close()]):
-          w1.write(2, 3.0).flow.eval()
-
   def _testWhileLoopWritePackGradients(self, dynamic_size, dtype):
     np_dtype = dtype.as_numpy_dtype
     with self.test_session(use_gpu=self._use_gpu) as session:
diff --git a/tensorflow/python/ops/tensor_array_ops.py b/tensorflow/python/ops/tensor_array_ops.py
index 08f71bd8e5..e3a6b3db7c 100644
--- a/tensorflow/python/ops/tensor_array_ops.py
+++ b/tensorflow/python/ops/tensor_array_ops.py
@@ -64,6 +64,13 @@ class TensorArray(object):
                flow=None, infer_shape=True, name=None):
     """Construct a new TensorArray or wrap an existing TensorArray handle.
 
+    A note about the parameter `name`:
+
+    The name of the `TensorArray` (even if passed in) is uniquified: each time
+    a new `TensorArray` is created at runtime it is assigned its own name for
+    the duration of the run.  This avoids name collissions if a `TensorArray`
+    is created within a `while_loop`.
+
     Args:
       dtype: (required) data type of the TensorArray.
       size: (optional) int32 scalar `Tensor`: the size of the TensorArray.
@@ -235,7 +242,7 @@ class TensorArray(object):
       value = gen_data_flow_ops._tensor_array_pack(
           handle=self._handle, flow_in=self._flow, dtype=self._dtype,
           name=name)
-      if self._elem_shape and self._elem_shape[0].dims:
+      if self._elem_shape and self._elem_shape[0].dims is not None:
         value.set_shape([None] + self._elem_shape[0].dims)
       return value
 
@@ -255,7 +262,7 @@ class TensorArray(object):
       value, _ = gen_data_flow_ops._tensor_array_concat(
           handle=self._handle, flow_in=self._flow, dtype=self._dtype,
           name=name)
-      if self._elem_shape and self._elem_shape[0].dims:
+      if self._elem_shape and self._elem_shape[0].dims is not None:
         value.set_shape([None] + self._elem_shape[0].dims[1:])
       return value
 
@@ -284,7 +291,7 @@ class TensorArray(object):
       if ta._infer_shape:
         val_shape = flow_out.op.inputs[1].get_shape()
         elem_shape = tensor_shape.unknown_shape()
-        if val_shape.dims:
+        if val_shape.dims is not None:
           elem_shape = tensor_shape.TensorShape(val_shape.dims[1:])
         if ta._elem_shape:
           if not elem_shape == ta._elem_shape[0]:
@@ -326,7 +333,7 @@ class TensorArray(object):
         val_shape = flow_out.op.inputs[1].get_shape()
         clengths = tensor_util.constant_value(flow_out.op.inputs[2])
         elem_shape = tensor_shape.unknown_shape()
-        if val_shape.dims:
+        if val_shape.dims is not None:
           if clengths is not None and clengths.max() == clengths.min():
             elem_shape = tensor_shape.TensorShape(
                 [clengths[0]] + val_shape.dims[1:])