Allow lists to be passed to tf.group().

PiperOrigin-RevId: 173308794

2 files changed, 16 insertions, 5 deletions

diff --git a/tensorflow/python/ops/control_flow_ops.py b/tensorflow/python/ops/control_flow_ops.py
index dcdbeefb70..10d8e01304 100644
--- a/tensorflow/python/ops/control_flow_ops.py
+++ b/tensorflow/python/ops/control_flow_ops.py
@@ -2910,7 +2910,7 @@ def _GroupControlDeps(dev, deps, name=None):
 def group(*inputs, **kwargs):
   """Create an op that groups multiple operations.
 
-  When this op finishes, all ops in `input` have finished. This op has no
+  When this op finishes, all ops in `inputs` have finished. This op has no
   output.
 
   See also @{tf.tuple$tuple} and
@@ -2938,7 +2938,10 @@ def group(*inputs, **kwargs):
 
     # Sorts *inputs according to their devices.
     ops_on_device = {}  # device -> operations specified on the device.
-    for inp in inputs:
+    for inp in nest.flatten(inputs):
+      if not hasattr(inp, "device"):
+        raise TypeError("Expected tf.group() expected Tensor arguments not "
+                        "'%s' with type '%s'" % (inp, type(inp)))
       if not hasattr(inp, "device"):
         if isinstance(inp, list):
           raise TypeError("To call tf.group() with a list, use "
diff --git a/tensorflow/python/ops/control_flow_ops_test.py b/tensorflow/python/ops/control_flow_ops_test.py
index 34c405f293..3e8f39dd24 100644
--- a/tensorflow/python/ops/control_flow_ops_test.py
+++ b/tensorflow/python/ops/control_flow_ops_test.py
@@ -115,11 +115,19 @@ class GroupTestCase(test_util.TensorFlowTestCase):
     """, self._StripGraph(gd))
 
   def testPassingList(self):
-    with ops.Graph().as_default():
+    with ops.Graph().as_default() as g:
       a = constant_op.constant(0, name="a")
       b = constant_op.constant(0, name="b")
-      with self.assertRaises(TypeError):
-        control_flow_ops.group([a.op, b.op])
+      control_flow_ops.group([a.op, b.op], name="root")
+    gd = g.as_graph_def()
+    self.assertProtoEquals("""
+      node { name: "a" op: "Const"}
+      node { name: "b" op: "Const"}
+      node { name: "root" op: "NoOp" input: "^a" input: "^b" }
+    """, self._StripGraph(gd))
+
+  def testPassingNonTensors(self):
+    with ops.Graph().as_default():
       with self.assertRaises(TypeError):
         control_flow_ops.group(1, 2)