TensorFlow has null dereference on ParallelConcat with XLA

@@ -78,7 +78,7 @@ class ParallelConcatUpdate : public OpKernel {
     OP_REQUIRES(
         ctx, value.dim_size(0) > loc_,
         errors::InvalidArgument("0th dimension of value = ", value.dim_size(0),
-                                " is less than loc_=", loc_));
+                                " must be greater than loc_ = ", loc_));
 
     auto update = ctx->input(1);
 

@@ -15,6 +15,7 @@ limitations under the License.
 
 #include <algorithm>
 #include <ostream>
+#include <vector>
 
 #include "tensorflow/core/framework/common_shape_fns.h"
 #include "tensorflow/core/framework/full_type.pb.h"
@@ -309,6 +310,12 @@ REGISTER_OP("ParallelConcat")
           return errors::InvalidArgument(
               "All input shapes must be fully defined.");
         }
+        if (c->Rank(c->input(i)) < 1) {
+          return errors::InvalidArgument(
+              "The rank of all input shapes must be greater than 0, "
+              "but input ",
+              i, " had rank ", c->Rank(c->input(i)), ".");
+        }
         DimensionHandle unused;
         if (!c->WithValue(c->Dim(c->input(i), 0), 1, &unused).ok()) {
           return errors::InvalidArgument("Size of first dimension must be 1.");

@@ -83,8 +83,9 @@ def f():
       y = gen_array_ops.parallel_concat(values=[["tf"]], shape=0)
       return y
 
-    with self.assertRaisesRegex(errors.InvalidArgumentError,
-                                r"0th dimension of value .* is less than"):
+    with self.assertRaisesRegex(
+        errors.InvalidArgumentError, r"0th dimension .* must be greater than"
+    ):
       f()
 
   def testSimpleParallelGPU(self):

@@ -18,6 +18,7 @@
 from tensorflow.python.eager import def_function
 from tensorflow.python.framework import dtypes
 from tensorflow.python.framework import tensor_spec
+from tensorflow.python.framework import test_util
 from tensorflow.python.ops import array_ops
 from tensorflow.python.ops import math_ops
 from tensorflow.python.ops import random_ops
@@ -91,6 +92,20 @@ def g(x):
     conc = g.get_concrete_function(tensor_spec.TensorSpec([10, None]))
     self.assertAllEqual(conc.output_shapes.as_list(), [10])
 
+  @test_util.run_in_graph_and_eager_modes
+  def testParallelConcatFailsWithRankZeroShape(self):
+    op = array_ops.ParallelConcat
+    para = {"shape": 0, "values": [1]}
+
+    def func():
+      y = op(**para)
+      return y
+
+    with self.assertRaisesRegex(
+        Exception, "(rank|dimension) of .* must be greater than .* 0"
+    ):
+      func()
+
 
 if __name__ == "__main__":
   test.main()