Null pointer exception in `DeserializeSparse`

@@ -16,6 +16,7 @@ limitations under the License.
 #include "tensorflow/core/framework/common_shape_fns.h"
 #include "tensorflow/core/framework/op.h"
 #include "tensorflow/core/framework/shape_inference.h"
+#include "tensorflow/core/framework/types.pb.h"
 #include "tensorflow/core/platform/errors.h"
 
 namespace tensorflow {
@@ -159,6 +160,8 @@ REGISTER_OP("DeserializeSparse")
     .Attr("Tserialized: {string, variant} = DT_STRING")
     .SetShapeFn([](InferenceContext* c) {
       // serialized sparse is [?, ..., ?, 3] vector.
+      ShapeHandle unused_shape;
+      TF_RETURN_IF_ERROR(c->WithRankAtLeast(c->input(0), 1, &unused_shape));
       DimensionHandle unused;
       TF_RETURN_IF_ERROR(c->WithValue(c->Dim(c->input(0), -1), 3, &unused));
       c->set_output(0, c->Matrix(InferenceContext::kUnknownDim,

@@ -16,10 +16,12 @@
 
 import numpy as np
 
+from tensorflow.python.eager import def_function
 from tensorflow.python.framework import dtypes
 from tensorflow.python.framework import sparse_tensor as sparse_tensor_lib
 from tensorflow.python.framework import test_util
 from tensorflow.python.ops import array_ops
+from tensorflow.python.ops import gen_resource_variable_ops
 from tensorflow.python.ops import sparse_ops
 from tensorflow.python.platform import test
 
@@ -460,6 +462,18 @@ def testDeserializeManyFailsInvalidProto(self):
     self._testDeserializeFailsInvalidProtoHelper(
         sparse_ops.serialize_sparse, sparse_ops.deserialize_many_sparse)
 
+  def testDeserializeInvalidVariant(self):
+    mu = gen_resource_variable_ops.mutex_v2()
+    mu_lock = gen_resource_variable_ops.mutex_lock(mutex=mu)
+
+    @def_function.function
+    def f():
+      return sparse_ops.deserialize_sparse(
+          serialized_sparse=mu_lock, dtype=dtypes.int32)
+
+    with self.assertRaisesRegex(ValueError, r"Shape must be at least rank 1"):
+      f()
+
 
 if __name__ == "__main__":
   test.main()