Fix error when attempting to expand 1D CompositeTensors.

PiperOrigin-RevId: 297909613
Change-Id: Icc958fb7aa4742e48999320a8ff49da691351831

tensorflow/python/keras/engine/data_adapter.py

@@ -1256,7 +1256,8 @@ def expand_1d(data):
   """Expands 1-dimensional `Tensor`s into 2-dimensional `Tensor`s."""
 
   def _expand_single_1d_tensor(t):
-    if (hasattr(t, "shape") and
+    # Leaves `CompositeTensor`s as-is.
+    if (isinstance(t, ops.Tensor) and
         isinstance(t.shape, tensor_shape.TensorShape) and t.shape.rank == 1):
       return array_ops.expand_dims_v2(t, axis=-1)
     return t

tensorflow/python/keras/engine/data_adapter_test.py

@@ -1062,6 +1062,15 @@ class TestValidationSplit(keras_parameterized.TestCase):
     self.assertIsNone(val_sw)
 
 
+class TestUtils(keras_parameterized.TestCase):
+
+  def test_expand_1d_sparse_tensors_untouched(self):
+    st = sparse_tensor.SparseTensor(
+        indices=[[0], [10]], values=[1, 2], dense_shape=[10])
+    st = data_adapter.expand_1d(st)
+    self.assertEqual(st.shape.rank, 1)
+
+
 if __name__ == '__main__':
   ops.enable_eager_execution()
   test.main()