fix wrap twice problem

mindspore/train/dataset_helper.py

@@ -39,6 +39,22 @@ def _send_data_no_flag(dataset, epoch_num):
     exec_dataset.send(epoch_num)
 
 
+def _dynamic_sink_scenario(dataset, dataset_iter):
+    """Special scenario with dynamic shape and sink_size=1."""
+    flag = False
+    ms_role = os.getenv("MS_ROLE")
+    if hasattr(dataset_iter, "sink_size") and \
+       dataset_iter.sink_size == 1 and \
+       dataset.get_dataset_size() != 1 and \
+       hasattr(dataset_iter, "sink_count") and \
+       dataset_iter.sink_count == 1 and \
+       context.get_context("device_target") == "Ascend" and \
+       context.get_context("mode") == context.GRAPH_MODE and \
+       ms_role != "MS_WORKER":
+        flag = True
+    return flag
+
+
 class _DataWrapper(nn.Cell):
     """
     Wraps the input network with a dataset which automatically fetches data with 'GetNext' function from the
@@ -107,14 +123,7 @@ def connect_network_with_dataset(network, dataset_helper):
         return network
 
     queue_name = dataset.__transfer_dataset__.queue_name
-    if hasattr(dataset_iter, "sink_size") and \
-       dataset_iter.sink_size == 1 and \
-       hasattr(dataset_iter, "sink_count") and \
-       dataset_iter.sink_count == 1 and \
-       context.get_context("device_target") == "Ascend" and \
-       context.get_context("mode") == context.GRAPH_MODE and \
-       ms_role != "MS_WORKER":
-
+    if _dynamic_sink_scenario(dataset, dataset_iter):
         if not hasattr(dataset_iter, '__network__'):
             dataset_iter.__network__ = network
         network = dataset_iter.__network__