From fb6c7ba2e127be6632ddb8f0497df54bfaedb59a Mon Sep 17 00:00:00 2001
From: hesham <h.farahat@huawei.com>
Date: Thu, 16 Apr 2020 00:07:28 -0400
Subject: [PATCH] Fix two problem when we create multiple instances of the same
 dataset (2 for-loops) -- Iterator list is keeping  all created iterators
 wihtout cleaning them up -- alter tree modifies the original.

---
 mindspore/ccsrc/dataset/api/python_bindings.cc |  6 ++++--
 mindspore/dataset/engine/iterators.py          | 12 +++++++++---
 2 files changed, 13 insertions(+), 5 deletions(-)

diff --git a/mindspore/ccsrc/dataset/api/python_bindings.cc b/mindspore/ccsrc/dataset/api/python_bindings.cc
index e2675ee217c..d9e0ccbba87 100644
--- a/mindspore/ccsrc/dataset/api/python_bindings.cc
+++ b/mindspore/ccsrc/dataset/api/python_bindings.cc
@@ -225,11 +225,13 @@ void bindTensor(py::module *m) {
   (void)py::class_<DataType>(*m, "DataType")
     .def(py::init<std::string>())
     .def(py::self == py::self)
-    .def("__str__", &DataType::ToString);
+    .def("__str__", &DataType::ToString)
+    .def("__deepcopy__", [](py::object &t, py::dict memo) { return t; });
 }
 
 void bindTensorOps1(py::module *m) {
-  (void)py::class_<TensorOp, std::shared_ptr<TensorOp>>(*m, "TensorOp");
+  (void)py::class_<TensorOp, std::shared_ptr<TensorOp>>(*m, "TensorOp")
+    .def("__deepcopy__", [](py::object &t, py::dict memo) { return t; });
 
   (void)py::class_<NormalizeOp, TensorOp, std::shared_ptr<NormalizeOp>>(
     *m, "NormalizeOp", "Tensor operation to normalize an image. Takes mean and std.")
diff --git a/mindspore/dataset/engine/iterators.py b/mindspore/dataset/engine/iterators.py
index 268a66c0cf0..69dd9ce0a97 100644
--- a/mindspore/dataset/engine/iterators.py
+++ b/mindspore/dataset/engine/iterators.py
@@ -15,6 +15,8 @@
 """Built-in iterators.
 """
 from abc import abstractmethod
+import copy
+import weakref
 
 from mindspore._c_dataengine import DEPipeline
 from mindspore._c_dataengine import OpName
@@ -27,7 +29,9 @@ ITERATORS_LIST = list()
 
 def _cleanup():
     for itr in ITERATORS_LIST:
-        itr.release()
+        iter_ref = itr()
+        if itr is not None:
+            iter_ref.release()
 
 
 def alter_tree(node):
@@ -73,8 +77,10 @@ class Iterator:
     """
 
     def __init__(self, dataset):
-        ITERATORS_LIST.append(self)
-        self.dataset = alter_tree(dataset)
+        ITERATORS_LIST.append(weakref.ref(self))
+        # create a copy of tree and work on it.
+        self.dataset = copy.deepcopy(dataset)
+        self.dataset = alter_tree(self.dataset)
         if not self.__is_tree():
             raise ValueError("The data pipeline is not a tree (i.e., one node has 2 consumers)")
         self.depipeline = DEPipeline()