!5944 [bug]fix bug in cell copy & test case

Merge pull request !5944 from vlne-v1/bug-cell-copy

mindspore/ccsrc/pybind_api/ir/cell_py.cc

@@ -45,6 +45,19 @@ REGISTER_PYBIND_DEFINE(Cell, ([](const py::module *m) {
                            .def("_del_attr", &Cell::DelAttr, "Delete Cell attr.")
                            .def(
                              "construct", []() { MS_LOG(EXCEPTION) << "we should define `construct` for all `cell`."; },
-                             "construct");
+                             "construct")
+                           .def(py::pickle(
+                             [](const Cell &cell) {  // __getstate__
+                               /* Return a tuple that fully encodes the state of the object */
+                               return py::make_tuple(py::str(cell.name()));
+                             },
+                             [](const py::tuple &tup) {  // __setstate__
+                               if (tup.size() != 1) {
+                                 throw std::runtime_error("Invalid state!");
+                               }
+                               /* Create a new C++ instance */
+                               Cell data(tup[0].cast<std::string>());
+                               return data;
+                             }));
                        }));
 }  // namespace mindspore

tests/ut/python/nn/test_cell.py

@@ -13,6 +13,7 @@
 # limitations under the License.
 # ============================================================================
 """ test cell """
+import copy
 import numpy as np
 import pytest
 
@@ -200,6 +201,11 @@ def test_exceptions():
         m.construct()
 
 
+def test_cell_copy():
+    net = ConvNet()
+    copy.deepcopy(net)
+
+
 def test_del():
     """ test_del """
     ta = Tensor(np.ones([2, 3]))