add exception handing in deserializer to tell which op actually caused the exception (#756)

src/ngraph/serializer.cpp

@@ -338,6 +338,8 @@ static shared_ptr<ngraph::Function>
     vector<string> func_result = func_js.at("result").get<vector<string>>();
     unordered_map<string, shared_ptr<Node>> node_map;
     for (json node_js : func_js.at("ops"))
+    {
+        try
         {
             string node_name = node_js.at("name").get<string>();
             string node_op = node_js.at("op").get<string>();
@@ -642,8 +644,11 @@ static shared_ptr<ngraph::Function>
                 {
                     auto padding_below = padding_below_maybe.get<vector<size_t>>();
                     auto padding_above = padding_above_maybe.get<vector<size_t>>();
-                node = make_shared<op::MaxPool>(
-                    args[0], window_shape, window_movement_strides, padding_below, padding_above);
+                    node = make_shared<op::MaxPool>(args[0],
+                                                    window_shape,
+                                                    window_movement_strides,
+                                                    padding_below,
+                                                    padding_above);
                 }
                 else
                 {
@@ -857,6 +862,20 @@ static shared_ptr<ngraph::Function>
             // the serialization for debugging.
             // node->set_name(node_name);
         }
+        catch (...)
+        {
+            string node_name;
+            try
+            {
+                node_name = node_js.at("name").get<string>();
+            }
+            catch (...)
+            {
+                node_name = "UNKNOWN";
+            }
+            throw runtime_error("Error parsing json at node '" + node_name + "'");
+        }
+    }
 
     //This handles both graphs w/ `op::Result` and legacy graphs w/o it
     //If we are dealing w/ a legacy graph, add op::Result for each output node