From 75b9dd8a0ec6f58d0b74860af00c430e00423f25 Mon Sep 17 00:00:00 2001
From: wmayer <wmayer@users.sourceforge.net>
Date: Tue, 10 Mar 2020 16:32:31 +0100
Subject: [PATCH] [skip ci] App: print affected Python type if serializing via
 JSON fails FemGui: add default implementations of __getstate__/__setstate__
 to _ViewProviderFemResultMechanical

---
 src/App/PropertyPythonObject.cpp                            | 2 ++
 .../Fem/femguiobjects/_ViewProviderFemResultMechanical.py   | 6 ++++++
 2 files changed, 8 insertions(+)

diff --git a/src/App/PropertyPythonObject.cpp b/src/App/PropertyPythonObject.cpp
index bf65c45ee0..d7aa79a295 100644
--- a/src/App/PropertyPythonObject.cpp
+++ b/src/App/PropertyPythonObject.cpp
@@ -109,6 +109,8 @@ std::string PropertyPythonObject::toString() const
         repr = str.as_std_string("ascii");
     }
     catch (Py::Exception&) {
+        Py::String typestr(this->object.type().str());
+        Base::Console().Error("PropertyPythonObject::toString(): failed for %s\n", typestr.as_string().c_str());
         Base::PyException e; // extract the Python error text
         e.ReportException();
     }
diff --git a/src/Mod/Fem/femguiobjects/_ViewProviderFemResultMechanical.py b/src/Mod/Fem/femguiobjects/_ViewProviderFemResultMechanical.py
index 1b7f41d57d..fbeb90fe56 100644
--- a/src/Mod/Fem/femguiobjects/_ViewProviderFemResultMechanical.py
+++ b/src/Mod/Fem/femguiobjects/_ViewProviderFemResultMechanical.py
@@ -85,6 +85,12 @@ class _ViewProviderFemResultMechanical(ViewProviderFemConstraint.ViewProxy):
                 FreeCAD.Console.PrintError("Error in onDelete: {0} \n".format(err))
         return True
 
+    def __getstate__(self):
+        return None
+
+    def __setstate__(self, data):
+        return None
+
 
 class _TaskPanel:
     """