From feff5fa9f0d88732331c6a5d2d5e117266aa1467 Mon Sep 17 00:00:00 2001
From: wmayer <wmayer@users.sourceforge.net>
Date: Mon, 3 Jun 2019 11:30:29 +0200
Subject: [PATCH] when trying to access ViewObject attribute check that
 FreeCADGui is already loaded

---
 src/App/DocumentObjectPyImp.cpp | 15 ++++++++++++++-
 1 file changed, 14 insertions(+), 1 deletion(-)

diff --git a/src/App/DocumentObjectPyImp.cpp b/src/App/DocumentObjectPyImp.cpp
index 2f91d8823a..8d6addac70 100644
--- a/src/App/DocumentObjectPyImp.cpp
+++ b/src/App/DocumentObjectPyImp.cpp
@@ -187,11 +187,24 @@ Py::List DocumentObjectPy::getState(void) const
 Py::Object DocumentObjectPy::getViewObject(void) const
 {
     try {
+        PyObject *dict = PySys_GetObject("modules");
+        if (!dict) {
+            return Py::None();
+        }
+
+        // check if the FreeCADGui module is already loaded, if not then don't try to load it
+        Py::Dict sysmod(dict);
+        if (!sysmod.hasKey("FreeCADGui")) {
+            return Py::None();
+        }
+
+        // double-check that the module doesn't have a null pointer
         Py::Module module(PyImport_ImportModule("FreeCADGui"),true);
-        if (!module.hasAttr("getDocument")) {
+        if (module.isNull() || !module.hasAttr("getDocument")) {
             // in v0.14+, the GUI module can be loaded in console mode (but doesn't have all its document methods)
             return Py::None();
         }
+
         Py::Callable method(module.getAttr("getDocument"));
         Py::Tuple arg(1);
         arg.setItem(0, Py::String(getDocumentObjectPtr()->getDocument()->getName()));