From 3ca2a408fb1aa4da10df3ba4d1bd55c9e423ee8a Mon Sep 17 00:00:00 2001
From: wmayer <wmayer@users.sourceforge.net>
Date: Fri, 30 Mar 2018 18:39:55 +0200
Subject: [PATCH] Fix invalid Python object error

Example below led to a crash:
import Path
v = Path.Tool(name='v', diameter=5.6)
tt = Path.Tooltable()
tt.addTools(v)
attrs = tt.templateAttrs()
uu = Path.Tooltable(tt.templateAttrs())
del attrs
---
 src/Mod/Path/App/TooltablePyImp.cpp | 14 ++++++++++----
 1 file changed, 10 insertions(+), 4 deletions(-)

diff --git a/src/Mod/Path/App/TooltablePyImp.cpp b/src/Mod/Path/App/TooltablePyImp.cpp
index ef250a7bc1..63e4adfdaa 100644
--- a/src/Mod/Path/App/TooltablePyImp.cpp
+++ b/src/Mod/Path/App/TooltablePyImp.cpp
@@ -391,12 +391,18 @@ void TooltablePy::setTools(Py::Dict arg)
             } else {
               PyErr_Clear();
               Path::Tool *tool = new Path::Tool;
-              Path::ToolPy pyTool(tool);
-              if (!pyTool.setFromTemplate(value)) {
-                PyErr_Print();
-                throw Py::Exception("something went wrong");
+              // The 'pyTool' object must be created on the heap otherwise Python
+              // will fail to properly track the reference counts and aborts
+              // in debug mode.
+              Path::ToolPy* pyTool = new Path::ToolPy(tool);
+              PyObject* success = pyTool->setFromTemplate(value);
+              if (!success) {
+                Py_DECREF(pyTool);
+                throw Py::Exception();
               }
               getTooltablePtr()->setTool(*tool, ckey);
+              Py_DECREF(pyTool);
+              Py_DECREF(success);
             }
         } else {
             throw Py::Exception("The dictionary can only contain int:tool pairs");