Extensions: Fix ViewProvider python interface

src/App/Extension.cpp

@@ -33,6 +33,7 @@
 #include "Base/Exception.h"
 #include <Base/Console.h>
 #include <Base/PyObjectBase.h>
+#include <ExtensionPy.h>
  
 /* We do not use a standard property macro for type initiation. The reason is that we have the first
  * PropertyData in the extension chain, there is no parent property data. 
@@ -96,7 +97,12 @@ void Extension::initExtension(ExtensionContainer* obj) {
 
 PyObject* Extension::getExtensionPyObject(void) {
 
-    return nullptr;
+    if (ExtensionPythonObject.is(Py::_None())){
+        // ref counter is set to 1
+        auto grp = new ExtensionPy(this);
+        ExtensionPythonObject = Py::Object(grp,true);
+    }
+    return Py::new_reference_to(ExtensionPythonObject);
 }
 
 const char* Extension::name() {

src/Gui/ViewProviderExtension.h

@@ -97,13 +97,14 @@ public:
     
     ViewProviderExtensionPythonT() {
         ExtensionT::m_isPythonExtension = true;
+        ExtensionT::initExtension(ViewProviderExtensionPythonT::getExtensionClassTypeId());
         
-        EXTENSION_ADD_PROPERTY(Proxy,(Py::Object()));
+        EXTENSION_ADD_PROPERTY(ExtensionProxy,(Py::Object()));
     }
     virtual ~ViewProviderExtensionPythonT() {
     }
 
-    App::PropertyPythonObject Proxy;
+    App::PropertyPythonObject ExtensionProxy;
 };
 
 typedef ViewProviderExtensionPythonT<Gui::ViewProviderExtension> ViewProviderExtensionPython;

src/Gui/ViewProviderPy.xml

@@ -1,13 +1,13 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <GenerateModel xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="generateMetaModel_Module.xsd">
 	<PythonExport 
-		Father="PropertyContainerPy" 
+		Father="ExtensionContainerPy" 
 		Name="ViewProviderPy" 
 		Twin="ViewProvider" 
 		TwinPointer="ViewProvider" 
 		Include="Gui/ViewProvider.h" 
 		Namespace="Gui" 
-		FatherInclude="App/PropertyContainerPy.h"
+		FatherInclude="App/ExtensionContainerPy.h"
 		FatherNamespace="App">
 		<Documentation>
 			<Author Licence="LGPL" Name="Werner Mayer" EMail="wmayer@users.sourceforge.net" />

src/Mod/Test/Document.py

@@ -234,7 +234,26 @@ class DocumentBasicCases(unittest.TestCase):
         self.Doc.removeObject(obj.Name)
         del obj
     
+  def testExtensionBugViewProvider(self):
 
+    class Layer():
+        def __init__(self, obj):
+            ''' Add the properties '''
+            obj.addExtension("App::GroupExtensionPython", self)
+            
+    class LayerViewProvider():
+      def __init__(self, obj):
+        ''' Add the properties '''
+        obj.addExtension("Gui::ViewProviderGroupExtensionPython", self)
+        obj.Proxy = self
+    
+    obj = FreeCAD.ActiveDocument.addObject("App::FeaturePython","Layer")
+    Layer(obj)
+    LayerViewProvider(obj.ViewObject)
+    self.failUnless(obj.hasExtension("App::GroupExtension"))
+    self.failUnless(obj.ViewObject.hasExtension("Gui::ViewProviderGroupExtension"))
+    self.failUnless(obj.ViewObject.hasExtension("Gui::ViewProviderGroupExtensionPython"))
+     
   def tearDown(self):
     #closing doc
     FreeCAD.closeDocument("CreateTest")