App: [skip ci] move execution of extensions to its own method

src/App/DocumentObject.cpp

@@ -113,7 +113,12 @@ App::DocumentObjectExecReturn *DocumentObject::recompute(void)
 
 DocumentObjectExecReturn *DocumentObject::execute(void)
 {
-    //call all extensions
+    return executeExtensions();
+}
+
+App::DocumentObjectExecReturn* DocumentObject::executeExtensions()
+{
+    //execute extensions but stop on error
     auto vector = getExtensionsDerivedFromType<App::DocumentObjectExtension>();
     for(auto ext : vector) {
         auto ret = ext->extensionExecute();

src/App/DocumentObject.h

@@ -567,6 +567,11 @@ protected:
       */
     virtual App::DocumentObjectExecReturn *execute(void);
 
+    /**
+     * Executes the extensions of a document object.
+     */
+    App::DocumentObjectExecReturn *executeExtensions();
+
     /** Status bits of the document object
      * The first 8 bits are used for the base system the rest can be used in
      * descendent classes to mark special statuses on the objects.