Part: Fix several coverity issues:

* CID 350581: Structurally dead code
* CID 350620: Structurally dead code
* CID 350563: Big parameter passed by value
* CID 350552: Uncaught exception
* CID 305193: Uncaught exception
* CID 350556: Uninitialized scalar field
* CID 350579: Uninitialized pointer read

src/Mod/Part/App/ExtrusionHelper.cpp

@@ -406,7 +406,7 @@ void ExtrusionHelper::checkInnerWires(std::vector<bool>& isInnerWire, const gp_D
     // recursively call the function until all wires are checked
     if (numCheckWires > 1)
         checkInnerWires(isInnerWire, direction, checklist, !forInner, prisms);
-};
+}
 
 void ExtrusionHelper::createTaperedPrismOffset(TopoDS_Wire sourceWire,
                                                const gp_Vec& translation,
@@ -452,11 +452,9 @@ void ExtrusionHelper::createTaperedPrismOffset(TopoDS_Wire sourceWire,
         }
         catch (const Base::Exception& e) {
             throw Base::RuntimeError(e.what());
-            result = TopoDS_Wire();
         }
         if (!mkOffset.IsDone()) {
             Standard_Failure::Raise("Extrusion: Offset could not be created");
-            result = TopoDS_Wire();
         }
         if (numEdges == 1) {
             // we need to move the offset wire first back to its original position

src/Mod/Part/App/GeometrySurfacePyImp.cpp

@@ -238,9 +238,6 @@ PyObject* GeometrySurfacePy::getDN(PyObject *args)
         PyErr_SetString(PartExceptionOCCError, e.GetMessageString());
         return nullptr;
     }
-
-    PyErr_SetString(PartExceptionOCCError, "Geometry is not a surface");
-    return nullptr;
 }
 
 PyObject* GeometrySurfacePy::value(PyObject *args)

src/Mod/Part/App/Tools.cpp

@@ -663,7 +663,7 @@ Handle(Poly_Polygon3D) Part::Tools::polygonOfEdge(const TopoDS_Edge& edge, TopLo
 // helper function to use in getNormal, here we pass the local properties
 // of the surface given by the #LProp_SLProps objects
 template <typename T>
-void getNormalBySLProp(T prop, double u, double v, Standard_Real lastU, Standard_Real lastV,
+void getNormalBySLProp(T& prop, double u, double v, Standard_Real lastU, Standard_Real lastV,
                      const Standard_Real tol, gp_Dir& dir, Standard_Boolean& done)
 {
     if (prop.D1U().Magnitude() > tol &&

src/Mod/Part/Gui/DlgProjectionOnSurface.cpp

@@ -195,7 +195,12 @@ DlgProjectionOnSurface::~DlgProjectionOnSurface()
   }
   for (auto it : m_shapeVec)
   {
-    higlight_object(it.partFeature, it.partName, false, 0);
+    try {
+      higlight_object(it.partFeature, it.partName, false, 0);
+    }
+    catch (Standard_NoSuchObject& e) {
+      Base::Console().Warning("DlgProjectionOnSurface::~DlgProjectionOnSurface: %s", e.GetMessageString());
+    }
   }
   Gui::Selection().rmvSelectionGate();
 }

src/Mod/Part/Gui/SectionCutting.cpp

@@ -247,7 +247,7 @@ void SectionCut::startCutting(bool isInitial)
         // refresh documents list
         onRefreshCutPBclicked();
 
-    App::DocumentObject* anObject;
+    App::DocumentObject* anObject = nullptr;
     std::vector<App::DocumentObjectT>::iterator it;
 
     // lambda function to delete objects

src/Mod/Part/Gui/TaskAttacher.cpp

@@ -119,6 +119,7 @@ TaskAttacher::TaskAttacher(Gui::ViewProviderDocumentObject *ViewProvider, QWidge
     , ViewProvider(ViewProvider)
     , ui(new Ui_TaskAttacher)
     , visibilityFunc(visFunc)
+    , completed(false)
 {
     //check if we are attachable
     if (!ViewProvider->getObject()->hasExtension(Part::AttachExtension::getExtensionClassTypeId()))