Fixed coverity issues

184348 Bad use of null-like value
175794 Copy-paste error
172913 Copy-paste error
169506 Structurally dead code
169504 Bad use of null-like value
169013 Copy-paste error

src/Mod/Draft/importDXF.py

@@ -1226,7 +1226,7 @@ def processdxf(document,filename,getShapes=False,reComputeFlag=True):
     # drawing solids
 
     solids = drawing.entities.get_type("solid")
-    if solids: FreeCAD.Console.PrintMessage("drawing "+str(len(circles))+" solids...\n")
+    if solids: FreeCAD.Console.PrintMessage("drawing "+str(len(solids))+" solids...\n")
     for solid in solids:
         lay = rawValue(solid,8)
         if dxfImportLayouts or (not rawValue(solid,67)):

src/Mod/Fem/femcommands/commands.py

@@ -436,7 +436,7 @@ class _CommandFemMaterialMechanicalNonlinear(CommandManager):
                     solver_object = None
                     break
         # set solver attribute for nonlinearity for ccxtools CalculiX solver or new frame work CalculiX solver
-        if hasattr(solver_object, "Proxy") and (solver_object.Proxy.Type == 'Fem::FemSolverCalculixCcxTools' or solver_object.Proxy.Type == 'Fem::FemSolverObjectCalculix'):
+        if solver_object and hasattr(solver_object, "Proxy") and (solver_object.Proxy.Type == 'Fem::FemSolverCalculixCcxTools' or solver_object.Proxy.Type == 'Fem::FemSolverObjectCalculix'):
             print('Set MaterialNonlinearity and GeometricalNonlinearity to nonlinear for ' + solver_object.Label)
             solver_object.MaterialNonlinearity = "nonlinear"
             solver_object.GeometricalNonlinearity = "nonlinear"

src/Mod/Fem/femguiobjects/FemSelectionWidgets.py

@@ -433,7 +433,7 @@ class GeometryElementsSelection(QtGui.QWidget):
                                 else:
                                     FreeCAD.Console.PrintMessage('Face belongs to more than one solid\n')
                                     solid_to_add = None
-                                found_edge = True
+                                found_face = True
                 if solid_to_add:
                     selection = (selection[0], 'Solid' + solid_to_add)
                     ele_ShapeType = 'Solid'

src/Mod/Fem/femguiobjects/_ViewProviderFemMaterial.py

@@ -315,7 +315,7 @@ class _TaskPanelFemMaterial:
                 self.material['KinematicViscosity'] = '0 m^2/s'
             if 'VolumetricThermalExpansionCoefficient' in self.material:
                 # unit type of VolumetricThermalExpansionCoefficient is ThermalExpansionCoefficient
-                if 'ThermalExpansionCoefficient' not in str(Units.Unit(self.material['VolumetricThermalExpansionCoefficient'])):
+                if 'VolumetricThermalExpansionCoefficient' not in str(Units.Unit(self.material['VolumetricThermalExpansionCoefficient'])):
                     print('VolumetricThermalExpansionCoefficient in material data seems to have no unit or a wrong unit (reset the value): ' + self.material['Name'])
                     self.material['VolumetricThermalExpansionCoefficient'] = '0 m/m/K'
             else:

src/Mod/Fem/femmesh/meshtools.py

@@ -545,7 +545,7 @@ def get_femelement_sets_from_group_data(femmesh, fem_objects):
         return False
     else:
         return True
-    print("")
+    #print("")
 
 
 def get_elset_short_name(obj, i):

src/Mod/Fem/femsolver/elmer/writer.py

@@ -480,7 +480,8 @@ class Writer(object):
                 dimension = "M/L^3"
                 if name.startswith("Edge"):
                     density = None  # not tested, but it seems needed because denisty does not exist (IMHO, bernd)
-                    density.Unit = Units.Unit(-2, 1)
+                    if density:
+                        density.Unit = Units.Unit(-2, 1)
                     dimension = "M/L^2"
                 density = convert(densityQuantity, dimension)