PVSC: Let Switch statements in PVSC XML have a default Case

Qt/Components/pqServerLauncher.cxx

@@ -474,11 +474,16 @@ void handleSwitchCases(const pqServerConfiguration& configuration, QProcessEnvir
         qWarning() << "'<Switch/> element can only contain <Case/> elements";
         continue;
       }
+    
       const char* case_value = caseXML->GetAttribute("value");
-      if (!case_value || value != case_value)
+
+      // Case: Explicitly does not match
+      if (case_value && value != case_value)
       {
         continue;
       }
+
+      // Case: Either matches or is default, i.e. no value
       handled = true;
       for (unsigned int i = 0; i < caseXML->GetNumberOfNestedElements(); i++)
       {
@@ -495,6 +500,17 @@ void handleSwitchCases(const pqServerConfiguration& configuration, QProcessEnvir
                      << setXML->GetName() << "'";
         }
       }
+
+      // Case: Default needs early exit; warn if not the last case
+      if(!case_value)
+      {
+        if(kk+1 < switchXML->GetNumberOfNestedElements())
+        {
+          qWarning() << "Default 'Case' possibly overshadows explicit 'Case' "
+                     << "statements for variable '" << variable << "'";
+        }
+        break;
+      }
     }
     if (!handled)
     {