Merge branch '3.4'

cura/Settings/MachineManager.py

@@ -1243,7 +1243,7 @@ class MachineManager(QObject):
     ##  Given a printer definition name, select the right machine instance. In case it doesn't exist, create a new
     #   instance with the same network key.
     @pyqtSlot(str)
-    def switchPrinterType(self, machine_name: str):
+    def switchPrinterType(self, machine_name: str) -> None:
         # Don't switch if the user tries to change to the same type of printer
         if self.activeMachineDefinitionName == machine_name:
             return
@@ -1254,6 +1254,8 @@ class MachineManager(QObject):
         # If there is no machine, then create a new one and set it to the non-hidden instance
         if not new_machine:
             new_machine = CuraStackBuilder.createMachine(machine_definition_id + "_sync", machine_definition_id)
+            if not new_machine:
+                return
             new_machine.addMetaDataEntry("um_network_key", self.activeMachineNetworkKey)
             new_machine.addMetaDataEntry("connect_group_name", self.activeMachineNetworkGroupName)
             new_machine.addMetaDataEntry("hidden", False)

plugins/3MFReader/ThreeMFWorkspaceReader.py

@@ -606,9 +606,10 @@ class ThreeMFWorkspaceReader(WorkspaceReader):
             machine_name = self._container_registry.uniqueName(self._machine_info.name)
 
             global_stack = CuraStackBuilder.createMachine(machine_name, self._machine_info.definition_id)
-            extruder_stack_dict = global_stack.extruders
+            if global_stack: #Only switch if creating the machine was successful.
+                extruder_stack_dict = global_stack.extruders
 
-            self._container_registry.addContainer(global_stack)
+                self._container_registry.addContainer(global_stack)
         else:
             # Find the machine
             global_stack = self._container_registry.findContainerStacks(name = self._machine_info.name, type = "machine")[0]

plugins/XmlMaterialProfile/XmlMaterialProfile.py

@@ -518,9 +518,10 @@ class XmlMaterialProfile(InstanceContainer):
                     meta_data["name"] = label.text
                 else:
                     meta_data["name"] = self._profile_name(material.text, color.text)
-                meta_data["brand"] = brand.text
-                meta_data["material"] = material.text
-                meta_data["color_name"] = color.text
+
+                meta_data["brand"] = brand.text if brand.text is not None else "Unknown Brand"
+                meta_data["material"] = material.text if material.text is not None else "Unknown Type"
+                meta_data["color_name"] = color.text if color.text is not None else "Unknown Color"
                 continue
 
             # setting_version is derived from the "version" tag in the schema earlier, so don't set it here
@@ -811,9 +812,10 @@ class XmlMaterialProfile(InstanceContainer):
                     base_metadata["name"] = label.text
                 else:
                     base_metadata["name"] = cls._profile_name(material.text, color.text)
-                base_metadata["brand"] = brand.text
-                base_metadata["material"] = material.text
-                base_metadata["color_name"] = color.text
+
+                base_metadata["brand"] = brand.text if brand.text is not None else "Unknown Brand"
+                base_metadata["material"] = material.text if material.text is not None else "Unknown Type"
+                base_metadata["color_name"] = color.text if color.text is not None else "Unknown Color"
                 continue
 
             #Setting_version is derived from the "version" tag in the schema earlier, so don't set it here.
@@ -976,6 +978,8 @@ class XmlMaterialProfile(InstanceContainer):
 
     @classmethod
     def _profile_name(cls, material_name, color_name):
+        if material_name is None:
+            return "Unknown Material"
         if color_name != "Generic":
             return "%s %s" % (color_name, material_name)
         else:

resources/qml/Preferences/MaterialsPage.qml

@@ -482,7 +482,7 @@ Item
             {
                 var currentItem = materialsModel.getItem(materialListView.currentIndex);
 
-                materialProperties.name = currentItem.name;
+                materialProperties.name = currentItem.name ? currentItem.name : "Unknown";
                 materialProperties.guid = currentItem.guid;
 
                 materialProperties.brand = currentItem.brand ? currentItem.brand : "Unknown";