More consistent 'include_in_backups' behavior

Instead of always selecting for backup all the VMs that were selected
during last saved backup, now the GUI tool will disregard last selected
VMs and instead use VM attribute 'include_in_backups'

fixes QubesOS/qubes-issues#4713

qubesmanager/backup.py

@@ -130,7 +130,10 @@ class BackupVMsWindow(ui_backupdlg.Ui_Backup, multiselectwidget.QtGui.QWizard):
             allow_none=False
         )
 
-        selected = self.load_settings()
+        self.unrecognized_config_label.setVisible(False)
+        self.load_settings()
+
+        selected = self.vms_to_include()
         self.__fill_vms_list__(selected)
 
         # Connect backup events for progress_bar
@@ -142,14 +145,28 @@ class BackupVMsWindow(ui_backupdlg.Ui_Backup, multiselectwidget.QtGui.QWizard):
     def on_backup_progress(self, __submitter, _event, **kwargs):
         self.progress_bar.setValue(int(float(kwargs['progress'])))
 
+    def vms_to_include(self):
+        """
+        Helper function that returns list of VMs with 'include_in_backups'
+        attribute set to True.
+        :return: list of VM names
+        """
+
+        result = []
+
+        for domain in self.qubes_app.domains:
+            if getattr(domain, 'include_in_backups', None):
+                result.append(domain.name)
+
+        return result
 
     def load_settings(self):
         """
         Helper function that tries to load existing backup profile
         (default path: /etc/qubes/backup/qubes-manager-backup.conf )
         and then apply its contents to the Backup window.
-        :return: list of vms to include in backup, if it exists in the profile,
-        or None if it does not
+        Ignores listed VMs, to prioritize include_in_backups feature.
+        :return: None
         """
         try:
             profile_data = backup_utils.load_backup_profile()
@@ -168,6 +185,8 @@ class BackupVMsWindow(ui_backupdlg.Ui_Backup, multiselectwidget.QtGui.QWizard):
             dest_vm_idx = self.appvm_combobox.findText(dest_vm_name)
             if dest_vm_idx > -1:
                 self.appvm_combobox.setCurrentIndex(dest_vm_idx)
+            else:
+                self.unrecognized_config_label.setVisible(True)
 
         if 'destination_path' in profile_data:
             dest_path = profile_data['destination_path']
@@ -181,11 +200,6 @@ class BackupVMsWindow(ui_backupdlg.Ui_Backup, multiselectwidget.QtGui.QWizard):
         if 'compression' in profile_data:
             self.compress_checkbox.setChecked(profile_data['compression'])
 
-        if 'include' in profile_data:
-            return profile_data['include']
-
-        return None
-
     def save_settings(self, use_temp):
         """
         Helper function that saves backup profile to either
@@ -231,9 +245,6 @@ class BackupVMsWindow(ui_backupdlg.Ui_Backup, multiselectwidget.QtGui.QWizard):
         self.select_vms_widget.available_list.sortItems()
         self.select_vms_widget.selected_list.sortItems()
 
-        self.unrecognized_config_label.setVisible(
-            selected is not None and
-            len(selected) != len(self.select_vms_widget.selected_list))
         self.total_size_label.setText(
             admin_utils.size_to_human(self.total_size))