Fix dom0 feature gathering

Author: ben-grande

qubes_config/global_config/basics_handler.py

@@ -222,9 +222,10 @@ def __init__(
         self.qapp = qapp
         self.widget = widget
         self.dependent_widget = dependent_widget
-        # TODO: ben: if changing default_dispvm, set old value to 0 first,
-        # this should be done in core-admin.
-        # TODO: ben: use dom0 feature 'preload-dispvm-max'
+        # TODO: ben: if changing default_dispvm, call the
+        # 'preload-dispvm-start' event for the old qube to update according
+        # to the disposable template 'preload-dispvm-max' feature. This
+        # should be done in core-admin.
         self.is_dvm_template = is_dvm_template
         self.preload_dispvm_adjustment = Gtk.Adjustment()
         self.preload_dispvm_adjustment.configure(0, 0, 50, 1, 10, 0)
@@ -265,9 +266,9 @@ def save(self):
         """Save changes: update system value and mark it as new initial value"""
         if not self.is_changed():
             return
-        if not (qube := self.get_dependent_value()):
+        if not self.get_dependent_value():
             return
-        self.qapp.domains[qube].features["preload-dispvm-max"] = int(
+        self.qapp.domains["dom0"].features["preload-dispvm-max"] = int(
             self.widget.get_value()
         )
 
@@ -294,11 +295,11 @@ def get_unsaved(self):
 
     def get_current_value(self):
         """This should never be called."""
-        if not (qube := self.get_dependent_value()):
+        if not self.get_dependent_value():
             return 0
-        if self.is_dvm_template:
+        if not self.is_dvm_template:
             return 0
-        return int(self.qapp.domains[qube].features.get("preload-dispvm-max", 0) or 0)
+        return int(self.qapp.domains["dom0"].features.get("preload-dispvm-max")) or 0
 
     def update_current_value(self):
         """This should never be called."""

qubes_config/tests/test_basics_handler.py

@@ -364,4 +364,7 @@ def test_basics_handler(real_builder, test_qapp):
     test_qapp.expected_calls[
         ("dom0", "admin.property.Set", "clockvm", b"test-blue")
     ] = b"0\x00"
+    test_qapp.expected_calls[
+        ("dom0", "admin.vm.feature.Get", "preload-dispvm-max", None)
+    ] = b"0\x00"
     basics_handler.save()