Reduce squadron location bookkeeping.

game/squadrons/airwing.py

@@ -19,7 +19,6 @@ class AirWing:
         self.squadrons: dict[AircraftType, list[Squadron]] = defaultdict(list)
 
     def add_squadron(self, squadron: Squadron) -> None:
-        squadron.location.squadrons.append(squadron)
         self.squadrons[squadron.aircraft].append(squadron)
 
     def squadrons_for(self, aircraft: AircraftType) -> Sequence[Squadron]:

game/squadrons/squadron.py

@@ -82,9 +82,7 @@ class Squadron:
         return self.coalition.player
 
     def assign_to_base(self, base: ControlPoint) -> None:
-        self.location.squadrons.remove(self)
         self.location = base
-        self.location.squadrons.append(self)
         logging.debug(f"Assigned {self} to {base}")
 
     @property

game/theater/controlpoint.py

@@ -325,8 +325,6 @@ class ControlPoint(MissionTarget, ABC):
 
         self.target_position: Optional[Point] = None
 
-        self.squadrons: list[Squadron] = []
-
     def __repr__(self) -> str:
         return f"<{self.__class__}: {self.name}>"
 
@@ -348,6 +346,12 @@ class ControlPoint(MissionTarget, ABC):
     def ground_objects(self) -> List[TheaterGroundObject[Any]]:
         return list(self.connected_objectives)
 
+    @property
+    def squadrons(self) -> Iterator[Squadron]:
+        for squadron in self.coalition.air_wing.iter_squadrons():
+            if squadron.location == self:
+                yield squadron
+
     @property
     @abstractmethod
     def heading(self) -> Heading: