Depopulate captured objectives.

Buildings are left to be captured, but the retreating coalition now
destroys their abandoned equipment.

Fixes https://github.com/dcs-liberation/dcs_liberation/issues/1158

changelog.md

@@ -9,6 +9,7 @@ Saves from 2.5 are not compatible with 3.0.
 * **[Campaign]** Ground units must now be recruited at a base with a factory and transferred to their destination. When buying units in the UI, the purchase will automatically be fulfilled at the closest factory, and a transfer will be created on the next turn.
 * **[Campaign]** Non-control point FOBs will no longer spawn.
 * **[Campaign]** Added squadrons and pilots. See https://github.com/dcs-liberation/dcs_liberation/wiki/Squadrons-and-pilots for more information.
+* **[Campaign]** Capturing a base now depopulates all of its attached objectives with units: air defenses, EWRs, ships, armor groups, etc. Buildings are captured.
 * **[Campaign AI]** AI now considers Ju-88s for CAS, strike, and DEAD missions.
 * **[Campaign AI]** AI planned AEW&C missions will now be scheduled ASAP.
 * **[Campaign AI]** AI now considers the range to the SAM's threat zone rather than the range to the SAM itself when determining target priorities.

game/theater/controlpoint.py

@@ -554,11 +554,17 @@ class ControlPoint(MissionTarget, ABC):
             airframe, count = self.base.aircraft.popitem()
             self._retreat_air_units(game, airframe, count)
 
+    def depopulate_uncapturable_tgos(self) -> None:
+        for tgo in self.connected_objectives:
+            if not tgo.capturable:
+                tgo.clear()
+
     # TODO: Should be Airbase specific.
     def capture(self, game: Game, for_player: bool) -> None:
         self.pending_unit_deliveries.refund_all(game)
         self.retreat_ground_units(game)
         self.retreat_air_units(game)
+        self.depopulate_uncapturable_tgos()
 
         if for_player:
             self.captured = True

game/theater/theatergroundobject.py

@@ -190,6 +190,13 @@ class TheaterGroundObject(MissionTarget):
     def strike_targets(self) -> List[Union[MissionTarget, Unit]]:
         return self.units
 
+    def clear(self) -> None:
+        self.groups = []
+
+    @property
+    def capturable(self) -> bool:
+        raise NotImplementedError
+
 
 class BuildingGroundObject(TheaterGroundObject):
     def __init__(
@@ -251,6 +258,10 @@ class BuildingGroundObject(TheaterGroundObject):
     def is_control_point(self) -> bool:
         return self.is_fob_structure
 
+    @property
+    def capturable(self) -> bool:
+        return True
+
 
 class SceneryGroundObject(BuildingGroundObject):
     def __init__(
@@ -322,6 +333,10 @@ class NavalGroundObject(TheaterGroundObject):
     def might_have_aa(self) -> bool:
         return True
 
+    @property
+    def capturable(self) -> bool:
+        return False
+
 
 class GenericCarrierGroundObject(NavalGroundObject):
     @property
@@ -386,6 +401,10 @@ class MissileSiteGroundObject(TheaterGroundObject):
             sea_object=False,
         )
 
+    @property
+    def capturable(self) -> bool:
+        return False
+
 
 class CoastalSiteGroundObject(TheaterGroundObject):
     def __init__(
@@ -407,6 +426,10 @@ class CoastalSiteGroundObject(TheaterGroundObject):
             sea_object=False,
         )
 
+    @property
+    def capturable(self) -> bool:
+        return False
+
 
 # TODO: Differentiate types.
 # This type gets used both for AA sites (SAM, AAA, or SHORAD). These should each
@@ -486,6 +509,10 @@ class SamGroundObject(TheaterGroundObject):
         else:
             return max(max_tel_range, max_telar_range, max_non_radar)
 
+    @property
+    def capturable(self) -> bool:
+        return False
+
 
 class VehicleGroupGroundObject(TheaterGroundObject):
     def __init__(
@@ -506,6 +533,10 @@ class VehicleGroupGroundObject(TheaterGroundObject):
             sea_object=False,
         )
 
+    @property
+    def capturable(self) -> bool:
+        return False
+
 
 class EwrGroundObject(TheaterGroundObject):
     def __init__(
@@ -542,6 +573,10 @@ class EwrGroundObject(TheaterGroundObject):
     def might_have_aa(self) -> bool:
         return True
 
+    @property
+    def capturable(self) -> bool:
+        return False
+
 
 class ShipGroundObject(NavalGroundObject):
     def __init__(