Disallow selling ground units.

Ground units should be transferred to a new location, not sold and
repurchased.

https://github.com/Khopa/dcs_liberation/issues/823

changelog.md

@@ -5,6 +5,7 @@ Saves from 2.5 are not compatible with 2.6.
 ## Features/Improvements
 
 * **[Campaign]** Ground units can now be transferred by road. See https://github.com/Khopa/dcs_liberation/wiki/Unit-Transfers for more information.
+* **[Campaign]** Ground units can no longer be sold. To move units to a new location, transfer them.
 
 ## Fixes
 

game/event/event.py

@@ -469,12 +469,15 @@ class UnitsDeliveryEvent:
             logging.info(f"Refunding {count} {unit_type.id} at {self.to_cp.name}")
             game.adjust_budget(price * count, player=self.to_cp.captured)
 
-    def available_next_turn(self, unit_type: Type[UnitType]) -> int:
+    def pending_orders(self, unit_type: Type[UnitType]) -> int:
         pending_units = self.units.get(unit_type)
         if pending_units is None:
             pending_units = 0
+        return pending_units
+
+    def available_next_turn(self, unit_type: Type[UnitType]) -> int:
         current_units = self.to_cp.base.total_units_of_type(unit_type)
-        return pending_units + current_units
+        return self.pending_orders(unit_type) + current_units
 
     def process(self, game: Game) -> None:
         bought_units: Dict[Type[UnitType], int] = {}

qt_ui/windows/basemenu/ground_forces/QArmorRecruitmentMenu.py

@@ -1,3 +1,5 @@
+from typing import Type
+
 from PySide2.QtCore import Qt
 from PySide2.QtWidgets import (
     QFrame,
@@ -65,13 +67,13 @@ class QArmorRecruitmentMenu(QFrame, QRecruitBehaviour):
         main_layout.addWidget(scroll)
         self.setLayout(main_layout)
 
-    def sell(self, unit_type: UnitType):
-        if self.pending_deliveries.available_next_turn(unit_type) <= 0:
+    def sell(self, unit_type: Type[UnitType]) -> None:
+        if self.pending_deliveries.pending_orders(unit_type) <= 0:
             QMessageBox.critical(
                 self,
                 "Could not sell ground unit",
-                f"Attempted to sell one {unit_type.id} at {self.cp.name} "
-                "but none are available.",
+                f"Attempted to cancel order of one {unit_type.id} at {self.cp.name} "
+                "but no orders are pending.",
                 QMessageBox.Ok,
             )
             return