Fix render fire clock progress turning into silo build progress after unit ownership transfer

changelog/snippets/fix.7051.md

@@ -0,0 +1 @@
+- (#7051) Fix a unit-transfer exploit that adds silo progress to nuke subs and the Seraphim battleship for free.

engine/Core/Blueprints/WeaponBlueprint.lua

@@ -280,7 +280,9 @@
 ---@field RateOfFire number
 --- if this weapon will find new target on miss events
 ---@field ReTargetOnMiss? boolean
---- if `true`, will set the orange work progress bar to display the reload progress of this weapon
+--- if `true`, will set the orange work progress bar to display the reload progress of this weapon.
+--- Should not be used for units with silo weapons, as the work progress of the reload will transfer
+--- as silo build progress after unit transfer.
 ---@field RenderFireClock? boolean
 --- used by the XSL0402 (Othuy "lighting storm") to define the time to re-aquire a new target before going
 --- through the next lighting strike process

lua/SimUtils.lua

@@ -289,7 +289,7 @@ function TransferUnitsOwnership(units, toArmy, captured, noRestrictions)
 
         -- B E F O R E
         local orientation = unit:GetOrientation()
-        local workprogress = unit:GetWorkProgress()
+        local siloWorkProgress = unit:IsUnitState("SiloBuildingAmmo") and unit:GetWorkProgress() or 0
         local numNukes = unit:GetNukeSiloAmmoCount() -- nuclear missiles; SML or SMD
         local numTacMsl = unit:GetTacticalSiloAmmoCount()
         local massKilled = unit.VetExperience
@@ -448,7 +448,7 @@ function TransferUnitsOwnership(units, toArmy, captured, noRestrictions)
         end
 
         if newUnit.Blueprint.CategoriesHash["SILO"] then
-            newUnit:GiveNukeSiloBlocks(workprogress)
+            newUnit:GiveNukeSiloBlocks(siloWorkProgress)
         end
 
         local newShield = newUnit.MyShield

lua/sim/Unit.lua

@@ -2556,6 +2556,11 @@ Unit = ClassUnit(moho.unit_methods, IntelComponent, VeterancyComponent, DebugUni
         self.SiloWeapon = weapon
         self.SiloProjectile = weapon:GetProjectileBlueprint()
 
+        -- Prevent work progress set by weapons using `RenderFireClock` from
+        -- turning into silo progress after ownership transfer of a unit paused
+        -- in the silo build state without having updated progress by the engine.
+        self:SetWorkProgress(0)
+
         -- for AI events
         self.Brain:OnUnitSiloBuildStart(self, weapon)
     end,

lua/sim/weapons/DefaultProjectileWeapon.lua

@@ -935,10 +935,14 @@ DefaultProjectileWeapon = ClassWeapon(Weapon) {
             local unit = self.unit
             local clockTime = math.round(10 * rateOfFire)
             local totalTime = clockTime
-            while clockTime >= 0 and
-                not self:BeenDestroyed() and
-                not unit.Dead do
-                unit:SetWorkProgress(1 - clockTime / totalTime)
+            while clockTime >= 0
+                and not self:BeenDestroyed()
+                and not unit.Dead
+            do
+                -- do not override work progress that is used for replenishing silo ammo upon unit transfer
+                if not unit:IsUnitState("SiloBuildingAmmo") then
+                    unit:SetWorkProgress(1 - clockTime / totalTime)
+                end
                 clockTime = clockTime - 1
                 WaitSeconds(0.1)
             end