[Vanilla Fix] Properly remove aircraft, jumpjet and rockets offmap when dead

CREDITS.md

@@ -775,3 +775,4 @@ This page lists all the individual contributions to the project by their author.
   - Wall overlay unit sell exploit fix
   - Multiplayer gamespeed fix for RealTimeTimers
   - Revert Ares patch to allow OpenTopped transport customization
+  - Fix for units with Fly, Jumpjet or Rocket locomotors crashing off-map not being cleaned up

docs/Fixed-or-Improved-Logics.md

@@ -273,6 +273,7 @@ This page describes all ingame logics that are fixed or improved in Phobos witho
 - Fixed the bug that vehicle fall on infantry will make all cell content has been removed.
 - Fixed buildings that have their owner changed during buildup skipping buildup and sometimes not correctly clearing the state.
 - Fixed preplaced aircraft outside visible map being incorrectly flagged as crashing under certain conditions.
+- Fixed units with Fly, Jumpjet or Rocket locomotors destroyed while crashing off-map never being fully cleaned up, permanently blocking production slots and counting towards unit limits.
 - Fixed `MovementZone=Subterannean` harvesters being unable to find docks if in area enclosed by water, cliffs etc.
 - Fixed an issue where some effects pointing to a unit were not properly cleared when the unit changed its owner.
 - Allow Reveal Crate to take effect when picking up by another player controlled house in campaign.

docs/Whats-New.md

@@ -658,6 +658,7 @@ Phobos fixes:
 - Fixed the bug that the upgrade building's power-enhancing effect depends only on its parent building and is not related to the upgrade building itself (by NetsuNegi)
 - Fixed an issue where hover vehicles could not be destroyed after malfunctioning on water surfaces (by FlyStar)
 - Fixed an issue where shadow matrix scaling was incorrectly applied to `TurretOffset` causing turret shadow misplacement (by Noble_Fish)
+- Fixed units with Fly, Jumpjet or Rocket locomotors destroyed while crashing off-map never being fully cleaned up, permanently blocking production slots and counting towards unit limits (by RAZER)
 
 Fixes / interactions with other extensions:
 <!--  - Allowed `AuxBuilding` and Ares' `SW.Aux/NegBuildings` to count building upgrades (by Ollerus)  -->

src/Misc/Hooks.BugFixes.cpp

@@ -2874,6 +2874,63 @@ DEFINE_HOOK(0x4DB874, FootClass_SetLocation_Extra, 0xA)
 	return SkipGameCode;
 }
 
+// Fix crash descent for aircraft/units off-map.
+// In all three locomotors below, MapClass::In_Radar blocks position/coordinate updates
+// when outside the map. This means crashing units off-map never descend to ground level
+// (or reach their destination), so the cleanup code (fire death weapon, UnInit) never runs.
+// The fix: at each locomotor's height/health check, treat off-map as ground-touch.
+// FlyLocomotionClass::Process - height check after crash descent calculation.
+// If off-map and crashing, skip the height > 0 check and go straight to ground-touch cleanup.
+// The IsCrashing guard is needed because healthy non-moving airborne aircraft also reach this
+// code path (Is_Moving()==false && Height>0) and must not be sent to cleanup.
+DEFINE_HOOK(0x4CD797, FlyLocomotionClass_CrashDescent_OffMap, 0x5)
+{
+	enum { GroundTouchCleanup = 0x4CD7AA };
+
+	GET(FlyLocomotionClass*, pThis, ESI);
+
+	const auto pLinkedTo = pThis->LinkedTo;
+
+	if (pLinkedTo->IsCrashing && !MapClass::Instance.IsWithinUsableArea(pLinkedTo->GetCoords()))
+		return GroundTouchCleanup;
+
+	return 0;
+}
+
+// JumpjetLocomotionClass::Process - height check before IsCrashing gate.
+// If off-map, skip height check and go to the IsCrashing check directly.
+DEFINE_HOOK(0x54CC16, JumpjetLocomotionClass_CrashDescent_OffMap, 0x8)
+{
+	enum { IsCrashingCheck = 0x54CC36 };
+
+	GET(JumpjetLocomotionClass*, pThis, EDI);
+
+	if (!MapClass::Instance.IsWithinUsableArea(pThis->LinkedTo->GetCoords()))
+	{
+		// Replicate the stack init from the stolen bytes (mov byte ptr [esp+21h], 0)
+		// so the "fell on something" flag is properly zeroed for the crash path.
+		REF_STACK(BYTE, fellOnSomething, STACK_OFFSET(0x34, -0x13));
+		fellOnSomething = 0;
+		return IsCrashingCheck;
+	}
+
+	return 0;
+}
+
+// RocketLocomotionClass::Process - health check after position update.
+// If off-map, bypass the Health > 0 skip and force detonation/cleanup.
+DEFINE_HOOK(0x662FD5, RocketLocomotionClass_Process_OffMap, 0x6)
+{
+	enum { ForceCleanup = 0x662FDF };
+
+	GET(RocketLocomotionClass*, pThis, EDI);
+
+	if (!MapClass::Instance.IsWithinUsableArea(pThis->LinkedTo->GetCoords()))
+		return ForceCleanup;
+
+	return 0;
+}
+
 DEFINE_HOOK(0x4DEC7F, FootClass_Crash_FallingDownFix, 0x7)
 {
 	GET(FootClass*, pThis, ESI);