From 0e4be8c7768fb3fe1a7baaa0fe0a30895b65d9b3 Mon Sep 17 00:00:00 2001
From: Ivan Savenko <saven.ivan@gmail.com>
Date: Wed, 19 Jun 2024 18:25:07 +0000
Subject: [PATCH] Fix crash on sieging Citadel or Castle

---
 AI/BattleAI/BattleExchangeVariant.cpp | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/AI/BattleAI/BattleExchangeVariant.cpp b/AI/BattleAI/BattleExchangeVariant.cpp
index 29ed104ea..1f83b58e8 100644
--- a/AI/BattleAI/BattleExchangeVariant.cpp
+++ b/AI/BattleAI/BattleExchangeVariant.cpp
@@ -621,6 +621,9 @@ BattleScore BattleExchangeEvaluator::calculateExchange(
 						if(!exchangeBattle->getForUpdate(u->unitId())->alive())
 							return false;
 
+						if (!u->getPosition().isValid())
+							return false; // e.g. tower shooters
+
 						return vstd::contains_if(reachabilityMap.at(u->getPosition()), [&attacker](const battle::Unit * other) -> bool
 							{
 								return attacker->unitId() == other->unitId();