Recompute fire-cleared map hash (#8768)

src/main/cpp/net/eagle0/shardok/ai/AIWaterCrossingCalculator.cpp

@@ -55,7 +55,7 @@ auto UnitIdsRequiringWaterCrossing(
                 .mutate_present(false);
     }
 
-    const auto mapId = ActionPointDistancesCache::GetMapId(mapCopy);
+    const auto mapId = RecomputeModifierHash(mapCopy.Get());
 
     vector<UnitId> unitIdsToReturn{};
 

src/test/cpp/net/eagle0/shardok/ai/AIWaterCrossingCalculator_test.cpp

@@ -19,6 +19,7 @@ class AIWaterCrossingCalculatorTest : public ::testing::Test {
         InitializeGameSettings();
 
         apdCache = std::make_shared<ActionPointDistancesCache>();
+        ActionPointDistancesCache::ClearThreadLocalCache();
 
         heavyCavalry = GetGameSettingsGetter().GetBattalionType(
                 net::eagle0::shardok::storage::fb::BattalionTypeId_HEAVY_CAVALRY);
@@ -148,6 +149,36 @@ TEST_F(AIWaterCrossingCalculatorTest, UnitsRequiringWaterCrossing_oneOtherSide_r
                     }));
 }
 
+TEST_F(AIWaterCrossingCalculatorTest,
+       UnitsRequiringWaterCrossing_fireChanges_reusesFireClearedDistances) {
+    CoordsSet destinations(hexMap);
+    destinations.Add(acrossDestination);
+    const auto battalionTypeGetter = [](BattalionTypeId typeId) {
+        return GetGameSettings()->GetGetter().GetBattalionType(typeId);
+    };
+
+    const auto beforeFire = UnitIdsRequiringWaterCrossing(
+            gameState,
+            0,
+            destinations,
+            apdCache,
+            battalionTypeGetter);
+    EXPECT_EQ(1, ActionPointDistancesCache::GetThreadLocalCacheSize());
+
+    MutableTerrain(hexMap, Coords(0, 0))->mutable_modifier().mutable_fire().mutate_present(true);
+    hexMap->mutate_modifier_hash(0);
+    hexMap->mutate_modifier_hash(ActionPointDistancesCache::GetMapId(hexMap).modifierId);
+
+    const auto afterFire = UnitIdsRequiringWaterCrossing(
+            gameState,
+            0,
+            destinations,
+            apdCache,
+            battalionTypeGetter);
+    EXPECT_EQ(beforeFire, afterFire);
+    EXPECT_EQ(1, ActionPointDistancesCache::GetThreadLocalCacheSize());
+}
+
 TEST_F(AIWaterCrossingCalculatorTest, CanReach_sameSide_returnsTrue) {
     EXPECT_TRUE(CanReach(origin, sameSideDestination, hexMap, mapId, apdCache, heavyCavalry));
 }