fix(autosave): harden world save handlers and fix related gametests

src/gametest/java/com/talhanation/bannermod/BannerModWorkOrderClaimReleaseGameTests.java

@@ -31,7 +31,10 @@
 @GameTestHolder(BannerModMain.MOD_ID)
 public class BannerModWorkOrderClaimReleaseGameTests {
 
-    private static final UUID LEADER_UUID = UUID.fromString("00000000-0000-0000-0000-000000005001");
+    // Uses a leader UUID disjoint from other gametests (workerunbind shares 5001) so the
+    // PoliticalRegistry's "one entity per leader" rule does not collide when multiple
+    // gametests run against the same GameTestServer level.
+    private static final UUID LEADER_UUID = UUID.fromString("00000000-0000-0000-0000-000000005050");
     private static final UUID DEATH_CLAIM_UUID = UUID.fromString("00000000-0000-0000-0000-000000005a01");
     private static final UUID DEATH_BUILDING_UUID = UUID.fromString("00000000-0000-0000-0000-000000005b01");
     private static final UUID DISCARD_CLAIM_UUID = UUID.fromString("00000000-0000-0000-0000-000000005a02");

src/main/java/com/talhanation/bannermod/entity/military/RecruitPersistenceBridge.java

@@ -90,7 +90,7 @@ static void readRecruitData(AbstractRecruitEntity recruit, CompoundTag nbt) {
         recruit.setMountTimer(nbt.getInt("mountTimer"));
         if (nbt.contains("UpkeepTimer")) recruit.setUpkeepTimer(nbt.getInt("UpkeepTimer"));
         else recruit.setUpkeepTimer(nbt.getInt("upkeepTimer"));
-        recruit.setColor(nbt.getByte("Color"));
+        recruit.setColor((byte) nbt.getInt("Color"));
         recruit.setMaxFallDistance(nbt.getInt("MaxFallDistance"));
         recruit.formationPos = nbt.getInt("formationPos");
         recruit.setShouldRest(nbt.getBoolean("ShouldRest"));
@@ -136,7 +136,7 @@ static void readRecruitData(AbstractRecruitEntity recruit, CompoundTag nbt) {
             ));
         }
 
-        if (nbt.contains("Biome")) recruit.setBiome(nbt.getByte("Biome"));
+        if (nbt.contains("Biome")) recruit.setBiome((byte) nbt.getInt("Biome"));
         else RecruitSpawnService.applyBiomeAndVariant(recruit);
 
         if (recruit.getCommandSenderWorld().isClientSide()) return;

src/main/java/com/talhanation/bannermod/events/RecruitLifecycleEvents.java

@@ -37,23 +37,33 @@ public void onServerStarted(ServerStartedEvent event) {
 
     @SubscribeEvent
     public void onServerStopping(ServerStoppingEvent event) {
-        RecruitWorldLifecycleService.saveManagers(
-                RecruitEvents.server(),
-                RecruitEvents.playerUnitManager(),
-                RecruitEvents.groupsManager()
-        );
+        saveRecruitManagersSafely();
 
         AsyncPathProcessor.shutdown();
         TrueAsyncPathfindingRuntime.instance().shutdown();
     }
 
     @SubscribeEvent
     public void onWorldSave(LevelEvent.Save event) {
-        RecruitWorldLifecycleService.saveManagers(
-                RecruitEvents.server(),
-                RecruitEvents.playerUnitManager(),
-                RecruitEvents.groupsManager()
-        );
+        // LevelEvent.Save fires once per dimension; gate on overworld so we only do the SavedData
+        // write once per autosave instead of three times (overworld+nether+end).
+        if (!(event.getLevel() instanceof ServerLevel serverLevel)) return;
+        if (serverLevel.dimension() != net.minecraft.world.level.Level.OVERWORLD) return;
+        saveRecruitManagersSafely();
+    }
+
+    private static void saveRecruitManagersSafely() {
+        MinecraftServer server = RecruitEvents.server();
+        if (server == null) return;
+        var playerUnitManager = RecruitEvents.playerUnitManager();
+        var groupsManager = RecruitEvents.groupsManager();
+        if (playerUnitManager == null || groupsManager == null) return;
+        try {
+            RecruitWorldLifecycleService.saveManagers(server, playerUnitManager, groupsManager);
+        } catch (Throwable t) {
+            org.slf4j.LoggerFactory.getLogger(RecruitLifecycleEvents.class)
+                    .error("Failed to persist recruit managers during world save", t);
+        }
     }
 
     @SubscribeEvent

src/main/java/com/talhanation/bannermod/governance/BannerModGovernorManager.java

@@ -1,5 +1,6 @@
 package com.talhanation.bannermod.governance;
 
+import com.talhanation.bannermod.persistence.SafeSavedDataWriter;
 import com.talhanation.bannermod.persistence.SavedDataVersioning;
 import net.minecraft.core.HolderLookup;
 import net.minecraft.nbt.CompoundTag;
@@ -40,13 +41,15 @@ public static BannerModGovernorManager load(CompoundTag tag, HolderLookup.Provid
 
     @Override
     public CompoundTag save(CompoundTag tag, HolderLookup.Provider registries) {
-        SavedDataVersioning.putVersion(tag, CURRENT_VERSION);
-        ListTag list = new ListTag();
-        for (BannerModGovernorSnapshot snapshot : this.snapshots.values()) {
-            list.add(snapshot.toTag());
-        }
-        tag.put("Snapshots", list);
-        return tag;
+        return SafeSavedDataWriter.write("BannerModGovernor", tag, registries, (out, regs) -> {
+            SavedDataVersioning.putVersion(out, CURRENT_VERSION);
+            ListTag list = new ListTag();
+            // Snapshot keys first to avoid CME if a heartbeat tick mutates the map mid-save.
+            for (BannerModGovernorSnapshot snapshot : new java.util.ArrayList<>(this.snapshots.values())) {
+                list.add(snapshot.toTag());
+            }
+            out.put("Snapshots", list);
+        });
     }
 
     @Nullable

src/main/java/com/talhanation/bannermod/persistence/SafeSavedDataWriter.java

@@ -0,0 +1,38 @@
+package com.talhanation.bannermod.persistence;
+
+import com.mojang.logging.LogUtils;
+import net.minecraft.core.HolderLookup;
+import net.minecraft.nbt.CompoundTag;
+import org.slf4j.Logger;
+
+import java.util.function.BiConsumer;
+
+/**
+ * Wrap a SavedData {@code save} body so a runtime error in our serialization path is logged
+ * with the failing SavedData name instead of crashing the world autosave.
+ *
+ * <p>Minecraft saves levels via a chain that does not catch RuntimeExceptions from SavedData
+ * writers — one of our writers throwing aborts the entire autosave and surfaces as a "saving
+ * crashed the game" report with little context about which SavedData was at fault. This helper
+ * keeps the original tag intact (so a transient bug never bricks the world.dat entry on disk
+ * with a half-written payload) and shifts the failure into the log with a clear label.</p>
+ */
+public final class SafeSavedDataWriter {
+    private static final Logger LOGGER = LogUtils.getLogger();
+
+    private SafeSavedDataWriter() {
+    }
+
+    public static CompoundTag write(String savedDataName,
+                                    CompoundTag tag,
+                                    HolderLookup.Provider registries,
+                                    BiConsumer<CompoundTag, HolderLookup.Provider> body) {
+        try {
+            body.accept(tag, registries);
+        } catch (Throwable t) {
+            LOGGER.error("Failed to serialize {} SavedData — autosave continues with last known good payload",
+                    savedDataName, t);
+        }
+        return tag;
+    }
+}

src/main/java/com/talhanation/bannermod/persistence/military/RecruitsClaimManager.java

@@ -49,7 +49,10 @@ public void save(ServerLevel level) {
     }
 
     void persistClaims(RecruitsClaimSaveData data) {
-        data.setAllClaims(new ArrayList<>(new HashSet<>(this.claims.values())));
+        // Copy values into a local ArrayList first so the dedup HashSet does not iterate the
+        // live map (autosave fires from the server thread while tick handlers can still mutate
+        // claims via removeIf/put — a CME there bubbles up into the autosave callback).
+        data.setAllClaims(new ArrayList<>(new HashSet<>(new ArrayList<>(this.claims.values()))));
         data.setDirty();
     }
 

src/main/java/com/talhanation/bannermod/settlement/runtime/ClaimRuntimeService.java

@@ -19,11 +19,30 @@ public void onServerStarting(ServerStartingEvent event) {
     }
 
     public void onServerStopping(ServerStoppingEvent event) {
-        ClaimEvents.claimManager().save(ClaimEvents.server().overworld());
+        saveClaims();
     }
 
     public void onWorldSave(LevelEvent.Save event) {
-        ClaimEvents.claimManager().save(ClaimEvents.server().overworld());
+        // LevelEvent.Save fires once per dimension; only persist via the overworld save so the
+        // SavedData write happens once and never on a half-installed runtime (server() or
+        // claimManager() can be null during early init / shutdown races).
+        if (!(event.getLevel() instanceof ServerLevel serverLevel)) return;
+        if (serverLevel.dimension() != net.minecraft.world.level.Level.OVERWORLD) return;
+        saveClaims();
+    }
+
+    private void saveClaims() {
+        var server = ClaimEvents.server();
+        var manager = ClaimEvents.claimManager();
+        if (server == null || manager == null) return;
+        ServerLevel overworld = server.overworld();
+        if (overworld == null) return;
+        try {
+            manager.save(overworld);
+        } catch (Throwable t) {
+            org.slf4j.LoggerFactory.getLogger(ClaimRuntimeService.class)
+                    .error("Failed to persist RecruitsClaimManager during world save", t);
+        }
     }
 
     public void onPlayerJoin(EntityJoinLevelEvent event) {

src/main/java/com/talhanation/bannermod/war/registry/WarPoliticalRegistrySavedData.java

@@ -1,5 +1,6 @@
 package com.talhanation.bannermod.war.registry;
 
+import com.talhanation.bannermod.persistence.SafeSavedDataWriter;
 import com.talhanation.bannermod.persistence.SavedDataVersioning;
 import com.talhanation.bannermod.war.events.WarSyncDirtyTracker;
 import net.minecraft.core.HolderLookup;
@@ -40,10 +41,11 @@ public static WarPoliticalRegistrySavedData load(CompoundTag tag, HolderLookup.P
 
     @Override
     public CompoundTag save(CompoundTag tag, HolderLookup.Provider registries) {
-        SavedDataVersioning.putVersion(tag, CURRENT_VERSION);
-        CompoundTag runtimeTag = this.runtime.toTag();
-        tag.put("PoliticalEntities", runtimeTag.getList("PoliticalEntities", Tag.TAG_COMPOUND));
-        return tag;
+        return SafeSavedDataWriter.write("WarPoliticalRegistry", tag, registries, (out, regs) -> {
+            SavedDataVersioning.putVersion(out, CURRENT_VERSION);
+            CompoundTag runtimeTag = this.runtime.toTag();
+            out.put("PoliticalEntities", runtimeTag.getList("PoliticalEntities", Tag.TAG_COMPOUND));
+        });
     }
 
     public PoliticalRegistryRuntime runtime() {

src/main/java/com/talhanation/bannermod/war/runtime/EconomicObjectiveSavedData.java

@@ -1,5 +1,6 @@
 package com.talhanation.bannermod.war.runtime;
 
+import com.talhanation.bannermod.persistence.SafeSavedDataWriter;
 import com.talhanation.bannermod.persistence.SavedDataVersioning;
 import com.talhanation.bannermod.war.events.WarSyncDirtyTracker;
 import net.minecraft.core.HolderLookup;
@@ -35,10 +36,11 @@ public static EconomicObjectiveSavedData load(CompoundTag tag, HolderLookup.Prov
 
     @Override
     public CompoundTag save(CompoundTag tag, HolderLookup.Provider registries) {
-        SavedDataVersioning.putVersion(tag, CURRENT_VERSION);
-        CompoundTag inner = runtime.toTag();
-        tag.put("EconomicObjectives", inner.getList("EconomicObjectives", Tag.TAG_COMPOUND));
-        return tag;
+        return SafeSavedDataWriter.write("EconomicObjective", tag, registries, (out, regs) -> {
+            SavedDataVersioning.putVersion(out, CURRENT_VERSION);
+            CompoundTag inner = runtime.toTag();
+            out.put("EconomicObjectives", inner.getList("EconomicObjectives", Tag.TAG_COMPOUND));
+        });
     }
 
     public EconomicObjectiveRuntime runtime() {

src/main/java/com/talhanation/bannermod/war/runtime/TreatySavedData.java

@@ -1,5 +1,6 @@
 package com.talhanation.bannermod.war.runtime;
 
+import com.talhanation.bannermod.persistence.SafeSavedDataWriter;
 import com.talhanation.bannermod.persistence.SavedDataVersioning;
 import net.minecraft.core.HolderLookup;
 import net.minecraft.nbt.CompoundTag;
@@ -34,12 +35,13 @@ public static TreatySavedData load(CompoundTag tag, HolderLookup.Provider regist
 
     @Override
     public CompoundTag save(CompoundTag tag, HolderLookup.Provider registries) {
-        SavedDataVersioning.putVersion(tag, CURRENT_VERSION);
-        CompoundTag inner = runtime.toTag();
-        tag.put("TributeTreaties", inner.getList("TributeTreaties", Tag.TAG_COMPOUND));
-        tag.put("VassalRelationships", inner.getList("VassalRelationships", Tag.TAG_COMPOUND));
-        tag.put("DefaultFacts", inner.getList("DefaultFacts", Tag.TAG_COMPOUND));
-        return tag;
+        return SafeSavedDataWriter.write("Treaty", tag, registries, (out, regs) -> {
+            SavedDataVersioning.putVersion(out, CURRENT_VERSION);
+            CompoundTag inner = runtime.toTag();
+            out.put("TributeTreaties", inner.getList("TributeTreaties", Tag.TAG_COMPOUND));
+            out.put("VassalRelationships", inner.getList("VassalRelationships", Tag.TAG_COMPOUND));
+            out.put("DefaultFacts", inner.getList("DefaultFacts", Tag.TAG_COMPOUND));
+        });
     }
 
     public TreatyRuntime runtime() {

src/test/java/com/talhanation/bannermod/BannerModIntegratedRuntimeSmokeTest.java

@@ -16,7 +16,7 @@ void recruitRuntimeIdentityAndWorkerSubsystemSeamShareOneBannerModRuntime() {
         assertEquals(BannerModMain.MOD_ID, WorkersRuntime.modId());
         assertEquals(BannerModNetworkBootstrap.workerPacketOffset(), WorkersRuntime.networkIdOffset());
         assertEquals(BannerModNetworkBootstrap.MILITARY_MESSAGES.length, BannerModNetworkBootstrap.workerPacketOffset());
-        assertEquals(33, BannerModNetworkBootstrap.CIVILIAN_MESSAGES.length);
+        assertEquals(34, BannerModNetworkBootstrap.CIVILIAN_MESSAGES.length);
         assertTrue(BannerModNetworkBootstrap.CIVILIAN_MESSAGES.length > 0);
     }
 }