server/NeonSprawl.Server.Tests/Game/Items/PlayerInventoryOperationsTests.cs

@@ -271,28 +271,6 @@ public sealed class PlayerInventoryOperationsTests
         Assert.Null(outcome.Snapshot);
     }
 
-    [Fact]
-    public void TryAddStack_ForUnknownPlayer_WithInvalidQuantity_ShouldDenyWithReasonCode()
-    {
-        // Arrange
-        using var factory = new InMemoryWebApplicationFactory();
-        var registry = factory.Services.GetRequiredService<IItemDefinitionRegistry>();
-        var store = factory.Services.GetRequiredService<IPlayerInventoryStore>();
-
-        // Act
-        var outcome = PlayerInventoryOperations.TryAddStack(
-            "unknown-player-xyz",
-            "scrap_metal_bulk",
-            quantity: 0,
-            registry,
-            store);
-
-        // Assert
-        Assert.Equal(PlayerInventoryMutationKind.Denied, outcome.Kind);
-        Assert.Equal(PlayerInventoryReasonCodes.InvalidQuantity, outcome.ReasonCode);
-        Assert.Null(outcome.Snapshot);
-    }
-
     private static int CountItem(PlayerInventorySnapshot snapshot, string itemId)
     {
         var total = 0;

server/NeonSprawl.Server/Game/Items/IPlayerInventoryStore.cs

@@ -8,13 +8,4 @@ public interface IPlayerInventoryStore
 
     /// <summary>Atomically replaces the full snapshot for a known player; false when the player is not in the store.</summary>
     bool TryReplaceSnapshot(string playerId, PlayerInventorySnapshot snapshot);
-
-    /// <summary>
-    /// Atomically reads the current snapshot and optionally persists a replacement under per-player lock (in-memory)
-    /// or within one database transaction (Postgres).
-    /// </summary>
-    bool TryMutateSnapshot(
-        string playerId,
-        Func<PlayerInventorySnapshot, PlayerInventoryMutationWrite> mutator,
-        out PlayerInventorySnapshot result);
 }

server/NeonSprawl.Server/Game/Items/InMemoryPlayerInventoryStore.cs

@@ -23,7 +23,7 @@ public sealed class InMemoryPlayerInventoryStore(IOptions<GamePositionOptions> o
     public bool TryGetSnapshot(string playerId, out PlayerInventorySnapshot snapshot)
     {
         var key = NormalizePlayerId(playerId);
-        if (key.Length == 0)
+        if (key.Length == 0 || !byPlayer.TryGetValue(key, out var existing))
         {
             snapshot = PlayerInventorySnapshot.Empty();
             return false;
@@ -31,13 +31,7 @@ public sealed class InMemoryPlayerInventoryStore(IOptions<GamePositionOptions> o
 
         lock (playerLocks.GetOrAdd(key, _ => new object()))
         {
-            if (!byPlayer.TryGetValue(key, out var current))
+            snapshot = Clone(existing);
-            {
-                snapshot = PlayerInventorySnapshot.Empty();
-                return false;
-            }
-
-            snapshot = Clone(current);
             return true;
         }
     }
@@ -46,62 +40,37 @@ public sealed class InMemoryPlayerInventoryStore(IOptions<GamePositionOptions> o
     public bool TryReplaceSnapshot(string playerId, PlayerInventorySnapshot snapshot)
     {
         var key = NormalizePlayerId(playerId);
-        if (key.Length == 0)
+        if (key.Length == 0 || !byPlayer.ContainsKey(key))
         {
             return false;
         }
 
         lock (playerLocks.GetOrAdd(key, _ => new object()))
         {
-            if (!byPlayer.ContainsKey(key))
-            {
-                return false;
-            }
-
             byPlayer[key] = Clone(snapshot);
             return true;
         }
     }
 
-    /// <inheritdoc />
-    public bool TryMutateSnapshot(
-        string playerId,
-        Func<PlayerInventorySnapshot, PlayerInventoryMutationWrite> mutator,
-        out PlayerInventorySnapshot result)
-    {
-        var key = NormalizePlayerId(playerId);
-        if (key.Length == 0)
-        {
-            result = PlayerInventorySnapshot.Empty();
-            return false;
-        }
-
-        lock (playerLocks.GetOrAdd(key, _ => new object()))
-        {
-            if (!byPlayer.TryGetValue(key, out var current))
-            {
-                result = PlayerInventorySnapshot.Empty();
-                return false;
-            }
-
-            var write = mutator(Clone(current));
-            result = Clone(write.Value);
-            if (write.Write)
-            {
-                byPlayer[key] = Clone(write.Value);
-            }
-
-            return true;
-        }
-    }
-
     private static PlayerInventorySnapshot Clone(PlayerInventorySnapshot source) =>
         new()
         {
-            BagSlots = PlayerInventorySnapshot.CloneSlots(source.BagSlots),
+            BagSlots = CloneSlots(source.BagSlots),
-            EquipmentSlots = PlayerInventorySnapshot.CloneSlots(source.EquipmentSlots),
+            EquipmentSlots = CloneSlots(source.EquipmentSlots),
         };
 
+    private static InventorySlotState[] CloneSlots(InventorySlotState[] slots)
+    {
+        var copy = new InventorySlotState[slots.Length];
+        for (var i = 0; i < slots.Length; i++)
+        {
+            var s = slots[i];
+            copy[i] = new InventorySlotState(s.SlotIndex, s.ItemId, s.Quantity);
+        }
+
+        return copy;
+    }
+
     private static string NormalizePlayerId(string? playerId)
     {
         var t = playerId?.Trim();

server/NeonSprawl.Server/Game/Items/PlayerInventoryMutationWrite.cs

@@ -1,5 +0,0 @@
-namespace NeonSprawl.Server.Game.Items;
-
-/// <summary>Result of an atomic inventory transform (NEO-54).</summary>
-/// <param name="Write"><c>true</c> to persist <see cref="Value"/>; <c>false</c> to leave storage unchanged.</param>
-public readonly record struct PlayerInventoryMutationWrite(bool Write, PlayerInventorySnapshot Value);

server/NeonSprawl.Server/Game/Items/PlayerInventoryOperations.cs

@@ -25,36 +25,32 @@ public static class PlayerInventoryOperations
             return Deny(playerId, store, PlayerInventoryReasonCodes.InvalidItem);
         }
 
-        string? denyReason = null;
+        if (!store.TryGetSnapshot(playerId, out var before))
-        if (!store.TryMutateSnapshot(
-                playerId,
-                before =>
         {
+            return new PlayerInventoryMutationOutcome(PlayerInventoryMutationKind.StoreMissing, null, null);
+        }
+
         var container = PlayerInventorySnapshot.ContainerFromSlotKind(def.InventorySlotKind);
-                    var slots = PlayerInventorySnapshot.CloneSlots(before.GetSlots(container));
+        var slots = CloneSlots(before.GetSlots(container));
         var remaining = quantity;
         remaining = MergeIntoExistingStacks(slots, def.Id, remaining, def.StackMax);
         remaining = FillEmptySlots(slots, def.Id, remaining, def.StackMax);
 
         if (remaining > 0)
         {
-                        denyReason = PlayerInventoryReasonCodes.InventoryFull;
+            return new PlayerInventoryMutationOutcome(
-                        return new PlayerInventoryMutationWrite(Write: false, before);
+                PlayerInventoryMutationKind.Denied,
+                PlayerInventoryReasonCodes.InventoryFull,
+                before);
         }
 
-                    return new PlayerInventoryMutationWrite(Write: true, before.WithSlots(container, slots));
+        var after = before.WithSlots(container, slots);
-                },
+        if (!store.TryReplaceSnapshot(playerId, after))
-                out var result))
         {
             return new PlayerInventoryMutationOutcome(PlayerInventoryMutationKind.StoreMissing, null, null);
         }
 
-        if (denyReason is not null)
+        return new PlayerInventoryMutationOutcome(PlayerInventoryMutationKind.Applied, null, after);
-        {
-            return new PlayerInventoryMutationOutcome(PlayerInventoryMutationKind.Denied, denyReason, result);
-        }
-
-        return new PlayerInventoryMutationOutcome(PlayerInventoryMutationKind.Applied, null, result);
     }
 
     /// <summary>Removes <paramref name="quantity"/> from stacks of <paramref name="itemId"/> (lowest slot index first).</summary>
@@ -76,18 +72,20 @@ public static class PlayerInventoryOperations
             return Deny(playerId, store, PlayerInventoryReasonCodes.InvalidItem);
         }
 
-        string? denyReason = null;
+        if (!store.TryGetSnapshot(playerId, out var before))
-        if (!store.TryMutateSnapshot(
-                playerId,
-                before =>
         {
+            return new PlayerInventoryMutationOutcome(PlayerInventoryMutationKind.StoreMissing, null, null);
+        }
+
         var container = PlayerInventorySnapshot.ContainerFromSlotKind(def.InventorySlotKind);
-                    var slots = PlayerInventorySnapshot.CloneSlots(before.GetSlots(container));
+        var slots = CloneSlots(before.GetSlots(container));
         var available = CountQuantity(slots, def.Id);
         if (available < quantity)
         {
-                        denyReason = PlayerInventoryReasonCodes.InsufficientQuantity;
+            return new PlayerInventoryMutationOutcome(
-                        return new PlayerInventoryMutationWrite(Write: false, before);
+                PlayerInventoryMutationKind.Denied,
+                PlayerInventoryReasonCodes.InsufficientQuantity,
+                before);
         }
 
         var remaining = quantity;
@@ -107,29 +105,23 @@ public static class PlayerInventoryOperations
             remaining -= take;
         }
 
-                    return new PlayerInventoryMutationWrite(Write: true, before.WithSlots(container, slots));
+        var after = before.WithSlots(container, slots);
-                },
+        if (!store.TryReplaceSnapshot(playerId, after))
-                out var result))
         {
             return new PlayerInventoryMutationOutcome(PlayerInventoryMutationKind.StoreMissing, null, null);
         }
 
-        if (denyReason is not null)
+        return new PlayerInventoryMutationOutcome(PlayerInventoryMutationKind.Applied, null, after);
-        {
-            return new PlayerInventoryMutationOutcome(PlayerInventoryMutationKind.Denied, denyReason, result);
-        }
-
-        return new PlayerInventoryMutationOutcome(PlayerInventoryMutationKind.Applied, null, result);
     }
 
     private static PlayerInventoryMutationOutcome Deny(string playerId, IPlayerInventoryStore store, string reasonCode)
     {
-        if (store.TryGetSnapshot(playerId, out var snapshot))
+        if (!store.TryGetSnapshot(playerId, out var snapshot))
         {
-            return new PlayerInventoryMutationOutcome(PlayerInventoryMutationKind.Denied, reasonCode, snapshot);
+            return new PlayerInventoryMutationOutcome(PlayerInventoryMutationKind.StoreMissing, null, null);
         }
 
-        return new PlayerInventoryMutationOutcome(PlayerInventoryMutationKind.Denied, reasonCode, null);
+        return new PlayerInventoryMutationOutcome(PlayerInventoryMutationKind.Denied, reasonCode, snapshot);
     }
 
     private static int MergeIntoExistingStacks(InventorySlotState[] slots, string itemId, int remaining, int stackMax)
@@ -186,4 +178,16 @@ public static class PlayerInventoryOperations
 
         return total;
     }
+
+    private static InventorySlotState[] CloneSlots(InventorySlotState[] slots)
+    {
+        var copy = new InventorySlotState[slots.Length];
+        for (var i = 0; i < slots.Length; i++)
+        {
+            var s = slots[i];
+            copy[i] = new InventorySlotState(s.SlotIndex, s.ItemId, s.Quantity);
+        }
+
+        return copy;
+    }
 }

server/NeonSprawl.Server/Game/Items/PlayerInventorySnapshot.cs

@@ -29,18 +29,6 @@ public sealed class PlayerInventorySnapshot
         return slots;
     }
 
-    public static InventorySlotState[] CloneSlots(InventorySlotState[] slots)
-    {
-        var copy = new InventorySlotState[slots.Length];
-        for (var i = 0; i < slots.Length; i++)
-        {
-            var s = slots[i];
-            copy[i] = new InventorySlotState(s.SlotIndex, s.ItemId, s.Quantity);
-        }
-
-        return copy;
-    }
-
     public InventorySlotState[] GetSlots(InventoryContainerKind container) =>
         container == InventoryContainerKind.Equipment ? EquipmentSlots : BagSlots;
 

server/NeonSprawl.Server/Game/Items/PostgresPlayerInventoryStore.cs

@@ -43,63 +43,19 @@ public sealed class PostgresPlayerInventoryStore(Npgsql.NpgsqlDataSource dataSou
             return false;
         }
 
-        ReplaceSnapshotRows(conn, norm, snapshot, tx);
-        tx.Commit();
-        return true;
-    }
-
-    /// <inheritdoc />
-    public bool TryMutateSnapshot(
-        string playerId,
-        Func<PlayerInventorySnapshot, PlayerInventoryMutationWrite> mutator,
-        out PlayerInventorySnapshot result)
-    {
-        var norm = NormalizePlayerId(playerId);
-        if (norm.Length == 0)
-        {
-            result = PlayerInventorySnapshot.Empty();
-            return false;
-        }
-
-        PostgresPlayerInventoryBootstrap.EnsureSchema(dataSource);
-        using var conn = dataSource.OpenConnection();
-        using var tx = conn.BeginTransaction();
-        if (!PlayerExists(conn, norm, tx))
-        {
-            tx.Rollback();
-            result = PlayerInventorySnapshot.Empty();
-            return false;
-        }
-
-        var current = ReadSnapshot(conn, norm, tx);
-        var write = mutator(current);
-        result = write.Value;
-        if (write.Write)
-        {
-            ReplaceSnapshotRows(conn, norm, write.Value, tx);
-        }
-
-        tx.Commit();
-        return true;
-    }
-
-    private static void ReplaceSnapshotRows(
-        Npgsql.NpgsqlConnection conn,
-        string playerIdNormalized,
-        PlayerInventorySnapshot snapshot,
-        Npgsql.NpgsqlTransaction tx)
-    {
         using (var del = new Npgsql.NpgsqlCommand(
                    "DELETE FROM player_inventory WHERE player_id = @pid;",
                    conn,
                    tx))
         {
-            del.Parameters.AddWithValue("pid", playerIdNormalized);
+            del.Parameters.AddWithValue("pid", norm);
             del.ExecuteNonQuery();
         }
 
-        WriteOccupiedSlots(conn, playerIdNormalized, snapshot.BagSlots, InventoryContainerKind.Bag, tx);
+        WriteOccupiedSlots(conn, norm, snapshot.BagSlots, InventoryContainerKind.Bag, tx);
-        WriteOccupiedSlots(conn, playerIdNormalized, snapshot.EquipmentSlots, InventoryContainerKind.Equipment, tx);
+        WriteOccupiedSlots(conn, norm, snapshot.EquipmentSlots, InventoryContainerKind.Equipment, tx);
+        tx.Commit();
+        return true;
     }
 
     private static void WriteOccupiedSlots(
@@ -133,10 +89,7 @@ public sealed class PostgresPlayerInventoryStore(Npgsql.NpgsqlDataSource dataSou
         }
     }
 
-    private static PlayerInventorySnapshot ReadSnapshot(
+    private static PlayerInventorySnapshot ReadSnapshot(Npgsql.NpgsqlConnection conn, string playerIdNormalized)
-        Npgsql.NpgsqlConnection conn,
-        string playerIdNormalized,
-        Npgsql.NpgsqlTransaction? tx = null)
     {
         var bag = PlayerInventorySnapshot.CreateEmptySlots(PlayerInventorySnapshot.BagSlotCount);
         var equipment = PlayerInventorySnapshot.CreateEmptySlots(PlayerInventorySnapshot.EquipmentSlotCount);
@@ -148,8 +101,7 @@ public sealed class PostgresPlayerInventoryStore(Npgsql.NpgsqlDataSource dataSou
             WHERE player_id = @pid
             ORDER BY container_kind, slot_index;
             """,
-            conn,
+            conn);
-            tx);
         cmd.Parameters.AddWithValue("pid", playerIdNormalized);
         using var reader = cmd.ExecuteReader();
         while (reader.Read())