1 files changed, 142 insertions, 0 deletions
diff --git a/src/SMAPI.Mods.ErrorHandler/Patches/SaveGamePatcher.cs b/src/SMAPI.Mods.ErrorHandler/Patches/SaveGamePatcher.cs
new file mode 100644
index 00000000..ef165831
--- /dev/null
+++ b/src/SMAPI.Mods.ErrorHandler/Patches/SaveGamePatcher.cs
@@ -0,0 +1,142 @@
+using System;
+using System.Collections.Generic;
+using System.Diagnostics.CodeAnalysis;
+using System.Linq;
+using HarmonyLib;
+using Microsoft.Xna.Framework.Content;
+using StardewModdingAPI.Framework.Patching;
+using StardewValley;
+using StardewValley.Buildings;
+using StardewValley.Locations;
+
+namespace StardewModdingAPI.Mods.ErrorHandler.Patches
+{
+    /// <summary>A Harmony patch for <see cref="SaveGame"/> which prevents some errors due to broken save data.</summary>
+    /// <remarks>Patch methods must be static for Harmony to work correctly. See the Harmony documentation before renaming patch arguments.</remarks>
+    [SuppressMessage("ReSharper", "InconsistentNaming", Justification = "Argument names are defined by Harmony and methods are named for clarity.")]
+    [SuppressMessage("ReSharper", "IdentifierTypo", Justification = "Argument names are defined by Harmony and methods are named for clarity.")]
+    internal class SaveGamePatcher : IHarmonyPatch
+    {
+        /*********
+        ** Fields
+        *********/
+        /// <summary>Writes messages to the console and log file.</summary>
+        private static IMonitor Monitor;
+
+        /// <summary>A callback invoked when custom content is removed from the save data to avoid a crash.</summary>
+        private static Action OnContentRemoved;
+
+
+        /*********
+        ** Public methods
+        *********/
+        /// <summary>Construct an instance.</summary>
+        /// <param name="monitor">Writes messages to the console and log file.</param>
+        /// <param name="onContentRemoved">A callback invoked when custom content is removed from the save data to avoid a crash.</param>
+        public SaveGamePatcher(IMonitor monitor, Action onContentRemoved)
+        {
+            SaveGamePatcher.Monitor = monitor;
+            SaveGamePatcher.OnContentRemoved = onContentRemoved;
+        }
+
+
+        /// <inheritdoc />
+        public void Apply(Harmony harmony)
+        {
+            harmony.Patch(
+                original: AccessTools.Method(typeof(SaveGame), nameof(SaveGame.loadDataToLocations)),
+                prefix: new HarmonyMethod(this.GetType(), nameof(SaveGamePatcher.Before_SaveGame_LoadDataToLocations))
+            );
+        }
+
+
+        /*********
+        ** Private methods
+        *********/
+        /// <summary>The method to call instead of <see cref="SaveGame.loadDataToLocations"/>.</summary>
+        /// <param name="gamelocations">The game locations being loaded.</param>
+        /// <returns>Returns whether to execute the original method.</returns>
+        private static bool Before_SaveGame_LoadDataToLocations(List<GameLocation> gamelocations)
+        {
+            bool removedAny =
+                SaveGamePatcher.RemoveBrokenBuildings(gamelocations)
+                | SaveGamePatcher.RemoveInvalidNpcs(gamelocations);
+
+            if (removedAny)
+                SaveGamePatcher.OnContentRemoved();
+
+            return true;
+        }
+
+        /// <summary>Remove buildings which don't exist in the game data.</summary>
+        /// <param name="locations">The current game locations.</param>
+        private static bool RemoveBrokenBuildings(IEnumerable<GameLocation> locations)
+        {
+            bool removedAny = false;
+
+            foreach (BuildableGameLocation location in locations.OfType<BuildableGameLocation>())
+            {
+                foreach (Building building in location.buildings.ToArray())
+                {
+                    try
+                    {
+                        BluePrint _ = new BluePrint(building.buildingType.Value);
+                    }
+                    catch (ContentLoadException)
+                    {
+                        SaveGamePatcher.Monitor.Log($"Removed invalid building type '{building.buildingType.Value}' in {location.Name} ({building.tileX}, {building.tileY}) to avoid a crash when loading save '{Constants.SaveFolderName}'. (Did you remove a custom building mod?)", LogLevel.Warn);
+                        location.buildings.Remove(building);
+                        removedAny = true;
+                    }
+                }
+            }
+
+            return removedAny;
+        }
+
+        /// <summary>Remove NPCs which don't exist in the game data.</summary>
+        /// <param name="locations">The current game locations.</param>
+        private static bool RemoveInvalidNpcs(IEnumerable<GameLocation> locations)
+        {
+            bool removedAny = false;
+
+            IDictionary<string, string> data = Game1.content.Load<Dictionary<string, string>>("Data\\NPCDispositions");
+            foreach (GameLocation location in SaveGamePatcher.GetAllLocations(locations))
+            {
+                foreach (NPC npc in location.characters.ToArray())
+                {
+                    if (npc.isVillager() && !data.ContainsKey(npc.Name))
+                    {
+                        try
+                        {
+                            npc.reloadSprite(); // this won't crash for special villagers like Bouncer
+                        }
+                        catch
+                        {
+                            SaveGamePatcher.Monitor.Log($"Removed invalid villager '{npc.Name}' in {location.Name} ({npc.getTileLocation()}) to avoid a crash when loading save '{Constants.SaveFolderName}'. (Did you remove a custom NPC mod?)", LogLevel.Warn);
+                            location.characters.Remove(npc);
+                            removedAny = true;
+                        }
+                    }
+                }
+            }
+
+            return removedAny;
+        }
+
+        /// <summary>Get all locations, including building interiors.</summary>
+        /// <param name="locations">The main game locations.</param>
+        private static IEnumerable<GameLocation> GetAllLocations(IEnumerable<GameLocation> locations)
+        {
+            foreach (GameLocation location in locations)
+            {
+                yield return location;
+                if (location is BuildableGameLocation buildableLocation)
+                {
+                    foreach (GameLocation interior in buildableLocation.buildings.Select(p => p.indoors.Value).Where(p => p != null))
+                        yield return interior;
+                }
+            }
+        }
+    }
+}