fix Harmony issue when assembly is loaded from memory (#711)

3 files changed, 42 insertions, 4 deletions

diff --git a/src/SMAPI/Constants.cs b/src/SMAPI/Constants.cs
index a898fccd..907a93b2 100644
--- a/src/SMAPI/Constants.cs
+++ b/src/SMAPI/Constants.cs
@@ -61,6 +61,9 @@ namespace StardewModdingAPI
         /// <summary>The absolute path to the folder containing SMAPI's internal files.</summary>
         internal static readonly string InternalFilesPath = Program.DllSearchPath;
 
+        /// <summary>The folder containing temporary files that are only valid for the current session.</summary>
+        internal static string InternalTempFilesPath => Path.Combine(Program.DllSearchPath, ".temp");
+
         /// <summary>The file path for the SMAPI configuration file.</summary>
         internal static string ApiConfigPath => Path.Combine(Constants.InternalFilesPath, "config.json");
 
diff --git a/src/SMAPI/Framework/ModLoading/AssemblyLoader.cs b/src/SMAPI/Framework/ModLoading/AssemblyLoader.cs
index 570686fe..78e717e9 100644
--- a/src/SMAPI/Framework/ModLoading/AssemblyLoader.cs
+++ b/src/SMAPI/Framework/ModLoading/AssemblyLoader.cs
@@ -36,6 +36,9 @@ namespace StardewModdingAPI.Framework.ModLoading
         /// <summary>The objects to dispose as part of this instance.</summary>
         private readonly HashSet<IDisposable> Disposables = new HashSet<IDisposable>();
 
+        /// <summary>The full path to the folder in which to save rewritten assemblies.</summary>
+        private readonly string TempFolderPath;
+
 
         /*********
         ** Public methods
@@ -44,11 +47,15 @@ namespace StardewModdingAPI.Framework.ModLoading
         /// <param name="targetPlatform">The current game platform.</param>
         /// <param name="monitor">Encapsulates monitoring and logging.</param>
         /// <param name="paranoidMode">Whether to detect paranoid mode issues.</param>
-        public AssemblyLoader(Platform targetPlatform, IMonitor monitor, bool paranoidMode)
+        /// <param name="tempFolderPath">The full path to the folder in which to save rewritten assemblies.</param>
+        public AssemblyLoader(Platform targetPlatform, IMonitor monitor, bool paranoidMode, string tempFolderPath)
         {
             this.Monitor = monitor;
             this.ParanoidMode = paranoidMode;
             this.AssemblyMap = this.TrackForDisposal(Constants.GetAssemblyMap(targetPlatform));
+            this.TempFolderPath = tempFolderPath;
+
+            // init resolver
             this.AssemblyDefinitionResolver = this.TrackForDisposal(new AssemblyDefinitionResolver());
             this.AssemblyDefinitionResolver.AddSearchDirectory(Constants.ExecutionPath);
             this.AssemblyDefinitionResolver.AddSearchDirectory(Constants.InternalFilesPath);
@@ -124,9 +131,23 @@ namespace StardewModdingAPI.Framework.ModLoading
                 if (changed)
                 {
                     if (!oneAssembly)
-                        this.Monitor.Log($"      Loading {assembly.File.Name} (rewritten in memory)...", LogLevel.Trace);
-                    using (MemoryStream outStream = new MemoryStream())
+                        this.Monitor.Log($"      Loading {assembly.File.Name} (rewritten)...", LogLevel.Trace);
+
+                    if (assembly.Definition.MainModule.AssemblyReferences.Any(p => p.Name == "0Harmony"))
+                    {
+                        // Note: the assembly must be loaded from disk for Harmony compatibility.
+                        // Loading it from memory sets the assembly module's FullyQualifiedName to
+                        // "<Unknown>", so Harmony incorrectly identifies the module in its
+                        // Patch.PatchMethod when handling multiple patches for the same method,
+                        // leading to "Token 0x... is not valid in the scope of module HarmonySharedState"
+                        // errors (e.g. https://smapi.io/log/A0gAsc3M).
+                        string tempPath = Path.Combine(this.TempFolderPath, $"{Path.GetFileNameWithoutExtension(assemblyPath)}.{Guid.NewGuid()}.dll");
+                        assembly.Definition.Write(tempPath);
+                        lastAssembly = Assembly.LoadFile(tempPath);
+                    }
+                    else
                     {
+                        using MemoryStream outStream = new MemoryStream();
                         assembly.Definition.Write(outStream);
                         byte[] bytes = outStream.ToArray();
                         lastAssembly = Assembly.Load(bytes);
diff --git a/src/SMAPI/Framework/SCore.cs b/src/SMAPI/Framework/SCore.cs
index de9c955d..12dc9c3d 100644
--- a/src/SMAPI/Framework/SCore.cs
+++ b/src/SMAPI/Framework/SCore.cs
@@ -213,6 +213,20 @@ namespace StardewModdingAPI.Framework
                 return;
             }
 #endif
+
+            // reset temp folder
+            if (Directory.Exists(Constants.InternalTempFilesPath))
+            {
+                try
+                {
+                    FileUtilities.ForceDelete(new DirectoryInfo(Constants.InternalTempFilesPath));
+                }
+                catch (Exception ex)
+                {
+                    this.Monitor.Log($"Couldn't delete temporary files at {Constants.InternalTempFilesPath}: {ex}", LogLevel.Trace);
+                }
+            }
+            Directory.CreateDirectory(Constants.InternalTempFilesPath);
         }
 
         /// <summary>Launch SMAPI.</summary>
@@ -748,7 +762,7 @@ namespace StardewModdingAPI.Framework
 
             // load mods
             IDictionary<IModMetadata, Tuple<string, string>> skippedMods = new Dictionary<IModMetadata, Tuple<string, string>>();
-            using (AssemblyLoader modAssemblyLoader = new AssemblyLoader(Constants.Platform, this.Monitor, this.Settings.ParanoidWarnings))
+            using (AssemblyLoader modAssemblyLoader = new AssemblyLoader(Constants.Platform, this.Monitor, this.Settings.ParanoidWarnings, Constants.InternalTempFilesPath))
             {
                 // init
                 HashSet<string> suppressUpdateChecks = new HashSet<string>(this.Settings.SuppressUpdateChecks, StringComparer.InvariantCultureIgnoreCase);