Slim uninstaller copies and enable stub compression (#118)

* Slim uninstaller copies and enable stub compression

* Ensure metadata accompanies slim uninstaller

Author: SuperJMN

src/DotnetPackaging.Exe.Installer/Core/Installer.cs

@@ -20,16 +20,7 @@ private static void RegisterUninstaller(string targetDir, InstallerMetadata meta
             return;
         }
 
-        try
-        {
-            var metadataPath = Path.Combine(targetDir, "metadata.json");
-            var json = JsonSerializer.Serialize(meta);
-            File.WriteAllText(metadataPath, json);
-        }
-        catch
-        {
-            // Best effort
-        }
+        PersistMetadata(targetDir, meta);
 
         // Strategy:
         // 1. Copy full installer as Uninstall.exe to "Uninstall" subdirectory to avoid DLL locks/conflicts with main app
@@ -39,14 +30,20 @@ private static void RegisterUninstaller(string targetDir, InstallerMetadata meta
         {
             var uninstallDir = Path.Combine(targetDir, "Uninstall");
             Directory.CreateDirectory(uninstallDir);
+            PersistMetadata(uninstallDir, meta);
 
             var uninstallerPath = Path.Combine(uninstallDir, "Uninstall.exe");
-            File.Copy(Environment.ProcessPath, uninstallerPath, overwrite: true);
+            var slimUninstallerResult = UninstallerBuilder.CreateSlimCopy(Environment.ProcessPath, uninstallerPath);
+            if (slimUninstallerResult.IsFailure)
+            {
+                Log.Warning("Slim uninstaller creation failed: {Error}. Using full installer copy instead.", slimUninstallerResult.Error);
+                File.Copy(Environment.ProcessPath, uninstallerPath, overwrite: true);
+            }
             Log.Information("Uninstaller copied to: {Path}", uninstallerPath);
-            
+
             WindowsRegistryService.Register(
-                meta.AppId, 
-                meta.ApplicationName, 
+                meta.AppId,
+                meta.ApplicationName,
                 meta.Version, 
                 meta.Vendor, 
                 targetDir, 
@@ -59,6 +56,20 @@ private static void RegisterUninstaller(string targetDir, InstallerMetadata meta
         }
     }
 
+    private static void PersistMetadata(string directory, InstallerMetadata meta)
+    {
+        try
+        {
+            var metadataPath = Path.Combine(directory, "metadata.json");
+            var json = JsonSerializer.Serialize(meta);
+            File.WriteAllText(metadataPath, json);
+        }
+        catch
+        {
+            // Best effort
+        }
+    }
+
     private static Result<string> ResolveMainExe(string targetDir, InstallerMetadata meta)
     {
         return Result.Try(() =>

src/DotnetPackaging.Exe.Installer/Core/UninstallerBuilder.cs

@@ -0,0 +1,55 @@
+using CSharpFunctionalExtensions;
+using Serilog;
+
+namespace DotnetPackaging.Exe.Installer.Core;
+
+internal static class UninstallerBuilder
+{
+    public static Result<string> CreateSlimCopy(string installerPath, string uninstallerPath)
+    {
+        return Result.Try(() =>
+        {
+            var destinationDirectory = Path.GetDirectoryName(uninstallerPath);
+            if (destinationDirectory is null)
+            {
+                throw new InvalidOperationException($"Cannot determine directory for '{uninstallerPath}'.");
+            }
+
+            Directory.CreateDirectory(destinationDirectory);
+
+            var payloadStart = PayloadExtractor.GetAppendedPayloadStart(installerPath);
+            if (payloadStart.HasValue)
+            {
+                CopyWithoutPayload(installerPath, uninstallerPath, payloadStart.Value);
+                Log.Information("Uninstaller written without embedded payload at {Path}", uninstallerPath);
+                return uninstallerPath;
+            }
+
+            File.Copy(installerPath, uninstallerPath, overwrite: true);
+            Log.Information("Embedded payload not found, copied installer to {Path}", uninstallerPath);
+            return uninstallerPath;
+        }, ex => $"Failed to create uninstaller: {ex.Message}");
+    }
+
+    private static void CopyWithoutPayload(string sourcePath, string destinationPath, long bytesToCopy)
+    {
+        using var source = File.OpenRead(sourcePath);
+        using var destination = File.Create(destinationPath);
+
+        var buffer = new byte[81920];
+        var remaining = bytesToCopy;
+
+        while (remaining > 0)
+        {
+            var toRead = (int)Math.Min(buffer.Length, remaining);
+            var read = source.Read(buffer, 0, toRead);
+            if (read == 0)
+            {
+                throw new EndOfStreamException("Unexpected end of file while copying installer payload.");
+            }
+
+            destination.Write(buffer, 0, read);
+            remaining -= read;
+        }
+    }
+}

src/DotnetPackaging.Exe/ExePackagingService.cs

@@ -356,13 +356,13 @@ private async Task<Result<Maybe<string>>> TryResolveLocalStub(string rid)
             Configuration = "Release",
             SingleFile = true,
             Trimmed = false,
-            MsBuildProperties = new Dictionary<string, string>
+                MsBuildProperties = new Dictionary<string, string>
             {
                 ["IncludeNativeLibrariesForSelfExtract"] = "true",
                 ["IncludeAllContentForSelfExtract"] = "true",
                 ["PublishTrimmed"] = "false",
                 ["DebugType"] = "embedded",
-                ["EnableCompressionInSingleFile"] = "false"
+                ["EnableCompressionInSingleFile"] = "true"
             }
         };