fix: auto-update now performs in-place self-replace with SHA256 verification

CHANGELOG.md

@@ -44,6 +44,11 @@ adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
   confirmation-gated code paths (CQ-003).
 
 ### Fixed
+- **Auto-update** — "Install" now performs a true in-place update: verifies
+  SHA256 hash of the downloaded build, writes an updater script that waits
+  for the current process to exit, copies the new executable over the old
+  one, and restarts. Previously it only launched the new exe from a temp
+  folder without replacing the original. Closes #240.
 - **Disk Health** — `TemperatureColorHex` returns grey (#9AA0A6) for drives
   without temperature sensors instead of misleading red (QA-004).
 - **Battery Health** — `HealthPercent` clamped to 0–100, `WearPercent`

README.md

@@ -267,7 +267,9 @@ long-running operation, so you always know which tab is working.
 - Background download of the new build with a progress bar. If the
   download is blocked, a "Manual download" button opens GitHub in the
   browser.
-- One-click "Install" launches the new build and hands off cleanly.
+- SHA256 hash verification before install — blocks corrupted downloads.
+- One-click "Install" replaces the running executable in-place and
+  restarts automatically (no manual file copying needed).
 - Full release-note history pulled live from GitHub.
 
 ## Screenshots

SysManager/SysManager.Tests/AboutViewModelTests.cs

@@ -2,6 +2,7 @@
 // Author: laurentiu021 · https://github.com/laurentiu021/SystemManager
 // License: MIT
 
+using System.IO;
 using SysManager.Services;
 using SysManager.ViewModels;
 
@@ -140,13 +141,38 @@ public void OpenDownloadFolderCommand_NoPath_DoesNotThrow()
     }
 
     [Fact]
-    public void InstallUpdateCommand_WithoutDownload_SetsErrorStatus()
+    public async Task InstallUpdateCommand_WithoutDownload_SetsErrorStatus()
     {
         var vm = new AboutViewModel { DownloadedPath = null };
-        vm.InstallUpdateCommand.Execute(null);
+        await vm.InstallUpdateCommand.ExecuteAsync(null);
         Assert.Contains("No downloaded", vm.DownloadStatus, StringComparison.OrdinalIgnoreCase);
     }
 
+    [Fact]
+    public async Task InstallUpdateCommand_WithFakePath_SetsNoFileStatus()
+    {
+        var vm = new AboutViewModel { DownloadedPath = @"C:\nonexistent\fake.exe" };
+        await vm.InstallUpdateCommand.ExecuteAsync(null);
+        Assert.Contains("No downloaded", vm.DownloadStatus, StringComparison.OrdinalIgnoreCase);
+    }
+
+    [Fact]
+    public async Task InstallUpdateCommand_WithPathButNoRelease_SetsNoReleaseStatus()
+    {
+        // Create a temp file to simulate a downloaded exe
+        var tmp = Path.GetTempFileName();
+        try
+        {
+            var vm = new AboutViewModel { DownloadedPath = tmp };
+            await vm.InstallUpdateCommand.ExecuteAsync(null);
+            Assert.Contains("No release info", vm.DownloadStatus, StringComparison.OrdinalIgnoreCase);
+        }
+        finally
+        {
+            File.Delete(tmp);
+        }
+    }
+
     [Fact]
     public async Task LoadHistoryCommand_NeverThrows()
     {

SysManager/SysManager/ViewModels/AboutViewModel.cs

@@ -362,30 +362,102 @@
     }
 
     [RelayCommand]
-    private void InstallUpdate()
+    private async Task InstallUpdateAsync()
     {
         if (string.IsNullOrWhiteSpace(DownloadedPath) || !File.Exists(DownloadedPath))
         {
             DownloadStatus = "No downloaded file to install.";
             return;
         }
+
+        if (_latest == null)
+        {
+            DownloadStatus = "No release info available.";
+            return;
+        }
+
+        // Step 1: Verify SHA256 hash before installing.
+        DownloadStatus = "Verifying file integrity...";
+        var (verified, expected, actual) = await _updates.VerifyHashAsync(_latest, DownloadedPath);
+        if (!verified)
+        {
+            DownloadStatus = expected != null && actual != null
+                ? $"SHA256 mismatch — file may be corrupted. Expected: {expected[..12]}… Got: {actual[..12]}…"
+                : "Hash verification failed — file may be corrupted. Try downloading again.";
+            return;
+        }
+
+        // Step 2: Determine current executable path.
+        var currentExe = Environment.ProcessPath;
+        if (string.IsNullOrWhiteSpace(currentExe) || !File.Exists(currentExe))
+        {
+            DownloadStatus = "Cannot determine current executable path.";
+            return;
+        }
+
+        // Step 3: Write an updater script that waits for this process to exit,
+        // copies the new exe over the old one, then launches the new version.
         try
         {
+            var pid = Environment.ProcessId;
+            var scriptPath = Path.Combine(
+                Path.GetDirectoryName(DownloadedPath)!,
+                "update.cmd");
+
+            var script = $"""
+                @echo off
+                title SysManager Updater
+                echo Waiting for SysManager to close...
+                :wait
+                tasklist /FI "PID eq {pid}" 2>NUL | find /I "{pid}" >NUL
+                if not errorlevel 1 (
+                    timeout /t 1 /nobreak >NUL
+                    goto wait
+                )
+                echo Applying update...
+                copy /Y "{DownloadedPath}" "{currentExe}" >NUL
+                if errorlevel 1 (
+                    echo Update failed — could not copy file. Press any key to exit.
+                    pause >NUL
+                    exit /b 1
+                )
+                echo Starting SysManager...
+                start "" "{currentExe}"
+                del "%~f0"
+                """;
+
+            await File.WriteAllTextAsync(scriptPath, script);
+
+            DownloadStatus = "Installing update — SysManager will restart...";
+
             Process.Start(new ProcessStartInfo
             {
-                FileName = DownloadedPath,
-                UseShellExecute = true  // lets UAC prompt if needed
+                FileName = "cmd.exe",
+                Arguments = $"/C \"{scriptPath}\"",
+                UseShellExecute = false,
+                CreateNoWindow = true,
+                WindowStyle = ProcessWindowStyle.Hidden
             });
-            // Close the current instance so the new one takes over.
+
+            // Give the script a moment to start before we exit.
+            await Task.Delay(500);
             System.Windows.Application.Current?.Shutdown();
         }
+        catch (IOException ex)
+        {
+            DownloadStatus = $"Update failed: {ex.Message}";
+        }
+        catch (UnauthorizedAccessException ex)
+        {
+            DownloadStatus = $"Update failed (access denied): {ex.Message}. Try running as administrator.";
+        }
         catch (InvalidOperationException ex)
         {
-            DownloadStatus = $"Couldn't launch installer: {ex.Message}";
+            DownloadStatus = $"Update failed: {ex.Message}";
         }
         catch (System.ComponentModel.Win32Exception ex)
         {
-            DownloadStatus = $"Couldn't launch installer: {ex.Message}";
+            DownloadStatus = $"Update failed: {ex.Message}";
         }
     }