From 767f640187fab9dd88988670aaf00aa7fefc67bd Mon Sep 17 00:00:00 2001
From: Tim Haasdyk <tim_haasdyk@sil.org>
Date: Tue, 18 Aug 2026 14:31:08 +0200
Subject: [PATCH] Log Windows updating the FW Lite MSIX package

Windows stages an .appinstaller update on its own schedule and registers it at
activation, force-terminating a running instance to do so. None of that reaches
our log today, so a forced shutdown looks like an unexplained restart.

Subscribe to PackageCatalog.PackageUpdating for our own package and log target
version, progress and errors. Diagnostics only, no behaviour change.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
---
 .../Platforms/Windows/PackageUpdateLogger.cs  | 59 +++++++++++++++++++
 .../Platforms/Windows/WindowsKernel.cs        |  1 +
 2 files changed, 60 insertions(+)
 create mode 100644 backend/FwLite/FwLiteMaui/Platforms/Windows/PackageUpdateLogger.cs

diff --git a/backend/FwLite/FwLiteMaui/Platforms/Windows/PackageUpdateLogger.cs b/backend/FwLite/FwLiteMaui/Platforms/Windows/PackageUpdateLogger.cs
new file mode 100644
index 0000000000..26f4611a28
--- /dev/null
+++ b/backend/FwLite/FwLiteMaui/Platforms/Windows/PackageUpdateLogger.cs
@@ -0,0 +1,59 @@
+using Windows.ApplicationModel;
+using Microsoft.Extensions.Logging;
+
+namespace FwLiteMaui;
+
+/// <summary>
+/// Logs Windows updating our own MSIX package. The OS stages an update on its own schedule and registers it
+/// at activation, force-terminating this process if it's running, which otherwise leaves nothing in our log.
+/// </summary>
+public class PackageUpdateLogger(ILogger<PackageUpdateLogger> logger) : IMauiInitializeService
+{
+    //field, not a local: the subscription stops firing once the catalog is collected
+    private PackageCatalog? _packageCatalog;
+    private int _loggedProgressDecile = -1;
+
+    public void Initialize(IServiceProvider services)
+    {
+        try
+        {
+            _packageCatalog = PackageCatalog.OpenForCurrentPackage();
+        }
+        catch (Exception e)
+        {
+            logger.LogWarning(e, "Unable to open the package catalog, OS package updates won't be logged");
+            return;
+        }
+
+        _packageCatalog.PackageUpdating += OnPackageUpdating;
+    }
+
+    private void OnPackageUpdating(PackageCatalog sender, PackageUpdatingEventArgs args)
+    {
+        var version = FormatVersion(args.TargetPackage);
+        if (args.ErrorCode is { HResult: not 0 })
+        {
+            logger.LogError(args.ErrorCode, "Windows failed to update this app to {TargetVersion}", version);
+            return;
+        }
+
+        if (args.IsComplete)
+        {
+            logger.LogInformation("Windows finished updating this app to {TargetVersion}", version);
+            return;
+        }
+
+        //progress fires often, so only log each 10% step
+        var decile = (int)(args.Progress / 10);
+        if (decile == _loggedProgressDecile) return;
+        _loggedProgressDecile = decile;
+        logger.LogInformation("Windows is updating this app to {TargetVersion}: {Progress}%", version, args.Progress);
+    }
+
+    private static string FormatVersion(Package? package)
+    {
+        if (package is null) return "unknown";
+        var version = package.Id.Version;
+        return $"{version.Major}.{version.Minor}.{version.Build}.{version.Revision}";
+    }
+}
diff --git a/backend/FwLite/FwLiteMaui/Platforms/Windows/WindowsKernel.cs b/backend/FwLite/FwLiteMaui/Platforms/Windows/WindowsKernel.cs
index df5af42166..7a46199d36 100644
--- a/backend/FwLite/FwLiteMaui/Platforms/Windows/WindowsKernel.cs
+++ b/backend/FwLite/FwLiteMaui/Platforms/Windows/WindowsKernel.cs
@@ -24,6 +24,7 @@ public static void AddFwLiteWindows(this IServiceCollection services, IHostEnvir
         if (!FwLiteMauiKernel.IsPortableApp)
         {
             services.AddSingleton<IMauiInitializeService, WindowsShortcutService>();
+            services.AddSingleton<IMauiInitializeService, PackageUpdateLogger>();
         }
 
         services.Configure<AuthConfig>(config =>