Fix OS detection error in UWP

global.json

@@ -1,6 +1,5 @@
 {
   "sdk": {
-    "version": "8.0.100",
-    "rollForward": "latestFeature"
+    "version": "8.0.200"
   }
 }

src/Grpc.Net.Client/Internal/NtDll.cs → src/Grpc.Net.Client/Internal/Native.cs

@@ -23,11 +23,14 @@ namespace Grpc.Net.Client.Internal;
 /// <summary>
 /// Types for calling RtlGetVersion. See https://www.pinvoke.net/default.aspx/ntdll/RtlGetVersion.html
 /// </summary>
-internal static class NtDll
+internal static class Native
 {
 #pragma warning disable SYSLIB1054 // Use 'LibraryImportAttribute' instead of 'DllImportAttribute' to generate P/Invoke marshalling code at compile time
     [DllImport("ntdll.dll", SetLastError = true, CharSet = CharSet.Unicode)]
     internal static extern NTSTATUS RtlGetVersion(ref OSVERSIONINFOEX versionInfo);
+
+    [DllImport("kernel32.dll", ExactSpelling = true)]
+    private static extern int GetCurrentApplicationUserModelId(ref uint applicationUserModelIdLength, byte[] applicationUserModelId);
 #pragma warning restore SYSLIB1054 // Use 'LibraryImportAttribute' instead of 'DllImportAttribute' to generate P/Invoke marshalling code at compile time
 
     internal static void DetectWindowsVersion(out Version version, out bool isWindowsServer)
@@ -46,6 +49,40 @@ internal static void DetectWindowsVersion(out Version version, out bool isWindow
         isWindowsServer = osVersionInfo.ProductType == VER_NT_SERVER;
     }
 
+    internal static bool IsUwp(string frameworkDescription, Version version)
+    {
+        if (frameworkDescription.StartsWith(".NET Native", StringComparison.OrdinalIgnoreCase))
+        {
+            return true;
+        }
+
+        // From https://github.com/dotnet/runtime/blob/d752f9a19f2d4bc4559e0e303e9374e4042a916e/src/libraries/Common/tests/TestUtilities/System/PlatformDetection.Windows.cs#L190
+        const int Windows8Build = 9200;
+        if (version.Build < Windows8Build)
+        {
+            return false;
+        }
+        else
+        {
+            var bufferSize = 0U;
+            var result = GetCurrentApplicationUserModelId(ref bufferSize, Array.Empty<byte>());
+            switch (result)
+            {
+                case 15703: // APPMODEL_ERROR_NO_APPLICATION
+                    return false;
+                case 0:     // ERROR_SUCCESS
+                case 122:   // ERROR_INSUFFICIENT_BUFFER
+                            // Success is actually insufficient buffer as we're really only looking for
+                            // not NO_APPLICATION and we're not actually giving a buffer here. The
+                            // API will always return NO_APPLICATION if we're not running under a
+                            // WinRT process, no matter what size the buffer is.
+                    return true;
+                default:
+                    throw new InvalidOperationException($"Failed to get AppModelId, result was {result}.");
+            }
+        }
+    }
+
     internal enum NTSTATUS : uint
     {
         /// <summary>

src/Grpc.Net.Client/Internal/OperatingSystem.cs

@@ -53,9 +53,10 @@ private OperatingSystem()
         // Get the value lazily so that it is only called if needed.
         _isWindowsServer = new Lazy<bool>(() =>
         {
-            if (IsWindows)
+            // RtlGetVersion is not available on UWP. Check it first.
+            if (IsWindows && !Native.IsUwp(RuntimeInformation.FrameworkDescription, Environment.OSVersion.Version))
             {
-                NtDll.DetectWindowsVersion(out _, out var isWindowsServer);
+                Native.DetectWindowsVersion(out _, out var isWindowsServer);
                 return isWindowsServer;
             }
 
@@ -72,9 +73,11 @@ private OperatingSystem()
         //
         // Get correct Windows version directly from Windows by calling RtlGetVersion.
         // https://www.pinvoke.net/default.aspx/ntdll/RtlGetVersion.html
-        if (IsWindows)
+        //
+        // RtlGetVersion is not available on UWP. Check it first.
+        if (IsWindows && !Native.IsUwp(RuntimeInformation.FrameworkDescription, Environment.OSVersion.Version))
         {
-            NtDll.DetectWindowsVersion(out var windowsVersion, out var windowsServer);
+            Native.DetectWindowsVersion(out var windowsVersion, out var windowsServer);
             OSVersion = windowsVersion;
             _isWindowsServer = new Lazy<bool>(() => windowsServer, LazyThreadSafetyMode.ExecutionAndPublication);
         }

test/Grpc.Net.Client.Tests/OperatingSystemTests.cs

@@ -29,7 +29,7 @@ public class OperatingSystemTests
     [Platform("Win", Reason = "Only runs on Windows where ntdll.dll is present.")]
     public void DetectWindowsVersion_Windows_MatchesEnvironment()
     {
-        NtDll.DetectWindowsVersion(out var version, out _);
+        Native.DetectWindowsVersion(out var version, out _);
 
         // It is safe to compare Environment.OSVersion.Version on netfx because tests have no compatibility setting.
         Assert.AreEqual(Environment.OSVersion.Version, version);
@@ -39,7 +39,7 @@ public void DetectWindowsVersion_Windows_MatchesEnvironment()
     [Platform("Win", Reason = "Only runs on Windows where ntdll.dll is present.")]
     public void InstanceAndIsWindowsServer_Windows_MatchesEnvironment()
     {
-        NtDll.DetectWindowsVersion(out var version, out var isWindowsServer);
+        Native.DetectWindowsVersion(out var version, out var isWindowsServer);
 
         Assert.AreEqual(true, OperatingSystem.Instance.IsWindows);
         Assert.AreEqual(version, OperatingSystem.Instance.OSVersion);