Braille spinner in decompiler tab title while decompiling

Assisted-by: Claude:claude-opus-4-7:Claude Code

Assisted-by: Claude:claude-opus-4-7:Claude Code

ILSpy.Tests/Editor/DecompilerViewTests.cs

@@ -16,6 +16,8 @@
 // OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
 // DEALINGS IN THE SOFTWARE.
 
+using System.Collections.Generic;
+using System.ComponentModel;
 using System.Linq;
 using System.Threading.Tasks;
 
@@ -27,6 +29,7 @@ using ICSharpCode.ILSpy.Properties;
 
 using ILSpy.AppEnv;
 using ILSpy.Commands;
+using ILSpy.TextView;
 using ILSpy.TreeNodes;
 using ILSpy.ViewModels;
 using ILSpy.Views;
@@ -220,6 +223,46 @@ public class DecompilerViewTests
 		tab.Title.Should().Be(node.Text!.ToString());
 	}
 
+	[AvaloniaTest]
+	public async Task Decompile_Tab_Title_Cycles_Round_Spinner_While_Decompiling()
+	{
+		var window = AppComposition.Current.GetExport<MainWindow>();
+		window.Show();
+		var vm = (MainWindowViewModel)window.DataContext!;
+		await vm.AssemblyTreeModel.WaitForAssembliesAsync(minimumCount: 3);
+
+		var firstNode = vm.AssemblyTreeModel.FindNode<AssemblyTreeNode>("System.Linq");
+		vm.AssemblyTreeModel.SelectedItem = firstNode;
+		var tab = await vm.DockWorkspace.WaitForDecompiledTextAsync();
+
+		var titles = new List<string>();
+		var editorTexts = new List<string>();
+		tab.PropertyChanged += OnTabPropertyChanged;
+
+		var coreLib = typeof(object).Assembly.GetName().Name!;
+		var second = vm.AssemblyTreeModel.FindNode<TypeTreeNode>(coreLib, "System", "System.Version");
+		vm.AssemblyTreeModel.SelectedItem = second;
+		await vm.DockWorkspace.WaitForDecompiledTextAsync();
+
+		tab.PropertyChanged -= OnTabPropertyChanged;
+
+		var glyphs = new[] { '⠋', '⠙', '⠹', '⠸', '⠼', '⠴', '⠦', '⠧', '⠇', '⠏' };
+		titles.Should().Contain(t => glyphs.Any(t.Contains),
+			"the tab title must show one of the Braille spinner frames while decompilation is in flight");
+		editorTexts.Should().NotContain(t => glyphs.Any(t.Contains),
+			"the editor's Text must not be overwritten with the spinner — title prefix only");
+		tab.Title.Should().NotContainAny("⠋", "⠙", "⠹", "⠸", "⠼", "⠴", "⠦", "⠧", "⠇", "⠏",
+			"the spinner glyph must clear once decompilation finishes");
+
+		void OnTabPropertyChanged(object? s, PropertyChangedEventArgs e)
+		{
+			if (e.PropertyName == nameof(DecompilerTabPageModel.Title))
+				titles.Add(tab.Title ?? string.Empty);
+			else if (e.PropertyName == nameof(DecompilerTabPageModel.Text))
+				editorTexts.Add(tab.Text ?? string.Empty);
+		}
+	}
+
 	[AvaloniaTest]
 	public async Task Selecting_Assembly_Node_Emits_Header_And_Assembly_Attributes()
 	{

ILSpy/TextView/DecompilerTabPageModel.cs

@@ -134,9 +134,12 @@ namespace ILSpy.TextView
 		{
 			// Tree-node Text can change after we capture the title (e.g. AssemblyTreeNode swaps
 			// from ShortName to "ShortName (version, tfm)" once the assembly finishes loading).
-			// Re-read it whenever the node fires Text so the tab header stays in sync.
-			if (e.PropertyName == nameof(ILSpyTreeNode.Text) && sender is ILSpyTreeNode node)
-				Title = node.Text?.ToString() ?? "(unnamed)";
+			// While a decompile is running the spinner prefixes the title — keep the prefix and
+			// just refresh the suffix; otherwise replace the title outright.
+			if (e.PropertyName != nameof(ILSpyTreeNode.Text) || sender is not ILSpyTreeNode node)
+				return;
+			var text = node.Text?.ToString() ?? "(unnamed)";
+			Title = IsDecompiling ? ComposeSpinnerTitle(0, text) : text;
 		}
 
 		public DecompilerTabPageModel()
@@ -162,6 +165,11 @@ namespace ILSpy.TextView
 			var newSyntaxExtension = language.FileExtension;
 			IsDecompiling = true;
 
+			// Spinner appears as a glyph prefix on the tab title while the decompile runs;
+			// editor state is left untouched so cancellation falls back cleanly.
+			Title = ComposeSpinnerTitle(0, currentNode?.Text?.ToString() ?? "(unnamed)");
+			_ = RunSpinnerAsync(cts.Token);
+
 			try
 			{
 				var (output, _) = await Task.Run(() => {
@@ -220,12 +228,47 @@ namespace ILSpy.TextView
 				// at the top of DecompileAsync).
 				if (ReferenceEquals(activeCts, cts))
 				{
-					if (Dispatcher.UIThread.CheckAccess())
+					void StopSpinner()
+					{
 						IsDecompiling = false;
+						// If we cancelled before producing fresh output, drop the spinner glyph
+						// from the title — the editor still shows the previous decompile.
+						if (currentNode != null)
+							Title = currentNode.Text?.ToString() ?? "(unnamed)";
+					}
+					if (Dispatcher.UIThread.CheckAccess())
+						StopSpinner();
 					else
-						await Dispatcher.UIThread.InvokeAsync(() => IsDecompiling = false);
+						await Dispatcher.UIThread.InvokeAsync(StopSpinner);
 				}
 			}
 		}
+
+		// Braille round-spinner: the dot pattern walks around the cell so each frame reads as
+		// a different orientation of a small spinning circle.
+		static readonly char[] SpinnerFrames = ['⠋', '⠙', '⠹', '⠸', '⠼', '⠴', '⠦', '⠧', '⠇', '⠏'];
+		static readonly TimeSpan SpinnerInterval = TimeSpan.FromMilliseconds(80);
+
+		static string ComposeSpinnerTitle(int frame, string baseTitle)
+			=> $"{SpinnerFrames[frame % SpinnerFrames.Length]} {baseTitle}";
+
+		async Task RunSpinnerAsync(CancellationToken token)
+		{
+			int frame = 1;
+			while (!token.IsCancellationRequested)
+			{
+				try
+				{
+					await Task.Delay(SpinnerInterval, token).ConfigureAwait(true);
+				}
+				catch (OperationCanceledException)
+				{
+					return;
+				}
+				if (token.IsCancellationRequested || !IsDecompiling)
+					return;
+				Title = ComposeSpinnerTitle(frame++, currentNode?.Text?.ToString() ?? "(unnamed)");
+			}
+		}
 	}
 }