prevent NRE on JoinableTaskFactory

vs-commitizen.Settings/OutputPaneWriter.cs

@@ -0,0 +1,44 @@
+using System;
+using Microsoft.VisualStudio;
+using Microsoft.VisualStudio.Shell;
+using Microsoft.VisualStudio.Shell.Interop;
+
+namespace vs_commitizen.Settings
+{
+    public static class OutputPaneWriter
+    {
+        private static Guid panelGuild = new Guid("5BB96421-E33D-40DA-9E8D-C657B7E94C70");
+
+        static IVsOutputWindowPane GetPane()
+        {
+            var outputWindow = Package.GetGlobalService(typeof(SVsOutputWindow)) as IVsOutputWindow;
+            if (outputWindow == null) return null;
+
+            IVsOutputWindowPane pane;
+
+            if (ErrorHandler.Failed(outputWindow.GetPane(ref panelGuild, out pane)) &&
+                (ErrorHandler.Succeeded(outputWindow.CreatePane(ref panelGuild, "vs-commitizen", 1, 1))))
+            {
+                outputWindow.GetPane(ref panelGuild, out pane);
+            }
+
+            ErrorHandler.ThrowOnFailure(pane.Activate());
+
+            return pane;
+        }
+
+        public static void Print(string message)
+        {
+            var pane = GetPane();
+
+            ErrorHandler.ThrowOnFailure(pane.OutputString(message + Environment.NewLine));
+        }
+
+        public static void Print(string str, Exception ex)
+        {
+            var pane = GetPane();
+
+            ErrorHandler.ThrowOnFailure(pane.OutputString(str + "\r\n\r\n" + ex));
+        }
+    }
+}

vs-commitizen.Settings/vs-commitizen.Settings.csproj

@@ -45,6 +45,7 @@
     <Compile Include="Bootstrap.cs" />
     <Compile Include="ExtensionRegistry.cs" />
     <Compile Include="IoC.cs" />
+    <Compile Include="OutputPaneWriter.cs" />
     <Compile Include="Properties\AssemblyInfo.cs" />
     <Compile Include="SettingsGeneral.cs">
       <SubType>Component</SubType>

vs-commitizen.vs2015/VsCommitizenNavigationItem.cs

@@ -6,6 +6,7 @@
 using System.ComponentModel.Composition;
 using System.Drawing;
 using System.Threading.Tasks;
+using vs_commitizen.Settings;
 using vs_commitizen.vs;
 
 namespace vs_commitizen.vs2015
@@ -37,9 +38,23 @@ private async void GitService_PropertyChanged(object sender, System.ComponentMod
 
         private async System.Threading.Tasks.Task UpdateIsVisibleAsync()
         {
-            await ThreadHelper.JoinableTaskFactory.SwitchToMainThreadAsync();
-            this.IsVisible = this.gitService?.ActiveRepositories.Count > 0;
-            await TaskScheduler.Default;
+            if (VsTaskLibraryHelper.ServiceInstance == null)
+                return;
+
+            try
+            {
+                var joinableTaskFactory = ThreadHelper.JoinableTaskFactory;
+                if (joinableTaskFactory == null)
+                    return;
+
+                await joinableTaskFactory.SwitchToMainThreadAsync();
+                this.IsVisible = this.gitService?.ActiveRepositories.Count > 0;
+                await TaskScheduler.Default;
+            }
+            catch (Exception ex)
+            {
+                OutputPaneWriter.Print($"UpdateIsVisibleAsync: {ex}");
+            }
         }
 
         public override void Execute()