Show message when there is no repo to navigate

Currently doesn't support opening/cloning repo so show message instead.

Author: jcansdale

src/GitHub.App/Services/GitHubContextService.cs

@@ -8,6 +8,7 @@
 using System.Text.RegularExpressions;
 using System.Runtime.InteropServices;
 using GitHub.Services;
+using GitHub.Extensions;
 using GitHub.Primitives;
 using Microsoft.VisualStudio;
 using Microsoft.VisualStudio.Shell;
@@ -308,6 +309,9 @@ public string ResolvePath(GitHubContext context)
 
         public GitObject ResolveGitObject(string repositoryDir, GitHubContext context)
         {
+            Guard.ArgumentNotNull(repositoryDir, nameof(repositoryDir));
+            Guard.ArgumentNotNull(context, nameof(context));
+
             using (var repository = gitService.GetRepository(repositoryDir))
             {
                 var path = context.TreeishPath;

src/GitHub.VisualStudio/Commands/OpenFromClipboardCommand.cs

@@ -12,6 +12,7 @@ public class OpenFromClipboardCommand : VsCommand<string>, IOpenFromClipboardCom
     {
         public const string NoGitHubUrlMessage = "Couldn't a find a GitHub URL in clipboard";
         public const string NoResolveMessage = "Couldn't resolve Git object";
+        public const string NoActiveRepositoryMessage = "There is no active repository to navigate";
 
         readonly Lazy<IGitHubContextService> gitHubContextService;
         readonly Lazy<ITeamExplorerContext> teamExplorerContext;
@@ -52,9 +53,9 @@ public override Task Execute(string url)
             }
 
             var repositoryDir = teamExplorerContext.Value.ActiveRepository?.LocalPath;
-            if (context == null)
+            if (repositoryDir == null)
             {
-                // No active repository
+                vsServices.Value.ShowMessageBoxInfo(NoActiveRepositoryMessage);
                 return Task.CompletedTask;
             }
 

test/GitHub.VisualStudio.UnitTests/Commands/OpenFromClipboardCommandTests.cs

@@ -23,6 +23,19 @@ public async Task NothingInClipboard()
             vsServices.Received(1).ShowMessageBoxInfo(OpenFromClipboardCommand.NoGitHubUrlMessage);
         }
 
+        [Test]
+        public async Task NoLocalRepository()
+        {
+            var context = new GitHubContext();
+            var repositoryDir = null as string;
+            var vsServices = Substitute.For<IVSServices>();
+            var target = CreateOpenFromClipboardCommand(vsServices: vsServices, contextFromClipboard: context, repositoryDir: repositoryDir);
+
+            await target.Execute(null);
+
+            vsServices.Received(1).ShowMessageBoxInfo(OpenFromClipboardCommand.NoActiveRepositoryMessage);
+        }
+
         [Test]
         public async Task CouldNotResolve()
         {