Convert to returing async Task rather than IObservable<Unit>

Author: jcansdale

src/GitHub.App/Services/PullRequestService.cs

@@ -187,28 +187,21 @@ public IObservable<Unit> Push(ILocalRepositoryModel repository)
         }
 
         [System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.Usage", "CA2201", Justification = "Prototype")]
-        public IObservable<Unit> SyncSubmodules(ILocalRepositoryModel repository)
+        public async Task SyncSubmodules(ILocalRepositoryModel repository)
         {
-            return Observable.Defer(async () =>
+            var exitCode = Where("git");
+            if (exitCode != 0)
             {
-                var exitCode = Where("git");
-                if (exitCode != 0)
-                {
-                    var ex = new ApplicationException(App.Resources.CouldntFindGitOnPath);
-                    return Observable.Throw<Unit>(ex);
-                }
-
-                var output = new StringWriter(CultureInfo.InvariantCulture);
-                exitCode = await SyncSubmodules(repository.LocalPath, line => output.WriteLine(line));
-                if (exitCode != 0)
-                {
-                    var message = output.ToString();
-                    var ex = new ApplicationException(message);
-                    return Observable.Throw<Unit>(ex);
-                }
+                throw new ApplicationException(App.Resources.CouldntFindGitOnPath);
+            }
 
-                return Observable.Return(Unit.Default);
-            });
+            var output = new StringWriter(CultureInfo.InvariantCulture);
+            exitCode = await SyncSubmodules(repository.LocalPath, line => output.WriteLine(line));
+            if (exitCode != 0)
+            {
+                var message = output.ToString();
+                throw new ApplicationException(message);
+            }
         }
 
         // LibGit2Sharp has limited submodule support so shelling out Git.exe for submodule commands.
@@ -228,8 +221,8 @@ async Task<int> SyncSubmodules(string workingDir, Action<string> progress = null
             {
                 await Task.WhenAll(
                     ReadLinesAsync(process.StandardOutput, progress),
-                    ReadLinesAsync(process.StandardError, progress));
-                process.WaitForExit();
+                    ReadLinesAsync(process.StandardError, progress),
+                    Task.Run(() => process.WaitForExit()));
                 return process.ExitCode;
             }
         }

src/GitHub.App/ViewModels/GitHubPane/PullRequestDetailViewModel.cs

@@ -103,7 +103,7 @@ public PullRequestDetailViewModel(
                 DoPush);
             SubscribeOperationError(Push);
 
-            SyncSubmodules = ReactiveCommand.CreateAsyncObservable(
+            SyncSubmodules = ReactiveCommand.CreateAsyncTask(
                 this.WhenAnyValue(x => x.UpdateState)
                     .Cast<UpdateCommandState>()
                     .Select(x => x != null && x.SyncSubmodulesEnabled),
@@ -676,9 +676,9 @@ IObservable<Unit> DoPush(object unused)
                 });
         }
 
-        IObservable<Unit> DoSyncSubmodules(object unused)
+        Task DoSyncSubmodules(object unused)
         {
-            return pullRequestsService.SyncSubmodules(LocalRepository).Do(_ => usageTracker.IncrementCounter(x => x.NumberOfSyncSubmodules).Forget());
+            return pullRequestsService.SyncSubmodules(LocalRepository).ContinueWith(_ => usageTracker.IncrementCounter(x => x.NumberOfSyncSubmodules).Forget());
         }
 
         class CheckoutCommandState : IPullRequestCheckoutState

src/GitHub.Exports.Reactive/Services/IPullRequestService.cs

@@ -56,7 +56,7 @@ IObservable<IPullRequestModel> CreatePullRequest(IModelService modelService,
         /// Sync submodules on the current branch.
         /// </summary>
         /// <param name="repository">The repository.</param>
-        IObservable<Unit> SyncSubmodules(ILocalRepositoryModel repository);
+        Task SyncSubmodules(ILocalRepositoryModel repository);
 
         /// <summary>
         /// Calculates the name of a local branch for a pull request avoiding clashes with existing branches.