Report progress using IProgress<string>

This should make it easier to display incremental progress.

Author: jcansdale

src/GitHub.App/Services/PullRequestService.cs

@@ -187,22 +187,16 @@ public IObservable<Unit> Push(ILocalRepositoryModel repository)
         }
 
         [System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.Usage", "CA2201", Justification = "Prototype")]
-        public async Task SyncSubmodules(ILocalRepositoryModel repository)
+        public async Task<bool> SyncSubmodules(ILocalRepositoryModel repository, IProgress<string> progress)
         {
             var exitCode = Where("git");
             if (exitCode != 0)
             {
-                throw new ApplicationException(App.Resources.CouldntFindGitOnPath);
+                progress.Report(App.Resources.CouldntFindGitOnPath);
+                return false;
             }
 
-            var output = new StringWriter(CultureInfo.InvariantCulture);
-            var progress = new Progress<string>(line => output.WriteLine(line));
-            exitCode = await SyncSubmodules(repository.LocalPath, progress);
-            if (exitCode != 0)
-            {
-                var message = output.ToString();
-                throw new ApplicationException(message);
-            }
+            return await SyncSubmodules(repository.LocalPath, progress) == 0;
         }
 
         // LibGit2Sharp has limited submodule support so shelling out Git.exe for submodule commands.

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

@@ -7,6 +7,7 @@
 using System.Reactive.Linq;
 using System.Reactive.Threading.Tasks;
 using System.Threading.Tasks;
+using System.Globalization;
 using GitHub.App;
 using GitHub.Extensions;
 using GitHub.Factories;
@@ -17,7 +18,6 @@
 using LibGit2Sharp;
 using ReactiveUI;
 using Serilog;
-using GitHub.Extensions.Reactive;
 
 namespace GitHub.ViewModels.GitHubPane
 {
@@ -676,9 +676,24 @@ IObservable<Unit> DoPush(object unused)
                 });
         }
 
-        Task DoSyncSubmodules(object unused)
+        async Task DoSyncSubmodules(object unused)
         {
-            return pullRequestsService.SyncSubmodules(LocalRepository).ContinueWith(_ => usageTracker.IncrementCounter(x => x.NumberOfSyncSubmodules).Forget());
+            usageTracker.IncrementCounter(x => x.NumberOfSyncSubmodules).Forget();
+
+            var progress = new CaptureProgress();
+            var complete = await pullRequestsService.SyncSubmodules(LocalRepository, progress);
+            if (!complete)
+            {
+                throw new ApplicationException(progress.ToString());
+            }
+        }
+
+        sealed class CaptureProgress : IProgress<string>, IDisposable
+        {
+            StringWriter writer = new StringWriter(CultureInfo.CurrentCulture);
+            public void Report(string value) => writer.WriteLine(value);
+            public override string ToString() => writer.ToString();
+            public void Dispose() => writer.Dispose();
         }
 
         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>
-        Task SyncSubmodules(ILocalRepositoryModel repository);
+        Task<bool> SyncSubmodules(ILocalRepositoryModel repository, IProgress<string> progress);
 
         /// <summary>
         /// Calculates the name of a local branch for a pull request avoiding clashes with existing branches.