Display error messages in GitHubPane.

Author: grokys

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

@@ -40,6 +40,7 @@ public sealed class GitHubPaneViewModel : ViewModelBase, IGitHubPaneViewModel, I
         readonly INotAGitHubRepositoryViewModel notAGitHubRepository;
         readonly INotAGitRepositoryViewModel notAGitRepository;
         readonly SemaphoreSlim navigating = new SemaphoreSlim(1);
+        readonly ObservableAsPropertyHelper<ContentOverride> contentOverride;
         readonly ObservableAsPropertyHelper<bool> isSearchEnabled;
         readonly ObservableAsPropertyHelper<string> title;
         readonly ReactiveCommand<Unit> refresh;
@@ -90,6 +91,17 @@ public GitHubPaneViewModel(
                 navigator.WhenAnyValue(x => x.Content))
                 .Select(x => x[0] == navigator ? x[1] as IPanePageViewModel : null);
 
+            contentOverride = currentPage
+                .SelectMany(x => x?.WhenAnyValue(y => y.IsLoading, y => y.Error) ??
+                                 Observable.Return<Tuple<bool, Exception>>(null))
+                .Select(x =>
+                {
+                    if (x == null || x.Item1) return ContentOverride.Spinner;
+                    else if (x.Item2 != null) return ContentOverride.Error;
+                    else return ContentOverride.None;
+                })
+                .ToProperty(this, x => x.ContentOverride);
+
             title = currentPage
                 .SelectMany(x => x?.WhenAnyValue(y => y.Title) ?? Observable.Return<string>(null))
                 .Select(x => x ?? "GitHub")
@@ -106,6 +118,7 @@ public GitHubPaneViewModel(
                         (loading, busy) => !loading && !busy)
                             ?? Observable.Return(false)),
                 _ => navigator.Content.Refresh());
+            refresh.ThrownExceptions.Subscribe();
 
             showPullRequests = ReactiveCommand.CreateAsyncTask(
                 this.WhenAny(x => x.Content, x => x.Value == navigator),
@@ -141,6 +154,9 @@ public IViewModel Content
             private set { this.RaiseAndSetIfChanged(ref content, value); }
         }
 
+        /// <inheritdoc/>
+        public ContentOverride ContentOverride => contentOverride.Value;
+
         /// <inheritdoc/>
         public bool IsSearchEnabled => isSearchEnabled.Value;
 

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

@@ -13,6 +13,7 @@ public abstract class PanePageViewModelBase : ViewModelBase, IPanePageViewModel,
     {
         static readonly Uri paneUri = new Uri("github://pane");
         Subject<Uri> navigate = new Subject<Uri>();
+        Exception error;
         bool isBusy;
         bool isLoading;
         string title;
@@ -29,6 +30,13 @@ protected PanePageViewModelBase()
             Dispose(false);
         }
 
+        /// <inheritdoc/>
+        public Exception Error
+        {
+            get { return error; }
+            protected set { this.RaiseAndSetIfChanged(ref error, value); }
+        }
+
         /// <inheritdoc/>
         public bool IsBusy
         {

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

@@ -41,7 +41,6 @@ public class PullRequestDetailViewModel : PanePageViewModelBase, IPullRequestDet
         IReadOnlyList<IPullRequestChangeNode> changedFilesTree;
         IPullRequestCheckoutState checkoutState;
         IPullRequestUpdateState updateState;
-        string errorMessage;
         string operationError;
         bool isCheckedOut;
         bool isFromFork;
@@ -217,15 +216,6 @@ public IPullRequestUpdateState UpdateState
             private set { this.RaiseAndSetIfChanged(ref updateState, value); }
         }
 
-        /// <summary>
-        /// Gets an error message to display if loading fails.
-        /// </summary>
-        public string ErrorMessage
-        {
-            get { return errorMessage; }
-            private set { this.RaiseAndSetIfChanged(ref errorMessage, value); }
-        }
-
         /// <summary>
         /// Gets the error message to be displayed in the action area as a result of an error in a
         /// git operation.
@@ -335,7 +325,6 @@ public async Task InitializeAsync(
         /// <summary>
         /// Loads the view model from octokit models.
         /// </summary>
-        /// <param name="remoteRepositoryOwner">The owner of the remote repository.</param>
         /// <param name="pullRequest">The pull request model.</param>
         public async Task Load(IPullRequestModel pullRequest)
         {
@@ -430,11 +419,6 @@ public async Task Load(IPullRequestModel pullRequest)
                     pullRequestsService.RemoveUnusedRemotes(LocalRepository).Subscribe(_ => { });
                 }
             }
-            catch (Exception ex)
-            {
-                log.Error(ex, "Error loading PullRequestModel");
-                ErrorMessage = ex.Message.Trim();
-            }
             finally
             {
                 IsBusy = false;
@@ -448,7 +432,9 @@ public override async Task Refresh()
         {
             try
             {
+                Error = null;
                 OperationError = null;
+                IsBusy = true;
                 var pullRequest = await modelService.GetPullRequest(RemoteRepositoryOwner, LocalRepository.Name, Number);
                 await Load(pullRequest);
             }
@@ -461,7 +447,8 @@ public override async Task Refresh()
                     LocalRepository.Name,
                     Number,
                     modelService.ApiClient.HostAddress.Title);
-                ErrorMessage = ex.Message.Trim();
+                Error = ex;
+                IsBusy = false;
             }
         }
 

src/GitHub.Exports.Reactive/ViewModels/GitHubPane/IPanePageViewModel.cs

@@ -9,6 +9,11 @@ namespace GitHub.ViewModels.GitHubPane
     /// </summary>
     public interface IPanePageViewModel : IViewModel
     {
+        /// <summary>
+        /// Gets an exception representing an error state to display.
+        /// </summary>
+        Exception Error { get; }
+
         /// <summary>
         /// Gets a value indicating whether the page is busy.
         /// </summary>

src/GitHub.Exports/ViewModels/GitHubPane/IGitHubPaneViewModel.cs

@@ -4,6 +4,28 @@
 
 namespace GitHub.ViewModels.GitHubPane
 {
+    /// <summary>
+    /// Describes the ways that the display of <see cref="IGitHubPaneViewModel.Content"/> can
+    /// be overridden.
+    /// </summary>
+    public enum ContentOverride
+    {
+        /// <summary>
+        /// No override, display the content.
+        /// </summary>
+        None,
+
+        /// <summary>
+        /// Display a spinner instead of the content.
+        /// </summary>
+        Spinner,
+
+        /// <summary>
+        /// Display an error instead of the content.
+        /// </summary>
+        Error
+    }
+
     /// <summary>
     /// The view model for the GitHub Pane.
     /// </summary>
@@ -19,6 +41,12 @@ public interface IGitHubPaneViewModel : IViewModel
         /// </summary>
         IViewModel Content { get; }
 
+        /// <summary>
+        /// Gets a value describing whether to display the <see cref="Content"/> or to override
+        /// it with another view.
+        /// </summary>
+        ContentOverride ContentOverride { get; }
+
         /// <summary>
         /// Gets a value indicating whether search is available on the current page.
         /// </summary>

src/GitHub.UI/Converters/EqualsToVisibilityConverter.cs

@@ -0,0 +1,30 @@
+using System;
+using System.Globalization;
+using System.Windows;
+using System.Windows.Data;
+using System.Windows.Markup;
+
+namespace GitHub.UI
+{
+    public class EqualsToVisibilityConverter : MarkupExtension, IValueConverter
+    {
+        readonly string visibleValue;
+
+        public EqualsToVisibilityConverter(string visibleValue)
+        {
+            this.visibleValue = visibleValue;
+        }
+
+        public object Convert(object value, Type targetType, object parameter, CultureInfo culture)
+        {
+            return value?.ToString() == visibleValue ? Visibility.Visible : Visibility.Collapsed;
+        }
+
+        public object ConvertBack(object value, Type targetType, object parameter, CultureInfo culture)
+        {
+            throw new NotImplementedException();
+        }
+
+        public override object ProvideValue(IServiceProvider serviceProvider) => this;
+    }
+}

src/GitHub.UI/GitHub.UI.csproj

@@ -89,6 +89,7 @@
       <DependentUpon>Spinner.xaml</DependentUpon>
     </Compile>
     <Compile Include="Converters\AllCapsConverter.cs" />
+    <Compile Include="Converters\EqualsToVisibilityConverter.cs" />
     <Compile Include="Converters\MultiBooleanToVisibilityConverter.cs" />
     <Compile Include="Converters\NullToVisibilityConverter.cs" />
     <Compile Include="Converters\BranchNameConverter.cs" />

src/GitHub.VisualStudio/Views/GitHubPane/GitHubPaneView.xaml

@@ -69,7 +69,7 @@
                Style="{StaticResource PaneHorizontalSeparator}" />
 
     <Grid>
-      <DockPanel Visibility="{Binding Content.Content.IsLoading, Converter={u:BooleanToInverseVisibilityConverter}, FallbackValue=Visible}">
+      <DockPanel Visibility="{Binding ContentOverride, Converter={u:EqualsToVisibilityConverter None}}">
         <u:GitHubProgressBar DockPanel.Dock="Top"
                              Foreground="{DynamicResource GitHubAccentBrush}"
                              IsIndeterminate="True"
@@ -81,7 +81,16 @@
                   Height="48"
                   HorizontalAlignment="Center"
                   VerticalAlignment="Center"
-                  Visibility="{Binding Content.Content.IsLoading, Converter={u:BooleanToVisibilityConverter}, FallbackValue=Collapsed}"/>
+                  Visibility="{Binding ContentOverride, Converter={u:EqualsToVisibilityConverter Spinner}, FallbackValue=Collapsed}"/>
+      <Border Background="White"
+              HorizontalAlignment="Stretch"
+              VerticalAlignment="Stretch"
+              Visibility="{Binding ContentOverride, Converter={u:EqualsToVisibilityConverter Error}, FallbackValue=Collapsed}">
+        <StackPanel HorizontalAlignment="Center" VerticalAlignment="Center">
+          <u:OcticonImage Icon="alert" Width="32" Height="32" Margin="8"/>
+          <TextBlock Text="{Binding Content.Content.Error.Message}" TextAlignment="Center" TextWrapping="Wrap"/>
+        </StackPanel>
+      </Border>
     </Grid>
   </DockPanel>
 </local:GenericGitHubPaneView>