Merge pull request #1836 from github/fixes/1348-dont-open-deleted-file

Don't allow "Open File in Solution" for deleted files.

Author: StanleyGoldman

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

@@ -7,7 +7,9 @@
 using System.Reactive.Disposables;
 using System.Reactive.Linq;
 using System.Reactive.Subjects;
+using System.Reactive.Threading.Tasks;
 using System.Threading.Tasks;
+using System.Windows.Input;
 using GitHub.Extensions;
 using GitHub.Models;
 using GitHub.Services;
@@ -50,7 +52,7 @@ public PullRequestFilesViewModel(
             DiffFileWithWorkingDirectory = ReactiveCommand.CreateAsyncTask(
                 isBranchCheckedOut,
                 x => (Task)editorService.OpenDiff(pullRequestSession, ((IPullRequestFileNode)x).RelativePath));
-            OpenFileInWorkingDirectory = ReactiveCommand.CreateAsyncTask(
+            OpenFileInWorkingDirectory = new NonDeletedFileCommand(
                 isBranchCheckedOut,
                 x => (Task)editorService.OpenFile(pullRequestSession, ((IPullRequestFileNode)x).RelativePath, true));
 
@@ -198,5 +200,37 @@ async Task<IInlineCommentThreadModel> GetFirstCommentThread(IPullRequestFileNode
 
             return threads.FirstOrDefault();
         }
+
+        /// <summary>
+        /// Implements the <see cref="OpenFileInWorkingDirectory"/> command.
+        /// </summary>
+        /// <remarks>
+        /// We need to "Open File in Solution" when the parameter passed to the command parameter
+        /// represents a deleted file. ReactiveCommand doesn't allow us to change the CanExecute
+        /// state depending on the parameter, so we override 
+        /// <see cref="ICommand.CanExecute(object)"/> to do this ourselves.
+        /// </remarks>
+        class NonDeletedFileCommand : ReactiveCommand<Unit>, ICommand
+        {
+            public NonDeletedFileCommand(
+                IObservable<bool> canExecute,
+                Func<object, Task> executeAsync)
+                : base(canExecute, x => executeAsync(x).ToObservable())
+            {
+            }
+
+            bool ICommand.CanExecute(object parameter)
+            {
+                if (parameter is IPullRequestFileNode node)
+                {
+                    if (node.Status == PullRequestFileStatus.Removed)
+                    {
+                        return false;
+                    }
+                }
+
+                return CanExecute(parameter);
+            }
+        }
     }
 }

src/GitHub.VisualStudio/Views/GitHubPane/PullRequestFilesView.xaml.cs

@@ -61,13 +61,15 @@ void ApplyContextMenuBinding<TItem>(object sender, ContextMenuEventArgs e) where
 
                 if (fileNode != null)
                 {
-                    container.ContextMenu.DataContext = this.DataContext;
-
                     foreach (var menuItem in container.ContextMenu.Items.OfType<MenuItem>())
                     {
                         menuItem.CommandParameter = fileNode;
                     }
 
+                    // HACK: MenuItem doesn't re-query ICommand.CanExecute when CommandParameter changes. Force
+                    // this to happen by resetting its DataContext to null and then to the correct value.
+                    container.ContextMenu.DataContext = null;
+                    container.ContextMenu.DataContext = this.DataContext;
                     e.Handled = false;
                 }
             }