Check for dirty repository state.

When checking out/updating PR branch as that will block the checkout.

Author: grokys

src/GitHub.App/SampleData/PullRequestDetailViewModelDesigner.cs

@@ -69,6 +69,7 @@ public PullRequestDetailViewModelDesigner()
         public CheckoutMode CheckoutMode { get; set; }
         public string CheckoutError { get; set; }
         public int CommitsBehind { get; set; }
+        public string CheckoutDisabledMessage { get; set; }
 
         public ReactiveCommand<Unit> Checkout { get; }
         public ReactiveCommand<object> OpenOnGitHub { get; }

src/GitHub.App/Services/PullRequestService.cs

@@ -83,6 +83,12 @@ public IObservable<string> GetPullRequestTemplate(ILocalRepositoryModel reposito
             });
         }
 
+        public IObservable<bool> CleanForCheckout(ILocalRepositoryModel repository)
+        {
+            var repo = gitService.GetRepository(repository.LocalPath);
+            return Observable.Return(!repo.RetrieveStatus().IsDirty);
+        }
+
         public IObservable<Unit> FetchAndCheckout(ILocalRepositoryModel repository, int pullRequestNumber, string localBranchName)
         {
             return DoFetchAndCheckout(repository, pullRequestNumber, localBranchName).ToObservable();

src/GitHub.App/ViewModels/PullRequestDetailViewModel.cs

@@ -33,7 +33,6 @@ public class PullRequestDetailViewModel : BaseViewModel, IPullRequestDetailViewM
     {
         readonly IRepositoryHost repositoryHost;
         readonly ILocalRepositoryModel repository;
-        readonly IGitService gitService;
         readonly IPullRequestService pullRequestsService;
         readonly IAvatarProvider avatarProvider;
         PullRequestState state;
@@ -47,29 +46,26 @@ public class PullRequestDetailViewModel : BaseViewModel, IPullRequestDetailViewM
         int changeCount;
         ChangedFilesView changedFilesView;
         OpenChangedFileAction openChangedFileAction;
-        bool uncommittedChanges;
         CheckoutMode checkoutMode;
         string checkoutError;
         int commitsBehind;
+        string checkoutDisabledMessage;
 
         /// <summary>
         /// Initializes a new instance of the <see cref="PullRequestDetailViewModel"/> class.
         /// </summary>
         /// <param name="connectionRepositoryHostMap">The connection repository host map.</param>
         /// <param name="teservice">The team explorer service.</param>
-        /// <param name="gitService">The git service.</param>
         /// <param name="pullRequestsService">The pull requests service.</param>
         /// <param name="avatarProvider">The avatar provider.</param>
         [ImportingConstructor]
         PullRequestDetailViewModel(
             IConnectionRepositoryHostMap connectionRepositoryHostMap,
             ITeamExplorerServiceHolder teservice,
-            IGitService gitService,
             IPullRequestService pullRequestsService,
             IAvatarProvider avatarProvider)
             : this(connectionRepositoryHostMap.CurrentRepositoryHost,
                   teservice.ActiveRepo,
-                  gitService,
                   pullRequestsService,
                   avatarProvider)
         {
@@ -80,25 +76,24 @@ public class PullRequestDetailViewModel : BaseViewModel, IPullRequestDetailViewM
         /// </summary>
         /// <param name="repositoryHost">The repository host.</param>
         /// <param name="teservice">The team explorer service.</param>
-        /// <param name="gitService">The git service.</param>
         /// <param name="pullRequestsService">The pull requests service.</param>
         /// <param name="avatarProvider">The avatar provider.</param>
         public PullRequestDetailViewModel(
             IRepositoryHost repositoryHost,
             ILocalRepositoryModel repository,
-            IGitService gitService,
             IPullRequestService pullRequestsService,
             IAvatarProvider avatarProvider)
         {
             this.repositoryHost = repositoryHost;
             this.repository = repository;
-            this.gitService = gitService;
             this.pullRequestsService = pullRequestsService;
             this.avatarProvider = avatarProvider;
 
-            Checkout = ReactiveCommand.CreateAsyncObservable(
-                this.WhenAnyValue(x => x.UncommittedChanges, x => !x),
-                DoCheckout);
+            var canCheckout = this.WhenAnyValue(
+                x => x.CheckoutMode,
+                x => x.CheckoutDisabledMessage,
+                (mode, disabled) => mode != CheckoutMode.UpToDate && disabled == null);
+            Checkout = ReactiveCommand.CreateAsyncObservable(canCheckout, DoCheckout);
 
             OpenOnGitHub = ReactiveCommand.Create();
 
@@ -216,15 +211,6 @@ public OpenChangedFileAction OpenChangedFileAction
             set { this.RaiseAndSetIfChanged(ref openChangedFileAction, value); }
         }
 
-        /// <summary>
-        /// Gets a value indicating whether there are uncommitted changes blocking a checkout.
-        /// </summary>
-        public bool UncommittedChanges
-        {
-            get { return uncommittedChanges; }
-            private set { this.RaiseAndSetIfChanged(ref uncommittedChanges, value); }
-        }
-
         /// <summary>
         /// Gets the checkout mode for the pull request.
         /// </summary>
@@ -253,6 +239,15 @@ public int CommitsBehind
             private set { this.RaiseAndSetIfChanged(ref commitsBehind, value); }
         }
 
+        /// <summary>
+        /// Gets a message indicating the why the <see cref="Checkout"/> command is disabled.
+        /// </summary>
+        public string CheckoutDisabledMessage
+        {
+            get { return checkoutDisabledMessage; }
+            private set { this.RaiseAndSetIfChanged(ref checkoutDisabledMessage, value); }
+        }
+
         /// <summary>
         /// Gets the changed files as a tree.
         /// </summary>
@@ -334,14 +329,6 @@ public async Task Load(PullRequest pullRequest, IList<PullRequestFile> files)
                 ChangedFilesTree.Add(change);
             }
 
-            var repo = gitService.GetRepository(repository.LocalPath);
-            UncommittedChanges = repo.RetrieveStatus().IsDirty;
-
-            if (UncommittedChanges)
-            {
-                CheckoutError = "Cannot check out: you have uncommitted changes";
-            }
-
             var localBranches = await pullRequestsService.GetLocalBranches(repository, Number).ToList();
 
             if (localBranches.Contains(repository.CurrentBranch))
@@ -371,6 +358,12 @@ public async Task Load(PullRequest pullRequest, IList<PullRequestFile> files)
                 CheckoutMode = CheckoutMode.Fetch;
             }
 
+            var clean = await pullRequestsService.CleanForCheckout(repository);
+
+            CheckoutDisabledMessage = (!clean && CheckoutMode != CheckoutMode.UpToDate) ?
+                $"Cannot {GetCheckoutModeDescription(CheckoutMode)} as your working directory has uncommitted changes." :
+                null;
+
             IsBusy = false;
         }
 
@@ -411,6 +404,22 @@ static IPullRequestDirectoryViewModel CreateChangedFilesTree(IEnumerable<IPullRe
             return dirs[string.Empty];
         }
 
+        static string GetCheckoutModeDescription(CheckoutMode checkoutMode)
+        {
+            switch (checkoutMode)
+            {
+                case CheckoutMode.NeedsPull:
+                    return "update branch";
+                case CheckoutMode.Switch:
+                    return "switch branches";
+                case CheckoutMode.Fetch:
+                    return "checkout pull request";
+                default:
+                    Debug.Fail("Invalid CheckoutMode in GetCheckoutModeDescription");
+                    return null;
+            }
+        }
+
         static PullRequestDirectoryViewModel GetDirectory(string path, Dictionary<string, PullRequestDirectoryViewModel> dirs)
         {
             PullRequestDirectoryViewModel dir;

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

@@ -12,6 +12,13 @@ IObservable<IPullRequestModel> CreatePullRequest(IRepositoryHost host,
             IBranch sourceBranch, IBranch targetBranch,
             string title, string body);
 
+        /// <summary>
+        /// Checks whether the specified repository is in a clean state that will allow a checkout.
+        /// </summary>
+        /// <param name="repository">The repository.</param>
+        /// <returns></returns>
+        IObservable<bool> CleanForCheckout(ILocalRepositoryModel repository);
+
         /// <summary>
         /// Fetches a pull request to a local branch and checks out the branch.
         /// </summary>

src/GitHub.Exports.Reactive/ViewModels/IPullRequestDetailViewModel.cs

@@ -149,6 +149,11 @@ public interface IPullRequestDetailViewModel : IViewModel, IHasBusy
         /// </summary>
         int CommitsBehind { get; }
 
+        /// <summary>
+        /// Gets a message indicating the why the <see cref="Checkout"/> command is disabled.
+        /// </summary>
+        string CheckoutDisabledMessage { get; }
+
         /// <summary>
         /// Gets a command that checks out the pull request locally.
         /// </summary>

src/GitHub.VisualStudio/UI/Views/PullRequestDetailView.xaml

@@ -19,7 +19,9 @@
     <d:DesignProperties.DataContext>
         <Binding>
             <Binding.Source>
-                <sampleData:PullRequestDetailViewModelDesigner CheckoutMode="NeedsPull" CommitsBehind="2"/>
+                <sampleData:PullRequestDetailViewModelDesigner CheckoutMode="NeedsPull" 
+                                                               CommitsBehind="2"
+                                                               CheckoutDisabledMessage="Cannot update branch as your working directory has uncommitted changes."/>
             </Binding.Source>
         </Binding>
     </d:DesignProperties.DataContext>
@@ -219,6 +221,21 @@
                     </TextBlock.Style>
                 </TextBlock>
 
+                <!-- Checkout disabled message -->
+                <TextBlock Margin="0 4" TextWrapping="Wrap">
+                    <ui:OcticonImage Icon="alert" Foreground="Orange" Margin="0 0 0 -4"/>
+                    <Run Text="{Binding CheckoutDisabledMessage}"/>
+                    <TextBlock.Style>
+                        <Style TargetType="TextBlock">
+                            <Style.Triggers>
+                                <DataTrigger Binding="{Binding CheckoutDisabledMessage}" Value="{x:Null}">
+                                    <Setter Property="Visibility" Value="Collapsed" />
+                                </DataTrigger>
+                            </Style.Triggers>
+                        </Style>
+                    </TextBlock.Style>
+                </TextBlock>
+
                 <!-- Checkout error message -->
                 <TextBlock Foreground="Red" Margin="0 4" Text="{Binding CheckoutError}" TextWrapping="Wrap">
                     <TextBlock.Style>

src/UnitTests/GitHub.App/Services/PullRequestServiceTests.cs

@@ -82,7 +82,7 @@ public void DefaultLocalBranchNameShouldNotClashWithExistingBranchNames()
             Assert.Equal("pr/123-foo1-3", result);
         }
 
-        private static IGitService MockGitService()
+        static IGitService MockGitService()
         {
             var repository = Substitute.For<IRepository>();
             var branches = MockBranches("pr/123-foo1", "pr/123-foo1-2");
@@ -94,7 +94,7 @@ private static IGitService MockGitService()
         }
     }
 
-    private static BranchCollection MockBranches(params string[] names)
+    static BranchCollection MockBranches(params string[] names)
     {
         var result = Substitute.For<BranchCollection>();