Fix: Fixed crash when switching git branches during merge conflict (#17894)

Signed-off-by: Saravanan G <workbysaran@gmail.com>
Co-authored-by: Yair <39923744+yaira2@users.noreply.github.com>

Author: workbysaran

src/Files.App/Data/Enums/GitCheckoutOptions.cs

@@ -23,6 +23,11 @@ public enum GitCheckoutOptions
 		/// </summary>
 		DiscardChanges,
 
+		/// <summary>
+		/// Abort merge and check out to the branch.
+		/// </summary>
+		AbortMerge,
+
 		/// <summary>
 		/// No operation to perform.
 		/// </summary>

src/Files.App/Helpers/Dialog/DynamicDialogFactory.cs

@@ -266,6 +266,53 @@ public static DynamicDialog GetFor_GitCheckoutConflicts(string checkoutBranchNam
 			return dialog;
 		}
 
+		public static DynamicDialog GetFor_GitMergeConflicts(string checkoutBranchName, string headBranchName)
+		{
+			DynamicDialog dialog = null!;
+
+			var optionsListView = new ListView()
+			{
+				ItemsSource = new string[]
+				{
+					string.Format(Strings.AbortMergeAndSwitch.GetLocalizedResource(), checkoutBranchName),
+					string.Format(Strings.StayAndResolveConflicts.GetLocalizedResource(), headBranchName)
+				},
+				SelectionMode = ListViewSelectionMode.Single
+			};
+			optionsListView.SelectedIndex = 0;
+
+			optionsListView.SelectionChanged += (listView, args) =>
+			{
+				dialog.ViewModel.AdditionalData = optionsListView.SelectedIndex == 0
+					? GitCheckoutOptions.AbortMerge
+					: GitCheckoutOptions.None;
+			};
+
+			dialog = new DynamicDialog(new DynamicDialogViewModel()
+			{
+				TitleText = Strings.SwitchBranch.GetLocalizedResource(),
+				PrimaryButtonText = Strings.Confirm.GetLocalizedResource(),
+				CloseButtonText = Strings.Cancel.GetLocalizedResource(),
+				SubtitleText = Strings.MergeInProgress.GetLocalizedResource(),
+				DisplayControl = new Grid()
+				{
+					MinWidth = 250d,
+					Children =
+					{
+						optionsListView
+					}
+				},
+				AdditionalData = GitCheckoutOptions.AbortMerge,
+				CloseButtonAction = (vm, e) =>
+				{
+					dialog.ViewModel.AdditionalData = GitCheckoutOptions.None;
+					vm.HideDialog();
+				}
+			});
+
+			return dialog;
+		}
+
 		public static DynamicDialog GetFor_GitHubConnectionError()
 		{
 			DynamicDialog dialog = new DynamicDialog(new DynamicDialogViewModel()

src/Files.App/Strings/en-US/Resources.resw

@@ -3132,6 +3132,15 @@
   <data name="UncommittedChanges" xml:space="preserve">
     <value>You have uncommitted changes on this branch. What would you like to do with them?</value>
   </data>
+  <data name="MergeInProgress" xml:space="preserve">
+    <value>You have an ongoing merge with unresolved conflicts. Please resolve the conflicts or abort the merge to switch branches.</value>
+  </data>
+  <data name="AbortMergeAndSwitch" xml:space="preserve">
+    <value>Abort merge and switch to '{0}'</value>
+  </data>
+  <data name="StayAndResolveConflicts" xml:space="preserve">
+    <value>Stay on '{0}' and resolve conflicts</value>
+  </data>
   <data name="SwitchBranch" xml:space="preserve">
     <value>Switch branch</value>
   </data>

src/Files.App/Utils/Git/GitHelpers.cs

@@ -194,7 +194,24 @@ public static async Task<bool> Checkout(string? repositoryPath, string? branch)
 
 			IsExecutingGitAction = true;
 
-			if (repository.RetrieveStatus().IsDirty)
+			if (repository.Index.Conflicts.Any())
+			{
+				var dialog = DynamicDialogFactory.GetFor_GitMergeConflicts(checkoutBranch.FriendlyName, repository.Head.FriendlyName);
+				await dialog.ShowAsync();
+
+				var resolveConflictOption = (GitCheckoutOptions)dialog.ViewModel.AdditionalData;
+
+				switch (resolveConflictOption)
+				{
+					case GitCheckoutOptions.None:
+						IsExecutingGitAction = false;
+						return false;
+					case GitCheckoutOptions.AbortMerge:
+						repository.Reset(ResetMode.Hard);
+						break;
+				}
+			}
+			else if (repository.RetrieveStatus().IsDirty)
 			{
 				var dialog = DynamicDialogFactory.GetFor_GitCheckoutConflicts(checkoutBranch.FriendlyName, repository.Head.FriendlyName);
 				await dialog.ShowAsync();
@@ -204,6 +221,7 @@ public static async Task<bool> Checkout(string? repositoryPath, string? branch)
 				switch (resolveConflictOption)
 				{
 					case GitCheckoutOptions.None:
+						IsExecutingGitAction = false;
 						return false;
 					case GitCheckoutOptions.DiscardChanges:
 						options.CheckoutModifiers = CheckoutModifiers.Force;
@@ -212,7 +230,10 @@ public static async Task<bool> Checkout(string? repositoryPath, string? branch)
 					case GitCheckoutOptions.StashChanges:
 						var signature = repository.Config.BuildSignature(DateTimeOffset.Now);
 						if (signature is null)
+						{
+							IsExecutingGitAction = false;
 							return false;
+						}
 
 						repository.Stashes.Add(signature);