Cancellation support for CustomDiffMergeTools (#9522)

When forms starting list of custom diff/merge tools are closed,
cancel the handling including the Git process.

CustomMergeTools: Decrease delay before listing

GitCommands/CustomDiffMergeToolCache.cs

@@ -47,7 +47,7 @@ public async Task ClearAsync()
         /// </summary>
         /// <param name="module">The Git module</param>
         /// <param name="delay">The delay before starting the operation</param>
-        public async Task<IEnumerable<string>> GetToolsAsync(GitModule module, int delay)
+        public async Task<IEnumerable<string>> GetToolsAsync(GitModule module, int delay, CancellationToken cancellationToken)
         {
             if (_tools is not null)
             {
@@ -56,17 +56,20 @@ public async Task<IEnumerable<string>> GetToolsAsync(GitModule module, int delay
 
             // The command will compete with other resources, avoid delaying startup
             // Do not bother with cancel tokens
-            await Task.Delay(delay);
+            await Task.Delay(delay, cancellationToken);
+
+            await _mutex.WaitAsync(cancellationToken).ConfigureAwait(false);
 
-            await _mutex.WaitAsync().ConfigureAwait(false);
             try
             {
                 if (_tools is null)
                 {
                     await TaskScheduler.Default;
+                    cancellationToken.ThrowIfCancellationRequested();
+
                     var toolKey = _isDiff ? SettingKeyString.DiffToolKey : SettingKeyString.MergeToolKey;
                     var defaultTool = module.GetEffectiveSetting(toolKey);
-                    string output = module.GetCustomDiffMergeTools(_isDiff);
+                    string output = module.GetCustomDiffMergeTools(_isDiff, cancellationToken);
                     _tools = ParseCustomDiffMergeTool(output, defaultTool);
                 }
             }

GitCommands/Git/GitModule.cs

@@ -3568,11 +3568,12 @@ public string GetFileText(ObjectId id, Encoding encoding)
         /// </summary>
         /// <param name="isDiff">diff or merge.</param>
         /// <returns>the Git output.</returns>
-        public string GetCustomDiffMergeTools(bool isDiff)
+        public string GetCustomDiffMergeTools(bool isDiff, CancellationToken cancellationToken)
         {
             // Note that --gui has no effect here
             GitArgumentBuilder args = new(isDiff ? "difftool" : "mergetool") { "--tool-help" };
-            return _gitExecutable.GetOutput(args);
+            ExecutionResult result = _gitExecutable.Execute(args, cancellationToken: cancellationToken);
+            return result.StandardOutput;
         }
 
         public string OpenWithDifftoolDirDiff(string? firstRevision, string? secondRevision, string? customTool = null)

GitUI/CommandsDialogs/FormCommit.cs

@@ -162,6 +162,7 @@ public sealed partial class FormCommit : GitModuleForm
         private readonly ToolStripMenuItem _addSelectionToCommitMessageToolStripMenuItem;
         private readonly AsyncLoader _unstagedLoader = new();
         private readonly bool _useFormCommitMessage = AppSettings.UseFormCommitMessage;
+        private readonly CancellationTokenSequence _customDiffToolsSequence = new();
         private readonly CancellationTokenSequence _interactiveAddSequence = new();
         private readonly CancellationTokenSequence _viewChangesSequence = new();
         private readonly SplitterManager _splitterManager = new(new AppSettingsPath("CommitDialog"));
@@ -411,6 +412,7 @@ protected override void Dispose(bool disposing)
             if (disposing)
             {
                 _unstagedLoader.Dispose();
+                _customDiffToolsSequence.Dispose();
                 _interactiveAddSequence.Dispose();
                 _viewChangesSequence.Dispose();
                 components?.Dispose();
@@ -629,7 +631,7 @@ public void LoadCustomDifftools()
                 new(stagedOpenDifftoolToolStripMenuItem9, stagedOpenDifftoolToolStripMenuItem9_Click),
             };
 
-            new CustomDiffMergeToolProvider().LoadCustomDiffMergeTools(Module, menus, components, isDiff: true);
+            new CustomDiffMergeToolProvider().LoadCustomDiffMergeTools(Module, menus, components, isDiff: true, cancellationToken: _customDiffToolsSequence.Next());
         }
 
         private void FileViewer_TopScrollReached(object sender, EventArgs e)

GitUI/CommandsDialogs/FormFileHistory.cs

@@ -31,6 +31,7 @@ public sealed partial class FormFileHistory : GitModuleForm
         private readonly FormBrowseMenus _formBrowseMenus;
         private readonly IFullPathResolver _fullPathResolver;
         private readonly FormFileHistoryController _controller = new();
+        private readonly CancellationTokenSequence _customDiffToolsSequence = new();
         private readonly CancellationTokenSequence _viewChangesSequence = new();
 
         private BuildReportTabPageExtension? _buildReportTabPageExtension;
@@ -177,6 +178,7 @@ protected override void Dispose(bool disposing)
             if (disposing)
             {
                 _asyncLoader.Dispose();
+                _customDiffToolsSequence.Dispose();
                 _viewChangesSequence.Dispose();
 
                 // if the form was instantiated by the translation app, all of the following would be null
@@ -215,7 +217,7 @@ public void LoadCustomDifftools()
             };
 
             const int ToolDelay = 10000;
-            new CustomDiffMergeToolProvider().LoadCustomDiffMergeTools(Module, menus, components, isDiff: true, ToolDelay);
+            new CustomDiffMergeToolProvider().LoadCustomDiffMergeTools(Module, menus, components, isDiff: true, ToolDelay, cancellationToken: _customDiffToolsSequence.Next());
         }
 
         private void LoadFileHistory()

GitUI/CommandsDialogs/FormResolveConflicts.cs

@@ -117,6 +117,7 @@ private enum ConflictResolutionPreference
         private int _filesDeletedLocallyAndModifiedRemotelySolved;
         private int _filesModifiedLocallyAndDeletedRemotelySolved;
         private int _conflictItemsCount;
+        private readonly CancellationTokenSequence _customDiffToolsSequence = new();
 
         [Obsolete("For VS designer and translation test only. Do not remove.")]
 #pragma warning disable CS8618 // Non-nullable field must contain a non-null value when exiting constructor. Consider declaring as nullable.
@@ -149,6 +150,17 @@ protected override void OnRuntimeLoad(EventArgs e)
             Hotkeys = HotkeySettingsManager.LoadHotkeys(HotkeySettingsName);
         }
 
+        protected override void Dispose(bool disposing)
+        {
+            if (disposing)
+            {
+                _customDiffToolsSequence.Dispose();
+                components?.Dispose();
+            }
+
+            base.Dispose(disposing);
+        }
+
         private void Mergetool_Click(object sender, EventArgs e)
         {
             using (WaitCursorScope.Enter())
@@ -302,8 +314,8 @@ private void LoadCustomMergetools()
                 new(customMergetool, customMergetool_Click),
             };
 
-            const int ToolDelay = 5000;
-            new CustomDiffMergeToolProvider().LoadCustomDiffMergeTools(Module, menus, components, isDiff: false, ToolDelay);
+            const int ToolDelay = 500;
+            new CustomDiffMergeToolProvider().LoadCustomDiffMergeTools(Module, menus, components, isDiff: false, ToolDelay, cancellationToken: _customDiffToolsSequence.Next());
         }
 
         private readonly Dictionary<string, string> _mergeScripts = new()

GitUI/CommandsDialogs/RevisionDiffControl.cs

@@ -43,6 +43,7 @@ public partial class RevisionDiffControl : GitModuleControl
         private readonly IFullPathResolver _fullPathResolver;
         private readonly IFindFilePredicateProvider _findFilePredicateProvider;
         private readonly IGitRevisionTester _gitRevisionTester;
+        private readonly CancellationTokenSequence _customDiffToolsSequence = new();
         private readonly CancellationTokenSequence _viewChangesSequence = new();
         private readonly RememberFileContextMenuController _rememberFileContextMenuController
             = RememberFileContextMenuController.Default;
@@ -187,7 +188,7 @@ public void LoadCustomDifftools()
                 new(diffTwoSelectedDifftoolToolStripMenuItem, diffTwoSelectedDiffToolToolStripMenuItem_Click)
             };
 
-            new CustomDiffMergeToolProvider().LoadCustomDiffMergeTools(Module, menus, components, isDiff: true);
+            new CustomDiffMergeToolProvider().LoadCustomDiffMergeTools(Module, menus, components, isDiff: true, cancellationToken: _customDiffToolsSequence.Next());
         }
 
         public void CancelLoadCustomDifftools()
@@ -257,6 +258,7 @@ protected override void Dispose(bool disposing)
         {
             if (disposing)
             {
+                _customDiffToolsSequence.Dispose();
                 _viewChangesSequence.Dispose();
                 components?.Dispose();
             }

GitUI/CustomDiffMergeToolProvider.cs

@@ -2,6 +2,7 @@
 using System.ComponentModel;
 using System.Drawing;
 using System.Linq;
+using System.Threading;
 using System.Threading.Tasks;
 using System.Windows.Forms;
 using GitCommands;
@@ -40,7 +41,7 @@ public async Task ClearAsync(bool isDiff)
         /// <param name="components">The calling Form components, to dispose correctly.</param>
         /// <param name="isDiff">True if diff, false if merge.</param>
         /// <param name="delay">The delay before starting the operation.</param>
-        public void LoadCustomDiffMergeTools(GitModule module, IList<CustomDiffMergeTool> menus, IContainer components, bool isDiff, int delay = FormBrowseToolDelay)
+        public void LoadCustomDiffMergeTools(GitModule module, IList<CustomDiffMergeTool> menus, IContainer components, bool isDiff, int delay = FormBrowseToolDelay, CancellationToken cancellationToken = default)
         {
             InitMenus(menus);
 
@@ -54,16 +55,17 @@ public void LoadCustomDiffMergeTools(GitModule module, IList<CustomDiffMergeTool
                 // get the tools, possibly with a delay as requesting requires considerable time
                 // cache is shared
                 List<string> tools = (await (isDiff ? CustomDiffMergeToolCache.DiffToolCache : CustomDiffMergeToolCache.MergeToolCache)
-                    .GetToolsAsync(module, delay))
+                    .GetToolsAsync(module, delay, cancellationToken))
                     .ToList();
 
-                if (tools.Count() <= 1)
+                if (tools.Count <= 1)
                 {
                     // No need to show the menu
                     return;
                 }
 
-                await ThreadHelper.JoinableTaskFactory.SwitchToMainThreadAsync();
+                await ThreadHelper.JoinableTaskFactory.SwitchToMainThreadAsync(cancellationToken);
+
                 foreach (var menu in menus)
                 {
                     menu.MenuItem.DropDown = new ContextMenuStrip(components);

GitUI/UserControls/RevisionGrid/RevisionGridControl.cs

@@ -108,6 +108,7 @@ public sealed partial class RevisionGridControl : GitModuleControl, IScriptHostC
         private DataGridViewColumn? _lastVisibleResizableColumn;
         private readonly ArtificialCommitChangeCount _workTreeChangeCount = new();
         private readonly ArtificialCommitChangeCount _indexChangeCount = new();
+        private readonly CancellationTokenSequence _customDiffToolsSequence = new();
 
         private RefFilterOptions _DONT_USE_ME_DIRECTLY_refFilterOptions = RefFilterOptions.All | RefFilterOptions.Boundary;
 
@@ -299,6 +300,7 @@ protected override void Dispose(bool disposing)
                 //// _revisionGraphColumnProvider not disposable
                 //// _selectionTimer handled by this.components
                 _buildServerWatcher?.Dispose();
+                _customDiffToolsSequence.Dispose();
 
                 if (_indexWatcher.IsValueCreated)
                 {
@@ -661,7 +663,7 @@ public void LoadCustomDifftools()
                 new(openCommitsWithDiffToolMenuItem, diffSelectedCommitsMenuItem_Click)
             };
 
-            new CustomDiffMergeToolProvider().LoadCustomDiffMergeTools(Module, menus, components, isDiff: true);
+            new CustomDiffMergeToolProvider().LoadCustomDiffMergeTools(Module, menus, components, isDiff: true, cancellationToken: _customDiffToolsSequence.Next());
         }
 
         public void CancelLoadCustomDifftools()