feature: merge multiple heads (#793)

* feature: allow merging multiple heads
* feature: allow merging multiple branches from branch tree

src/Commands/Merge.cs

@@ -4,13 +4,15 @@ namespace SourceGit.Commands
 {
     public class Merge : Command
     {
-        public Merge(string repo, string source, string mode, Action<string> outputHandler)
+        public Merge(string repo, string source, string mode, string strategy, Action<string> outputHandler)
         {
             _outputHandler = outputHandler;
             WorkingDirectory = repo;
             Context = repo;
             TraitErrorAsOutput = true;
-            Args = $"merge --progress {source} {mode}";
+            if (strategy != null)
+                strategy = string.Concat("--strategy=", strategy);
+            Args = $"merge --progress {strategy} {source} {mode}";
         }
 
         protected override void OnReadline(string line)

src/Models/MergeStrategy.cs

@@ -0,0 +1,24 @@
+using System.Collections.Generic;
+
+namespace SourceGit.Models
+{
+    public class MergeStrategy
+    {
+        public string Name { get; internal set; }
+        public string Desc { get; internal set; }
+        public string Arg { get; internal set; }
+
+        public static List<MergeStrategy> ForMultiple { get; private set; } = [
+            new MergeStrategy(string.Empty, "Let Git automatically select a strategy", null),
+            new MergeStrategy("Octopus", "Attempt merging multiple heads", "octopus"),
+            new MergeStrategy("Ours", "Record the merge without modifying the tree", "ours"),
+            ];
+
+        public MergeStrategy(string n, string d, string a)
+        {
+            Name = n;
+            Desc = d;
+            Arg = a;
+        }
+    }
+}

src/Resources/Locales/en_US.axaml

@@ -58,6 +58,7 @@
   <x:String x:Key="Text.BranchCM.FetchInto" xml:space="preserve">Fetch ${0}$ into ${1}$...</x:String>
   <x:String x:Key="Text.BranchCM.Finish" xml:space="preserve">Git Flow - Finish ${0}$</x:String>
   <x:String x:Key="Text.BranchCM.Merge" xml:space="preserve">Merge ${0}$ into ${1}$...</x:String>
+  <x:String x:Key="Text.BranchCM.MergeMultiBranches" xml:space="preserve">Merge selected {0} branches</x:String>
   <x:String x:Key="Text.BranchCM.Pull" xml:space="preserve">Pull ${0}$</x:String>
   <x:String x:Key="Text.BranchCM.PullInto" xml:space="preserve">Pull ${0}$ into ${1}$...</x:String>
   <x:String x:Key="Text.BranchCM.Push" xml:space="preserve">Push ${0}$</x:String>
@@ -110,6 +111,7 @@
   <x:String x:Key="Text.CommitCM.CopySHA" xml:space="preserve">Copy SHA</x:String>
   <x:String x:Key="Text.CommitCM.CustomAction" xml:space="preserve">Custom Action</x:String>
   <x:String x:Key="Text.CommitCM.InteractiveRebase" xml:space="preserve">Interactive Rebase ${0}$ to Here</x:String>
+  <x:String x:Key="Text.CommitCM.MergeMultiple" xml:space="preserve">Merge ...</x:String>
   <x:String x:Key="Text.CommitCM.Rebase" xml:space="preserve">Rebase ${0}$ to Here</x:String>
   <x:String x:Key="Text.CommitCM.Reset" xml:space="preserve">Reset ${0}$ to Here</x:String>
   <x:String x:Key="Text.CommitCM.Revert" xml:space="preserve">Revert Commit</x:String>
@@ -404,6 +406,10 @@
   <x:String x:Key="Text.Merge.Into" xml:space="preserve">Into:</x:String>
   <x:String x:Key="Text.Merge.Mode" xml:space="preserve">Merge Option:</x:String>
   <x:String x:Key="Text.Merge.Source" xml:space="preserve">Source Branch:</x:String>
+  <x:String x:Key="Text.MergeMultiple" xml:space="preserve">Merge commits</x:String>
+  <x:String x:Key="Text.MergeMultiple.Commit" xml:space="preserve">Commit(s):</x:String>
+  <x:String x:Key="Text.MergeMultiple.CommitChanges" xml:space="preserve">Commit all changes</x:String>
+  <x:String x:Key="Text.MergeMultiple.Strategy" xml:space="preserve">Strategy:</x:String>
   <x:String x:Key="Text.MoveRepositoryNode" xml:space="preserve">Move Repository Node</x:String>
   <x:String x:Key="Text.MoveRepositoryNode.Target" xml:space="preserve">Select parent node for:</x:String>
   <x:String x:Key="Text.Name" xml:space="preserve">Name:</x:String>

src/ViewModels/Histories.cs

@@ -228,22 +228,28 @@ namespace SourceGit.ViewModels
             {
                 var selected = new List<Models.Commit>();
                 var canCherryPick = true;
+                var canMerge = true;
+
                 foreach (var item in list.SelectedItems)
                 {
                     if (item is Models.Commit c)
                     {
                         selected.Add(c);
 
-                        if (c.IsMerged || c.Parents.Count > 1)
+                        if (c.IsMerged)
+                        {
+                            canMerge = false;
                             canCherryPick = false;
+                        }
+                        else if (c.Parents.Count > 1)
+                        {
+                            canCherryPick = false;
+                        }
                     }
                 }
 
                 // Sort selected commits in order.
-                selected.Sort((l, r) =>
+                selected.Sort((l, r) => _commits.IndexOf(r) - _commits.IndexOf(l));
-                {
-                    return _commits.IndexOf(r) - _commits.IndexOf(l);
-                });
 
                 var multipleMenu = new ContextMenu();
 
@@ -259,9 +265,25 @@ namespace SourceGit.ViewModels
                         e.Handled = true;
                     };
                     multipleMenu.Items.Add(cherryPickMultiple);
-                    multipleMenu.Items.Add(new MenuItem() { Header = "-" });
                 }
 
+                if (canMerge)
+                {
+                    var mergeMultiple = new MenuItem();
+                    mergeMultiple.Header = App.Text("CommitCM.MergeMultiple");
+                    mergeMultiple.Icon = App.CreateMenuIcon("Icons.Merge");
+                    mergeMultiple.Click += (_, e) =>
+                    {
+                        if (PopupHost.CanCreatePopup())
+                            PopupHost.ShowPopup(new MergeMultiple(_repo, selected));
+                        e.Handled = true;
+                    };
+                    multipleMenu.Items.Add(mergeMultiple);
+                }
+
+                if (canCherryPick || canMerge)
+                    multipleMenu.Items.Add(new MenuItem() { Header = "-" });
+
                 var saveToPatchMultiple = new MenuItem();
                 saveToPatchMultiple.Icon = App.CreateMenuIcon("Icons.Diff");
                 saveToPatchMultiple.Header = App.Text("CommitCM.SaveAsPatch");

src/ViewModels/Merge.cs

@@ -37,7 +37,7 @@ namespace SourceGit.ViewModels
 
             return Task.Run(() =>
             {
-                var succ = new Commands.Merge(_repo.FullPath, Source, SelectedMode.Arg, SetProgressDescription).Exec();
+                var succ = new Commands.Merge(_repo.FullPath, Source, SelectedMode.Arg, null, SetProgressDescription).Exec();
                 CallUIThread(() => _repo.SetWatcherEnabled(true));
                 return succ;
             });

src/ViewModels/MergeMultiple.cs

@@ -0,0 +1,59 @@
+using System.Collections.Generic;
+using System.Threading.Tasks;
+using SourceGit.Models;
+
+namespace SourceGit.ViewModels
+{
+    public class MergeMultiple : Popup
+    {
+        public List<string> Strategies = ["octopus", "ours"];
+
+        public List<Commit> Targets
+        {
+            get;
+            private set;
+        }
+
+        public bool AutoCommit
+        {
+            get;
+            set;
+        }
+
+        public MergeStrategy Strategy
+        {
+            get;
+            set;
+        }
+
+        public MergeMultiple(Repository repo, List<Commit> targets)
+        {
+            _repo = repo;
+            Targets = targets;
+            AutoCommit = true;
+            Strategy = MergeStrategy.ForMultiple.Find(s => s.Arg == null);
+            View = new Views.MergeMultiple() { DataContext = this };
+        }
+
+        public override Task<bool> Sure()
+        {
+            _repo.SetWatcherEnabled(false);
+            ProgressDescription = "Merge head(s) ...";
+
+            return Task.Run(() =>
+            {
+                var succ = new Commands.Merge(
+                    _repo.FullPath,
+                    string.Join(" ", Targets.ConvertAll(c => c.Decorators.Find(d => d.Type == DecoratorType.RemoteBranchHead || d.Type == DecoratorType.LocalBranchHead)?.Name ?? c.Decorators.Find(d => d.Type == DecoratorType.Tag)?.Name ?? c.SHA)),
+                    AutoCommit ? string.Empty : "--no-commit",
+                    Strategy?.Arg,
+                    SetProgressDescription).Exec();
+
+                CallUIThread(() => _repo.SetWatcherEnabled(true));
+                return succ;
+            });
+        }
+
+        private readonly Repository _repo = null;
+    }
+}

src/ViewModels/Pull.cs

@@ -172,7 +172,7 @@ namespace SourceGit.ViewModels
                     else
                     {
                         SetProgressDescription($"Merge {_selectedBranch.FriendlyName} into {_current.Name} ...");
-                        rs = new Commands.Merge(_repo.FullPath, _selectedBranch.FriendlyName, "", SetProgressDescription).Exec();
+                        rs = new Commands.Merge(_repo.FullPath, _selectedBranch.FriendlyName, "", null, SetProgressDescription).Exec();
                     }
                 }
                 else

src/ViewModels/Repository.cs

@@ -13,6 +13,7 @@ using Avalonia.Media.Imaging;
 using Avalonia.Threading;
 
 using CommunityToolkit.Mvvm.ComponentModel;
+using SourceGit.Models;
 
 namespace SourceGit.ViewModels
 {
@@ -950,6 +951,12 @@ namespace SourceGit.ViewModels
                 PopupHost.ShowPopup(new DeleteMultipleBranches(this, branches, isLocal));
         }
 
+        public void MergeMultipleBranches(List<Models.Branch> branches)
+        {
+            if (PopupHost.CanCreatePopup())
+                PopupHost.ShowPopup(new MergeMultiple(this, branches.ConvertAll(b => _histories?.Commits?.Find(c => c.SHA == b.Head))));
+        }
+
         public void CreateNewTag()
         {
             if (_currentBranch == null)

src/Views/BranchTree.axaml.cs

@@ -405,6 +405,17 @@ namespace SourceGit.Views
                     ev.Handled = true;
                 };
                 menu.Items.Add(deleteMulti);
+
+                var mergeMulti = new MenuItem();
+                mergeMulti.Header = App.Text("BranchCM.MergeMultiBranches", branches.Count);
+                mergeMulti.Icon = App.CreateMenuIcon("Icons.Merge");
+                mergeMulti.Click += (_, ev) =>
+                {
+                    repo.MergeMultipleBranches(branches);
+                    ev.Handled = true;
+                };
+                menu.Items.Add(mergeMulti);
+
                 menu?.Open(this);
             }
         }

src/Views/MergeMultiple.axaml

@@ -0,0 +1,79 @@
+<UserControl xmlns="https://github.com/avaloniaui"
+             xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
+             xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
+             xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
+             xmlns:m="using:SourceGit.Models"
+             xmlns:vm="using:SourceGit.ViewModels"
+             xmlns:c="using:SourceGit.Converters"
+             mc:Ignorable="d" d:DesignWidth="800" d:DesignHeight="450"
+             x:Class="SourceGit.Views.MergeMultiple"
+             x:DataType="vm:MergeMultiple">
+  <StackPanel Orientation="Vertical" Margin="8,0">
+    <TextBlock FontSize="18"
+               Classes="bold"
+               Text="{DynamicResource Text.MergeMultiple}"/>
+    <Grid Margin="0,16,0,0" RowDefinitions="Auto,32,32" ColumnDefinitions="100,*">
+      <TextBlock Grid.Row="0" Grid.Column="0"
+                 HorizontalAlignment="Right" VerticalAlignment="Center"
+                 Margin="0,0,8,0"
+                 Text="{DynamicResource Text.MergeMultiple.Commit}"/>
+      <ListBox Grid.Row="0" Grid.Column="1"
+               MinHeight="32" MaxHeight="100"
+               ItemsSource="{Binding Targets}"
+               Background="{DynamicResource Brush.Contents}"
+               BorderThickness="1"
+               BorderBrush="{DynamicResource Brush.Border2}"
+               Padding="4"
+               CornerRadius="4"
+               ScrollViewer.HorizontalScrollBarVisibility="Disabled"
+               ScrollViewer.VerticalScrollBarVisibility="Auto">
+        <ListBox.Styles>
+          <Style Selector="ListBoxItem">
+            <Setter Property="Padding" Value="4,0"/>
+            <Setter Property="Height" Value="26"/>
+            <Setter Property="CornerRadius" Value="4"/>
+          </Style>
+        </ListBox.Styles>
+
+        <ListBox.ItemsPanel>
+          <ItemsPanelTemplate>
+            <StackPanel Orientation="Vertical"/>
+          </ItemsPanelTemplate>
+        </ListBox.ItemsPanel>
+
+        <ListBox.ItemTemplate>
+          <DataTemplate DataType="m:Commit">
+            <Grid ColumnDefinitions="14,Auto,*">
+              <Path Grid.Column="0" Width="14" Height="14" Margin="0,8,0,0" Data="{StaticResource Icons.Commit}"/>
+              <TextBlock Grid.Column="1" FontFamily="{DynamicResource Fonts.Monospace}" VerticalAlignment="Center" Text="{Binding SHA, Converter={x:Static c:StringConverters.ToShortSHA}}" Foreground="DarkOrange" Margin="6,0,4,0"/>
+              <TextBlock Grid.Column="2" VerticalAlignment="Center" Text="{Binding Subject}" TextTrimming="CharacterEllipsis"/>
+            </Grid>
+          </DataTemplate>
+        </ListBox.ItemTemplate>
+      </ListBox>
+      
+      <CheckBox Grid.Row="1" Grid.Column="1"
+                Content="{DynamicResource Text.MergeMultiple.CommitChanges}"
+                IsChecked="{Binding AutoCommit, Mode=TwoWay}"/>
+
+      <TextBlock Grid.Row="2" Grid.Column="0"
+                 HorizontalAlignment="Right" VerticalAlignment="Center"
+                 Margin="0,0,8,0"
+                 Text="{DynamicResource Text.MergeMultiple.Strategy}"/>
+      <ComboBox Grid.Row="2" Grid.Column="1"
+                Height="28" Padding="8,0"
+                VerticalAlignment="Center" HorizontalAlignment="Stretch"
+                ItemsSource="{Binding Source={x:Static m:MergeStrategy.ForMultiple}}"
+                SelectedItem="{Binding Strategy, Mode=TwoWay}">
+        <ComboBox.ItemTemplate>
+          <DataTemplate DataType="m:MergeStrategy">
+            <StackPanel Orientation="Horizontal" Height="20" VerticalAlignment="Center">
+              <TextBlock Text="{Binding Name}"/>
+              <TextBlock Text="{Binding Desc}" Margin="8,0,0,0" FontSize="11" Foreground="{DynamicResource Brush.FG2}"/>
+            </StackPanel>
+          </DataTemplate>
+        </ComboBox.ItemTemplate>
+      </ComboBox>
+    </Grid>
+  </StackPanel>
+</UserControl>

src/Views/MergeMultiple.axaml.cs

@@ -0,0 +1,12 @@
+using Avalonia.Controls;
+
+namespace SourceGit.Views
+{
+    public partial class MergeMultiple : UserControl
+    {
+        public MergeMultiple()
+        {
+            InitializeComponent();
+        }
+    }
+}