From f8debc04876bc24eaa8d04731e30fed13d379cf8 Mon Sep 17 00:00:00 2001
From: Daniil Tatianin <99danilt@gmail.com>
Date: Wed, 23 Sep 2026 22:33:58 +0300
Subject: [PATCH] feature: configurable description guide length for commit
 messages

Add a `Description Guide Length` preference next to the existing subject
guide length. The commit message editor now:

- shows a `DESCRIPTION n/limit` counter (longest body line) with the same
  warning color and icon used for the subject
- draws the vertical column guide at the configured length instead of a
  hardcoded 80 columns

Since the working copy commit box, the reword editor in interactive
rebase, the commit template editor and the standalone editor mode all
share `CommitMessageToolBox`, the guide applies everywhere a message is
written. The default stays at 80 so existing users see no change.

Signed-off-by: Daniil Tatianin <99danilt@gmail.com>
---
 src/Resources/Locales/en_US.axaml       |  2 +
 src/Resources/Locales/zh_CN.axaml       |  2 +
 src/Resources/Locales/zh_TW.axaml       |  2 +
 src/ViewModels/Preferences.cs           |  7 +++
 src/Views/CommitMessageToolBox.axaml    | 18 +++++++
 src/Views/CommitMessageToolBox.axaml.cs | 72 ++++++++++++++++++++++++-
 src/Views/Preferences.axaml             | 39 ++++++++++----
 7 files changed, 131 insertions(+), 11 deletions(-)

diff --git a/src/Resources/Locales/en_US.axaml b/src/Resources/Locales/en_US.axaml
index 4dc15a4c36..2ac3000d4e 100644
--- a/src/Resources/Locales/en_US.axaml
+++ b/src/Resources/Locales/en_US.axaml
@@ -204,6 +204,7 @@
   <x:String x:Key="Text.CommitDetail.Info.SHA" xml:space="preserve">SHA</x:String>
   <x:String x:Key="Text.CommitDetail.Info.Signer" xml:space="preserve">Signer:</x:String>
   <x:String x:Key="Text.CommitDetail.Info.WebLinks" xml:space="preserve">Open in Browser</x:String>
+  <x:String x:Key="Text.CommitMessageTextBox.DescriptionCount" xml:space="preserve">DESCRIPTION</x:String>
   <x:String x:Key="Text.CommitMessageTextBox.Placeholder" xml:space="preserve">Enter commit message. Please use an empty-line to separate subject and description!</x:String>
   <x:String x:Key="Text.CommitMessageTextBox.SubjectCount" xml:space="preserve">SUBJECT</x:String>
   <x:String x:Key="Text.Compare" xml:space="preserve">Compare</x:String>
@@ -696,6 +697,7 @@
   <x:String x:Key="Text.Preferences.General" xml:space="preserve">GENERAL</x:String>
   <x:String x:Key="Text.Preferences.General.Check4UpdatesOnStartup" xml:space="preserve">Check for updates on startup</x:String>
   <x:String x:Key="Text.Preferences.General.DateFormat" xml:space="preserve">Date Format</x:String>
+  <x:String x:Key="Text.Preferences.General.DescriptionGuideLength" xml:space="preserve">Description Guide Length</x:String>
   <x:String x:Key="Text.Preferences.General.EnableCompactFolders" xml:space="preserve">Enable compact folders in changes tree</x:String>
   <x:String x:Key="Text.Preferences.General.Locale" xml:space="preserve">Language</x:String>
   <x:String x:Key="Text.Preferences.General.MaxHistoryCommits" xml:space="preserve">History Commits</x:String>
diff --git a/src/Resources/Locales/zh_CN.axaml b/src/Resources/Locales/zh_CN.axaml
index a7f35949ba..28f8eb8ae5 100644
--- a/src/Resources/Locales/zh_CN.axaml
+++ b/src/Resources/Locales/zh_CN.axaml
@@ -208,6 +208,7 @@
   <x:String x:Key="Text.CommitDetail.Info.SHA" xml:space="preserve">提交指纹</x:String>
   <x:String x:Key="Text.CommitDetail.Info.Signer" xml:space="preserve">签名者 ：</x:String>
   <x:String x:Key="Text.CommitDetail.Info.WebLinks" xml:space="preserve">浏览器中查看</x:String>
+  <x:String x:Key="Text.CommitMessageTextBox.DescriptionCount" xml:space="preserve">描述</x:String>
   <x:String x:Key="Text.CommitMessageTextBox.Placeholder" xml:space="preserve">请输入提交的信息。注意：主题与具体描述中间需要空白行分隔！</x:String>
   <x:String x:Key="Text.CommitMessageTextBox.SubjectCount" xml:space="preserve">主题</x:String>
   <x:String x:Key="Text.Compare" xml:space="preserve">比较</x:String>
@@ -700,6 +701,7 @@
   <x:String x:Key="Text.Preferences.General" xml:space="preserve">通用配置</x:String>
   <x:String x:Key="Text.Preferences.General.Check4UpdatesOnStartup" xml:space="preserve">启动时检测软件更新</x:String>
   <x:String x:Key="Text.Preferences.General.DateFormat" xml:space="preserve">日期时间格式</x:String>
+  <x:String x:Key="Text.Preferences.General.DescriptionGuideLength" xml:space="preserve">DESCRIPTION字数检测</x:String>
   <x:String x:Key="Text.Preferences.General.EnableCompactFolders" xml:space="preserve">在变更列表树中启用紧凑文件夹模式</x:String>
   <x:String x:Key="Text.Preferences.General.Locale" xml:space="preserve">显示语言</x:String>
   <x:String x:Key="Text.Preferences.General.MaxHistoryCommits" xml:space="preserve">最大历史提交数</x:String>
diff --git a/src/Resources/Locales/zh_TW.axaml b/src/Resources/Locales/zh_TW.axaml
index 85612abe12..ac0d36a326 100644
--- a/src/Resources/Locales/zh_TW.axaml
+++ b/src/Resources/Locales/zh_TW.axaml
@@ -198,6 +198,7 @@
   <x:String x:Key="Text.CommitDetail.Info.SHA" xml:space="preserve">提交編號</x:String>
   <x:String x:Key="Text.CommitDetail.Info.Signer" xml:space="preserve">簽署人:</x:String>
   <x:String x:Key="Text.CommitDetail.Info.WebLinks" xml:space="preserve">在瀏覽器中檢視</x:String>
+  <x:String x:Key="Text.CommitMessageTextBox.DescriptionCount" xml:space="preserve">描述</x:String>
   <x:String x:Key="Text.CommitMessageTextBox.Placeholder" xml:space="preserve">請輸入提交訊息，標題與詳細描述之間請使用單行空白區隔。</x:String>
   <x:String x:Key="Text.CommitMessageTextBox.SubjectCount" xml:space="preserve">標題</x:String>
   <x:String x:Key="Text.Compare" xml:space="preserve">比較</x:String>
@@ -690,6 +691,7 @@
   <x:String x:Key="Text.Preferences.General" xml:space="preserve">一般設定</x:String>
   <x:String x:Key="Text.Preferences.General.Check4UpdatesOnStartup" xml:space="preserve">啟動時檢查軟體更新</x:String>
   <x:String x:Key="Text.Preferences.General.DateFormat" xml:space="preserve">日期時間格式</x:String>
+  <x:String x:Key="Text.Preferences.General.DescriptionGuideLength" xml:space="preserve">提交描述字數偵測</x:String>
   <x:String x:Key="Text.Preferences.General.EnableCompactFolders" xml:space="preserve">在樹狀變更目錄中啟用密集資料夾模式</x:String>
   <x:String x:Key="Text.Preferences.General.Locale" xml:space="preserve">顯示語言</x:String>
   <x:String x:Key="Text.Preferences.General.MaxHistoryCommits" xml:space="preserve">最大歷史提交數</x:String>
diff --git a/src/ViewModels/Preferences.cs b/src/ViewModels/Preferences.cs
index 4803ec4296..c1fa46e0d9 100644
--- a/src/ViewModels/Preferences.cs
+++ b/src/ViewModels/Preferences.cs
@@ -141,6 +141,12 @@ public int SubjectGuideLength
             set => SetProperty(ref _subjectGuideLength, value);
         }
 
+        public int DescriptionGuideLength
+        {
+            get => _descriptionGuideLength;
+            set => SetProperty(ref _descriptionGuideLength, value);
+        }
+
         public int DateTimeFormat
         {
             get => Models.DateTimeFormat.ActiveIndex;
@@ -820,6 +826,7 @@ private bool RemoveInvalidRepositoriesRecursive(List<RepositoryNode> collection)
 
         private int _maxHistoryCommits = 20000;
         private int _subjectGuideLength = 50;
+        private int _descriptionGuideLength = 80;
         private bool _useFixedTabWidth = true;
         private bool _useAutoHideScrollBars = true;
         private bool _useGitHubStyleAvatar = true;
diff --git a/src/Views/CommitMessageToolBox.axaml b/src/Views/CommitMessageToolBox.axaml
index 8f65e5372c..5ca9490dac 100644
--- a/src/Views/CommitMessageToolBox.axaml
+++ b/src/Views/CommitMessageToolBox.axaml
@@ -21,6 +21,7 @@
                                 Text="{Binding #ThisControl.CommitMessage, Mode=TwoWay}"
                                 Watermark="{DynamicResource Text.CommitMessageTextBox.Placeholder}"
                                 SubjectGuideLength="{Binding Source={x:Static vm:Preferences.Instance}, Path=SubjectGuideLength, Mode=OneWay}"
+                                DescriptionGuideLength="{Binding Source={x:Static vm:Preferences.Instance}, Path=DescriptionGuideLength, Mode=OneWay}"
                                 GuideLineBrush="{DynamicResource Brush.Border2}"
                                 FontFamily="{DynamicResource Fonts.Monospace}">
           <v:CommitMessageTextBox.Styles>
@@ -138,6 +139,23 @@
                        Text="{Binding #Editor.SubjectGuideLength, Mode=OneWay}"
                        VerticalAlignment="Center"/>
             <Path Width="10" Height="10" Margin="4,0,0,0" Data="{StaticResource Icons.Error}" Fill="DarkGoldenrod" IsVisible="{Binding #Editor.WarnSubjectLength, Mode=OneWay}"/>
+            <TextBlock Classes="info_label"
+                       Margin="12,0,0,0"
+                       FontSize="13"
+                       HorizontalAlignment="Left"
+                       Text="{DynamicResource Text.CommitMessageTextBox.DescriptionCount}"/>
+            <TextBlock Margin="8,0,0,0"
+                       FontSize="11"
+                       Text="{Binding #Editor.DescriptionLength}"
+                       Foreground="{Binding #Editor.WarnDescriptionLength, Converter={x:Static c:BoolConverters.IsWarningToBrush}, Mode=OneWay}"
+                       VerticalAlignment="Center"/>
+            <TextBlock FontSize="11"
+                       Text="/"
+                       VerticalAlignment="Center"/>
+            <TextBlock FontSize="11"
+                       Text="{Binding #Editor.DescriptionGuideLength, Mode=OneWay}"
+                       VerticalAlignment="Center"/>
+            <Path Width="10" Height="10" Margin="4,0,0,0" Data="{StaticResource Icons.Error}" Fill="DarkGoldenrod" IsVisible="{Binding #Editor.WarnDescriptionLength, Mode=OneWay}"/>
           </StackPanel>
         </Grid>
       </Border>
diff --git a/src/Views/CommitMessageToolBox.axaml.cs b/src/Views/CommitMessageToolBox.axaml.cs
index 373e737261..ba447e9761 100644
--- a/src/Views/CommitMessageToolBox.axaml.cs
+++ b/src/Views/CommitMessageToolBox.axaml.cs
@@ -81,6 +81,40 @@ public bool WarnSubjectLength
             set => SetAndRaise(WarnSubjectLengthProperty, ref _warnSubjectLen, value);
         }
 
+        public static readonly DirectProperty<CommitMessageTextBox, int> DescriptionLengthProperty =
+            AvaloniaProperty.RegisterDirect<CommitMessageTextBox, int>(
+                nameof(DescriptionLength),
+                static o => o.DescriptionLength);
+
+        public int DescriptionLength
+        {
+            get => _descriptionLen;
+            set => SetAndRaise(DescriptionLengthProperty, ref _descriptionLen, value);
+        }
+
+        public static readonly DirectProperty<CommitMessageTextBox, int> DescriptionGuideLengthProperty =
+            AvaloniaProperty.RegisterDirect<CommitMessageTextBox, int>(
+                nameof(DescriptionGuideLength),
+                static o => o.DescriptionGuideLength,
+                static (o, v) => o.DescriptionGuideLength = v);
+
+        public int DescriptionGuideLength
+        {
+            get => _descriptionGuideLen;
+            set => SetAndRaise(DescriptionGuideLengthProperty, ref _descriptionGuideLen, value);
+        }
+
+        public static readonly DirectProperty<CommitMessageTextBox, bool> WarnDescriptionLengthProperty =
+            AvaloniaProperty.RegisterDirect<CommitMessageTextBox, bool>(
+                nameof(WarnDescriptionLength),
+                static o => o.WarnDescriptionLength);
+
+        public bool WarnDescriptionLength
+        {
+            get => _warnDescriptionLen;
+            set => SetAndRaise(WarnDescriptionLengthProperty, ref _warnDescriptionLen, value);
+        }
+
         public static readonly DirectProperty<CommitMessageTextBox, List<CommitMessageTextBoxSuggestion>> SuggestionsProperty =
             AvaloniaProperty.RegisterDirect<CommitMessageTextBox, List<CommitMessageTextBoxSuggestion>>(
                 nameof(Suggestions),
@@ -173,7 +207,7 @@ public override void Render(DrawingContext context)
                 new Typeface(font),
                 ViewModels.Preferences.Instance.DefaultFontSize,
                 Brushes.White);
-            var columnGuideX = columnTest.WidthIncludingTrailingWhitespace * 80 + 5.5;
+            var columnGuideX = columnTest.WidthIncludingTrailingWhitespace * _descriptionGuideLen + 5.5;
             context.DrawLine(pen, new Point(columnGuideX, Math.Max(0, y)), new Point(columnGuideX, Bounds.Height));
         }
 
@@ -209,10 +243,12 @@ protected override void OnPropertyChanged(AvaloniaPropertyChangedEventArgs chang
                 {
                     _subjectEndCharIdx = -1;
                     SubjectLength = 0;
+                    DescriptionLength = 0;
                     return;
                 }
 
                 var subjectLen = 0;
+                var descriptionLen = 0;
                 var lastNonLineBreakCharIdx = 0;
                 var lastLineStart = 0;
                 for (var i = 0; i < text.Length; i++)
@@ -226,7 +262,10 @@ protected override void OnPropertyChanged(AvaloniaPropertyChangedEventArgs chang
                         if (string.IsNullOrWhiteSpace(line))
                         {
                             if (subjectLen > 0)
+                            {
+                                descriptionLen = GetMaxLineLength(text, lastLineStart);
                                 break;
+                            }
 
                             continue;
                         }
@@ -253,12 +292,18 @@ protected override void OnPropertyChanged(AvaloniaPropertyChangedEventArgs chang
                 }
 
                 SubjectLength = subjectLen;
+                DescriptionLength = descriptionLen;
                 _subjectEndCharIdx = lastNonLineBreakCharIdx;
             }
             else if (change.Property == SubjectLengthProperty || change.Property == SubjectGuideLengthProperty)
             {
                 WarnSubjectLength = _subjectLen > _subjectGuideLen;
             }
+            else if (change.Property == DescriptionLengthProperty || change.Property == DescriptionGuideLengthProperty)
+            {
+                WarnDescriptionLength = _descriptionLen > _descriptionGuideLen;
+                InvalidateVisual();
+            }
             else if (change.Property == SubjectEndYProperty)
             {
                 InvalidateVisual();
@@ -377,6 +422,28 @@ protected override void OnKeyDown(KeyEventArgs e)
                 base.OnKeyDown(e);
         }
 
+        private static int GetMaxLineLength(string text, int start)
+        {
+            var maxLen = 0;
+            var lineStart = start;
+            for (var i = start; i <= text.Length; i++)
+            {
+                if (i == text.Length || text[i] == '\n')
+                {
+                    var lineLen = i - lineStart;
+                    while (lineLen > 0 && char.IsWhiteSpace(text[lineStart + lineLen - 1]))
+                        lineLen--;
+
+                    if (lineLen > maxLen)
+                        maxLen = lineLen;
+
+                    lineStart = i + 1;
+                }
+            }
+
+            return maxLen;
+        }
+
         private void OnLayoutUpdated(object sender, EventArgs e)
         {
             if (_textPresenter == null || !IsEffectivelyVisible)
@@ -447,6 +514,9 @@ private void OnLayoutUpdated(object sender, EventArgs e)
         private int _subjectEndCharIdx = -1;
         private double _subjectEndY = 0;
         private bool _warnSubjectLen = false;
+        private int _descriptionLen = 0;
+        private int _descriptionGuideLen = 80;
+        private bool _warnDescriptionLen = false;
         private int _suggestionMatchStartIdx = -1;
         private List<CommitMessageTextBoxSuggestion> _suggestions = null;
         private int _selectedSuggestionIdx = 0;
diff --git a/src/Views/Preferences.axaml b/src/Views/Preferences.axaml
index 55c2b17276..6960d93be7 100644
--- a/src/Views/Preferences.axaml
+++ b/src/Views/Preferences.axaml
@@ -47,7 +47,7 @@
           <TabItem.Header>
             <TextBlock Classes="tab_header" Text="{DynamicResource Text.Preferences.General}"/>
           </TabItem.Header>
-          <Grid Margin="8" RowDefinitions="32,32,32,32,32,32,32,32,32,32,32,32,Auto" ColumnDefinitions="Auto,*">
+          <Grid Margin="8" RowDefinitions="32,32,32,32,32,32,32,32,32,32,32,32,32,Auto" ColumnDefinitions="Auto,*">
             <TextBlock Grid.Row="0" Grid.Column="0"
                        Text="{DynamicResource Text.Preferences.General.Locale}"
                        HorizontalAlignment="Right"
@@ -123,10 +123,29 @@
             </Grid>
 
             <TextBlock Grid.Row="4" Grid.Column="0"
-                       Text="{DynamicResource Text.Preferences.General.MaxHistoryCommits}"
+                       Text="{DynamicResource Text.Preferences.General.DescriptionGuideLength}"
                        HorizontalAlignment="Right"
                        Margin="0,0,16,0"/>
             <Grid Grid.Row="4" Grid.Column="1" ColumnDefinitions="*,64">
+              <Slider Grid.Column="0"
+                      Minimum="50" Maximum="200"
+                      TickPlacement="BottomRight" TickFrequency="10"
+                      IsSnapToTickEnabled="False"
+                      VerticalAlignment="Center"
+                      Foreground="{DynamicResource Brush.Border1}"
+                      Value="{Binding DescriptionGuideLength, Mode=TwoWay}"/>
+
+              <TextBlock Grid.Column="1"
+                         HorizontalAlignment="Right" VerticalAlignment="Center"
+                         Foreground="{DynamicResource Brush.FG1}"
+                         Text="{Binding DescriptionGuideLength, Mode=OneWay}"/>
+            </Grid>
+
+            <TextBlock Grid.Row="5" Grid.Column="0"
+                       Text="{DynamicResource Text.Preferences.General.MaxHistoryCommits}"
+                       HorizontalAlignment="Right"
+                       Margin="0,0,16,0"/>
+            <Grid Grid.Row="5" Grid.Column="1" ColumnDefinitions="*,64">
               <Slider Grid.Column="0"
                       Minimum="5000" Maximum="100000"
                       TickPlacement="BottomRight" TickFrequency="5000"
@@ -141,42 +160,42 @@
                          Text="{Binding MaxHistoryCommits}"/>
             </Grid>
 
-            <CheckBox Grid.Row="5" Grid.Column="1"
+            <CheckBox Grid.Row="6" Grid.Column="1"
                       Height="32"
                       Content="{DynamicResource Text.Preferences.General.ShowChangesPageByDefault}"
                       IsChecked="{Binding ShowLocalChangesByDefault, Mode=TwoWay}"/>
 
-            <CheckBox Grid.Row="6" Grid.Column="1"
+            <CheckBox Grid.Row="7" Grid.Column="1"
                       Height="32"
                       Content="{DynamicResource Text.Preferences.General.ShowChangesTabInCommitDetailByDefault}"
                       IsChecked="{Binding ShowChangesInCommitDetailByDefault, Mode=TwoWay}"/>
 
-            <CheckBox Grid.Row="7" Grid.Column="1"
+            <CheckBox Grid.Row="8" Grid.Column="1"
                       Height="32"
                       Content="{DynamicResource Text.Preferences.General.ShowTagsInGraph}"
                       IsChecked="{Binding ShowTagsInGraph, Mode=TwoWay}"/>
 
-            <CheckBox Grid.Row="8" Grid.Column="1"
+            <CheckBox Grid.Row="9" Grid.Column="1"
                       Height="32"
                       Content="{DynamicResource Text.Preferences.General.ShowRelativeTimeInGraph}"
                       IsChecked="{Binding DisplayTimeAsPeriodInHistories, Mode=TwoWay}"/>
 
-            <CheckBox Grid.Row="9" Grid.Column="1"
+            <CheckBox Grid.Row="10" Grid.Column="1"
                       Height="32"
                       Content="{DynamicResource Text.Preferences.General.UseCompactBranchNames}"
                       IsChecked="{Binding UseCompactBranchNamesInGraph, Mode=TwoWay}"/>
 
-            <CheckBox Grid.Row="10" Grid.Column="1"
+            <CheckBox Grid.Row="11" Grid.Column="1"
                       Height="32"
                       Content="{DynamicResource Text.Preferences.General.EnableCompactFolders}"
                       IsChecked="{Binding EnableCompactFoldersInChangesTree, Mode=TwoWay}"/>
 
-            <CheckBox Grid.Row="11" Grid.Column="1"
+            <CheckBox Grid.Row="12" Grid.Column="1"
                       Height="32"
                       Content="{DynamicResource Text.Preferences.General.UseGitHubStyleAvatar}"
                       IsChecked="{Binding UseGitHubStyleAvatar, Mode=TwoWay}"/>
 
-            <CheckBox Grid.Row="12" Grid.Column="1"
+            <CheckBox Grid.Row="13" Grid.Column="1"
                       Height="32"
                       Content="{DynamicResource Text.Preferences.General.Check4UpdatesOnStartup}"
                       IsVisible="{x:Static s:App.IsCheckForUpdateCommandVisible}"