refactor(RevisionDiffControl): Use simpler types

Refs: #12160

Directory.Packages.props

@@ -14,6 +14,7 @@
     <PackageVersion Include="LibGit2Sharp" Version="0.27.2" />
     <PackageVersion Include="Microsoft.SourceLink.GitHub" Version="1.1.1" />
     <PackageVersion Include="Microsoft.Toolkit.HighPerformance" Version="7.1.2" />
+    <PackageVersion Include="StrongOf" Version="1.2.4" />
     <PackageVersion Include="System.ComponentModel.Composition" Version="6.0.0" /> <!-- Required by GitExtensions.PluginManager -->
     <PackageVersion Include="Microsoft.VisualStudio.Composition" Version="17.2.41" />
     <PackageVersion Include="Microsoft.VisualStudio.Threading" Version="17.4.27" />

setup/installer/Product.wxs

@@ -197,6 +197,9 @@
       <Component Id="SpellChecker.dll" Guid="*">
         <File Source="$(var.ArtifactsPublishPath)\SpellChecker.dll" />
       </Component>
+      <Component Id="StrongOf.dll" Guid="*">
+        <File Source="$(var.ArtifactsPublishPath)\BenjaminAbt.StrongOf.dll" />
+      </Component>
       <Component Id="System.ComponentModel.Composition.dll" Guid="*">
         <File Source="$(var.ArtifactsPublishPath)\System.ComponentModel.Composition.dll" />
       </Component>
@@ -674,6 +677,7 @@
       <ComponentRef Id="SmartFormat.dll" />
       <ComponentRef Id="SmartFormat.ZString.dll" />
       <ComponentRef Id="SpellChecker.dll" />
+      <ComponentRef Id="StrongOf.dll" />
       <ComponentRef Id="System.ComponentModel.Composition.dll" />
       <ComponentRef Id="System.Composition.AttributedModel.dll" />
       <ComponentRef Id="System.Composition.Convention.dll" />

src/app/GitExtensions.Extensibility/Git/RelativePath.cs

@@ -0,0 +1,10 @@
+using StrongOf;
+
+namespace GitExtensions.Extensibility.Git;
+
+/// <summary>
+///  Contains a path relative to the root of a repository (with POSIX path separators).
+/// </summary>
+public sealed class RelativePath(string value) : StrongString<RelativePath>(value)
+{
+}

src/app/GitExtensions.Extensibility/GitExtensions.Extensibility.csproj

@@ -9,6 +9,7 @@
 
   <ItemGroup>
     <PackageReference Include="AdysTech.CredentialManager" />
+    <PackageReference Include="StrongOf" />
   </ItemGroup>
 
   <ItemGroup>

src/app/GitUI/CommandsDialogs/RevisionDiffControl.cs

@@ -46,9 +46,9 @@ namespace GitUI.CommandsDialogs
         private readonly RememberFileContextMenuController _rememberFileContextMenuController
             = RememberFileContextMenuController.Default;
         private Action? _refreshGitStatus;
-        private FileStatusItem? _selectedBlameItem;
+        private GitItemStatus? _selectedBlameItem;
         private string? _fallbackFollowedFile;
-        private FileStatusItem? _lastExplicitlySelectedItem;
+        private RelativePath? _lastExplicitlySelectedItem;
         private bool _isImplicitListSelection = false;
 
         public RevisionDiffControl()
@@ -310,7 +310,7 @@ namespace GitUI.CommandsDialogs
 
             // First try the last item explicitly selected
             if (_lastExplicitlySelectedItem is not null
-                && firstGroupItems.FirstOrDefault(i => i.Item.Name.Equals(_lastExplicitlySelectedItem.Item.Name))?.Item is GitItemStatus explicitItem)
+                && firstGroupItems.FirstOrDefault(i => i.Item.Name.Equals(_lastExplicitlySelectedItem.Value))?.Item is GitItemStatus explicitItem)
             {
                 DiffFiles.SelectedGitItem = explicitItem;
                 return;
@@ -628,17 +628,17 @@ namespace GitUI.CommandsDialogs
         private void DiffFiles_SelectedIndexChanged(object sender, EventArgs e)
         {
             // Switch to diff if the selection changes
-            FileStatusItem? item = DiffFiles.SelectedItem;
-            if (item is not null && blameToolStripMenuItem.Checked && item.Item.Name != _selectedBlameItem?.Item.Name)
+            GitItemStatus? item = DiffFiles.SelectedGitItem;
+            if (item is not null && blameToolStripMenuItem.Checked && item.Name != _selectedBlameItem?.Name)
             {
                 blameToolStripMenuItem.Checked = false;
             }
 
             // If this is not occurring after a revision change (implicit selection)
             // save the selected item so it can be the "preferred" selection
-            if (!_isImplicitListSelection && item is not null && !item.Item.IsRangeDiff)
+            if (!_isImplicitListSelection && item is not null && !item.IsRangeDiff)
             {
-                _lastExplicitlySelectedItem = item;
+                _lastExplicitlySelectedItem = RelativePath.From(item.Name);
                 _selectedBlameItem = null;
             }
 
@@ -785,7 +785,7 @@ namespace GitUI.CommandsDialogs
             {
                 int? line = DiffText.Visible ? DiffText.CurrentFileLine : BlameControl.CurrentFileLine;
                 blameToolStripMenuItem.Checked = !blameToolStripMenuItem.Checked;
-                _selectedBlameItem = blameToolStripMenuItem.Checked ? DiffFiles.SelectedItem : null;
+                _selectedBlameItem = blameToolStripMenuItem.Checked ? DiffFiles.SelectedItem.Item : null;
                 ShowSelectedFile(ensureNoSwitchToFilter: true, line);
                 return;
             }