CompareView "Show Identical" now actually filters rows

The ShowIdentical toggle was wired model-side
(CompareTabPageModel.OnShowIdenticalChanged → RootEntry.EnsureChildrenFiltered)
and view-side (Rebind on PropertyChanged), and the cascade was
correctly setting IsHidden via ComparisonEntryTreeNode.Filter. But the
HierarchicalModel's ChildrenSelector and SetRoots passed node.Children
through unfiltered — so IsHidden flags had no effect on what the
DataGrid actually rendered. Toggling the checkbox looked like a no-op.

Assisted-by: Claude:claude-opus-4-7:Claude Code

ILSpy.Tests/Compare/CompareViewRenderTests.cs

@@ -106,4 +106,56 @@ public class CompareViewRenderTests
 			() => grid.GetVisualDescendants().OfType<DataGridRow>().Any(),
 			description: "the diff grid must render at least one row once the merged tree is bound");
 	}
+
+	[AvaloniaTest]
+	public async Task CompareView_ShowIdentical_Toggle_Changes_Visible_Row_Set()
+	{
+		// Comparing an assembly with itself yields only identical rows. With ShowIdentical=false
+		// (default) every row should be hidden; flipping ShowIdentical=true must surface them.
+		// Regression: the bug was that the HierarchicalModel's ChildrenSelector returned
+		// node.Children unfiltered, so IsHidden flags set by ApplyFilterToChild had no effect
+		// on what the DataGrid actually rendered.
+		var window = AppComposition.Current.GetExport<MainWindow>();
+		window.Show();
+		var vm = (MainWindowViewModel)window.DataContext!;
+		await vm.AssemblyTreeModel.WaitForAssembliesAsync(minimumCount: 1);
+
+		var assembly = vm.AssemblyTreeModel.AssemblyList!.GetAssemblies()
+			.First(a => a.IsLoadedAsValidAssembly);
+
+		// Construct the compare model directly with the same assembly on both sides so every
+		// entry collapses to DiffKind.None. The View renders via the standard OpenNewTab path.
+		var page = new CompareTabPageModel(assembly, assembly);
+		vm.DockWorkspace.OpenNewTab(page);
+
+		var view = await window.WaitForComponent<CompareView>();
+		var grid = await view.WaitForComponent<DataGrid>();
+		await Waiters.WaitForAsync(() => grid.HierarchicalModel != null);
+		global::Avalonia.Threading.Dispatcher.UIThread.RunJobs();
+
+		// Baseline: ShowIdentical=false. All rows are identical-only, so the visible row count
+		// must be zero (every entry filters to Hidden).
+		page.ShowIdentical.Should().BeFalse("baseline state");
+		var rowsBeforeToggle = grid.GetVisualDescendants().OfType<DataGridRow>().Count();
+		rowsBeforeToggle.Should().Be(0,
+			"with ShowIdentical=false and only-identical content, no rows must be visible");
+
+		// Flip ShowIdentical=true and re-evaluate.
+		page.ShowIdentical = true;
+		global::Avalonia.Threading.Dispatcher.UIThread.RunJobs();
+		await Waiters.WaitForAsync(
+			() => grid.GetVisualDescendants().OfType<DataGridRow>().Any(),
+			description: "flipping ShowIdentical=true must surface previously-hidden identical rows");
+
+		var rowsAfterToggle = grid.GetVisualDescendants().OfType<DataGridRow>().Count();
+		rowsAfterToggle.Should().BeGreaterThan(0,
+			"with ShowIdentical=true, identical rows must surface in the grid");
+
+		// Flip back and verify it returns to the hidden state.
+		page.ShowIdentical = false;
+		global::Avalonia.Threading.Dispatcher.UIThread.RunJobs();
+		await Waiters.WaitForAsync(
+			() => grid.GetVisualDescendants().OfType<DataGridRow>().Count() == 0,
+			description: "flipping ShowIdentical=false again must re-hide all identical rows");
+	}
 }

ILSpy/Views/CompareView.axaml.cs

@@ -18,6 +18,7 @@
 
 using System;
 using System.ComponentModel;
+using System.Linq;
 
 using Avalonia.Controls;
 using Avalonia.Controls.DataGridHierarchical;
@@ -80,15 +81,24 @@ namespace ILSpy.Compare
 						ilspy.EnsureChildrenFiltered();
 					else
 						node.EnsureLazyChildren();
-					return node.Children;
+					return FilterHidden(node.Children);
 				},
 				IsLeafSelector = node => !node.ShowExpander,
 				VirtualizeChildren = false,
 				IsExpandedPropertyPath = nameof(SharpTreeNode.IsExpanded),
 			};
 			var model = new HierarchicalModel<SharpTreeNode>(options);
-			model.SetRoots(root.Children);
+			model.SetRoots(FilterHidden(root.Children));
 			DiffGrid.HierarchicalModel = model;
 		}
+
+		// ShowIdentical=false hides identical rows by setting IsHidden=true via
+		// ComparisonEntryTreeNode.Filter, but the DataGrid's HierarchicalModel only sees
+		// what ChildrenSelector / SetRoots feed it — IsHidden alone has no effect on the
+		// rendered row set. Filter the children here so the cascade-set IsHidden flags
+		// actually reach the grid. Same pattern AssemblyListPane.FilterChildren uses for
+		// the assembly tree's ShowApiLevel cascade.
+		static System.Collections.Generic.IEnumerable<SharpTreeNode> FilterHidden(System.Collections.Generic.IEnumerable<SharpTreeNode> children)
+			=> children.Where(c => c is not TreeNodes.ILSpyTreeNode it || !it.IsHidden).ToList();
 	}
 }