Fixes #4453. Regression in wide glyph rendering on all drivers (#4458)

Tests/UnitTestsParallelizable/Drivers/OutputBaseTests.cs

@@ -1,4 +1,4 @@
-#nullable enable
+#nullable enable
 
 namespace DriverTests;
 
@@ -154,6 +154,62 @@ public class OutputBaseTests
         Assert.Equal (new Point (2, 0), output.GetCursorPosition ());
     }
 
+    [Theory]
+    [InlineData (true)]
+    [InlineData (false)]
+    public void Write_Virtual_Or_NonVirtual_Uses_WriteToConsole_And_Clears_Dirty_Flags_Mixed_Graphemes (bool isLegacyConsole)
+    {
+        // Arrange
+        // FakeOutput exposes this because it's in test scope
+        var output = new FakeOutput { IsLegacyConsole = isLegacyConsole };
+        IOutputBuffer buffer = output.LastBuffer!;
+        buffer.SetSize (3, 1);
+
+        // Write '🦮' at col 0 and 'A' at col 3; leave col 1 untouched (not dirty)
+        buffer.Move (0, 0);
+        buffer.AddStr ("🦮A");
+
+        // Confirm some dirtiness before to write
+        Assert.True (buffer.Contents! [0, 0].IsDirty);
+        Assert.False (buffer.Contents! [0, 1].IsDirty);
+        Assert.True (buffer.Contents! [0, 2].IsDirty);
+
+        // Act
+        output.Write (buffer);
+
+        Assert.Contains ("🦮", output.Output);
+        Assert.Contains ("A", output.Output);
+
+        // Dirty flags cleared for the written cells
+        Assert.False (buffer.Contents! [0, 0].IsDirty);
+        Assert.False (buffer.Contents! [0, 1].IsDirty);
+        Assert.False (buffer.Contents! [0, 2].IsDirty);
+
+        Assert.Equal (new (0, 0), output.GetCursorPosition ());
+
+        // Now write 'X' at col 1 which replaces with the replacement character the col 0
+        buffer.Move (1, 0);
+        buffer.AddStr ("X");
+
+        // Confirm dirtiness state before to write
+        Assert.True (buffer.Contents! [0, 0].IsDirty);
+        Assert.True (buffer.Contents! [0, 1].IsDirty);
+        Assert.True (buffer.Contents! [0, 2].IsDirty);
+
+        output.Write (buffer);
+
+        Assert.Contains ("<22>", output.Output);
+        Assert.Contains ("X", output.Output);
+
+        // Dirty flags cleared for the written cells
+        Assert.False (buffer.Contents! [0, 0].IsDirty);
+        Assert.False (buffer.Contents! [0, 1].IsDirty);
+        Assert.False (buffer.Contents! [0, 2].IsDirty);
+
+        // Verify SetCursorPositionImpl was invoked by WriteToConsole (cursor set to a written column)
+        Assert.Equal (new (0, 0), output.GetCursorPosition ());
+    }
+
     [Theory]
     [InlineData (true)]
     [InlineData (false)]

Tests/UnitTestsParallelizable/ViewBase/Draw/ViewDrawTextAndLineCanvasTests.cs

@@ -240,7 +240,7 @@ public class ViewDrawTextAndLineCanvasTests () : FakeDriverBase
         Point screenPos = new Point (15, 15);
         view.LineCanvas.AddLine (screenPos, 5, Orientation.Horizontal, LineStyle.Single);
 
-        view.RenderLineCanvas ();
+        view.RenderLineCanvas (null);
 
         // Verify the line was drawn (check for horizontal line character)
         for (int i = 0; i < 5; i++)
@@ -272,7 +272,7 @@ public class ViewDrawTextAndLineCanvasTests () : FakeDriverBase
 
         Assert.NotEqual (Rectangle.Empty, view.LineCanvas.Bounds);
 
-        view.RenderLineCanvas ();
+        view.RenderLineCanvas (null);
 
         // LineCanvas should be cleared after rendering
         Assert.Equal (Rectangle.Empty, view.LineCanvas.Bounds);
@@ -302,7 +302,7 @@ public class ViewDrawTextAndLineCanvasTests () : FakeDriverBase
 
         Rectangle boundsBefore = view.LineCanvas.Bounds;
 
-        view.RenderLineCanvas ();
+        view.RenderLineCanvas (null);
 
         // LineCanvas should NOT be cleared when SuperViewRendersLineCanvas is true
         Assert.Equal (boundsBefore, view.LineCanvas.Bounds);