Fix `clipBehavior` for `Drawer` with shape and add `clipBehavior` property. (#124104)

packages/flutter/lib/src/material/drawer.dart

@@ -153,6 +153,7 @@ class Drawer extends StatelessWidget {
     this.width,
     this.child,
     this.semanticLabel,
+    this.clipBehavior,
   }) : assert(elevation == null || elevation >= 0.0);
 
   /// Sets the color of the [Material] that holds all of the [Drawer]'s
@@ -237,6 +238,14 @@ class Drawer extends StatelessWidget {
   ///    value is used.
   final String? semanticLabel;
 
+  /// {@macro flutter.material.Material.clipBehavior}
+  ///
+  /// The [clipBehavior] argument specifies how to clip the drawer's [shape].
+  ///
+  /// If the drawer has a [shape], it defaults to [Clip.hardEdge]. Otherwise,
+  /// defaults to [Clip.none].
+  final Clip? clipBehavior;
+
   @override
   Widget build(BuildContext context) {
     assert(debugCheckHasMaterialLocalizations(context));
@@ -255,6 +264,9 @@ class Drawer extends StatelessWidget {
     final bool useMaterial3 = Theme.of(context).useMaterial3;
     final bool isDrawerStart = DrawerController.maybeOf(context)?.alignment != DrawerAlignment.end;
     final DrawerThemeData defaults= useMaterial3 ? _DrawerDefaultsM3(context): _DrawerDefaultsM2(context);
+    final ShapeBorder? effectiveShape = shape ?? (isDrawerStart
+      ? (drawerTheme.shape ?? defaults.shape)
+      : (drawerTheme.endShape ?? defaults.endShape));
     return Semantics(
       scopesRoute: true,
       namesRoute: true,
@@ -267,9 +279,8 @@ class Drawer extends StatelessWidget {
           elevation: elevation ?? drawerTheme.elevation ?? defaults.elevation!,
           shadowColor: shadowColor ?? drawerTheme.shadowColor ?? defaults.shadowColor,
           surfaceTintColor: surfaceTintColor ?? drawerTheme.surfaceTintColor ?? defaults.surfaceTintColor,
-          shape: shape ?? (isDrawerStart
-            ? (drawerTheme.shape ?? defaults.shape)
-            : (drawerTheme.endShape ?? defaults.endShape)),
+          shape: effectiveShape,
+          clipBehavior: effectiveShape != null ? (clipBehavior ?? Clip.hardEdge) : Clip.none,
           child: child,
         ),
       ),

packages/flutter/test/material/drawer_test.dart

@@ -688,6 +688,57 @@ void main() {
     );
   });
 
+  testWidgets('Drawer clip behavior', (WidgetTester tester) async {
+    await tester.pumpWidget(
+      MaterialApp(
+        theme: ThemeData(useMaterial3: true),
+        home: const Scaffold(
+          drawer: Drawer(),
+        ),
+      ),
+    );
+
+    final Finder drawerMaterial = find.descendant(
+      of: find.byType(Drawer),
+      matching: find.byType(Material),
+    );
+
+    final ScaffoldState state = tester.firstState(find.byType(Scaffold));
+
+    // Open the drawer.
+    state.openDrawer();
+    await tester.pump();
+    await tester.pump(const Duration(seconds: 1));
+
+    // Test default clip behavior.
+    Material material = tester.widget<Material>(drawerMaterial);
+    expect(material.clipBehavior, Clip.hardEdge);
+
+    state.closeDrawer();
+    await tester.pumpAndSettle();
+
+    // Provide a custom clip behavior.
+    await tester.pumpWidget(
+      MaterialApp(
+        theme: ThemeData(useMaterial3: true),
+        home: const Scaffold(
+          drawer: Drawer(
+            clipBehavior: Clip.antiAlias,
+          ),
+        ),
+      ),
+    );
+
+    // Open the drawer again.
+    state.openDrawer();
+    await tester.pump();
+    await tester.pump(const Duration(seconds: 1));
+
+    // Clip behavior is now updated.
+    material = tester.widget<Material>(drawerMaterial);
+    expect(material.clipBehavior, Clip.antiAlias);
+  });
+
   group('Material 2', () {
     // Tests that are only relevant for Material 2. Once ThemeData.useMaterial3
     // is turned on by default, these tests can be removed.
@@ -732,5 +783,57 @@ void main() {
       material = tester.widget<Material>(drawerMaterial);
       expect(material.shape, null);
     });
+
+    testWidgets('Drawer clip behavior', (WidgetTester tester) async {
+      await tester.pumpWidget(
+        MaterialApp(
+          theme: ThemeData(useMaterial3: false),
+          home: const Scaffold(
+            drawer: Drawer(),
+          ),
+        ),
+      );
+
+      final Finder drawerMaterial = find.descendant(
+        of: find.byType(Drawer),
+        matching: find.byType(Material),
+      );
+
+      final ScaffoldState state = tester.firstState(find.byType(Scaffold));
+
+      // Open the drawer.
+      state.openDrawer();
+      await tester.pump();
+      await tester.pump(const Duration(seconds: 1));
+
+      // Test default clip behavior.
+      Material material = tester.widget<Material>(drawerMaterial);
+      expect(material.clipBehavior, Clip.none);
+
+      state.closeDrawer();
+      await tester.pumpAndSettle();
+
+      // Provide a shape and custom clip behavior.
+      await tester.pumpWidget(
+        MaterialApp(
+          theme: ThemeData(useMaterial3: false),
+          home: const Scaffold(
+            drawer: Drawer(
+              clipBehavior: Clip.hardEdge,
+              shape: RoundedRectangleBorder(),
+            ),
+          ),
+        ),
+      );
+
+      // Open the drawer again.
+      state.openDrawer();
+      await tester.pump();
+      await tester.pump(const Duration(seconds: 1));
+
+      // Clip behavior is now updated.
+      material = tester.widget<Material>(drawerMaterial);
+      expect(material.clipBehavior, Clip.hardEdge);
+    });
   });
 }