Allow Clip.none as a valid clipBehavior (#95593)

packages/flutter/lib/src/rendering/proxy_box.dart

@@ -1429,13 +1429,13 @@ class RenderClipRect extends _RenderCustomClip<Rect> {
   /// If [clipper] is null, the clip will match the layout size and position of
   /// the child.
   ///
-  /// The [clipBehavior] must not be null or [Clip.none].
+  /// The [clipBehavior] must not be null. If [clipBehavior] is
+  /// [Clip.none], no clipping will be applied.
   RenderClipRect({
     RenderBox? child,
     CustomClipper<Rect>? clipper,
     Clip clipBehavior = Clip.antiAlias,
   }) : assert(clipBehavior != null),
-       assert(clipBehavior != Clip.none),
        super(child: child, clipper: clipper, clipBehavior: clipBehavior);
 
   @override
@@ -1455,15 +1455,20 @@ class RenderClipRect extends _RenderCustomClip<Rect> {
   @override
   void paint(PaintingContext context, Offset offset) {
     if (child != null) {
-      _updateClip();
-      layer = context.pushClipRect(
-        needsCompositing,
-        offset,
-        _clip!,
-        super.paint,
-        clipBehavior: clipBehavior,
-        oldLayer: layer as ClipRectLayer?,
-      );
+      if (clipBehavior != Clip.none) {
+        _updateClip();
+        layer = context.pushClipRect(
+          needsCompositing,
+          offset,
+          _clip!,
+          super.paint,
+          clipBehavior: clipBehavior,
+          oldLayer: layer as ClipRectLayer?,
+        );
+      } else {
+        context.paintChild(child!, offset);
+        layer = null;
+      }
     } else {
       layer = null;
     }
@@ -1495,14 +1500,14 @@ class RenderClipRRect extends _RenderCustomClip<RRect> {
   ///
   /// If [clipper] is non-null, then [borderRadius] is ignored.
   ///
-  /// The [clipBehavior] argument must not be null or [Clip.none].
+  /// The [clipBehavior] argument must not be null. If [clipBehavior] is
+  /// [Clip.none], no clipping will be applied.
   RenderClipRRect({
     RenderBox? child,
     BorderRadius borderRadius = BorderRadius.zero,
     CustomClipper<RRect>? clipper,
     Clip clipBehavior = Clip.antiAlias,
   }) : assert(clipBehavior != null),
-       assert(clipBehavior != Clip.none),
        _borderRadius = borderRadius,
        super(child: child, clipper: clipper, clipBehavior: clipBehavior) {
     assert(_borderRadius != null || clipper != null);
@@ -1541,14 +1546,21 @@ class RenderClipRRect extends _RenderCustomClip<RRect> {
   @override
   void paint(PaintingContext context, Offset offset) {
     if (child != null) {
-      _updateClip();
-      layer = context.pushClipRRect(
-        needsCompositing,
-        offset,
-        _clip!.outerRect,
-        _clip!,
-        super.paint, clipBehavior: clipBehavior, oldLayer: layer as ClipRRectLayer?,
-      );
+      if (clipBehavior != Clip.none) {
+        _updateClip();
+        layer = context.pushClipRRect(
+          needsCompositing,
+          offset,
+          _clip!.outerRect,
+          _clip!,
+          super.paint,
+          clipBehavior: clipBehavior,
+          oldLayer: layer as ClipRRectLayer?,
+        );
+      } else {
+        context.paintChild(child!, offset);
+        layer = null;
+      }
     } else {
       layer = null;
     }
@@ -1578,13 +1590,13 @@ class RenderClipOval extends _RenderCustomClip<Rect> {
   /// If [clipper] is null, the oval will be inscribed into the layout size and
   /// position of the child.
   ///
-  /// The [clipBehavior] argument must not be null or [Clip.none].
+  /// The [clipBehavior] argument must not be null. If [clipBehavior] is
+  /// [Clip.none], no clipping will be applied.
   RenderClipOval({
     RenderBox? child,
     CustomClipper<Rect>? clipper,
     Clip clipBehavior = Clip.antiAlias,
   }) : assert(clipBehavior != null),
-       assert(clipBehavior != Clip.none),
        super(child: child, clipper: clipper, clipBehavior: clipBehavior);
 
   Rect? _cachedRect;
@@ -1620,16 +1632,21 @@ class RenderClipOval extends _RenderCustomClip<Rect> {
   @override
   void paint(PaintingContext context, Offset offset) {
     if (child != null) {
-      _updateClip();
-      layer = context.pushClipPath(
-        needsCompositing,
-        offset,
-        _clip!,
-        _getClipPath(_clip!),
-        super.paint,
-        clipBehavior: clipBehavior,
-        oldLayer: layer as ClipPathLayer?,
-      );
+      if (clipBehavior != Clip.none) {
+        _updateClip();
+        layer = context.pushClipPath(
+          needsCompositing,
+          offset,
+          _clip!,
+          _getClipPath(_clip!),
+          super.paint,
+          clipBehavior: clipBehavior,
+          oldLayer: layer as ClipPathLayer?,
+        );
+      } else {
+        context.paintChild(child!, offset);
+        layer = null;
+      }
     } else {
       layer = null;
     }
@@ -1667,13 +1684,13 @@ class RenderClipPath extends _RenderCustomClip<Path> {
   /// consider using a [RenderClipRect], which can achieve the same effect more
   /// efficiently.
   ///
-  /// The [clipBehavior] argument must not be null or [Clip.none].
+  /// The [clipBehavior] argument must not be null. If [clipBehavior] is
+  /// [Clip.none], no clipping will be applied.
   RenderClipPath({
     RenderBox? child,
     CustomClipper<Path>? clipper,
     Clip clipBehavior = Clip.antiAlias,
   }) : assert(clipBehavior != null),
-       assert(clipBehavior != Clip.none),
        super(child: child, clipper: clipper, clipBehavior: clipBehavior);
 
   @override
@@ -1693,16 +1710,21 @@ class RenderClipPath extends _RenderCustomClip<Path> {
   @override
   void paint(PaintingContext context, Offset offset) {
     if (child != null) {
-      _updateClip();
-      layer = context.pushClipPath(
-        needsCompositing,
-        offset,
-        Offset.zero & size,
-        _clip!,
-        super.paint,
-        clipBehavior: clipBehavior,
-        oldLayer: layer as ClipPathLayer?,
-      );
+      if (clipBehavior != Clip.none) {
+        _updateClip();
+        layer = context.pushClipPath(
+          needsCompositing,
+          offset,
+          Offset.zero & size,
+          _clip!,
+          super.paint,
+          clipBehavior: clipBehavior,
+          oldLayer: layer as ClipPathLayer?,
+        );
+      } else {
+        context.paintChild(child!, offset);
+        layer = null;
+      }
     } else {
       layer = null;
     }

packages/flutter/lib/src/widgets/basic.dart

@@ -662,10 +662,15 @@ class ClipRect extends SingleChildRenderObjectWidget {
   /// If [clipper] is null, the clip will match the layout size and position of
   /// the child.
   ///
-  /// The [clipBehavior] argument must not be null or [Clip.none].
-  const ClipRect({ Key? key, this.clipper, this.clipBehavior = Clip.hardEdge, Widget? child })
-      : assert(clipBehavior != null),
-        super(key: key, child: child);
+  /// The [clipBehavior] argument must not be null. If [clipBehavior] is
+  /// [Clip.none], no clipping will be applied.
+  const ClipRect({
+    Key? key,
+    this.clipper,
+    this.clipBehavior = Clip.hardEdge,
+    Widget? child,
+  }) : assert(clipBehavior != null),
+       super(key: key, child: child);
 
   /// If non-null, determines which clip to use.
   final CustomClipper<Rect>? clipper;
@@ -677,13 +682,11 @@ class ClipRect extends SingleChildRenderObjectWidget {
 
   @override
   RenderClipRect createRenderObject(BuildContext context) {
-    assert(clipBehavior != Clip.none);
     return RenderClipRect(clipper: clipper, clipBehavior: clipBehavior);
   }
 
   @override
   void updateRenderObject(BuildContext context, RenderClipRect renderObject) {
-    assert(clipBehavior != Clip.none);
     renderObject
       ..clipper = clipper
       ..clipBehavior = clipBehavior;
@@ -723,7 +726,8 @@ class ClipRRect extends SingleChildRenderObjectWidget {
   ///
   /// If [clipper] is non-null, then [borderRadius] is ignored.
   ///
-  /// The [clipBehavior] argument must not be null or [Clip.none].
+  /// The [clipBehavior] argument must not be null. If [clipBehavior] is
+  /// [Clip.none], no clipping will be applied.
   const ClipRRect({
     Key? key,
     this.borderRadius = BorderRadius.zero,
@@ -752,13 +756,15 @@ class ClipRRect extends SingleChildRenderObjectWidget {
 
   @override
   RenderClipRRect createRenderObject(BuildContext context) {
-    assert(clipBehavior != Clip.none);
-    return RenderClipRRect(borderRadius: borderRadius!, clipper: clipper, clipBehavior: clipBehavior);
+    return RenderClipRRect(
+      borderRadius: borderRadius!,
+      clipper: clipper,
+      clipBehavior: clipBehavior,
+    );
   }
 
   @override
   void updateRenderObject(BuildContext context, RenderClipRRect renderObject) {
-    assert(clipBehavior != Clip.none);
     renderObject
       ..borderRadius = borderRadius!
       ..clipBehavior = clipBehavior
@@ -793,10 +799,15 @@ class ClipOval extends SingleChildRenderObjectWidget {
   /// If [clipper] is null, the oval will be inscribed into the layout size and
   /// position of the child.
   ///
-  /// The [clipBehavior] argument must not be null or [Clip.none].
-  const ClipOval({Key? key, this.clipper, this.clipBehavior = Clip.antiAlias, Widget? child})
-      : assert(clipBehavior != null),
-        super(key: key, child: child);
+  /// The [clipBehavior] argument must not be null. If [clipBehavior] is
+  /// [Clip.none], no clipping will be applied.
+  const ClipOval({
+    Key? key,
+    this.clipper,
+    this.clipBehavior = Clip.antiAlias,
+    Widget? child,
+  }) : assert(clipBehavior != null),
+       super(key: key, child: child);
 
   /// If non-null, determines which clip to use.
   ///
@@ -816,13 +827,11 @@ class ClipOval extends SingleChildRenderObjectWidget {
 
   @override
   RenderClipOval createRenderObject(BuildContext context) {
-    assert(clipBehavior != Clip.none);
     return RenderClipOval(clipper: clipper, clipBehavior: clipBehavior);
   }
 
   @override
   void updateRenderObject(BuildContext context, RenderClipOval renderObject) {
-    assert(clipBehavior != Clip.none);
     renderObject
       ..clipper = clipper
       ..clipBehavior = clipBehavior;
@@ -866,7 +875,8 @@ class ClipPath extends SingleChildRenderObjectWidget {
   /// consider using a [ClipRect], which can achieve the same effect more
   /// efficiently.
   ///
-  /// The [clipBehavior] argument must not be null or [Clip.none].
+  /// The [clipBehavior] argument must not be null. If [clipBehavior] is
+  /// [Clip.none], no clipping will be applied.
   const ClipPath({
     Key? key,
     this.clipper,
@@ -886,7 +896,6 @@ class ClipPath extends SingleChildRenderObjectWidget {
     Widget? child,
   }) {
     assert(clipBehavior != null);
-    assert(clipBehavior != Clip.none);
     assert(shape != null);
     return Builder(
       key: key,
@@ -917,13 +926,11 @@ class ClipPath extends SingleChildRenderObjectWidget {
 
   @override
   RenderClipPath createRenderObject(BuildContext context) {
-    assert(clipBehavior != Clip.none);
     return RenderClipPath(clipper: clipper, clipBehavior: clipBehavior);
   }
 
   @override
   void updateRenderObject(BuildContext context, RenderClipPath renderObject) {
-    assert(clipBehavior != Clip.none);
     renderObject
       ..clipper = clipper
       ..clipBehavior = clipBehavior;
@@ -1014,7 +1021,8 @@ class PhysicalModel extends SingleChildRenderObjectWidget {
       shape: shape,
       clipBehavior: clipBehavior,
       borderRadius: borderRadius,
-      elevation: elevation, color: color,
+      elevation: elevation,
+      color: color,
       shadowColor: shadowColor,
     );
   }

packages/flutter/test/widgets/clip_test.dart

@@ -87,6 +87,10 @@ void main() {
     await tester.pumpWidget(const ClipRect(clipBehavior: Clip.antiAlias));
 
     expect(renderClip.clipBehavior, equals(Clip.antiAlias));
+
+    await tester.pumpWidget(const ClipRect(clipBehavior: Clip.none));
+
+    expect(renderClip.clipBehavior, equals(Clip.none));
   });
 
   test('ClipRRect constructs with the right default values', () {
@@ -105,6 +109,10 @@ void main() {
     await tester.pumpWidget(const ClipRRect(clipBehavior: Clip.hardEdge));
 
     expect(renderClip.clipBehavior, equals(Clip.hardEdge));
+
+    await tester.pumpWidget(const ClipRRect(clipBehavior: Clip.none));
+
+    expect(renderClip.clipBehavior, equals(Clip.none));
   });
 
   testWidgets('ClipOval updates clipBehavior in updateRenderObject', (WidgetTester tester) async {
@@ -117,6 +125,10 @@ void main() {
     await tester.pumpWidget(const ClipOval(clipBehavior: Clip.hardEdge));
 
     expect(renderClip.clipBehavior, equals(Clip.hardEdge));
+
+    await tester.pumpWidget(const ClipOval(clipBehavior: Clip.none));
+
+    expect(renderClip.clipBehavior, equals(Clip.none));
   });
 
   testWidgets('ClipPath updates clipBehavior in updateRenderObject', (WidgetTester tester) async {
@@ -129,6 +141,10 @@ void main() {
     await tester.pumpWidget(const ClipPath(clipBehavior: Clip.hardEdge));
 
     expect(renderClip.clipBehavior, equals(Clip.hardEdge));
+
+    await tester.pumpWidget(const ClipPath(clipBehavior: Clip.none));
+
+    expect(renderClip.clipBehavior, equals(Clip.none));
   });
 
   testWidgets('ClipPath', (WidgetTester tester) async {