Issues/58665 reland and prevent the material widget from absorbing gesture (#60536)

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

@@ -681,7 +681,12 @@ class _AppBarState extends State<AppBar> {
         fit: StackFit.passthrough,
         children: <Widget>[
           widget.flexibleSpace,
-          appBar,
+          // Creates a material widget to prevent the flexibleSpace from
+          // obscuring the ink splashes produced by appBar children.
+          Material(
+            type: MaterialType.transparency,
+            child: appBar,
+          ),
         ],
       );
     }

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

@@ -366,6 +366,7 @@ class _MaterialState extends State<Material> with TickerProviderStateMixin {
       },
       child: _InkFeatures(
         key: _inkFeatureRenderer,
+        absorbHitTest: widget.type != MaterialType.transparency,
         color: backgroundColor,
         child: contents,
         vsync: this,
@@ -477,6 +478,7 @@ class _RenderInkFeatures extends RenderProxyBox implements MaterialInkController
   _RenderInkFeatures({
     RenderBox child,
     @required this.vsync,
+    this.absorbHitTest,
     this.color,
   }) : assert(vsync != null),
        super(child);
@@ -493,6 +495,8 @@ class _RenderInkFeatures extends RenderProxyBox implements MaterialInkController
   @override
   Color color;
 
+  bool absorbHitTest;
+
   List<InkFeature> _inkFeatures;
 
   @override
@@ -517,7 +521,7 @@ class _RenderInkFeatures extends RenderProxyBox implements MaterialInkController
   }
 
   @override
-  bool hitTestSelf(Offset position) => true;
+  bool hitTestSelf(Offset position) => absorbHitTest;
 
   @override
   void paint(PaintingContext context, Offset offset) {
@@ -539,6 +543,7 @@ class _InkFeatures extends SingleChildRenderObjectWidget {
     Key key,
     this.color,
     @required this.vsync,
+    @required this.absorbHitTest,
     Widget child,
   }) : super(key: key, child: child);
 
@@ -549,17 +554,21 @@ class _InkFeatures extends SingleChildRenderObjectWidget {
 
   final TickerProvider vsync;
 
+  final bool absorbHitTest;
+
   @override
   _RenderInkFeatures createRenderObject(BuildContext context) {
     return _RenderInkFeatures(
       color: color,
+      absorbHitTest: absorbHitTest,
       vsync: vsync,
     );
   }
 
   @override
   void updateRenderObject(BuildContext context, _RenderInkFeatures renderObject) {
-    renderObject.color = color;
+    renderObject..color = color
+                ..absorbHitTest = absorbHitTest;
     assert(vsync == renderObject.vsync);
   }
 }

packages/flutter/test/material/app_bar_test.dart

@@ -10,6 +10,7 @@ import 'package:flutter/rendering.dart';
 import 'package:flutter/services.dart';
 import 'package:flutter_test/flutter_test.dart';
 
+import '../rendering/mock_canvas.dart';
 import '../widgets/semantics_tester.dart';
 
 Widget buildSliverAppBarApp({
@@ -1103,6 +1104,48 @@ void main() {
     expect(find.byIcon(Icons.menu), findsNothing);
   });
 
+  testWidgets('AppBar ink splash draw on the correct canvas', (WidgetTester tester) async {
+    // This is a regression test for https://github.com/flutter/flutter/issues/58665
+    final Key key = UniqueKey();
+    await tester.pumpWidget(
+      MaterialApp(
+        home: Center(
+          child: AppBar(
+            title: const Text('Abc'),
+            actions: <Widget>[
+              IconButton(
+                key: key,
+                icon: const Icon(Icons.add_circle),
+                tooltip: 'First button',
+                onPressed: () {},
+              ),
+            ],
+            flexibleSpace: DecoratedBox(
+              decoration: BoxDecoration(
+                gradient: LinearGradient(
+                  begin: const Alignment(0.0, -1.0),
+                  end: const Alignment(-0.04, 1.0),
+                  colors: <Color>[Colors.blue.shade500, Colors.blue.shade800],
+                ),
+              ),
+            ),
+          ),
+        ),
+      ),
+    );
+    final RenderObject painter = tester.renderObject(
+      find.descendant(
+        of: find.descendant(
+          of: find.byType(AppBar),
+          matching: find.byType(Stack),
+        ),
+        matching: find.byType(Material)
+      )
+    );
+    await tester.tap(find.byKey(key));
+    expect(painter, paints..save()..translate()..save()..translate()..circle(x: 24.0, y: 28.0));
+  });
+
   testWidgets('AppBar handles loose children 0', (WidgetTester tester) async {
     final GlobalKey key = GlobalKey();
     await tester.pumpWidget(

packages/flutter/test/material/material_test.dart

@@ -219,6 +219,35 @@ void main() {
     expect(modelE.shadowColor, equals(const Color(0xFFFF0000)));
   });
 
+  testWidgets('Transparent material widget does not absorb hit test', (WidgetTester tester) async {
+    // This is a regression test for https://github.com/flutter/flutter/issues/58665.
+    bool pressed = false;
+    await tester.pumpWidget(
+      MaterialApp(
+        home: Scaffold(
+          body: Stack(
+            children: <Widget>[
+              RaisedButton(
+                onPressed: () {
+                  pressed = true;
+                },
+              ),
+              Material(
+                type: MaterialType.transparency,
+                child: Container(
+                  width: 400.0,
+                  height: 500.0,
+                ),
+              ),
+            ],
+          ),
+        ),
+      ),
+    );
+    await tester.tap(find.byType(RaisedButton));
+    expect(pressed, isTrue);
+  });
+
   group('Elevation Overlay', () {
 
     testWidgets('applyElevationOverlayColor set to false does not change surface color', (WidgetTester tester) async {