Do not crash when dragging ReorderableListView with two fingers simultaneously (#88508)

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

@@ -522,6 +522,7 @@ class SliverReorderableListState extends State<SliverReorderableList> with Ticke
   int? _insertIndex;
   Offset? _finalDropPosition;
   MultiDragGestureRecognizer? _recognizer;
+  int? _recognizerPointer;
   bool _autoScrolling = false;
   // To implement the gap for the dragged item, we replace the dragged item
   // with a zero sized box, and then translate all of the later items down
@@ -579,12 +580,18 @@ class SliverReorderableListState extends State<SliverReorderableList> with Ticke
     setState(() {
       if (_dragInfo != null) {
         cancelReorder();
+      } else if (_recognizer != null && _recognizerPointer != event.pointer) {
+        _recognizer!.dispose();
+        _recognizer = null;
+        _recognizerPointer = null;
       }
+
       if (_items.containsKey(index)) {
         _dragIndex = index;
         _recognizer = recognizer
           ..onStart = _dragStart
           ..addPointer(event);
+        _recognizerPointer = event.pointer;
       } else {
         // TODO(darrenaustin): Can we handle this better, maybe scroll to the item?
         throw Exception('Attempting to start a drag on a non-visible item');

packages/flutter/test/widgets/reorderable_list_test.dart

@@ -7,6 +7,53 @@ import 'package:flutter/material.dart';
 import 'package:flutter_test/flutter_test.dart';
 
 void main() {
+  // Regression test for https://github.com/flutter/flutter/issues/88191
+  testWidgets('Do not crash when dragging with two fingers simultaneously', (WidgetTester tester) async {
+    final List<int> items = List<int>.generate(3, (int index) => index);
+    void handleReorder(int fromIndex, int toIndex) {
+      if (toIndex > fromIndex) {
+        toIndex -= 1;
+      }
+      items.insert(toIndex, items.removeAt(fromIndex));
+    }
+
+    await tester.pumpWidget(MaterialApp(
+      home: ReorderableList(
+        itemBuilder: (BuildContext context, int index) {
+          return ReorderableDragStartListener(
+            index: index,
+            key: ValueKey<int>(items[index]),
+            child: SizedBox(
+              height: 100,
+              child: Row(
+                crossAxisAlignment: CrossAxisAlignment.start,
+                children: <Widget>[
+                  Text('item ${items[index]}'),
+                ],
+              ),
+            ),
+          );
+        },
+        itemCount: items.length,
+        onReorder: handleReorder,
+      ),
+    ));
+
+    final TestGesture drag1 = await tester.startGesture(tester.getCenter(find.text('item 0')));
+    final TestGesture drag2 = await tester.startGesture(tester.getCenter(find.text('item 0')));
+    await tester.pump(kLongPressTimeout);
+
+    await drag1.moveBy(const Offset(0, 100));
+    await drag2.moveBy(const Offset(0, 100));
+    await tester.pumpAndSettle();
+
+    await drag1.up();
+    await drag2.up();
+    await tester.pumpAndSettle();
+
+    expect(tester.takeException(), isNull);
+  });
+
   testWidgets('negative itemCount should assert', (WidgetTester tester) async {
     final List<int> items = <int>[1, 2, 3];
     await tester.pumpWidget(MaterialApp(