Clear primary-touch ownership after resetting the iOS pointer handler

packages/react-native/React/Fabric/RCTSurfacePointerHandler.mm

@@ -726,6 +726,8 @@ - (void)reset
     _activePointers.clear();
     _identifierPool.reset();
   }
+
+  _primaryTouchPointerId = -1;
 }
 
 - (BOOL)canPreventGestureRecognizer:(UIGestureRecognizer *)preventedGestureRecognizer

packages/react-native/React/Tests/TouchHandling/RCTSurfacePointerHandlerTests.mm

@@ -0,0 +1,140 @@
+/*
+ * Copyright (c) Meta Platforms, Inc. and affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
+#import <React/RCTSurfacePointerHandler.h>
+#import <XCTest/XCTest.h>
+#import <react/renderer/components/view/TouchEventEmitter.h>
+#import <react/renderer/core/EventDispatcher.h>
+#import <react/renderer/runtimescheduler/RuntimeScheduler.h>
+
+using namespace facebook::react;
+
+@interface PointerTouch : UITouch
+@property (nonatomic, weak) UIView *targetView;
+@end
+
+@implementation PointerTouch
+- (UIView *)view
+{
+  return self.targetView;
+}
+- (UITouchType)type
+{
+  return UITouchTypeDirect;
+}
+- (UITouchPhase)phase
+{
+  return UITouchPhaseBegan;
+}
+- (CGPoint)locationInView:(UIView *)view
+{
+  return CGPointMake(20, 20);
+}
+- (NSTimeInterval)timestamp
+{
+  return 1;
+}
+- (CGFloat)force
+{
+  return 1;
+}
+- (CGFloat)maximumPossibleForce
+{
+  return 1;
+}
+- (CGFloat)majorRadius
+{
+  return 1;
+}
+- (CGFloat)altitudeAngle
+{
+  return M_PI_2;
+}
+- (CGFloat)azimuthAngleInView:(UIView *)view
+{
+  return 0;
+}
+@end
+
+@interface PointerTargetView : UIView
+@property (nonatomic) SharedTouchEventEmitter emitter;
+@end
+
+@implementation PointerTargetView
+- (SharedTouchEventEmitter)touchEventEmitterAtPoint:(CGPoint)point
+{
+  return _emitter;
+}
+@end
+
+struct PointerReceipt {
+  std::string type;
+  int pointerId;
+  bool isPrimary;
+};
+
+@interface RCTSurfacePointerHandlerTests : XCTestCase
+@end
+
+@implementation RCTSurfacePointerHandlerTests
+
+- (void)testLoneTouchAfterActiveResetIsPrimary
+{
+  std::vector<PointerReceipt> receipts;
+  RuntimeScheduler scheduler([](auto &&) {});
+  EventQueueProcessor processor([](auto &, auto *, auto &, auto, auto &, auto) {}, [](auto &) {}, [](auto &) {}, {});
+  auto dispatcher = std::make_shared<EventDispatcher>(
+      processor,
+      std::make_unique<EventBeat>(std::make_shared<EventBeat::OwnerBox>(), scheduler),
+      [](auto &) {},
+      std::weak_ptr<EventLogger>{});
+  auto listener = std::make_shared<EventListener>([&receipts](const RawEvent &event) {
+    const auto &pointer = static_cast<const PointerEvent &>(*event.eventPayload);
+    receipts.push_back({event.type, pointer.pointerId, pointer.isPrimary});
+    return true;
+  });
+  dispatcher->addListener(listener);
+
+  PointerTargetView *target = [[PointerTargetView alloc] initWithFrame:CGRectMake(0, 0, 100, 100)];
+  target.emitter = std::make_shared<TouchEventEmitter>(nullptr, dispatcher);
+  UIWindow *window = [[UIWindow alloc] initWithFrame:CGRectMake(0, 0, 100, 100)];
+  UIViewController *controller = [UIViewController new];
+  controller.view = target;
+  window.rootViewController = controller;
+  window.hidden = NO;
+  RCTSurfacePointerHandler *handler = [RCTSurfacePointerHandler new];
+  [handler attachToView:target];
+
+  @autoreleasepool {
+    PointerTouch *touch = [PointerTouch new];
+    touch.targetView = target;
+    [handler touchesBegan:[NSSet setWithObject:touch] withEvent:nil];
+    [handler reset];
+  }
+
+  PointerTouch *next = [PointerTouch new];
+  next.targetView = target;
+  [handler touchesBegan:[NSSet setWithObject:next] withEvent:nil];
+
+  XCTAssertEqual(receipts.size(), 3u);
+  if (receipts.size() == 3) {
+    XCTAssertTrue(receipts[2].isPrimary);
+    XCTAssertEqual(receipts[0].type, "topPointerDown");
+    XCTAssertTrue(receipts[0].isPrimary);
+    XCTAssertEqual(receipts[1].type, "topPointerCancel");
+    XCTAssertTrue(receipts[1].isPrimary);
+    XCTAssertEqual(receipts[1].pointerId, receipts[0].pointerId);
+    XCTAssertEqual(receipts[2].type, "topPointerDown");
+  }
+
+  [handler reset];
+  [handler detachFromView:target];
+  dispatcher->removeListener(listener);
+  window.hidden = YES;
+}
+
+@end

packages/rn-tester/Podfile

@@ -60,6 +60,10 @@ end
 
 target 'RNTester' do
   pods('RNTester')
+
+  target 'RNTesterPointerTests' do
+    inherit! :search_paths
+  end
 end
 
 target 'RNTesterUnitTests' do

packages/rn-tester/RNTester/RNTesterPointerTests.xctestplan

@@ -0,0 +1,39 @@
+{
+  "configurations": [
+    {
+      "id": "1D5134C7-450A-44B6-A8B1-13CD24FD50B9",
+      "name": "Address Sanitizer",
+      "options": {
+        "addressSanitizer": {
+          "detectStackUseAfterReturn": true,
+          "enabled": true
+        }
+      }
+    }
+  ],
+  "defaultOptions": {
+    "codeCoverage": false,
+    "environmentVariableEntries": [
+      {
+        "key": "CI_USE_PACKAGER",
+        "value": "1"
+      }
+    ],
+    "targetForVariableExpansion": {
+      "containerPath": "container:RNTesterPods.xcodeproj",
+      "identifier": "13B07F861A680F5B00A75B9A",
+      "name": "RNTester"
+    },
+    "undefinedBehaviorSanitizerEnabled": true
+  },
+  "testTargets": [
+    {
+      "target": {
+        "containerPath": "container:RNTesterPods.xcodeproj",
+        "identifier": "0497DB7F2CEA00B0FE0F8B15",
+        "name": "RNTesterPointerTests"
+      }
+    }
+  ],
+  "version": 1
+}