From b889a0629a2b4d7c0be784b923af2b33168de455 Mon Sep 17 00:00:00 2001
From: Nicolas Gallagher <necolas@fb.com>
Date: Fri, 27 Sep 2019 16:54:07 -0700
Subject: [PATCH] [react-interactions] Tap cancels on second pointerdown

This patch causes onTapCancel to be called whenever a second pointer interacts
with the responder target.
---
 .../react-interactions/events/src/dom/Tap.js  | 44 ++++++++++++-------
 .../src/dom/__tests__/Tap-test.internal.js    | 17 +++++++
 .../dom/testing-library/domEventSequences.js  | 21 +++++++--
 3 files changed, 62 insertions(+), 20 deletions(-)

diff --git a/packages/react-interactions/events/src/dom/Tap.js b/packages/react-interactions/events/src/dom/Tap.js
index db6df9a70c932..38e11bf349eee 100644
--- a/packages/react-interactions/events/src/dom/Tap.js
+++ b/packages/react-interactions/events/src/dom/Tap.js
@@ -496,26 +496,29 @@ const responderImpl = {
       case 'pointerdown':
       case 'mousedown':
       case 'touchstart': {
-        if (hasPointerEvents) {
-          const pointerId = nativeEvent.pointerId;
-          state.activePointerId = pointerId;
-          // Make mouse and touch pointers consistent.
-          // Flow bug: https://github.com/facebook/flow/issues/8055
-          // $FlowExpectedError
-          eventTarget.releasePointerCapture(pointerId);
-        } else {
-          if (eventType === 'touchstart') {
-            const targetTouches = nativeEvent.targetTouches;
-            if (targetTouches.length > 0) {
-              state.activePointerId = targetTouches[0].identifier;
-            }
-          }
-          if (eventType === 'mousedown' && state.ignoreEmulatedEvents) {
-            return;
-          }
+        if (eventType === 'mousedown' && state.ignoreEmulatedEvents) {
+          return;
         }
 
         if (!state.isActive) {
+          if (hasPointerEvents) {
+            const pointerId = nativeEvent.pointerId;
+            state.activePointerId = pointerId;
+            // Make mouse and touch pointers consistent.
+            // Flow bug: https://github.com/facebook/flow/issues/8055
+            // $FlowExpectedError
+            eventTarget.releasePointerCapture(pointerId);
+          } else {
+            if (eventType === 'touchstart') {
+              const targetTouches = nativeEvent.targetTouches;
+              if (targetTouches.length === 1) {
+                state.activePointerId = targetTouches[0].identifier;
+              } else {
+                return;
+              }
+            }
+          }
+
           const activate = shouldActivate(event);
           const activateAuxiliary = isAuxiliary(nativeEvent.buttons, event);
 
@@ -547,6 +550,13 @@ const responderImpl = {
             state.initialPosition.y = gestureState.y;
             dispatchStart(context, props, state);
           }
+        } else if (
+          !isActivePointer(event, state) ||
+          (eventType === 'touchstart' && nativeEvent.targetTouches.length > 1)
+        ) {
+          // Cancel the gesture if a second pointer becomes active on the target.
+          state.isActive = false;
+          dispatchCancel(context, props, state);
         }
         break;
       }
diff --git a/packages/react-interactions/events/src/dom/__tests__/Tap-test.internal.js b/packages/react-interactions/events/src/dom/__tests__/Tap-test.internal.js
index 3cfa5e55b0736..3b30443daf392 100644
--- a/packages/react-interactions/events/src/dom/__tests__/Tap-test.internal.js
+++ b/packages/react-interactions/events/src/dom/__tests__/Tap-test.internal.js
@@ -652,6 +652,23 @@ describeWithPointerEvent('Tap responder', hasPointerEvents => {
       expect(onTapUpdate).not.toBeCalled();
     });
 
+    test('second pointer down', () => {
+      const pointerType = 'touch';
+      const target = createEventTarget(ref.current);
+      const buttons = buttonsType.primary;
+      target.pointerdown({buttons, pointerId: 1, pointerType});
+      if (hasPointerEvents) {
+        target.pointerdown({buttons, pointerId: 2, pointerType});
+      } else {
+        // TouchEvents
+        target.pointerdown([
+          {pointerId: 1, pointerType},
+          {pointerId: 2, pointerType},
+        ]);
+      }
+      expect(onTapCancel).toHaveBeenCalledTimes(1);
+    });
+
     testWithPointerType('pointer move outside target', pointerType => {
       const downTarget = createEventTarget(ref.current);
       const upTarget = createEventTarget(container);
diff --git a/packages/react-interactions/events/src/dom/testing-library/domEventSequences.js b/packages/react-interactions/events/src/dom/testing-library/domEventSequences.js
index 344d9700181cf..be5a58cfe9dbc 100644
--- a/packages/react-interactions/events/src/dom/testing-library/domEventSequences.js
+++ b/packages/react-interactions/events/src/dom/testing-library/domEventSequences.js
@@ -18,6 +18,12 @@ function getPointerType(payload) {
   let pointerType = 'mouse';
   if (payload != null && payload.pointerType != null) {
     pointerType = payload.pointerType;
+  } else if (
+    Array.isArray(payload) &&
+    payload[0] != null &&
+    payload[0].pointerType != null
+  ) {
+    pointerType = payload[0].pointerType;
   }
   return pointerType;
 }
@@ -77,7 +83,12 @@ export function pointercancel(target, payload) {
 export function pointerdown(target, defaultPayload) {
   const dispatch = arg => target.dispatchEvent(arg);
   const pointerType = getPointerType(defaultPayload);
-  const payload = {buttons: buttonsType.primary, ...defaultPayload};
+
+  // Payload could be an array for TouchEvents
+  const payload =
+    hasPointerEvent() || pointerType === 'mouse'
+      ? {buttons: buttonsType.primary, ...defaultPayload}
+      : defaultPayload;
 
   if (pointerType === 'mouse') {
     if (hasPointerEvent()) {
@@ -156,8 +167,12 @@ export function pointermove(target, payload) {
 export function pointerup(target, defaultPayload = {}) {
   const dispatch = arg => target.dispatchEvent(arg);
   const pointerType = getPointerType(defaultPayload);
-  // eslint-disable-next-line no-unused-vars
-  const {buttons, ...payload} = defaultPayload;
+
+  // Payload could be an array for TouchEvents
+  const payload = defaultPayload;
+  if (defaultPayload.buttons) {
+    delete payload.buttons;
+  }
 
   if (pointerType === 'mouse') {
     if (hasPointerEvent()) {