From e16703e6c7776ff39e30c448df075f48bdbe08ea Mon Sep 17 00:00:00 2001
From: Dominic Gannaway <trueadm@users.noreply.github.com>
Date: Mon, 11 May 2020 22:09:52 +0100
Subject: [PATCH] Modern Event System: revise ancestor logic (#18886)

---
 .../src/events/DOMModernPluginEventSystem.js  | 31 ++++---
 ...OMModernPluginEventSystem-test.internal.js | 89 +++++++++++++++++++
 2 files changed, 107 insertions(+), 13 deletions(-)

diff --git a/packages/react-dom/src/events/DOMModernPluginEventSystem.js b/packages/react-dom/src/events/DOMModernPluginEventSystem.js
index 095e1b6ce8..03ecd50ade 100644
--- a/packages/react-dom/src/events/DOMModernPluginEventSystem.js
+++ b/packages/react-dom/src/events/DOMModernPluginEventSystem.js
@@ -417,13 +417,13 @@ export function dispatchEventForPluginEventSystem(
       // sub-tree for that root and make that our ancestor instance.
       let node = targetInst;
 
-      while (true) {
+      mainLoop: while (true) {
         if (node === null) {
           return;
         }
         const nodeTag = node.tag;
         if (nodeTag === HostRoot || nodeTag === HostPortal) {
-          const container = node.stateNode.containerInfo;
+          let container = node.stateNode.containerInfo;
           if (isMatchingRootContainer(container, targetContainerNode)) {
             break;
           }
@@ -449,18 +449,23 @@ export function dispatchEventForPluginEventSystem(
               grandNode = grandNode.return;
             }
           }
-          const parentSubtreeInst = getClosestInstanceFromNode(container);
-          if (parentSubtreeInst === null) {
-            return;
+          // Now we need to find it's corresponding host fiber in the other
+          // tree. To do this we can use getClosestInstanceFromNode, but we
+          // need to validate that the fiber is a host instance, otherwise
+          // we need to traverse up through the DOM till we find the correct
+          // node that is from the other tree.
+          while (container !== null) {
+            const parentNode = getClosestInstanceFromNode(container);
+            if (parentNode === null) {
+              return;
+            }
+            const parentTag = parentNode.tag;
+            if (parentTag === HostComponent || parentTag === HostText) {
+              node = ancestorInst = parentNode;
+              continue mainLoop;
+            }
+            container = container.parentNode;
           }
-          const parentTag = parentSubtreeInst.tag;
-          // getClosestInstanceFromNode can return a HostRoot or SuspenseComponent.
-          // So we need to ensure we only set the ancestor to a HostComponent or HostText.
-          if (parentTag === HostComponent || parentTag === HostText) {
-            ancestorInst = parentSubtreeInst;
-          }
-          node = parentSubtreeInst;
-          continue;
         }
         node = node.return;
       }
diff --git a/packages/react-dom/src/events/__tests__/DOMModernPluginEventSystem-test.internal.js b/packages/react-dom/src/events/__tests__/DOMModernPluginEventSystem-test.internal.js
index 538353fff4..a690b574e9 100644
--- a/packages/react-dom/src/events/__tests__/DOMModernPluginEventSystem-test.internal.js
+++ b/packages/react-dom/src/events/__tests__/DOMModernPluginEventSystem-test.internal.js
@@ -224,6 +224,95 @@ describe('DOMModernPluginEventSystem', () => {
           expect(log[5]).toEqual(['bubble', buttonElement]);
         });
 
+        it('handle propagation of click events between disjointed roots #2', () => {
+          const buttonRef = React.createRef();
+          const button2Ref = React.createRef();
+          const divRef = React.createRef();
+          const spanRef = React.createRef();
+          const log = [];
+          const onClick = jest.fn(e => log.push(['bubble', e.currentTarget]));
+          const onClickCapture = jest.fn(e =>
+            log.push(['capture', e.currentTarget]),
+          );
+
+          function Child() {
+            return (
+              <div
+                ref={divRef}
+                onClick={onClick}
+                onClickCapture={onClickCapture}>
+                Click me!
+              </div>
+            );
+          }
+
+          function Parent() {
+            return (
+              <button
+                ref={button2Ref}
+                onClick={onClick}
+                onClickCapture={onClickCapture}
+              />
+            );
+          }
+
+          function GrandParent() {
+            return (
+              <button
+                ref={buttonRef}
+                onClick={onClick}
+                onClickCapture={onClickCapture}>
+                <span ref={spanRef} />
+              </button>
+            );
+          }
+
+          // We make a wrapper with an inner container that we
+          // render to. So it looks like <div><span></span></div>
+          // We then render to all three:
+          // - container
+          // - parentContainer
+          // - childContainer
+
+          const parentContainer = document.createElement('div');
+          const childContainer = document.createElement('div');
+
+          ReactDOM.render(<GrandParent />, container);
+          ReactDOM.render(<Parent />, parentContainer);
+          ReactDOM.render(<Child />, childContainer);
+
+          parentContainer.appendChild(childContainer);
+          spanRef.current.appendChild(parentContainer);
+
+          // Inside <GrandParent />
+          const buttonElement = buttonRef.current;
+          dispatchClickEvent(buttonElement);
+          expect(onClick).toHaveBeenCalledTimes(1);
+          expect(onClickCapture).toHaveBeenCalledTimes(1);
+          expect(log[0]).toEqual(['capture', buttonElement]);
+          expect(log[1]).toEqual(['bubble', buttonElement]);
+
+          // Inside <Child />
+          const divElement = divRef.current;
+          dispatchClickEvent(divElement);
+          expect(onClick).toHaveBeenCalledTimes(3);
+          expect(onClickCapture).toHaveBeenCalledTimes(3);
+          expect(log[2]).toEqual(['capture', divElement]);
+          expect(log[3]).toEqual(['bubble', divElement]);
+          expect(log[4]).toEqual(['capture', buttonElement]);
+          expect(log[5]).toEqual(['bubble', buttonElement]);
+
+          // Inside <Parent />
+          const buttonElement2 = button2Ref.current;
+          dispatchClickEvent(buttonElement2);
+          expect(onClick).toHaveBeenCalledTimes(5);
+          expect(onClickCapture).toHaveBeenCalledTimes(5);
+          expect(log[6]).toEqual(['capture', buttonElement2]);
+          expect(log[7]).toEqual(['bubble', buttonElement2]);
+          expect(log[8]).toEqual(['capture', buttonElement]);
+          expect(log[9]).toEqual(['bubble', buttonElement]);
+        });
+
         it('handle propagation of click events between disjointed comment roots', () => {
           const buttonRef = React.createRef();
           const divRef = React.createRef();