From d830cd998490c12164da6a9e1ddff56daff80030 Mon Sep 17 00:00:00 2001
From: Dan Abramov <dan.abramov@gmail.com>
Date: Mon, 4 May 2020 01:43:51 +0100
Subject: [PATCH] [Blocks] Fix stale data on updates (#18810)

* [Blocks] Failing test for nested load

* Simplify the test

* Add a similar test that fails in PROD

* Copy .type when cloning work in progress
---
 .../react-reconciler/src/ReactFiber.new.js    |  4 +
 .../react-reconciler/src/ReactFiber.old.js    |  4 +
 .../src/__tests__/ReactBlocks-test.js         | 83 +++++++++++++++++++
 3 files changed, 91 insertions(+)

diff --git a/packages/react-reconciler/src/ReactFiber.new.js b/packages/react-reconciler/src/ReactFiber.new.js
index b428e11374..c3f8d2b169 100644
--- a/packages/react-reconciler/src/ReactFiber.new.js
+++ b/packages/react-reconciler/src/ReactFiber.new.js
@@ -282,6 +282,8 @@ export function createWorkInProgress(current: Fiber, pendingProps: any): Fiber {
     current.alternate = workInProgress;
   } else {
     workInProgress.pendingProps = pendingProps;
+    // Needed because Blocks store data on type.
+    workInProgress.type = current.type;
 
     // We already have an alternate.
     // Reset the effect tag.
@@ -415,6 +417,8 @@ export function resetWorkInProgress(workInProgress: Fiber, renderLanes: Lanes) {
     workInProgress.memoizedProps = current.memoizedProps;
     workInProgress.memoizedState = current.memoizedState;
     workInProgress.updateQueue = current.updateQueue;
+    // Needed because Blocks store data on type.
+    workInProgress.type = current.type;
 
     // Clone the dependencies object. This is mutated during the render phase, so
     // it cannot be shared with the current fiber.
diff --git a/packages/react-reconciler/src/ReactFiber.old.js b/packages/react-reconciler/src/ReactFiber.old.js
index 3ef1b33032..1ebb767ec6 100644
--- a/packages/react-reconciler/src/ReactFiber.old.js
+++ b/packages/react-reconciler/src/ReactFiber.old.js
@@ -277,6 +277,8 @@ export function createWorkInProgress(current: Fiber, pendingProps: any): Fiber {
     current.alternate = workInProgress;
   } else {
     workInProgress.pendingProps = pendingProps;
+    // Needed because Blocks store data on type.
+    workInProgress.type = current.type;
 
     // We already have an alternate.
     // Reset the effect tag.
@@ -413,6 +415,8 @@ export function resetWorkInProgress(
     workInProgress.memoizedProps = current.memoizedProps;
     workInProgress.memoizedState = current.memoizedState;
     workInProgress.updateQueue = current.updateQueue;
+    // Needed because Blocks store data on type.
+    workInProgress.type = current.type;
 
     // Clone the dependencies object. This is mutated during the render phase, so
     // it cannot be shared with the current fiber.
diff --git a/packages/react-reconciler/src/__tests__/ReactBlocks-test.js b/packages/react-reconciler/src/__tests__/ReactBlocks-test.js
index b5cc0b2128..56be938649 100644
--- a/packages/react-reconciler/src/__tests__/ReactBlocks-test.js
+++ b/packages/react-reconciler/src/__tests__/ReactBlocks-test.js
@@ -257,4 +257,87 @@ describe('ReactBlocks', () => {
       </>,
     );
   });
+
+  // Regression test.
+  // @gate experimental
+  it('does not render stale data after ping', async () => {
+    function Child() {
+      return <span>Name: {readString('Sebastian')}</span>;
+    }
+
+    const loadParent = block(
+      function Parent(props, data) {
+        return (
+          <Suspense fallback="Loading...">
+            {data.name ? <Child /> : <span>Empty</span>}
+          </Suspense>
+        );
+      },
+      function load(name) {
+        return {name};
+      },
+    );
+
+    function App({Page}) {
+      return <Page />;
+    }
+
+    await ReactNoop.act(async () => {
+      ReactNoop.render(<App Page={loadParent(null)} />);
+    });
+    expect(ReactNoop).toMatchRenderedOutput(<span>Empty</span>);
+
+    await ReactNoop.act(async () => {
+      ReactNoop.render(<App Page={loadParent('Sebastian')} />);
+    });
+    await ReactNoop.act(async () => {
+      jest.advanceTimersByTime(1000);
+    });
+    expect(ReactNoop).toMatchRenderedOutput(<span>Name: Sebastian</span>);
+  });
+
+  // Regression test.
+  // @gate experimental
+  it('does not render stale data after ping and setState', async () => {
+    function Child() {
+      return <span>Name: {readString('Sebastian')}</span>;
+    }
+
+    let _setSuspend;
+    const loadParent = block(
+      function Parent(props, data) {
+        const [suspend, setSuspend] = useState(true);
+        _setSuspend = setSuspend;
+        if (!suspend) {
+          return <span>{data.name}</span>;
+        }
+        return (
+          <Suspense fallback="Loading...">
+            {data.name ? <Child /> : <span>Empty</span>}
+          </Suspense>
+        );
+      },
+      function load(name) {
+        return {name};
+      },
+    );
+
+    function App({Page}) {
+      return <Page />;
+    }
+
+    await ReactNoop.act(async () => {
+      ReactNoop.render(<App Page={loadParent(null)} />);
+    });
+    expect(ReactNoop).toMatchRenderedOutput(<span>Empty</span>);
+
+    await ReactNoop.act(async () => {
+      ReactNoop.render(<App Page={loadParent('Sebastian')} />);
+    });
+    await ReactNoop.act(async () => {
+      _setSuspend(false);
+      jest.advanceTimersByTime(1000);
+    });
+    expect(ReactNoop).toMatchRenderedOutput(<span>Sebastian</span>);
+  });
 });