Use SyncLane for discrete event hydration (#21038)

Discrete event hydration doesn't need to be interruptible, since
there's nothing higher priority than discrete events. So we can use
SyncLane instead of a special hydration lane.

packages/react-dom/src/__tests__/ReactDOMServerPartialHydration-test.internal.js

@@ -2187,17 +2187,17 @@ describe('ReactDOMServerPartialHydration', () => {
     expect(container.textContent).toBe('Click meHello');
 
     // We're now partially hydrated.
-    a.click();
+    await act(async () => {
+      a.click();
+    });
     expect(clicks).toBe(0);
 
     // Resolving the promise so that rendering can complete.
-    suspend = false;
-    resolve();
-    await promise;
-
-    Scheduler.unstable_flushAll();
-    jest.runAllTimers();
-
+    await act(async () => {
+      suspend = false;
+      resolve();
+      await promise;
+    });
     expect(clicks).toBe(1);
 
     expect(container.textContent).toBe('Hello');
@@ -2270,18 +2270,19 @@ describe('ReactDOMServerPartialHydration', () => {
     jest.runAllTimers();
 
     // We're now partially hydrated.
-    a.click();
+    await act(async () => {
+      a.click();
+    });
     // We should not have invoked the event yet because we're not
     // yet hydrated.
     expect(onEvent).toHaveBeenCalledTimes(0);
 
     // Resolving the promise so that rendering can complete.
-    suspend = false;
-    resolve();
-    await promise;
-
-    Scheduler.unstable_flushAll();
-    jest.runAllTimers();
+    await act(async () => {
+      suspend = false;
+      resolve();
+      await promise;
+    });
 
     expect(onEvent).toHaveBeenCalledTimes(2);
 
@@ -2344,7 +2345,9 @@ describe('ReactDOMServerPartialHydration', () => {
     root.render(<App />);
 
     // We'll do one click before hydrating.
-    a.click();
+    await act(async () => {
+      a.click();
+    });
     // This should be delayed.
     expect(clicks).toBe(0);
 
@@ -2352,17 +2355,17 @@ describe('ReactDOMServerPartialHydration', () => {
     jest.runAllTimers();
 
     // We're now partially hydrated.
-    a.click();
+    await act(async () => {
+      a.click();
+    });
     expect(clicks).toBe(0);
 
     // Resolving the promise so that rendering can complete.
-    suspend = false;
-    resolve();
-    await promise;
-
-    Scheduler.unstable_flushAll();
-    jest.runAllTimers();
-
+    await act(async () => {
+      suspend = false;
+      resolve();
+      await promise;
+    });
     expect(clicks).toBe(2);
 
     document.body.removeChild(container);
@@ -2436,19 +2439,19 @@ describe('ReactDOMServerPartialHydration', () => {
     jest.runAllTimers();
 
     // We're now partially hydrated.
-    a.click();
+    await act(async () => {
+      a.click();
+    });
     // We should not have invoked the event yet because we're not
     // yet hydrated.
     expect(onEvent).toHaveBeenCalledTimes(0);
 
     // Resolving the promise so that rendering can complete.
-    suspend = false;
-    resolve();
-    await promise;
-
-    Scheduler.unstable_flushAll();
-    jest.runAllTimers();
-
+    await act(async () => {
+      suspend = false;
+      resolve();
+      await promise;
+    });
     expect(onEvent).toHaveBeenCalledTimes(2);
 
     document.body.removeChild(container);
@@ -2510,17 +2513,18 @@ describe('ReactDOMServerPartialHydration', () => {
     jest.runAllTimers();
 
     // We're now partially hydrated.
-    span.click();
+    await act(async () => {
+      span.click();
+    });
     expect(clicksOnChild).toBe(0);
     expect(clicksOnParent).toBe(0);
 
     // Resolving the promise so that rendering can complete.
-    suspend = false;
-    resolve();
-    await promise;
-
-    Scheduler.unstable_flushAll();
-    jest.runAllTimers();
+    await act(async () => {
+      suspend = false;
+      resolve();
+      await promise;
+    });
 
     expect(clicksOnChild).toBe(1);
     // This will be zero due to the stopPropagation.
@@ -2589,16 +2593,17 @@ describe('ReactDOMServerPartialHydration', () => {
     Scheduler.unstable_flushAll();
 
     // The Suspense boundary is not yet hydrated.
-    a.click();
+    await act(async () => {
+      a.click();
+    });
     expect(clicks).toBe(0);
 
     // Resolving the promise so that rendering can complete.
-    suspend = false;
-    resolve();
-    await promise;
-
-    Scheduler.unstable_flushAll();
-    jest.runAllTimers();
+    await act(async () => {
+      suspend = false;
+      resolve();
+      await promise;
+    });
 
     // We're now full hydrated.
 
@@ -2858,20 +2863,22 @@ describe('ReactDOMServerPartialHydration', () => {
     expect(container.textContent).toBe('Click meHello');
 
     // We're now partially hydrated.
-    form.dispatchEvent(
-      new Event('submit', {
-        bubbles: true,
-      }),
-    );
+    await act(async () => {
+      form.dispatchEvent(
+        new Event('submit', {
+          bubbles: true,
+        }),
+      );
+    });
     expect(submits).toBe(0);
 
     // Resolving the promise so that rendering can complete.
-    suspend = false;
-    resolve();
-    await promise;
+    await act(async () => {
+      suspend = false;
+      resolve();
+      await promise;
+    });
 
-    Scheduler.unstable_flushAll();
-    jest.runAllTimers();
     expect(submits).toBe(1);
     expect(container.textContent).toBe('Hello');
     document.body.removeChild(container);

packages/react-dom/src/__tests__/ReactDOMServerSelectiveHydration-test.internal.js

@@ -255,22 +255,25 @@ describe('ReactDOMServerSelectiveHydration', () => {
     expect(Scheduler).toHaveYielded([]);
 
     // This click target cannot be hydrated yet because it's suspended.
-    const result = dispatchClickEvent(spanD);
-
-    expect(Scheduler).toHaveYielded(['App']);
-
-    expect(result).toBe(true);
-
-    // Continuing rendering will render B next.
-    expect(Scheduler).toFlushAndYield(['B', 'C']);
-
-    suspend = false;
-    resolve();
-    await promise;
+    await act(async () => {
+      const result = dispatchClickEvent(spanD);
+      expect(result).toBe(true);
+    });
+    expect(Scheduler).toHaveYielded([
+      'App',
+      // Continuing rendering will render B next.
+      'B',
+      'C',
+    ]);
 
+    await act(async () => {
+      suspend = false;
+      resolve();
+      await promise;
+    });
     // After the click, we should prioritize D and the Click first,
     // and only after that render A and C.
-    expect(Scheduler).toFlushAndYield(['D', 'Clicked D', 'A']);
+    expect(Scheduler).toHaveYielded(['D', 'Clicked D', 'A']);
 
     document.body.removeChild(container);
   });
@@ -348,13 +351,15 @@ describe('ReactDOMServerSelectiveHydration', () => {
 
     expect(Scheduler).toHaveYielded(['App']);
 
-    suspend = false;
-    resolve();
-    await promise;
+    await act(async () => {
+      suspend = false;
+      resolve();
+      await promise;
+    });
 
     // We should prioritize hydrating A, C and D first since we clicked in
     // them. Only after they're done will we hydrate B.
-    expect(Scheduler).toFlushAndYield([
+    expect(Scheduler).toHaveYielded([
       'A',
       'Clicked A',
       'C',
@@ -506,21 +511,21 @@ describe('ReactDOMServerSelectiveHydration', () => {
     // Nothing has been hydrated so far.
     expect(Scheduler).toHaveYielded([]);
 
-    const target = createEventTarget(spanD);
-    target.virtualclick();
-
-    expect(Scheduler).toHaveYielded(['App']);
-
     // Continuing rendering will render B next.
-    expect(Scheduler).toFlushAndYield(['B', 'C']);
-
-    suspend = false;
-    resolve();
-    await promise;
+    await act(async () => {
+      const target = createEventTarget(spanD);
+      target.virtualclick();
+    });
+    expect(Scheduler).toHaveYielded(['App', 'B', 'C']);
 
     // After the click, we should prioritize D and the Click first,
     // and only after that render A and C.
-    expect(Scheduler).toFlushAndYield(['D', 'Clicked D', 'A']);
+    await act(async () => {
+      suspend = false;
+      resolve();
+      await promise;
+    });
+    expect(Scheduler).toHaveYielded(['D', 'Clicked D', 'A']);
 
     document.body.removeChild(container);
   });
@@ -602,13 +607,15 @@ describe('ReactDOMServerSelectiveHydration', () => {
 
     expect(Scheduler).toHaveYielded(['App']);
 
-    suspend = false;
-    resolve();
-    await promise;
+    await act(async () => {
+      suspend = false;
+      resolve();
+      await promise;
+    });
 
     // We should prioritize hydrating A, C and D first since we clicked in
     // them. Only after they're done will we hydrate B.
-    expect(Scheduler).toFlushAndYield([
+    expect(Scheduler).toHaveYielded([
       'A',
       'Clicked A',
       'C',
@@ -701,9 +708,11 @@ describe('ReactDOMServerSelectiveHydration', () => {
 
     expect(Scheduler).toHaveYielded(['App']);
 
-    suspend = false;
-    resolve();
-    await promise;
+    await act(async () => {
+      suspend = false;
+      resolve();
+      await promise;
+    });
 
     // We should prioritize hydrating D first because we clicked it.
     // Next we should hydrate C since that's the current hover target.
@@ -711,7 +720,7 @@ describe('ReactDOMServerSelectiveHydration', () => {
     // the same time since B was already scheduled.
     // This is ok because it will at least not continue for nested
     // boundary. See the next test below.
-    expect(Scheduler).toFlushAndYield([
+    expect(Scheduler).toHaveYielded([
       'D',
       'Clicked D',
       'B', // Ideally this should be later.

packages/react-dom/src/events/__tests__/DOMPluginEventSystem-test.internal.js

@@ -67,6 +67,7 @@ describe('DOMPluginEventSystem', () => {
           ReactDOM = require('react-dom');
           Scheduler = require('scheduler');
           ReactDOMServer = require('react-dom/server');
+          act = require('react-dom/test-utils').unstable_concurrentAct;
           container = document.createElement('div');
           document.body.appendChild(container);
           startNativeEventListenerClearDown();
@@ -636,16 +637,17 @@ describe('DOMPluginEventSystem', () => {
           Scheduler.unstable_flushAll();
 
           // The Suspense boundary is not yet hydrated.
-          a.click();
+          await act(async () => {
+            a.click();
+          });
           expect(clicks).toBe(0);
 
           // Resolving the promise so that rendering can complete.
-          suspend = false;
-          resolve();
-          await promise;
-
-          Scheduler.unstable_flushAll();
-          jest.runAllTimers();
+          await act(async () => {
+            suspend = false;
+            resolve();
+            await promise;
+          });
 
           // We're now full hydrated.
 

packages/react-reconciler/src/ReactFiberReconciler.new.js

@@ -78,7 +78,6 @@ import {
 import {StrictLegacyMode} from './ReactTypeOfMode';
 import {
   SyncLane,
-  InputDiscreteHydrationLane,
   SelectiveHydrationLane,
   NoTimestamp,
   getHighestPriorityPendingLanes,
@@ -388,7 +387,7 @@ export function attemptSynchronousHydration(fiber: Fiber): void {
       // If we're still blocked after this, we need to increase
       // the priority of any promises resolving within this
       // boundary so that they next attempt also has higher pri.
-      const retryLane = InputDiscreteHydrationLane;
+      const retryLane = SyncLane;
       markRetryLaneIfNotHydrated(fiber, retryLane);
       break;
   }
@@ -422,7 +421,7 @@ export function attemptDiscreteHydration(fiber: Fiber): void {
     return;
   }
   const eventTime = requestEventTime();
-  const lane = InputDiscreteHydrationLane;
+  const lane = SyncLane;
   scheduleUpdateOnFiber(fiber, lane, eventTime);
   markRetryLaneIfNotHydrated(fiber, lane);
 }

packages/react-reconciler/src/ReactFiberReconciler.old.js

@@ -78,7 +78,6 @@ import {
 import {StrictLegacyMode} from './ReactTypeOfMode';
 import {
   SyncLane,
-  InputDiscreteHydrationLane,
   SelectiveHydrationLane,
   NoTimestamp,
   getHighestPriorityPendingLanes,
@@ -388,7 +387,7 @@ export function attemptSynchronousHydration(fiber: Fiber): void {
       // If we're still blocked after this, we need to increase
       // the priority of any promises resolving within this
       // boundary so that they next attempt also has higher pri.
-      const retryLane = InputDiscreteHydrationLane;
+      const retryLane = SyncLane;
       markRetryLaneIfNotHydrated(fiber, retryLane);
       break;
   }
@@ -422,7 +421,7 @@ export function attemptDiscreteHydration(fiber: Fiber): void {
     return;
   }
   const eventTime = requestEventTime();
-  const lane = InputDiscreteHydrationLane;
+  const lane = SyncLane;
   scheduleUpdateOnFiber(fiber, lane, eventTime);
   markRetryLaneIfNotHydrated(fiber, lane);
 }