Revert "Revert "[Float] Suspend unstyled content for up to 1 minute (#26532)""

kassens · kassens · commit 7eca7179173c · 2023-04-19T19:08:23.000-04:00
This reverts commit 314f7d3.
diff --git a/packages/react-dom-bindings/src/client/ReactDOMHostConfig.js b/packages/react-dom-bindings/src/client/ReactDOMHostConfig.js
@@ -3333,28 +3333,34 @@ export function waitForCommitToBeReady(): null | (Function => Function) {
   // tasks to wait on.
   if (state.count > 0) {
     return commit => {
-      unsuspendAfterTimeout(state);
+      // We almost never want to show content before its styles have loaded. But
+      // eventually we will give up and allow unstyled content. So this number is
+      // somewhat arbitrary — big enough that you'd only reach it under
+      // extreme circumstances.
+      // TODO: Figure out what the browser engines do during initial page load and
+      // consider aligning our behavior with that.
+      const stylesheetTimer = setTimeout(() => {
+        if (state.stylesheets) {
+          insertSuspendedStylesheets(state, state.stylesheets);
+        }
+        if (state.unsuspend) {
+          const unsuspend = state.unsuspend;
+          state.unsuspend = null;
+          unsuspend();
+        }
+      }, 60000); // one minute
+
       state.unsuspend = commit;
 
-      return () => (state.unsuspend = null);
+      return () => {
+        state.unsuspend = null;
+        clearTimeout(stylesheetTimer);
+      };
     };
   }
   return null;
 }
 
-function unsuspendAfterTimeout(state: SuspendedState) {
-  setTimeout(() => {
-    if (state.stylesheets) {
-      insertSuspendedStylesheets(state, state.stylesheets);
-    }
-    if (state.unsuspend) {
-      const unsuspend = state.unsuspend;
-      state.unsuspend = null;
-      unsuspend();
-    }
-  }, 500);
-}
-
 function onUnsuspend(this: SuspendedState) {
   this.count--;
   if (this.count === 0) {
diff --git a/packages/react-dom/src/__tests__/ReactDOMFloat-test.js b/packages/react-dom/src/__tests__/ReactDOMFloat-test.js
@@ -3163,7 +3163,7 @@ body {
     );
   });
 
-  it('can unsuspend after a timeout even if some assets never load', async () => {
+  it('stylesheets block render, with a really long timeout', async () => {
     function App({children}) {
       return (
         <html>
@@ -3191,7 +3191,22 @@ body {
       </html>,
     );
 
-    jest.advanceTimersByTime(1000);
+    // Advance time by 50 seconds. Even still, the transition is suspended.
+    jest.advanceTimersByTime(50000);
+    await waitForAll([]);
+    expect(getMeaningfulChildren(document)).toEqual(
+      <html>
+        <head>
+          <link rel="preload" href="foo" as="style" />
+        </head>
+        <body />
+      </html>,
+    );
+
+    // Advance time by 10 seconds more. A full minute total has elapsed. At this
+    // point, something must have really gone wrong, so we time out and allow
+    // unstyled content to be displayed.
+    jest.advanceTimersByTime(10000);
     expect(getMeaningfulChildren(document)).toEqual(
       <html>
         <head>
