Merge pull request #5148 from preactjs/revert-5055-v10.x

Author: JoviDeCroock

hooks/src/index.js

@@ -64,9 +64,9 @@ options._render = vnode => {
 				hookItem._pendingArgs = hookItem._nextValue = undefined;
 			});
 		} else {
-			if (hooks._pendingEffects.length) {
-				flushAfterPaintEffects();
-			}
+			hooks._pendingEffects.some(invokeCleanup);
+			hooks._pendingEffects.some(invokeEffect);
+			hooks._pendingEffects = [];
 			currentIndex = 0;
 		}
 	}

hooks/test/browser/useEffect.test.jsx

@@ -1,5 +1,5 @@
 import { act, teardown as teardownAct } from 'preact/test-utils';
-import { createElement, render, Fragment, Component, options } from 'preact';
+import { createElement, render, Fragment, Component } from 'preact';
 import { useEffect, useState, useRef } from 'preact/hooks';
 import { setupScratch, teardown } from '../../../test/_util/helpers';
 import { useEffectAssertions } from './useEffectAssertions';
@@ -665,62 +665,4 @@ describe('useEffect', () => {
 			setVal(1);
 		});
 	});
-
-	it('should flush all pending effects when one component re-renders before afterPaint', () => {
-		// Regression test: when only one component re-renders (via setState)
-		// before afterPaint has flushed effects, ALL pending effects from
-		// ALL components should be flushed as a batch before the re-render
-		// proceeds. This matches React's flushPendingEffects() behavior.
-		//
-		// Without the fix, only the re-rendering component's stale effects
-		// were flushed in _render, leaving sibling effects unflushed until
-		// they got their own re-render or afterPaint fired.
-		const order = [];
-		let setB;
-
-		function A() {
-			useEffect(() => {
-				order.push('A effect');
-			}, []);
-			return <div>A</div>;
-		}
-
-		function B() {
-			const [val, _setB] = useState(0);
-			setB = _setB;
-			useEffect(() => {
-				order.push('B effect');
-			}, []);
-			return <div>{val}</div>;
-		}
-
-		function App() {
-			return (
-				<div>
-					<A />
-					<B />
-				</div>
-			);
-		}
-
-		render(<App />, scratch);
-
-		// Effects are queued but not yet flushed (afterPaint hasn't fired).
-		expect(order).to.deep.equal([]);
-
-		// Force B to re-render synchronously by overriding debounceRendering.
-		// This simulates what happens when a store subscription or
-		// useLayoutEffect triggers a re-render before afterPaint.
-		const prev = options.debounceRendering;
-		options.debounceRendering = cb => cb();
-		setB(1);
-		options.debounceRendering = prev;
-
-		// With the fix: B's _render detects stale effects and calls
-		// flushAfterPaintEffects(), which flushes BOTH A's and B's effects.
-		// Without the fix: only B's effects would flush here; A's effect
-		// would be deferred.
-		expect(order).to.include('A effect');
-		expect(order).to.include('B effect');
-	});
 });