fix: ensure effect queue is properly cleaned up after flush error

close #97

Author: johnsoncodehk

src/index.ts

@@ -40,8 +40,8 @@ const {
 		let firstInsertedIndex = insertIndex;
 
 		do {
-			effect.flags &= ~ReactiveFlags.Watching;
 			queued[insertIndex++] = effect;
+			effect.flags &= ~ReactiveFlags.Watching;
 			effect = effect.subs?.sub as EffectNode;
 			if (effect === undefined || !(effect.flags & ReactiveFlags.Watching)) {
 				break;
@@ -256,13 +256,21 @@ function run(e: EffectNode): void {
 }
 
 function flush(): void {
-	while (notifyIndex < queuedLength) {
-		const effect = queued[notifyIndex]!;
-		queued[notifyIndex++] = undefined;
-		run(effect);
+	try {
+		while (notifyIndex < queuedLength) {
+			const effect = queued[notifyIndex]!;
+			queued[notifyIndex++] = undefined;
+			run(effect);
+		}
+	} finally {
+		while (notifyIndex < queuedLength) {
+			const effect = queued[notifyIndex]!;
+			queued[notifyIndex++] = undefined;
+			effect.flags |= ReactiveFlags.Watching | ReactiveFlags.Recursed;
+		}
+		notifyIndex = 0;
+		queuedLength = 0;
 	}
-	notifyIndex = 0;
-	queuedLength = 0;
 }
 
 function computedOper<T>(this: ComputedNode<T>): T {

tests/effect.spec.ts

@@ -286,3 +286,44 @@ test('should support custom recurse effect', () => {
 
 	expect(triggers).toBe(6);
 });
+
+test('should not execute skipped effects from previous failed flush when updating unrelated signal', () => {
+	const a = signal(0);
+	const b = signal(0);
+	const c = signal(0);
+	const d = computed(() => (c(), 0));
+
+	let effect3Executed = false;
+
+	effect(() => {
+		a();
+	});
+	effect(() => {
+		if (a() === 2) {
+			throw new Error('Error in effect 2');
+		}
+	});
+	effect(() => {
+		a();
+		d();
+		effect3Executed = true;
+	});
+	effect(() => {
+		b();
+	});
+
+	a(1);
+
+	effect3Executed = false;
+	try {
+		a(2);
+	} catch (e) {
+		expect((e as Error).message).toBe('Error in effect 2');
+	}
+
+	expect(effect3Executed).toBe(false);
+	b(1);
+	expect(effect3Executed).toBe(false);
+	c(1);
+	expect(effect3Executed).toBe(true);
+});