fix: ensure signal write invalidation within effects is persistent

Author: trueadm

packages/svelte/src/internal/client/reactivity/sources.js

@@ -3,7 +3,6 @@ import { DEV } from 'esm-env';
 import {
 	component_context,
 	active_reaction,
-	new_deps,
 	active_effect,
 	untracked_writes,
 	get,
@@ -194,7 +193,6 @@ export function internal_set(source, value) {
 			(active_effect.f & CLEAN) !== 0 &&
 			(active_effect.f & (BRANCH_EFFECT | ROOT_EFFECT)) === 0
 		) {
-
 			if (untracked_writes === null) {
 				set_untracked_writes([source]);
 			} else {

packages/svelte/src/internal/client/runtime.js

@@ -464,8 +464,12 @@ export function update_reaction(reaction) {
 
 		// If we're inside an effect and we have untracked writes, then we need to
 		// ensure that if any of those untracked writes result in re-invalidation
-		// of the current effect, then we need to re-schedule the current effect
-		if (untracked_writes !== null && (reaction.f & (DERIVED | MAYBE_DIRTY | DIRTY)) === 0) {
+		// of the current effect, then that happens accordingly
+		if (
+			is_runes() &&
+			untracked_writes !== null &&
+			(reaction.f & (DERIVED | MAYBE_DIRTY | DIRTY)) === 0
+		) {
 			for (i = 0; i < /** @type {Source[]} */ (untracked_writes).length; i++) {
 				schedule_possible_effect_self_invalidation(
 					untracked_writes[i],