From 0a5628f456dc4e88b9c9ca21679770b9398e9a83 Mon Sep 17 00:00:00 2001
From: Rich Harris <rich.harris@vercel.com>
Date: Sun, 2 Feb 2025 21:03:38 -0500
Subject: [PATCH] improve waterfall detection

---
 packages/svelte/src/internal/client/reactivity/deriveds.js | 5 +++--
 packages/svelte/src/internal/client/reactivity/effects.js  | 2 +-
 2 files changed, 4 insertions(+), 3 deletions(-)

diff --git a/packages/svelte/src/internal/client/reactivity/deriveds.js b/packages/svelte/src/internal/client/reactivity/deriveds.js
index 6de1ec6ec7..f1d63bd1fa 100644
--- a/packages/svelte/src/internal/client/reactivity/deriveds.js
+++ b/packages/svelte/src/internal/client/reactivity/deriveds.js
@@ -86,10 +86,11 @@ export function derived(fn) {
 /**
  * @template V
  * @param {() => Promise<V>} fn
+ * @param {boolean} detect_waterfall Whether to print a warning if the value is not read immediately after update
  * @returns {Promise<Source<V>>}
  */
 /*#__NO_SIDE_EFFECTS__*/
-export function async_derived(fn) {
+export function async_derived(fn, detect_waterfall = true) {
 	let parent = /** @type {Effect | null} */ (active_effect);
 
 	if (parent === null) {
@@ -121,7 +122,7 @@ export function async_derived(fn) {
 
 				internal_set(value, v);
 
-				if (DEV) {
+				if (DEV && detect_waterfall) {
 					recent_async_deriveds.add(value);
 
 					setTimeout(() => {
diff --git a/packages/svelte/src/internal/client/reactivity/effects.js b/packages/svelte/src/internal/client/reactivity/effects.js
index 6e2a7600fd..4e9ef51726 100644
--- a/packages/svelte/src/internal/client/reactivity/effects.js
+++ b/packages/svelte/src/internal/client/reactivity/effects.js
@@ -358,7 +358,7 @@ export function template_effect(fn, sync = [], async = [], d = derived) {
 		var restore = capture();
 		var unsuspend = suspend();
 
-		Promise.all(async.map(async_derived)).then((result) => {
+		Promise.all(async.map((expression) => async_derived(expression, false))).then((result) => {
 			restore();
 
 			if ((effect.f & DESTROYED) !== 0) {