From 435775227e424c4fdb2f93a0c38955dc163c8f46 Mon Sep 17 00:00:00 2001
From: Rich Harris <rich.harris@vercel.com>
Date: Tue, 25 Nov 2025 15:05:53 -0500
Subject: [PATCH 1/2] chore: better log_effect_tree

---
 .../svelte/src/internal/client/dev/debug.js   | 26 +++++++++++++++++--
 1 file changed, 24 insertions(+), 2 deletions(-)

diff --git a/packages/svelte/src/internal/client/dev/debug.js b/packages/svelte/src/internal/client/dev/debug.js
index 2714a3af1f69..86e524eeeb14 100644
--- a/packages/svelte/src/internal/client/dev/debug.js
+++ b/packages/svelte/src/internal/client/dev/debug.js
@@ -12,6 +12,7 @@ import {
 	RENDER_EFFECT,
 	ROOT_EFFECT
 } from '#client/constants';
+import { snapshot } from '../../shared/clone.js';
 
 /**
  *
@@ -84,6 +85,16 @@ export function log_effect_tree(effect, depth = 0) {
 		console.groupEnd();
 	}
 
+	if (effect.nodes_start && effect.nodes_end) {
+		// eslint-disable-next-line no-console
+		console.log(effect.nodes_start);
+
+		if (effect.nodes_start !== effect.nodes_end) {
+			// eslint-disable-next-line no-console
+			console.log(effect.nodes_end);
+		}
+	}
+
 	let child = effect.first;
 	while (child !== null) {
 		log_effect_tree(child, depth + 1);
@@ -103,7 +114,13 @@ function log_dep(dep) {
 		const derived = /** @type {Derived} */ (dep);
 
 		// eslint-disable-next-line no-console
-		console.groupCollapsed('%cderived', 'font-weight: normal', derived.v);
+		console.groupCollapsed(
+			`%c$derived %c${dep.label ?? '<unknown>'}`,
+			'font-weight: bold; color: CornflowerBlue',
+			'font-weight: normal',
+			snapshot(derived.v)
+		);
+
 		if (derived.deps) {
 			for (const d of derived.deps) {
 				log_dep(d);
@@ -114,6 +131,11 @@ function log_dep(dep) {
 		console.groupEnd();
 	} else {
 		// eslint-disable-next-line no-console
-		console.log('state', dep.v);
+		console.log(
+			`%c$state %c${dep.label ?? '<unknown>'}`,
+			'font-weight: bold; color: CornflowerBlue',
+			'font-weight: normal',
+			snapshot(dep.v)
+		);
 	}
 }

From a85d8f1f6e4df43eb1685eaa87f7163589c95b4c Mon Sep 17 00:00:00 2001
From: Simon Holthausen <simon.holthausen@vercel.com>
Date: Tue, 25 Nov 2025 22:50:21 +0100
Subject: [PATCH 2/2] untrack

---
 packages/svelte/src/internal/client/dev/debug.js | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/packages/svelte/src/internal/client/dev/debug.js b/packages/svelte/src/internal/client/dev/debug.js
index 86e524eeeb14..ebb612cb6128 100644
--- a/packages/svelte/src/internal/client/dev/debug.js
+++ b/packages/svelte/src/internal/client/dev/debug.js
@@ -13,6 +13,7 @@ import {
 	ROOT_EFFECT
 } from '#client/constants';
 import { snapshot } from '../../shared/clone.js';
+import { untrack } from '../runtime.js';
 
 /**
  *
@@ -118,7 +119,7 @@ function log_dep(dep) {
 			`%c$derived %c${dep.label ?? '<unknown>'}`,
 			'font-weight: bold; color: CornflowerBlue',
 			'font-weight: normal',
-			snapshot(derived.v)
+			untrack(() => snapshot(derived.v))
 		);
 
 		if (derived.deps) {
@@ -135,7 +136,7 @@ function log_dep(dep) {
 			`%c$state %c${dep.label ?? '<unknown>'}`,
 			'font-weight: bold; color: CornflowerBlue',
 			'font-weight: normal',
-			snapshot(dep.v)
+			untrack(() => snapshot(dep.v))
 		);
 	}
 }