From bda8955687acd3bfd11b7835c43738346a6f2e6f Mon Sep 17 00:00:00 2001
From: 7nik <kifiranet@gmail.com>
Date: Fri, 27 Jun 2025 11:40:18 +0300
Subject: [PATCH] re-throw svelte error immediately

---
 packages/svelte/src/internal/client/render.js                 | 4 ++++
 .../runtime-legacy/samples/keyed-each-dev-unique/_config.js   | 1 -
 .../samples/inspect-state-unsafe-mutation/_config.js          | 1 -
 .../runtime-runes/samples/props-bound-fallback/_config.js     | 1 -
 4 files changed, 4 insertions(+), 3 deletions(-)

diff --git a/packages/svelte/src/internal/client/render.js b/packages/svelte/src/internal/client/render.js
index dfb40f1796..7df1d419e0 100644
--- a/packages/svelte/src/internal/client/render.js
+++ b/packages/svelte/src/internal/client/render.js
@@ -136,6 +136,10 @@ export function hydrate(component, options) {
 
 		return /**  @type {Exports} */ (instance);
 	} catch (error) {
+		// re-throw Svelte errors - they are certainly not related to hydration
+		if (error instanceof Error && error.message.includes('https://svelte.dev/e/')) {
+			throw error;
+		}
 		if (error !== HYDRATION_ERROR) {
 			// eslint-disable-next-line no-console
 			console.error('Failed to hydrate: ', error);
diff --git a/packages/svelte/tests/runtime-legacy/samples/keyed-each-dev-unique/_config.js b/packages/svelte/tests/runtime-legacy/samples/keyed-each-dev-unique/_config.js
index 97ccaebac2..6e64245d86 100644
--- a/packages/svelte/tests/runtime-legacy/samples/keyed-each-dev-unique/_config.js
+++ b/packages/svelte/tests/runtime-legacy/samples/keyed-each-dev-unique/_config.js
@@ -1,7 +1,6 @@
 import { test } from '../../test';
 
 export default test({
-	mode: ['server', 'client'],
 	compileOptions: {
 		dev: true
 	},
diff --git a/packages/svelte/tests/runtime-runes/samples/inspect-state-unsafe-mutation/_config.js b/packages/svelte/tests/runtime-runes/samples/inspect-state-unsafe-mutation/_config.js
index 27b9cc7fec..dcf3a8bc3d 100644
--- a/packages/svelte/tests/runtime-runes/samples/inspect-state-unsafe-mutation/_config.js
+++ b/packages/svelte/tests/runtime-runes/samples/inspect-state-unsafe-mutation/_config.js
@@ -2,7 +2,6 @@ import { flushSync } from 'svelte';
 import { test } from '../../test';
 
 export default test({
-	mode: ['client'],
 	compileOptions: {
 		dev: true
 	},
diff --git a/packages/svelte/tests/runtime-runes/samples/props-bound-fallback/_config.js b/packages/svelte/tests/runtime-runes/samples/props-bound-fallback/_config.js
index 26cb426127..d04d8884ca 100644
--- a/packages/svelte/tests/runtime-runes/samples/props-bound-fallback/_config.js
+++ b/packages/svelte/tests/runtime-runes/samples/props-bound-fallback/_config.js
@@ -5,7 +5,6 @@ import { test } from '../../test';
 // uses a prop it does not write to but has a fallback value
 export default test({
 	accessors: false, // so that prop actually becomes $.prop and not $.prop_source
-	mode: ['server', 'client'],
 	html: `<button>0</button><span>0</span>`,
 
 	test({ assert, target }) {