From a903e9408b6d916fa45a57fb570ac6b74742717d Mon Sep 17 00:00:00 2001
From: Paolo Ricciuti <ricciutipaolo@gmail.com>
Date: Fri, 16 Jan 2026 22:35:05 +0100
Subject: [PATCH] fix: mark subtree of svelte boundary as dynamic (#17468)

---
 .changeset/curly-cats-make.md                                | 5 +++++
 .../src/compiler/phases/2-analyze/visitors/SvelteBoundary.js | 3 +++
 .../tests/runtime-runes/samples/static-boundary/_config.js   | 5 +++++
 .../tests/runtime-runes/samples/static-boundary/main.svelte  | 5 +++++
 4 files changed, 18 insertions(+)
 create mode 100644 .changeset/curly-cats-make.md
 create mode 100644 packages/svelte/tests/runtime-runes/samples/static-boundary/_config.js
 create mode 100644 packages/svelte/tests/runtime-runes/samples/static-boundary/main.svelte

diff --git a/.changeset/curly-cats-make.md b/.changeset/curly-cats-make.md
new file mode 100644
index 0000000000..393f8ec7e8
--- /dev/null
+++ b/.changeset/curly-cats-make.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: mark subtree of svelte boundary as dynamic
diff --git a/packages/svelte/src/compiler/phases/2-analyze/visitors/SvelteBoundary.js b/packages/svelte/src/compiler/phases/2-analyze/visitors/SvelteBoundary.js
index 35af96ba12..e0014aa7b2 100644
--- a/packages/svelte/src/compiler/phases/2-analyze/visitors/SvelteBoundary.js
+++ b/packages/svelte/src/compiler/phases/2-analyze/visitors/SvelteBoundary.js
@@ -1,6 +1,7 @@
 /** @import { AST } from '#compiler' */
 /** @import { Context } from '../types' */
 import * as e from '../../../errors.js';
+import { mark_subtree_dynamic } from './shared/fragment.js';
 
 const valid = ['onerror', 'failed', 'pending'];
 
@@ -23,5 +24,7 @@ export function SvelteBoundary(node, context) {
 		}
 	}
 
+	mark_subtree_dynamic(context.path);
+
 	context.next();
 }
diff --git a/packages/svelte/tests/runtime-runes/samples/static-boundary/_config.js b/packages/svelte/tests/runtime-runes/samples/static-boundary/_config.js
new file mode 100644
index 0000000000..d986ed8cd5
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/static-boundary/_config.js
@@ -0,0 +1,5 @@
+import { test } from '../../test';
+
+export default test({
+	html: '<div><div>test</div></div>'
+});
diff --git a/packages/svelte/tests/runtime-runes/samples/static-boundary/main.svelte b/packages/svelte/tests/runtime-runes/samples/static-boundary/main.svelte
new file mode 100644
index 0000000000..7f43a1afaf
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/static-boundary/main.svelte
@@ -0,0 +1,5 @@
+<div>
+	<svelte:boundary>
+		<div>test</div>
+	</svelte:boundary>
+</div>
\ No newline at end of file