From aa547c58e5442fdb683b62f04e5dca30d47f378b Mon Sep 17 00:00:00 2001
From: Rich Harris <rich.harris@vercel.com>
Date: Sat, 25 Oct 2025 22:36:07 -0400
Subject: [PATCH] WIP

---
 .../server/visitors/SvelteElement.js          | 28 ++++++++++++++++---
 .../svelte/src/internal/server/renderer.js    | 27 ++++++++++++++----
 2 files changed, 46 insertions(+), 9 deletions(-)

diff --git a/packages/svelte/src/compiler/phases/3-transform/server/visitors/SvelteElement.js b/packages/svelte/src/compiler/phases/3-transform/server/visitors/SvelteElement.js
index 2e61897924..145167a690 100644
--- a/packages/svelte/src/compiler/phases/3-transform/server/visitors/SvelteElement.js
+++ b/packages/svelte/src/compiler/phases/3-transform/server/visitors/SvelteElement.js
@@ -6,7 +6,12 @@ import { dev, locator } from '../../../../state.js';
 import * as b from '#compiler/builders';
 import { determine_namespace_for_children } from '../../utils.js';
 import { build_element_attributes } from './shared/element.js';
-import { build_template, create_child_block, PromiseOptimiser } from './shared/utils.js';
+import {
+	build_template,
+	create_async_block,
+	create_child_block,
+	PromiseOptimiser
+} from './shared/utils.js';
 
 /**
  * @param {AST.SvelteElement} node
@@ -39,11 +44,14 @@ export function SvelteElement(node, context) {
 
 	const optimiser = new PromiseOptimiser();
 
+	/** @type {Statement[]} */
+	let statements = [];
+
 	build_element_attributes(node, { ...context, state }, optimiser.transform);
 
 	if (dev) {
 		const location = /** @type {Location} */ (locator(node.start));
-		context.state.template.push(
+		statements.push(
 			b.stmt(
 				b.call(
 					'$.push_element',
@@ -74,9 +82,21 @@ export function SvelteElement(node, context) {
 		statement = create_child_block(b.block([optimiser.apply(), statement]), true);
 	}
 
-	context.state.template.push(statement);
+	statements.push(statement);
 
 	if (dev) {
-		context.state.template.push(b.stmt(b.call('$.pop_element')));
+		statements.push(b.stmt(b.call('$.pop_element')));
 	}
+
+	if (node.metadata.expression.is_async()) {
+		statements = [
+			create_async_block(
+				b.block(statements),
+				node.metadata.expression.blockers(),
+				node.metadata.expression.has_await
+			)
+		];
+	}
+
+	context.state.template.push(...statements);
 }
diff --git a/packages/svelte/src/internal/server/renderer.js b/packages/svelte/src/internal/server/renderer.js
index d20792c91f..fa7b0116d2 100644
--- a/packages/svelte/src/internal/server/renderer.js
+++ b/packages/svelte/src/internal/server/renderer.js
@@ -104,10 +104,27 @@ export class Renderer {
 	 * @param {(renderer: Renderer) => void} fn
 	 */
 	async(blockers, fn) {
+		let callback = fn;
+
+		if (blockers.length > 0) {
+			const context = ssr_context;
+
+			callback = (renderer) => {
+				return Promise.all(blockers).then(() => {
+					const previous_context = ssr_context;
+
+					try {
+						set_ssr_context(context);
+						return fn(renderer);
+					} finally {
+						set_ssr_context(previous_context);
+					}
+				});
+			};
+		}
+
 		this.#out.push(BLOCK_OPEN);
-		this.child(
-			blockers.length > 0 ? (renderer) => Promise.all(blockers).then(() => fn(renderer)) : fn
-		);
+		this.child(callback);
 		this.#out.push(BLOCK_CLOSE);
 	}
 
@@ -122,13 +139,13 @@ export class Renderer {
 
 		for (const fn of thunks.slice(1)) {
 			promise = promise.then(() => {
-				const previous_ssr_context = ssr_context;
+				const previous_context = ssr_context;
 				set_ssr_context(context);
 
 				try {
 					return fn();
 				} finally {
-					set_ssr_context(previous_ssr_context);
+					set_ssr_context(previous_context);
 				}
 			});
 		}