remove script_suspend in favour of component-level suspending

Author: Rich-Harris

packages/svelte/src/compiler/phases/3-transform/client/transform-client.js

@@ -371,7 +371,11 @@ export function client_component(analysis, options) {
 		const body = b.function_declaration(
 			b.id('$$body'),
 			[b.id('$$anchor'), b.id('$$props')],
-			b.block([...component_block.body, b.stmt(b.call('$.exit'))])
+			b.block([
+				b.var('$$unsuspend', b.call('$.suspend')),
+				...component_block.body,
+				b.stmt(b.call('$$unsuspend'))
+			])
 		);
 		body.async = true;
 

packages/svelte/src/compiler/phases/3-transform/client/visitors/AwaitExpression.js

@@ -1,7 +1,6 @@
 /** @import { AwaitExpression, Expression } from 'estree' */
 /** @import { Context } from '../types' */
 import * as b from '../../../../utils/builders.js';
-import { get_rune } from '../../../scope.js';
 
 /**
  * @param {AwaitExpression} node
@@ -14,22 +13,9 @@ export function AwaitExpression(node, context) {
 		return context.next();
 	}
 
-	const inside_derived = context.path.some(
-		(n) =>
-			n.type === 'VariableDeclaration' &&
-			n.declarations.some(
-				(d) =>
-					d.init?.type === 'CallExpression' && get_rune(d.init, context.state.scope) === '$derived'
-			)
-	);
-
-	const expression = b.call(
+	return b.call(
 		b.await(
 			b.call('$.save', node.argument && /** @type {Expression} */ (context.visit(node.argument)))
 		)
 	);
-
-	return inside_derived
-		? expression
-		: b.await(b.call('$.script_suspend', b.arrow([], expression, true)));
 }

packages/svelte/src/internal/client/dom/blocks/boundary.js

@@ -243,23 +243,18 @@ export function boundary(node, props, boundary_fn) {
 	}
 }
 
-// TODO separate this stuff out — suspending and context preservation should
-// be distinct concepts
-
 export function capture() {
 	var previous_effect = active_effect;
 	var previous_reaction = active_reaction;
 	var previous_component_context = component_context;
 
-	return function restore(should_exit = true) {
+	return function restore() {
 		set_active_effect(previous_effect);
 		set_active_reaction(previous_reaction);
 		set_component_context(previous_component_context);
 
 		// prevent the active effect from outstaying its welcome
-		if (should_exit) {
-			queue_post_micro_task(exit);
-		}
+		queue_post_micro_task(exit);
 	};
 }
 
@@ -295,22 +290,6 @@ export function suspend() {
 	};
 }
 
-/**
- * @template T
- * @param {() => Promise<T>} fn
- */
-export async function script_suspend(fn) {
-	const restore = capture();
-	const unsuspend = suspend();
-	try {
-		exit();
-		return await fn();
-	} finally {
-		restore(false);
-		unsuspend();
-	}
-}
-
 /**
  * @template T
  * @param {Promise<T>} promise
@@ -326,7 +305,7 @@ export async function save(promise) {
 	};
 }
 
-export function exit() {
+function exit() {
 	set_active_effect(null);
 	set_active_reaction(null);
 	set_component_context(null);

packages/svelte/src/internal/client/index.js

@@ -130,7 +130,7 @@ export {
 	update_store,
 	mark_store_binding
 } from './reactivity/store.js';
-export { boundary, exit, save, suspend, script_suspend } from './dom/blocks/boundary.js';
+export { boundary, save, suspend } from './dom/blocks/boundary.js';
 export { set_text } from './render.js';
 export {
 	get,