prevent context leakage

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

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

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

@@ -297,6 +297,10 @@ export async function suspend(promise) {
 	// @ts-ignore
 	boundary?.fn(ASYNC_INCREMENT);
 
+	// prevent the active effect from outstaying its welcome
+	// TODO is a microtask too late? is this correct?
+	queue_post_micro_task(exit);
+
 	const value = await promise;
 
 	return {

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

@@ -98,6 +98,13 @@ export function set_active_effect(effect) {
 	active_effect = effect;
 }
 
+// TODO remove this, once we're satisfied that we're not leaking context
+setInterval(() => {
+	if (active_effect !== null || active_reaction !== null) {
+		debugger;
+	}
+});
+
 /**
  * When sources are created within a derived, we record them so that we can safely allow
  * local mutations to these sources without the side-effect error being invoked unnecessarily.