use enumerable: false for temporary no-longer-exists getters

.changeset/ninety-walls-heal.md

@@ -0,0 +1,5 @@
+---
+'@sveltejs/kit': patch
+---
+
+use `enumerable: false` on "[x] no longer exists" getters so that they are not triggered by spreading

packages/kit/src/runtime/app/stores.js

@@ -17,27 +17,37 @@ export function stores() {
 export const getStores = () => {
 	const stores = getContext('__svelte__');
 
-	return {
+	const readonly_stores = {
 		page: {
 			subscribe: stores.page.subscribe
 		},
 		navigating: {
 			subscribe: stores.navigating.subscribe
 		},
-		// TODO remove this (for 1.0? after 1.0?)
-		// @ts-expect-error - deprecated, not part of type definitions, but still callable
-		get preloading() {
-			console.error('stores.preloading is deprecated; use stores.navigating instead');
-			return {
-				subscribe: stores.navigating.subscribe
-			};
-		},
-		get session() {
-			removed_session();
-			return {};
-		},
 		updated: stores.updated
 	};
+
+	// TODO remove this for 1.0
+	Object.defineProperties(readonly_stores, {
+		preloading: {
+			get() {
+				console.error('stores.preloading is deprecated; use stores.navigating instead');
+				return {
+					subscribe: stores.navigating.subscribe
+				};
+			},
+			enumerable: false
+		},
+		session: {
+			get() {
+				removed_session();
+				return {};
+			},
+			enumerable: false
+		}
+	});
+
+	return readonly_stores;
 };
 
 /** @type {typeof import('$app/stores').page} */

packages/kit/src/runtime/client/client.js

@@ -583,25 +583,36 @@ export function create_client({ target, base, trailing_slash }) {
 					// does await parent() inside an if branch which wasn't executed yet.
 					uses.parent = true;
 					return parent;
+				}
+			};
+
+			// TODO remove this for 1.0
+			Object.defineProperties(load_input, {
+				props: {
+					get() {
+						throw new Error(
+							'@migration task: Replace `props` with `data` stuff https://github.com/sveltejs/kit/discussions/5774#discussioncomment-3292693'
+						);
+					},
+					enumerable: false
 				},
-				// @ts-expect-error
-				get props() {
-					throw new Error(
-						'@migration task: Replace `props` with `data` stuff https://github.com/sveltejs/kit/discussions/5774#discussioncomment-3292693'
-					);
-				},
-				get session() {
-					// TODO remove this for 1.0
-					throw new Error(
-						'session is no longer available. See https://github.com/sveltejs/kit/discussions/5883'
-					);
+				session: {
+					get() {
+						throw new Error(
+							'session is no longer available. See https://github.com/sveltejs/kit/discussions/5883'
+						);
+					},
+					enumerable: false
 				},
-				get stuff() {
-					throw new Error(
-						'@migration task: Remove stuff https://github.com/sveltejs/kit/discussions/5774#discussioncomment-3292693'
-					);
+				stuff: {
+					get() {
+						throw new Error(
+							'@migration task: Remove stuff https://github.com/sveltejs/kit/discussions/5774#discussioncomment-3292693'
+						);
+					},
+					enumerable: false
 				}
-			};
+			});
 
 			if (import.meta.env.DEV) {
 				try {

packages/kit/src/runtime/server/page/load_data.js

@@ -55,23 +55,31 @@ export async function load_data({ event, fetcher, node, parent, server_data_prom
 		return server_data;
 	}
 
-	const data = await node.shared.load.call(null, {
+	const load_input = {
 		url: state.prerendering ? new PrerenderingURL(event.url) : new LoadURL(event.url),
 		params: event.params,
 		data: server_data,
 		routeId: event.routeId,
-		get session() {
-			// TODO remove for 1.0
-			throw new Error(
-				'session is no longer available. See https://github.com/sveltejs/kit/discussions/5883'
-			);
-		},
 		fetch: fetcher,
 		setHeaders: event.setHeaders,
 		depends: () => {},
 		parent
+	};
+
+	// TODO remove this for 1.0
+	Object.defineProperties(load_input, {
+		session: {
+			get() {
+				throw new Error(
+					'session is no longer available. See https://github.com/sveltejs/kit/discussions/5883'
+				);
+			},
+			enumerable: false
+		}
 	});
 
+	const data = await node.shared.load.call(null, load_input);
+
 	return data ? unwrap_promises(data) : null;
 }