Fix optional App.Error properties in error helper typings

.changeset/wicked-olives-fold.md

@@ -0,0 +1,5 @@
+---
+'@sveltejs/kit': patch
+---
+
+ fix: adjust error overload for optional `App.Error` parameters

packages/kit/src/exports/index.js

@@ -42,11 +42,11 @@ export { VERSION } from '../version.js';
  * Make sure you're not catching the thrown error, which would prevent SvelteKit from handling it.
  * @param {number} status The [HTTP status code](https://developer.mozilla.org/en-US/docs/Web/HTTP/Status#client_error_responses). Must be in the range 400-599.
  * @param {string} message The error message.
- * @param {{ status: number; message: string } extends App.Error ? never : Omit<App.Error, 'status' | 'message'>} properties Additional properties of the App.Error type.
+ * @param {keyof Omit<App.Error, 'status' | 'message'> extends never ? never : Omit<App.Error, 'status' | 'message'>} properties Additional properties of the App.Error type.
  * @overload
  * @param {number} status
  * @param {string} message
- * @param {{ status: number; message: string } extends App.Error ? never : Omit<App.Error, 'status' | 'message'>} properties
+ * @param {keyof Omit<App.Error, 'status' | 'message'> extends never ? never : Omit<App.Error, 'status' | 'message'>} properties
  * @return {never}
  * @throws {import('./public.js').HttpError} This error instructs SvelteKit to initiate HTTP error handling.
  * @throws {Error} If the provided status is invalid (not between 400 and 599).

packages/kit/test/types/error.test.ts

@@ -1,6 +1,14 @@
 import { error, type HandleClientError, type HandleServerError } from '@sveltejs/kit';
 import type { StandardSchemaV1 } from '@standard-schema/spec';
 
+declare global {
+	namespace App {
+		interface Error {
+			description?: string;
+		}
+	}
+}
+
 const app_error: App.Error = { status: 500, message: 'Unexpected error' };
 
 // @ts-expect-error App.Error requires status
@@ -98,9 +106,14 @@ function f() {
 	error(400);
 }
 
+function g() {
+	error(400, 'Bad request', { description: 'Invalid request data' });
+}
+
 a;
 b;
 c;
 d;
 e;
 f;
+g;

packages/kit/types/index.d.ts

@@ -2443,10 +2443,7 @@ declare module '@sveltejs/kit' {
 	 * @throws {import('./public.js').HttpError} This error instructs SvelteKit to initiate HTTP error handling.
 	 * @throws {Error} If the provided status is invalid (not between 400 and 599).
 	 */
-	export function error(status: number, message: string, properties: {
-		status: number;
-		message: string;
-	} extends App.Error ? never : Omit<App.Error, "status" | "message">): never;
+	export function error(status: number, message: string, properties: keyof Omit<App.Error, "status" | "message"> extends never ? never : Omit<App.Error, "status" | "message">): never;
 	/**
 	 * Throws an error with a HTTP status code and an optional message.
 	 * When called during request handling, this will cause SvelteKit to