fix: assign correct status code to form submission error on the client

.changeset/large-parrots-grow.md

@@ -0,0 +1,5 @@
+---
+'@sveltejs/kit': patch
+---
+
+fix: assign correct status code to form submission error on the client

packages/kit/src/runtime/client/remote-functions/form.svelte.js

@@ -105,7 +105,7 @@ export function form(id) {
 						void _goto(form_result.location, { invalidateAll }, 0);
 					} else {
 						result = undefined;
-						throw new HttpError(500, form_result.error);
+						throw new HttpError(form_result.status ?? 500, form_result.error);
 					}
 				} catch (e) {
 					result = undefined;

packages/kit/test/apps/basics/src/routes/remote/form/form.remote.js

@@ -20,7 +20,7 @@ export const task_one = form(async (form_data) => {
 	task = /** @type {string} */ (form_data.get('task'));
 
 	if (task === 'error') {
-		error(500, { message: 'Expected error' });
+		error(400, { message: 'Expected error' });
 	}
 	if (task === 'redirect') {
 		redirect(303, '/remote');

packages/kit/test/apps/basics/test/test.js

@@ -1612,6 +1612,7 @@ test.describe('remote functions', () => {
 		await page.goto('/remote/form');
 		await page.fill('#input-task', 'error');
 		await page.click('#submit-btn-one');
+		expect(await page.textContent('h1')).toBe('400');
 		expect(await page.textContent('#message')).toBe(
 			'This is your custom error page saying: "Expected error"'
 		);
@@ -1635,6 +1636,7 @@ test.describe('remote functions', () => {
 		await page.goto('/remote/form');
 		await page.fill('#input-task', 'error');
 		await page.click('#submit-btn-two');
+		expect(await page.textContent('h1')).toBe('500');
 		expect(await page.textContent('#message')).toBe(
 			'This is your custom error page saying: "Unexpected error (500 Internal Error)"'
 		);