handleError for SvelteKit 3: ids only for unknown errors, compact 404 log line; error page suggestions prefer the real parent over the section

src/hooks.server.ts

@@ -42,18 +42,20 @@ export const handle: Handle = async ({ event, resolve }) => {
 	return response;
 };
 
-// Unexpected errors (anything not thrown with error()) and unknown routes. 5xx get a short id
-// that the error page shows and the log line starts with ("[error ab12cd34]"), so a screenshot
-// or report can be matched to the stack trace. The client only gets a generic message: no
-// stack, no internals. Query strings are left out of the log (they can carry tokens).
-export const handleError: HandleServerError = ({ error, event, status, message }) => {
-	const route = event.route.id ?? '(no route)';
-	const where = `${event.request.method} ${event.url.pathname} route=${route}`;
-	if (status === 404) {
-		console.warn(`[404] ${where}`);
-		return { message: 'Not Found' };
+// Runs for every error (SvelteKit 3 passes a `kind`). Unknown errors (bugs, failing services)
+// get a short id that the error page shows and the log line starts with ("[error ab12cd34]"),
+// so a screenshot or report can be matched to the stack trace; the client only gets the
+// generic "Internal Error", never the stack. 404s get one compact line (Caddy keeps no access
+// log), other error() calls are expected and stay quiet. Query strings are never logged.
+export const handleError: HandleServerError = (input) => {
+	const { event } = input;
+	const where = `${event.request.method} ${event.url.pathname} route=${event.route.id ?? '(none)'}`;
+	if (input.kind === 'unknown') {
+		const id = crypto.randomUUID().slice(0, 8);
+		console.error(`[error ${id}] 500 ${where}`, input.error);
+		return { id };
 	}
-	const id = crypto.randomUUID().slice(0, 8);
-	console.error(`[error ${id}] ${status} ${where}`, error);
-	return { message: status >= 500 ? 'Internal Error' : message, id };
+	if (input.error.status === 404) console.warn(`[404] ${where}`);
+	else if (input.error.status >= 500)
+		console.error(`[${input.error.status}] ${where} ${input.error.message}`);
 };