From d0ab92540dad28dfa01cd21c879bff20814e22e2 Mon Sep 17 00:00:00 2001
From: Arkadiy Kukarkin <parkan@gmail.com>
Date: Thu, 23 Apr 2026 16:11:05 +0200
Subject: [PATCH] api: fix out-of-bounds on lone-error handler returns

When a registered handler returns only an error (e.g. ResetHandler,
InitHandler, RemovePreparationHandler), len(results) == 1. The branch
that handles this case was indexing results[1] to extract the error,
which panics the request goroutine on any non-nil error.

Use results[0] since the only result value is the error itself.
---
 api/api.go | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/api/api.go b/api/api.go
index 8c2d8a2c0..13a98d49b 100644
--- a/api/api.go
+++ b/api/api.go
@@ -281,7 +281,7 @@ func (s *Server) toEchoHandler(handlerFunc any) echo.HandlerFunc {
 		if len(results) == 1 {
 			// Handle the returned error
 			if results[0].Interface() != nil {
-				err, ok := results[1].Interface().(error)
+				err, ok := results[0].Interface().(error)
 				if !ok {
 					return c.JSON(http.StatusInternalServerError, HTTPError{Err: "invalid handler function signature"})
 				}