From 0ed9d18b27f8d9566fe7708315e54db15555c490 Mon Sep 17 00:00:00 2001
From: Niko Marmeladkov <niko@n1kt.ru>
Date: Tue, 30 Jun 2026 14:33:41 +0300
Subject: [PATCH] Fix nil interface trap in GetByNumber

Map lookup returns typed nil *Session for missing keys, which wraps into CallSession interface as non-nil typed nil. Nil check silently passes, causing nil dereference.
---
 internal/server/server.go | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/internal/server/server.go b/internal/server/server.go
index 48c7f3e..e8aa272 100644
--- a/internal/server/server.go
+++ b/internal/server/server.go
@@ -357,7 +357,11 @@ func (s *Server) Unregister(number string) {
 func (s *Server) GetByNumber(number string) call.CallSession {
 	s.sessionsMu.RLock()
 	defer s.sessionsMu.RUnlock()
-	return s.sessions[number]
+	sess := s.sessions[number]
+	if sess == nil {
+		return nil
+	}
+	return sess
 }
 
 func (s *Server) GetAll() []call.CallSession {