From 7356871ceae36054be376c032c40fc7dc2bed8ab Mon Sep 17 00:00:00 2001
From: John <ebusd@ebusd.eu>
Date: Sat, 19 Mar 2022 12:58:48 +0100
Subject: [PATCH] fix missing prefix with mqtt integration and without
 --mqtttopic (fixes #575)

---
 src/ebusd/mqtthandler.cpp | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/src/ebusd/mqtthandler.cpp b/src/ebusd/mqtthandler.cpp
index 06fdb51d..61ab9df6 100755
--- a/src/ebusd/mqtthandler.cpp
+++ b/src/ebusd/mqtthandler.cpp
@@ -1020,6 +1020,9 @@ MqttHandler::MqttHandler(UserInfo* userInfo, BusHandler* busHandler, MessageMap*
     m_replacers.set("version", PACKAGE_VERSION);
     if (m_replacers["prefix"].empty()) {
       string line = m_replacers.get("topic", true);
+      if (line.empty() || line=="/") {
+        line = string(PACKAGE);  // ensure prefix if cmdline topic is absent
+      }
       m_replacers.set("prefix", line);
       m_replacers.set("prefixn", removeTrailingNonTopicPart(line));
     }