From 014ca7e8a16e3882cf2e4b7875860765eb1a6034 Mon Sep 17 00:00:00 2001
From: ReenigneArcher <42013603+ReenigneArcher@users.noreply.github.com>
Date: Mon, 27 Mar 2023 16:46:25 -0400
Subject: [PATCH] commands: fix prep commands when empty (#1083)

---
 src/config.cpp | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/src/config.cpp b/src/config.cpp
index 4a454b41..0aecc3ca 100644
--- a/src/config.cpp
+++ b/src/config.cpp
@@ -762,12 +762,18 @@ void list_string_f(std::unordered_map<std::string, std::string> &vars, const std
     input.emplace_back(begin, pos);
   }
 }
+
 void list_prep_cmd_f(std::unordered_map<std::string, std::string> &vars, const std::string &name, std::vector<prep_cmd_t> &input) {
   std::string string;
   string_f(vars, name, string);
 
   std::stringstream jsonStream;
 
+  // check if string is empty, i.e. when the value doesn't exist in the config file
+  if(string.empty()) {
+    return;
+  }
+
   // We need to add a wrapping object to make it valid JSON, otherwise ptree cannot parse it.
   jsonStream << "{\"prep_cmd\":" << string << "}";