From 4ec1e17418d539cea7eb4fb5469e905684ca6457 Mon Sep 17 00:00:00 2001
From: Remi Gacogne <remi.gacogne@powerdns.com>
Date: Fri, 16 Dec 2016 14:39:46 +0100
Subject: [PATCH] LuaWrapper: Use the correct index when storing a function

The LuaWrapper used to assume that the function was at the
top of the stack, making it effectively impossible to have
a callback function parameter anywhere else than as the last
parameter.
---
 ext/luawrapper/include/LuaContext.hpp | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/ext/luawrapper/include/LuaContext.hpp b/ext/luawrapper/include/LuaContext.hpp
index e9627d689..b31e9cd39 100644
--- a/ext/luawrapper/include/LuaContext.hpp
+++ b/ext/luawrapper/include/LuaContext.hpp
@@ -1642,10 +1642,10 @@ private:
     // structure that will ensure that a certain is stored somewhere in the registry
     struct ValueInRegistry {
         // this constructor will clone and hold the value at the top of the stack in the registry
-        ValueInRegistry(lua_State* lua) : lua{lua}
+        ValueInRegistry(lua_State* lua, int index=-1) : lua{lua}
         {
             lua_pushlightuserdata(lua, this);
-            lua_pushvalue(lua, -2);
+            lua_pushvalue(lua, -1 + index);
             lua_settable(lua, LUA_REGISTRYINDEX);
         }
         
@@ -1821,8 +1821,8 @@ private:
 
 private:
     friend LuaContext;
-    explicit LuaFunctionCaller(lua_State* state) :
-        valueHolder(std::make_shared<ValueInRegistry>(state)),
+    explicit LuaFunctionCaller(lua_State* state, int index) :
+        valueHolder(std::make_shared<ValueInRegistry>(state, index)),
         state(state)
     {}
 };
@@ -2521,7 +2521,7 @@ struct LuaContext::Reader<LuaContext::LuaFunctionCaller<TRetValue (TParameters..
     {
         if (lua_isfunction(state, index) == 0 && lua_isuserdata(state, index) == 0)
             return boost::none;
-        return ReturnType(state);
+        return ReturnType(state, index);
     }
 };
 
-- 
2.40.0