From ea8c6e9fc81fb4a5bf44e6c2d5a3506b52e530e1 Mon Sep 17 00:00:00 2001
From: Robin Gareus <robin@gareus.org>
Date: Thu, 30 Mar 2017 05:06:34 +0200
Subject: [PATCH] Fix hiding  Lua __metatable -- prevent setmetatable()
 override

---
 libs/ardour/globals.cc                |  8 ++++++++
 libs/lua/LuaBridge/detail/Namespace.h | 18 +++++++++++++++---
 2 files changed, 23 insertions(+), 3 deletions(-)

diff --git a/libs/ardour/globals.cc b/libs/ardour/globals.cc
index bd96bfa242..ded1637012 100644
--- a/libs/ardour/globals.cc
+++ b/libs/ardour/globals.cc
@@ -84,6 +84,8 @@
 #include "midi++/port.h"
 #include "midi++/mmc.h"
 
+#include "LuaBridge/LuaBridge.h"
+
 #include "ardour/analyser.h"
 #include "ardour/audio_library.h"
 #include "ardour/audio_backend.h"
@@ -423,6 +425,12 @@ ARDOUR::init (bool use_windows_vst, bool try_optimization, const char* localedir
 		return true;
 	}
 
+#ifndef NDEBUG
+	if (getenv("LUA_METATABLES")) {
+		luabridge::Security::setHideMetatables (false);
+	}
+#endif
+
 	if (!PBD::init()) return false;
 
 #ifdef ENABLE_NLS
diff --git a/libs/lua/LuaBridge/detail/Namespace.h b/libs/lua/LuaBridge/detail/Namespace.h
index a8e190da43..5ea139ee22 100644
--- a/libs/lua/LuaBridge/detail/Namespace.h
+++ b/libs/lua/LuaBridge/detail/Namespace.h
@@ -363,7 +363,7 @@ private:
 
       if (Security::hideMetatables ())
       {
-        lua_pushnil (L);
+        lua_pushboolean (L, false);
         rawsetfield (L, -2, "__metatable");
       }
     }
@@ -400,7 +400,7 @@ private:
 
       if (Security::hideMetatables ())
       {
-        lua_pushnil (L);
+        lua_pushboolean (L, false);
         rawsetfield (L, -2, "__metatable");
       }
     }
@@ -442,7 +442,7 @@ private:
 
       if (Security::hideMetatables ())
       {
-        lua_pushnil (L);
+        lua_pushboolean (L, false);
         rawsetfield (L, -2, "__metatable");
       }
     }
@@ -1161,8 +1161,14 @@ private:
         lua_setfield(L, -2, "__index");
         lua_pushcclosure (L, CFunc::array_newindex<T>, 0);
         lua_setfield(L, -2, "__newindex");
+        if (Security::hideMetatables ())
+        {
+          lua_pushboolean (L, false);
+          rawsetfield (L, -2, "__metatable");
+        }
         lua_pop (L, 1);
 
+
         createConstTable (name);
         lua_pushcfunction (L, &CFunc::gcMetaMethod <T>);
         rawsetfield (L, -2, "__gc");
@@ -1532,6 +1538,12 @@ private:
       lua_pushcfunction (L, &tostringMetaMethod);
       rawsetfield (L, -2, "__tostring");
 #endif
+      if (Security::hideMetatables ())
+      {
+        lua_pushboolean (L, false);
+        rawsetfield (L, -2, "__metatable");
+      }
+
     }
   }