Fix unit tests failing for Lua 5.3

* Fix compatibility function lua_getiuservalue() for Lua 5.3
* Fix handling of nil function upvalues in lanes.nameof()

2 files changed, 6 insertions, 7 deletions

diff --git a/src/compat.cpp b/src/compat.cpp
index c332ddc..7e90142 100644
--- a/src/compat.cpp
+++ b/src/compat.cpp
@@ -120,9 +120,9 @@ int lua_getiuservalue(lua_State* const L_, StackIndex const idx_, UserValueIndex
 #endif// LUA_VERSION_NUM > 501
     STACK_CHECK(L_, 1);
     int const _uvType{ lua_type(L_, -1) };
-    // under Lua 5.2, there is a single uservalue that is either nil or a table.
-    // If nil, don't transfer it, as it can cause issues when copying to a Keeper state because of nil sentinel conversion
-    return (LUA_VERSION_NUM == 502 && _uvType == LUA_TNIL) ? LUA_TNONE : _uvType;
+    // under Lua 5.2 and 5.3, there is a single uservalue, that can be nil.
+    // emulate 5.4 behavior by returning LUA_TNONE when that's the case
+    return (_uvType == LUA_TNIL) ? LUA_TNONE : _uvType;
 }
 
 // #################################################################################################
diff --git a/src/nameof.cpp b/src/nameof.cpp
index 938685c..f236f73 100644
--- a/src/nameof.cpp
+++ b/src/nameof.cpp
@@ -60,6 +60,7 @@ FqnLength DiscoverObjectNameRecur(lua_State* const L_, FqnLength const shortest_
             // decorate the key string with something that tells us the type of the value
             switch (luaG_type(L_, StackIndex{ -2 })) {
             default:
+                LUA_ASSERT(L_, false); // there is something wrong if we end up here
                 luaG_pushstring(L_, "??");                                                         // L_: o "r" {c} {fqn} ... k v "k" "??"
                 break;
             case LuaType::FUNCTION:
@@ -78,7 +79,6 @@ FqnLength DiscoverObjectNameRecur(lua_State* const L_, FqnLength const shortest_
         FqnLength const _depth{ lua_rawlen(L_, kFQN) + 1 };
         lua_rawseti(L_, kFQN, static_cast<int>(_depth));                                           // L_: o "r" {c} {fqn} ... k v
         STACK_CHECK(L_, 0);
-        STACK_CHECK(L_, 0);
         return _depth;
     };
 
@@ -114,7 +114,7 @@ FqnLength DiscoverObjectNameRecur(lua_State* const L_, FqnLength const shortest_
 
         // filter out uninteresting values
         auto const _valType{ luaG_type(L_, kIdxTop) };
-        if (_valType == LuaType::BOOLEAN || _valType == LuaType::LIGHTUSERDATA || _valType == LuaType::NUMBER || _valType == LuaType::STRING) {
+        if (_valType == LuaType::NIL || _valType == LuaType::BOOLEAN || _valType == LuaType::LIGHTUSERDATA || _valType == LuaType::NUMBER || _valType == LuaType::STRING) {
             lua_pop(L_, 1);                                                                        // L_: o "r" {c} {fqn} ... k
             return _r;
         }
@@ -164,7 +164,6 @@ FqnLength DiscoverObjectNameRecur(lua_State* const L_, FqnLength const shortest_
 
     static constexpr auto _scanUserData = [](lua_State* const L_, FqnLength const shortest_) -> FqnLength {
         FqnLength r_{ shortest_ };
-        FqnLength const _depth{ lua_rawlen(L_, kFQN) + 1 };
         STACK_GROW(L_, 2);
         STACK_CHECK_START_REL(L_, 0);
         if (lua_getmetatable(L_, kIdxTop)) {                                                       // L_: o "r" {c} {fqn} ... U {mt}
@@ -233,7 +232,7 @@ FqnLength DiscoverObjectNameRecur(lua_State* const L_, FqnLength const shortest_
 
     FqnLength r_;
     // scan location contents
-    switch (luaG_type(L_, kIdxTop)) {                                                              // L_: o "r" {c} {fqn} ... <>
+    switch (_typeWhere) {                                                                          // L_: o "r" {c} {fqn} ... <>
     default:
         raise_luaL_error(L_, "unexpected error, please investigate");
         break;