Lindas now accept deep user data as valid keys

3 files changed, 17 insertions, 1 deletions

diff --git a/src/deep.cpp b/src/deep.cpp
index 8754178..bac011f 100644
--- a/src/deep.cpp
+++ b/src/deep.cpp
@@ -130,8 +130,15 @@ void DeepFactory::DeleteDeepObject(lua_State* const L_, DeepPrelude* const o_)
 
 // #################################################################################################
 
+bool DeepFactory::IsDeepUserdata(lua_State* const L_, int const idx_)
+{
+    return LookupFactory(L_, idx_, LookupMode::LaneBody) != nullptr;
+}
+
+// #################################################################################################
+
 // Return the registered factory for 'index' (deep userdata proxy),  or nullptr if 'index' is not a deep userdata proxy.
-[[nodiscard]] DeepFactory* DeepFactory::LookupFactory(lua_State* const L_, int const index_, LookupMode const mode_)
+DeepFactory* DeepFactory::LookupFactory(lua_State* const L_, int const index_, LookupMode const mode_)
 {
     // when looking inside a keeper, we are 100% sure the object is a deep userdata
     if (mode_ == LookupMode::FromKeeper) {
diff --git a/src/deep.h b/src/deep.h
index bb86c20..c4c6fd7 100644
--- a/src/deep.h
+++ b/src/deep.h
@@ -66,6 +66,7 @@ class DeepFactory
     public:
     // NVI: public interface
     static void DeleteDeepObject(lua_State* L_, DeepPrelude* o_);
+    [[nodiscard]] static bool IsDeepUserdata(lua_State* const L_, int const idx_);
     [[nodiscard]] static DeepFactory* LookupFactory(lua_State* L_, int index_, LookupMode mode_);
     static void PushDeepProxy(DestState L_, DeepPrelude* o_, int nuv_, LookupMode mode_, lua_State* errL_);
     void pushDeepUserdata(DestState L_, int nuv_) const;
diff --git a/src/linda.cpp b/src/linda.cpp
index 4edc029..079ab9d 100644
--- a/src/linda.cpp
+++ b/src/linda.cpp
@@ -46,6 +46,7 @@ namespace {
 
     static void CheckKeyTypes(lua_State* const L_, int const start_, int const end_)
     {
+        STACK_CHECK_START_REL(L_, 0);
         for (int const _i : std::ranges::iota_view{ start_, end_ + 1 }) {
             switch (LuaType const _t{ luaG_type(L_, _i) }) {
             case LuaType::BOOLEAN:
@@ -53,6 +54,12 @@ namespace {
             case LuaType::STRING:
                 break;
 
+            case LuaType::USERDATA:
+                if (!DeepFactory::IsDeepUserdata(L_, _i)) {
+                    raise_luaL_error(L_, "argument #%d: can't use non-deep userdata as a key", _i);
+                }
+                break;
+
             case LuaType::LIGHTUSERDATA:
                 {
                     static constexpr std::array<std::reference_wrapper<UniqueKey const>, 3> kKeysToCheck{ kLindaBatched, kCancelError, kNilSentinel };
@@ -69,6 +76,7 @@ namespace {
                 raise_luaL_error(L_, "argument #%d: invalid key type (not a boolean, string, number or light userdata)", _i);
             }
         }
+        STACK_CHECK(L_, 0);
     }
 
     // #############################################################################################