fix lua stack manipulations

src/logic/scripting/lua/libs/libinput.cpp

@@ -40,6 +40,7 @@ static int l_add_callback(lua::State* L) {
                 throw std::runtime_error("on_hud_open is not called yet");
             }
             auto key = input_util::keycode_from(bindname.substr(pos + 1));
+            lua::pushvalue(L, 2);
             auto callback = lua::create_simple_handler(L);
             hud->keepAlive(Events::keyCallbacks[key].add(callback));
             return 0;

src/logic/scripting/lua/lua_util.cpp

@@ -219,7 +219,7 @@ void lua::dump_stack(State* L) {
 static std::shared_ptr<std::string> create_lambda_handler(State* L) {
     auto ptr = reinterpret_cast<ptrdiff_t>(topointer(L, -1));
     auto name = util::mangleid(ptr);
-    getglobal(L, LAMBDAS_TABLE);
+    requireglobal(L, LAMBDAS_TABLE);
     pushvalue(L, -2);
     setfield(L, name);
     pop(L, 2);
@@ -227,7 +227,7 @@ static std::shared_ptr<std::string> create_lambda_handler(State* L) {
     return std::shared_ptr<std::string>(
         new std::string(name),
         [=](std::string* name) {
-            getglobal(L, LAMBDAS_TABLE);
+            requireglobal(L, LAMBDAS_TABLE);
             pushnil(L);
             setfield(L, *name);
             pop(L);
@@ -239,41 +239,48 @@ static std::shared_ptr<std::string> create_lambda_handler(State* L) {
 runnable lua::create_runnable(State* L) {
     auto funcptr = create_lambda_handler(L);
     return [=]() {
-        getglobal(L, LAMBDAS_TABLE);
+        if (!get_from(L, LAMBDAS_TABLE, *funcptr, false))
-        getfield(L, *funcptr);
+            return;
-        if (call_nothrow(L, 0)) {
+        call_nothrow(L, 0, 0);
-            pop(L);
+        pop(L);
-        }
     };
 }
 
 KeyCallback lua::create_simple_handler(State* L) {
     auto funcptr = create_lambda_handler(L);
     return [=]() -> bool {
-        getglobal(L, LAMBDAS_TABLE);
+        if (!get_from(L, LAMBDAS_TABLE, *funcptr, false))
-        getfield(L, *funcptr);
-        if (call_nothrow(L, 0)) {
-            bool result = toboolean(L, -1);
-            pop(L);
-            return result;
-        } else {
             return false;
+        int top = gettop(L) - 1;
+        if (call_nothrow(L, 0)) {
+            int nres = gettop(L) - top;
+            if (nres) {
+                bool result = toboolean(L, -1);
+                pop(L, 1 + nres);
+                return result;
+            }
         }
+        pop(L);
+        return false;
     };
 }
 
 scripting::common_func lua::create_lambda(State* L) {
     auto funcptr = create_lambda_handler(L);
     return [=](const std::vector<dv::value>& args) -> dv::value {
-        getglobal(L, LAMBDAS_TABLE);
+        int top = gettop(L) + 1;
-        getfield(L, *funcptr);
+        if (!get_from(L, LAMBDAS_TABLE, *funcptr, false))
+            return nullptr;
         for (const auto& arg : args) {
             pushvalue(L, arg);
         }
         if (call(L, args.size(), 1)) {
-            auto result = tovalue(L, -1);
+            int nres = gettop(L) - top;
-            pop(L, 2);
+            if (nres) {
-            return result;
+                auto result = tovalue(L, -1);
+                pop(L, 1 + nres);
+                return result;
+            }
         }
         pop(L);
         return nullptr;
@@ -283,16 +290,21 @@ scripting::common_func lua::create_lambda(State* L) {
 scripting::common_func lua::create_lambda_nothrow(State* L) {
     auto funcptr = create_lambda_handler(L);
     return [=](const std::vector<dv::value>& args) -> dv::value {
-        getglobal(L, LAMBDAS_TABLE);
+        int top = gettop(L) - 1;
-        getfield(L, *funcptr);
+        if (!get_from(L, LAMBDAS_TABLE, *funcptr, false))
+            return nullptr;
         for (const auto& arg : args) {
             pushvalue(L, arg);
         }
         if (call_nothrow(L, args.size(), 1)) {
-            auto result = tovalue(L, -1);
+            int nres = gettop(L) - top;
-            pop(L);
+            if (nres) {
-            return result;
+                auto result = tovalue(L, -1);
+                pop(L, 1 + nres);
+                return result;
+            }
         }
+        pop(L);
         return nullptr;
     };
 }

src/logic/scripting/lua/lua_util.hpp

@@ -539,10 +539,12 @@ namespace lua {
             if (getfield(L, name)) {
                 return 1;
             } else if (required) {
+                pop(L);
                 throw std::runtime_error(
                     "table " + tableName + " has no member " + name
                 );
             }
+            pop(L);
             return 0;
         } else {
             throw std::runtime_error("table " + tableName + " not found");