Defer to read_from_map in VoxelManip ctor

concrete problem: the getEmergeThread safety check was missing there

src/script/lua_api/l_vmanip.cpp

@@ -369,36 +369,35 @@ LuaVoxelManip::LuaVoxelManip(Map *map) : vm(new MMVManip(map))
 {
 }
 
-LuaVoxelManip::LuaVoxelManip(Map *map, v3s16 p1, v3s16 p2)
-{
-	vm = new MMVManip(map);
-
-	v3s16 bp1 = getNodeBlockPos(p1);
-	v3s16 bp2 = getNodeBlockPos(p2);
-	sortBoxVerticies(bp1, bp2);
-	vm->initialEmerge(bp1, bp2);
-}
-
 LuaVoxelManip::~LuaVoxelManip()
 {
 	if (!is_mapgen_vm)
 		delete vm;
 }
 
-// LuaVoxelManip()
+// LuaVoxelManip([p1, p2])
 // Creates an LuaVoxelManip and leaves it on top of stack
 int LuaVoxelManip::create_object(lua_State *L)
 {
 	GET_ENV_PTR;
 
-	Map *map = &(env->getMap());
+	LuaVoxelManip *o = new LuaVoxelManip(&env->getMap());
-	LuaVoxelManip *o = (lua_istable(L, 1) && lua_istable(L, 2)) ?
-		new LuaVoxelManip(map, check_v3s16(L, 1), check_v3s16(L, 2)) :
-		new LuaVoxelManip(map);
 
 	*(void **)(lua_newuserdata(L, sizeof(void *))) = o;
 	luaL_getmetatable(L, className);
 	lua_setmetatable(L, -2);
+
+	// Call read_from_map so we don't have to duplicate it here
+	const int top = lua_gettop(L);
+	if (lua_istable(L, 1) && lua_istable(L, 2)) {
+		lua_pushcfunction(L, l_read_from_map);
+		lua_pushvalue(L, top);
+		lua_pushvalue(L, 1);
+		lua_pushvalue(L, 2);
+		lua_call(L, 3, 0);
+	}
+	lua_settop(L, top);
+
 	return 1;
 }
 

src/script/lua_api/l_vmanip.h

@@ -64,7 +64,6 @@ public:
 	MMVManip *vm = nullptr;
 
 	LuaVoxelManip(MMVManip *mmvm, bool is_mapgen_vm);
-	LuaVoxelManip(Map *map, v3s16 p1, v3s16 p2);
 	LuaVoxelManip(Map *map);
 	~LuaVoxelManip();