5 files changed, 26 insertions, 1 deletions
diff --git a/src/script/lua_api/l_base.cpp b/src/script/lua_api/l_base.cpp
index 8ab0a20b6..e62aa2368 100644
--- a/src/script/lua_api/l_base.cpp
+++ b/src/script/lua_api/l_base.cpp
@@ -21,7 +21,8 @@ with this program; if not, write to the Free Software Foundation, Inc.,
 #include "lua_api/l_internal.h"
 #include "cpp_api/s_base.h"
 #include "content/mods.h"
-#include <server.h>
+#include "server.h"
+#include <cmath>
 
 ScriptApiBase *ModApiBase::getScriptApiBase(lua_State *L)
 {
@@ -84,3 +85,8 @@ bool ModApiBase::registerFunction(lua_State *L, const char *name,
 
 	return true;
 }
+
+bool ModApiBase::isNaN(lua_State *L, int idx)
+{
+	return lua_type(L, idx) == LUA_TNUMBER && std::isnan(lua_tonumber(L, idx));
+}
diff --git a/src/script/lua_api/l_base.h b/src/script/lua_api/l_base.h
index 0a75b4c1a..20aa4cc09 100644
--- a/src/script/lua_api/l_base.h
+++ b/src/script/lua_api/l_base.h
@@ -69,4 +69,6 @@ public:
 			const char* name,
 			lua_CFunction func,
 			int top);
+
+	static bool isNaN(lua_State *L, int idx);
 };
diff --git a/src/script/lua_api/l_object.cpp b/src/script/lua_api/l_object.cpp
index b3c3a55bf..8377f95c8 100644
--- a/src/script/lua_api/l_object.cpp
+++ b/src/script/lua_api/l_object.cpp
@@ -895,6 +895,9 @@ int ObjectRef::l_set_yaw(lua_State *L)
 	ObjectRef *ref = checkobject(L, 1);
 	LuaEntitySAO *co = getluaobject(ref);
 	if (co == NULL) return 0;
+	if (isNaN(L, 2))
+		throw LuaError("ObjectRef::set_yaw: NaN value is not allowed.");
+
 	float yaw = luaL_checknumber(L, 2) * core::RADTODEG;
 	// Do it
 	co->setYaw(yaw);
diff --git a/src/script/lua_api/l_util.cpp b/src/script/lua_api/l_util.cpp
index 501261dd7..c1b760941 100644
--- a/src/script/lua_api/l_util.cpp
+++ b/src/script/lua_api/l_util.cpp
@@ -240,6 +240,15 @@ int ModApiUtil::l_is_yes(lua_State *L)
 	return 1;
 }
 
+// is_nan(arg)
+int ModApiUtil::l_is_nan(lua_State *L)
+{
+	NO_MAP_LOCK_REQUIRED;
+
+	lua_pushboolean(L, isNaN(L, 1));
+	return 1;
+}
+
 // get_builtin_path()
 int ModApiUtil::l_get_builtin_path(lua_State *L)
 {
@@ -481,6 +490,7 @@ void ModApiUtil::Initialize(lua_State *L, int top)
 	API_FCT(get_password_hash);
 
 	API_FCT(is_yes);
+	API_FCT(is_nan);
 
 	API_FCT(get_builtin_path);
 
@@ -513,6 +523,7 @@ void ModApiUtil::InitializeClient(lua_State *L, int top)
 	API_FCT(write_json);
 
 	API_FCT(is_yes);
+	API_FCT(is_nan);
 
 	API_FCT(compress);
 	API_FCT(decompress);
diff --git a/src/script/lua_api/l_util.h b/src/script/lua_api/l_util.h
index 4392a4339..5697aab15 100644
--- a/src/script/lua_api/l_util.h
+++ b/src/script/lua_api/l_util.h
@@ -65,6 +65,9 @@ private:
 	// is_yes(arg)
 	static int l_is_yes(lua_State *L);
 
+	// is_nan(arg)
+	static int l_is_nan(lua_State *L);
+
 	// get_builtin_path()
 	static int l_get_builtin_path(lua_State *L);