Fix isNan on setYaw Lua call (#7380)

* Fix isNan on setYaw Lua call

doc/client_lua_api.txt

@@ -609,6 +609,8 @@ Helper functions
     * Converts a string representing an area box into two positions
 * `minetest.is_yes(arg)`
     * returns whether `arg` can be interpreted as yes
+* `minetest.is_nan(arg)`
+    * returns true true when the passed number represents NaN.
 * `table.copy(table)`: returns a table
     * returns a deep copy of `table`
 

doc/lua_api.txt

@@ -2541,6 +2541,8 @@ Helper functions
       in formspecs.
 * `minetest.is_yes(arg)`
     * returns true if passed 'y', 'yes', 'true' or a number that isn't zero.
+* `minetest.is_nan(arg)`
+    * returns true when the passed number represents NaN.
 * `minetest.get_us_time()`
     * returns time with microsecond precision. May not return wall time.
 * `table.copy(table)`: returns a table

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));
+}

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);
 };

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);

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);

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);