Fix python.args usage and optimize call_python

lupa/_lupa.pyx

@@ -1648,6 +1648,7 @@ cdef int py_object_gc(lua_State* L) nogil:
 cdef bint call_python(LuaRuntime runtime, lua_State *L, py_object* py_obj) except -1:
     # Callers must assure that py_obj.obj is not NULL, i.e. it points to a valid Python object.
     cdef int i, nargs = lua.lua_gettop(L) - 1
+    cdef Py_ssize_t j
     cdef tuple args
     cdef dict kwargs
 
@@ -1657,16 +1658,31 @@ cdef bint call_python(LuaRuntime runtime, lua_State *L, py_object* py_obj) excep
         lua.lua_settop(L, 0)  # FIXME
         result = f()
     else:
-        args = ()
-        kwargs = {}
-
-        for i in range(nargs):
-            arg = py_from_lua(runtime, L, i+2)
-            if isinstance(arg, _PyArguments):
-                args += (<_PyArguments>arg).args
-                kwargs = dict(**kwargs, **(<_PyArguments>arg).kwargs)
-            else:
-                args += (arg, )
+        # Special treatment for the last argument
+        last_arg = py_from_lua(runtime, L, nargs + 1)
+
+        if isinstance(last_arg, _PyArguments):
+            # Calling a function and _PyArguments is the last argument
+            # Lua f(..., python.args{a, b, c=1, d=2}) => Python as f(..., a, b, c=1, d=2)
+            kwargs = (<_PyArguments>last_arg).kwargs
+            moreargs = (<_PyArguments>last_arg).args
+            args = cpython.tuple.PyTuple_New(nargs - 1 + len(moreargs))
+            for j, arg in enumerate(moreargs):
+                cpython.ref.Py_INCREF(arg)
+                cpython.tuple.PyTuple_SET_ITEM(args, nargs - 1 + j, arg)
+        else:
+            # Calling a function normally
+            # Lua f(...) => Python as f(...)
+            kwargs = None
+            args = cpython.tuple.PyTuple_New(nargs)
+            cpython.ref.Py_INCREF(last_arg)
+            cpython.tuple.PyTuple_SET_ITEM(args, nargs - 1, last_arg)
+
+        # Process the rest of the arguments
+        for i in range(nargs - 1):
+            arg = py_from_lua(runtime, L, i + 2)
+            cpython.ref.Py_INCREF(arg)
+            cpython.tuple.PyTuple_SET_ITEM(args, i, arg)
 
         if args and PyMethod_Check(f) and (<PyObject*>args[0]) is PyMethod_GET_SELF(f):
             # Calling a bound method and self is already the first argument.
@@ -1681,7 +1697,11 @@ cdef bint call_python(LuaRuntime runtime, lua_State *L, py_object* py_obj) excep
             f = <object>PyMethod_GET_FUNCTION(f)
 
         lua.lua_settop(L, 0)  # FIXME
-        result = f(*args, **kwargs)
+
+        if kwargs:
+            result = f(*args, **kwargs)
+        else:
+            result = f(*args)
 
     return py_function_result_to_lua(runtime, L, result)
 

lupa/tests/test.py

@@ -2712,11 +2712,27 @@ def test_all_types(self):
                 self.assertIncorrect('python.args{[kwargs["%s"]] = true}' % objtype,
                         regex='table key is neither an integer nor a string')
 
-    def test_kwargs_merge(self):
-        self.assertResult('python.args{1, a=1}, python.args{2}, python.args{}, python.args{b=2}', (1, 2), dict(a=1, b=2))
+    def test_args_merge(self):
+        self.assertResult('1, 2, python.args{a=5, b=6}', (1, 2), dict(a=5, b=6))
+        self.assertResult('1, 2, python.args{3, 4, a=5, b=6}', (1, 2, 3, 4), dict(a=5, b=6))
 
-    def test_kwargs_merge_conflict(self):
-        self.assertIncorrect('python.args{a=1}, python.args{a=2}', regex='multiple values')
+
+    def test_multiple_args(self):
+        _G = self.lua.globals()
+
+        x = self.lua.eval('python.args{1, 2, a=5, b=6}')
+        _G.x = x
+        self.assertEqual(_G.x, x)
+
+        y = self.lua.eval('python.args{11, c=13}')
+        _G.y = y
+        self.assertEqual(_G.y, y)
+
+        callfxy = self.lua.eval('function(f) return f(x, y) end')
+
+        # contrary to y, x will not be unpacked
+        self.assertEqual(callfxy(self.get_args), (x, 11))
+        self.assertEqual(callfxy(self.get_kwargs), dict(c=13))
 
 
 class PythonArgumentsInLuaMethodsTest(PythonArgumentsInLuaTest):