py/objtype: Allow passing keyword arguments to native base __init__.

Allowing passing keyword arguments to a native base's __init__, i.e.
`make_new` in the C code.  Previously only positional arguments were
allowed.

The main trade-off in this commit is that every call to the native base's
`make_new` is now going to be preceded by a call to
`mp_map_init_fixed_table` even though most of what that does is unused and
instead it merely serves as a way to pass the number of keyword arguments.

Fixes issue #15465.

Signed-off-by: stijn <stijn@ignitron.net>

1 files changed, 3 insertions, 1 deletions

diff --git a/py/objfun.c b/py/objfun.c
index 8279605e9..0b1b8c115 100644
--- a/py/objfun.c
+++ b/py/objfun.c
@@ -107,7 +107,9 @@ static mp_obj_t fun_builtin_var_call(mp_obj_t self_in, size_t n_args, size_t n_k
     if (self->sig & 1) {
         // function allows keywords
 
-        // we create a map directly from the given args array
+        // we create a map directly from the given args array; self->fun.kw does still
+        // expect args to have both positional and keyword arguments, ordered as:
+        // arg0 arg1 ... arg<n_args> key0 value0 key1 value1 ... key<n_kw> value<n_kw>
         mp_map_t kw_args;
         mp_map_init_fixed_table(&kw_args, n_kw, args + n_args);