py/runtime: Check that keys in dicts passed as ** args are strings.

Prior to this patch the code would crash if a key in a ** dict was anything
other than a str or qstr.  This is because mp_setup_code_state() assumes
that keys in kwargs are qstrs (for efficiency).

Thanks to @jepler for finding the bug.

1 files changed, 4 insertions, 4 deletions

diff --git a/py/runtime.c b/py/runtime.c
index 54ec0d70b..ca68fe982 100644
--- a/py/runtime.c
+++ b/py/runtime.c
@@ -748,8 +748,8 @@ void mp_call_prepare_args_n_kw_var(bool have_self, size_t n_args_n_kw, const mp_
             if (MP_MAP_SLOT_IS_FILLED(map, i)) {
                 // the key must be a qstr, so intern it if it's a string
                 mp_obj_t key = map->table[i].key;
-                if (MP_OBJ_IS_TYPE(key, &mp_type_str)) {
-                    key = mp_obj_str_intern(key);
+                if (!MP_OBJ_IS_QSTR(key)) {
+                    key = mp_obj_str_intern_checked(key);
                 }
                 args2[args2_len++] = key;
                 args2[args2_len++] = map->table[i].value;
@@ -778,8 +778,8 @@ void mp_call_prepare_args_n_kw_var(bool have_self, size_t n_args_n_kw, const mp_
             }
 
             // the key must be a qstr, so intern it if it's a string
-            if (MP_OBJ_IS_TYPE(key, &mp_type_str)) {
-                key = mp_obj_str_intern(key);
+            if (!MP_OBJ_IS_QSTR(key)) {
+                key = mp_obj_str_intern_checked(key);
             }
 
             // get the value corresponding to the key