py: Factor out mp_obj_is_package() function.

py/builtinimport.c

@@ -55,6 +55,12 @@
 
 #define PATH_SEP_CHAR '/'
 
+bool mp_obj_is_package(mp_obj_t module) {
+    mp_obj_t dest[2];
+    mp_load_method_maybe(module, MP_QSTR___path__, dest);
+    return dest[0] != MP_OBJ_NULL;
+}
+
 STATIC mp_import_stat_t stat_dir_or_file(vstr_t *path) {
     //printf("stat %s\n", vstr_str(path));
     mp_import_stat_t stat = mp_import_stat(vstr_str(path));

py/obj.h

@@ -555,6 +555,8 @@ typedef struct _mp_obj_module_t {
     mp_obj_dict_t *globals;
 } mp_obj_module_t;
 mp_obj_dict_t *mp_obj_module_get_globals(mp_obj_t self_in);
+// check if given module object is a package
+bool mp_obj_is_package(mp_obj_t module);
 
 // staticmethod and classmethod types; defined here so we can make const versions
 // this structure is used for instances of both staticmethod and classmethod

py/runtime.c

@@ -1098,8 +1098,7 @@ import_error:
     }
 
     // See if it's a package, then can try FS import
-    mp_load_method_maybe(module, MP_QSTR___path__, dest);
-    if (dest[0] == MP_OBJ_NULL) {
+    if (!mp_obj_is_package(module)) {
         goto import_error;
     }