From e53fb1bf031a53ad23a45846addf14e25cebb97d Mon Sep 17 00:00:00 2001
From: Paul Sokolovsky <pfalcon@users.sourceforge.net>
Date: Sat, 14 May 2016 15:47:08 +0300
Subject: [PATCH] py/modstruct: Raise ValueError on unsupported format char.

---
 py/modstruct.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/py/modstruct.c b/py/modstruct.c
index cd32097388..eabc951aef 100644
--- a/py/modstruct.c
+++ b/py/modstruct.c
@@ -120,8 +120,9 @@ STATIC mp_obj_t struct_calcsize(mp_obj_t fmt_in) {
             if (sz == 0) {
                 sz = (mp_uint_t)mp_binary_get_size(fmt_type, *fmt, &align);
             }
-            // TODO
-            assert(sz != (mp_uint_t)-1);
+            if (sz == 0) {
+                nlr_raise(mp_obj_new_exception_msg(&mp_type_ValueError, "unsupported format"));
+            }
             // Apply alignment
             size = (size + align - 1) & ~(align - 1);
             size += sz;