StackRduino
diff --git a/‎py/objstr.c‎
Lines changed: 2 additions & 1 deletion b/‎py/objstr.c‎
Lines changed: 2 additions & 1 deletion
diff --git a/‎tests/basics/string_format_modulo.py‎
Lines changed: 5 additions & 0 deletions b/‎tests/basics/string_format_modulo.py‎
Lines changed: 5 additions & 0 deletions
@@ -1299,7 +1299,7 @@ STATIC mp_obj_t str_modulo_format(mp_obj_t pattern, mp_uint_t n_args, const mp_o
             continue;
         }
         if (++str >= top) {
-            break;
+            goto incomplete_format;
         }
         if (*str == '%') {
             vstr_add_byte(&vstr, '%');
@@ -1369,6 +1369,7 @@ STATIC mp_obj_t str_modulo_format(mp_obj_t pattern, mp_uint_t n_args, const mp_o
         }
 
         if (str >= top) {
+incomplete_format:
             if (MICROPY_ERROR_REPORTING == MICROPY_ERROR_REPORTING_TERSE) {
                 terse_str_format_value_error();
             } else {
 
@@ -111,3 +111,8 @@
     '%l' % 1
 except ValueError:
     print('ValueError')
+
+try:
+    'a%' % 1
+except ValueError:
+    print('ValueError')
Original file line number	Diff line number	Diff line change
`@@ -1299,7 +1299,7 @@ STATIC mp_obj_t str_modulo_format(mp_obj_t pattern, mp_uint_t n_args, const mp_o`
`1299`	`1299`	`continue;`
`1300`	`1300`	`}`
`1301`	`1301`	`if (++str >= top) {`
`1302`		`- break;`
	`1302`	`+ goto incomplete_format;`
`1303`	`1303`	`}`
`1304`	`1304`	`if (*str == '%') {`
`1305`	`1305`	`vstr_add_byte(&vstr, '%');`
`@@ -1369,6 +1369,7 @@ STATIC mp_obj_t str_modulo_format(mp_obj_t pattern, mp_uint_t n_args, const mp_o`
`1369`	`1369`	`}`
`1370`	`1370`
`1371`	`1371`	`if (str >= top) {`
	`1372`	`+incomplete_format:`
`1372`	`1373`	`if (MICROPY_ERROR_REPORTING == MICROPY_ERROR_REPORTING_TERSE) {`
`1373`	`1374`	`terse_str_format_value_error();`
`1374`	`1375`	`} else {`