Added assertions for getjsonname() return.

upb/json/parser.rl

@@ -1364,9 +1364,11 @@ static void add_jsonname_table(upb_json_parsermethod *m, const upb_msgdef* md) {
     const upb_fielddef *f = upb_msg_iter_field(&i);
     size_t field_len = upb_fielddef_getjsonname(f, buf, len);
     if (field_len > len) {
+      size_t len2;
       buf = realloc(buf, field_len);
       len = field_len;
-      upb_fielddef_getjsonname(f, buf, len);
+      len2 = upb_fielddef_getjsonname(f, buf, len);
+      UPB_ASSERT_VAR(len2, len == len2);
     }
     upb_strtable_insert(t, buf, upb_value_constptr(f));
 

upb/json/printer.c

@@ -47,9 +47,11 @@ void freestrpc(void *ptr) {
 strpc *newstrpc(upb_handlers *h, const upb_fielddef *f) {
   /* TODO(haberman): handle malloc failure. */
   strpc *ret = malloc(sizeof(*ret));
+  size_t len;
   ret->len = upb_fielddef_getjsonname(f, NULL, 0);
   ret->ptr = malloc(ret->len);
-  upb_fielddef_getjsonname(f, ret->ptr, ret->len);
+  len = upb_fielddef_getjsonname(f, ret->ptr, ret->len);
+  UPB_ASSERT_VAR(len, len == ret->len);
   ret->len--;  /* NULL */
 
   upb_handlers_addcleanup(h, ret, freestrpc);