message: Don't assume there's a sub-message

Also add unit-test. Fixes: issue #2256.
2022-05-12 19:58:08 +03:00
parent 9062b9d67f
commit eb22ec450c
4 changed files with 35 additions and 8 deletions
--- a/lib/message/mu-message.cc
+++ b/lib/message/mu-message.cc
@ -417,7 +417,10 @@ process_message_part(const MimeMessagePart& msg_part,
 		     Message::Private& info)
 {
 	auto submsg{msg_part.get_message()};
-	submsg.for_each([&](auto&& parent, auto&& child_obj) {
+	if (!submsg)
+		return;
+
+	submsg->for_each([&](auto&& parent, auto&& child_obj) {

 		/* XXX: we only handle one level */