fix: No new chats for MDNs with alias (#5196) (#5199)

close #5196

src/receive_imf/tests.rs

@@ -310,6 +310,56 @@ async fn test_read_receipt_and_unarchive() -> Result<()> {
     Ok(())
 }
 
+#[tokio::test(flavor = "multi_thread", worker_threads = 2)]
+async fn test_mdn_and_alias() -> Result<()> {
+    let mut tcm = TestContextManager::new();
+    let alice = tcm.alice().await;
+    let bob = tcm.bob().await;
+    let alice_chat = alice.create_chat(&bob).await;
+    let sent = alice.send_text(alice_chat.id, "alice -> bob").await;
+    let msg_id = sent.sender_msg_id;
+    receive_imf(
+        &alice,
+        format!(
+            "Received: (Postfix, from userid 1000); Mon, 4 Dec 2006 14:51:39 +0100 (CET)\n\
+             From: bob@example.net\n\
+             To: alicechat@example.org\n\
+             Subject: message opened\n\
+             Date: Sun, 22 Mar 2020 23:37:57 +0000\n\
+             Chat-Version: 1.0\n\
+             Message-ID: <aranudiaerudiaduiaertd@example.com>\n\
+             Content-Type: multipart/report; report-type=disposition-notification; boundary=\"SNIPP\"\n\
+             \n\
+             \n\
+             --SNIPP\n\
+             Content-Type: text/plain; charset=utf-8\n\
+             \n\
+             Read receipts do not guarantee sth. was read.\n\
+             \n\
+             \n\
+             --SNIPP\n\
+             Content-Type: message/disposition-notification\n\
+             \n\
+             Reporting-UA: Delta Chat 1.28.0\n\
+             Original-Recipient: rfc822;bob@example.com\n\
+             Final-Recipient: rfc822;bob@example.com\n\
+             Original-Message-ID: <{msg_id}>\n\
+             Disposition: manual-action/MDN-sent-automatically; displayed\n\
+             \n\
+             \n\
+             --SNIPP--",
+        )
+        .as_bytes(),
+        false,
+    )
+    .await?;
+
+    let chats = Chatlist::try_load(&alice, 0, None, None).await?;
+    assert_eq!(chats.len(), 1);
+
+    Ok(())
+}
+
 #[tokio::test(flavor = "multi_thread", worker_threads = 2)]
 async fn test_no_from() {
     // if there is no from given, from_id stays 0 which is just fine. These messages