feat: sort past members by the timestamp of removal

src/chat.rs

@@ -3493,6 +3493,8 @@ pub async fn get_chat_contacts(context: &Context, chat_id: ChatId) -> Result<Vec
 }
 
 /// Returns a vector of contact IDs for given chat ID that are no longer part of the group.
+///
+/// Members that have been removed recently are in the beginning of the list.
 pub async fn get_past_chat_contacts(context: &Context, chat_id: ChatId) -> Result<Vec<ContactId>> {
     let now = time();
     let list = context
@@ -3505,7 +3507,7 @@ pub async fn get_past_chat_contacts(context: &Context, chat_id: ChatId) -> Resul
              WHERE cc.chat_id=?
              AND cc.add_timestamp < cc.remove_timestamp
              AND ? < cc.remove_timestamp
-             ORDER BY c.id=1, c.last_seen DESC, c.id DESC",
+             ORDER BY c.id=1, cc.remove_timestamp DESC, c.id DESC",
             (chat_id, now.saturating_sub(60 * 24 * 3600)),
             |row| row.get::<_, ContactId>(0),
             |ids| ids.collect::<Result<Vec<_>, _>>().map_err(Into::into),

src/chat/chat_tests.rs

@@ -3418,6 +3418,61 @@ async fn test_expire_past_members_after_60_days() -> Result<()> {
     Ok(())
 }
 
+/// Test that past members are ordered by the timestamp of their removal.
+#[tokio::test(flavor = "multi_thread", worker_threads = 2)]
+async fn test_past_members_order() -> Result<()> {
+    let t = &TestContext::new_alice().await;
+
+    let bob_contact_id = Contact::create(t, "Bob", "bob@example.net").await?;
+    let charlie_contact_id = Contact::create(t, "Charlie", "charlie@example.org").await?;
+    let fiona_contact_id = Contact::create(t, "Fiona", "fiona@example.net").await?;
+
+    let chat_id = create_group_chat(t, ProtectionStatus::Unprotected, "Group chat").await?;
+    add_contact_to_chat(t, chat_id, bob_contact_id).await?;
+    add_contact_to_chat(t, chat_id, charlie_contact_id).await?;
+    add_contact_to_chat(t, chat_id, fiona_contact_id).await?;
+    t.send_text(chat_id, "Hi! I created a group.").await;
+
+    assert_eq!(get_past_chat_contacts(t, chat_id).await?.len(), 0);
+
+    remove_contact_from_chat(t, chat_id, charlie_contact_id).await?;
+
+    let past_contacts = get_past_chat_contacts(t, chat_id).await?;
+    assert_eq!(past_contacts.len(), 1);
+    assert_eq!(past_contacts[0], charlie_contact_id);
+
+    SystemTime::shift(Duration::from_secs(5));
+    remove_contact_from_chat(t, chat_id, bob_contact_id).await?;
+
+    let past_contacts = get_past_chat_contacts(t, chat_id).await?;
+    assert_eq!(past_contacts.len(), 2);
+    assert_eq!(past_contacts[0], bob_contact_id);
+    assert_eq!(past_contacts[1], charlie_contact_id);
+
+    SystemTime::shift(Duration::from_secs(5));
+    remove_contact_from_chat(t, chat_id, fiona_contact_id).await?;
+
+    let past_contacts = get_past_chat_contacts(t, chat_id).await?;
+    assert_eq!(past_contacts.len(), 3);
+    assert_eq!(past_contacts[0], fiona_contact_id);
+    assert_eq!(past_contacts[1], bob_contact_id);
+    assert_eq!(past_contacts[2], charlie_contact_id);
+
+    // Adding and removing Bob
+    // moves him to the top of past member list.
+    SystemTime::shift(Duration::from_secs(5));
+    add_contact_to_chat(t, chat_id, bob_contact_id).await?;
+    remove_contact_from_chat(t, chat_id, bob_contact_id).await?;
+
+    let past_contacts = get_past_chat_contacts(t, chat_id).await?;
+    assert_eq!(past_contacts.len(), 3);
+    assert_eq!(past_contacts[0], bob_contact_id);
+    assert_eq!(past_contacts[1], fiona_contact_id);
+    assert_eq!(past_contacts[2], charlie_contact_id);
+
+    Ok(())
+}
+
 /// Test the case when Alice restores a backup older than 60 days
 /// with outdated member list.
 #[tokio::test(flavor = "multi_thread", worker_threads = 2)]