fix: Add "member added" messages to OutBroadcast when executing SetPgpContacts sync message (#7952)

If one of broadcast owner's devices didn't add a new subscriber for any reason, e.g. because of
missing SecureJoin messages, this device shall add "member added" messages when syncing the member
list from the `SetPgpContacts` message.

src/chat.rs

@@ -1,7 +1,7 @@
 //! # Chat module.
 
 use std::cmp;
-use std::collections::{HashMap, HashSet};
+use std::collections::{BTreeSet, HashMap, HashSet};
 use std::fmt;
 use std::io::Cursor;
 use std::marker::Sync;
@@ -5031,18 +5031,18 @@ async fn set_contacts_by_fingerprints(
         matches!(chat.typ, Chattype::Group | Chattype::OutBroadcast),
         "{id} is not a group or broadcast",
     );
-    let mut contacts = HashSet::new();
+    let mut contacts = BTreeSet::new();
     for (fingerprint, addr) in fingerprint_addrs {
         let contact = Contact::add_or_lookup_ex(context, "", addr, fingerprint, Origin::Hidden)
             .await?
             .0;
         contacts.insert(contact);
     }
-    let contacts_old = HashSet::<ContactId>::from_iter(get_chat_contacts(context, id).await?);
+    let contacts_old = BTreeSet::<ContactId>::from_iter(get_chat_contacts(context, id).await?);
     if contacts == contacts_old {
         return Ok(());
     }
-    context
+    let broadcast_contacts_added = context
         .sql
         .transaction(move |transaction| {
             // For broadcast channels, we only add members,
@@ -5059,12 +5059,31 @@ async fn set_contacts_by_fingerprints(
             let mut statement = transaction.prepare(
                 "INSERT OR IGNORE INTO chats_contacts (chat_id, contact_id) VALUES (?, ?)",
             )?;
+            let mut broadcast_contacts_added = Vec::new();
             for contact_id in &contacts {
-                statement.execute((id, contact_id))?;
+                if statement.execute((id, contact_id))? > 0 && chat.typ == Chattype::OutBroadcast {
+                    broadcast_contacts_added.push(*contact_id);
+                }
             }
-            Ok(())
+            Ok(broadcast_contacts_added)
         })
         .await?;
+    let timestamp = smeared_time(context);
+    for added_id in broadcast_contacts_added {
+        let msg = stock_str::msg_add_member_local(context, added_id, ContactId::UNDEFINED).await;
+        add_info_msg_with_cmd(
+            context,
+            id,
+            &msg,
+            SystemMessage::MemberAddedToGroup,
+            Some(timestamp),
+            timestamp,
+            None,
+            Some(ContactId::SELF),
+            Some(added_id),
+        )
+        .await?;
+    }
     context.emit_event(EventType::ChatModified(id));
     Ok(())
 }

src/chat/chat_tests.rs

@@ -2997,18 +2997,41 @@ async fn test_broadcast_recipients_sync1() -> Result<()> {
     alice2.recv_msg_trash(&request_with_auth).await;
 
     let member_added = alice1.pop_sent_msg().await;
-    let a2_member_added = alice2.recv_msg(&member_added).await;
+    let a2_charlie_added = alice2.recv_msg(&member_added).await;
     let _c_member_added = charlie.recv_msg(&member_added).await;
+    let a2_chatlist = Chatlist::try_load(alice2, 0, Some("Channel"), None).await?;
+    assert_eq!(a2_chatlist.get_msg_id(0)?.unwrap(), a2_charlie_added.id);
 
     // Alice1 will now sync the full member list to Alice2:
     sync(alice1, alice2).await;
-    let a2_chatlist = Chatlist::try_load(alice2, 0, Some("Channel"), None).await?;
-    assert_eq!(a2_chatlist.get_msg_id(0)?.unwrap(), a2_member_added.id);
-
     let a2_bob_contact = alice2.add_or_lookup_contact_id(bob).await;
     let a2_charlie_contact = alice2.add_or_lookup_contact_id(charlie).await;
+    let a2_chatlist = Chatlist::try_load(alice2, 0, Some("Channel"), None).await?;
+    let msg_id = a2_chatlist.get_msg_id(0)?.unwrap();
+    let a2_bob_added = Message::load_from_db(alice2, msg_id).await?;
+    assert_ne!(a2_bob_added.id, a2_charlie_added.id);
+    assert_eq!(
+        a2_bob_added.text,
+        stock_str::msg_add_member_local(alice2, a2_bob_contact, ContactId::UNDEFINED).await
+    );
+    assert_eq!(a2_bob_added.from_id, ContactId::SELF);
+    assert_eq!(
+        a2_bob_added.param.get_cmd(),
+        SystemMessage::MemberAddedToGroup
+    );
+    assert_eq!(
+        ContactId::new(
+            a2_bob_added
+                .param
+                .get_int(Param::ContactAddedRemoved)
+                .unwrap()
+                .try_into()
+                .unwrap()
+        ),
+        a2_bob_contact
+    );
 
-    let a2_chat_members = get_chat_contacts(alice2, a2_member_added.chat_id).await?;
+    let a2_chat_members = get_chat_contacts(alice2, a2_charlie_added.chat_id).await?;
     assert!(a2_chat_members.contains(&a2_bob_contact));
     assert!(a2_chat_members.contains(&a2_charlie_contact));
     assert_eq!(a2_chat_members.len(), 2);