fix: Send pre-message after successful sending of post-message (#8063)

On the receiving side, download post messages w/o known pre-message after 30s to protect from lost
messages.

This isn't easy to test in Rust though because the `smtp` sending code requires an SMTP connection,
so it's only tested (by already existing tests) that messages are queued in the right order.

Another problem is that the `smtp` sending logic doesn't try to send any messages following a
failed-to-send message until the retry limit is reached, so if there's smth wrong with a
post-message, other unrelated messages are delayed, but this problem has already existed.

src/chat.rs

@@ -2970,15 +2970,6 @@ WHERE id=?
         )?;
         for recipients_chunk in recipients.chunks(chunk_size) {
             let recipients_chunk = recipients_chunk.join(" ");
-            if let Some(pre_msg) = &rendered_pre_msg {
-                let row_id = stmt.execute((
-                    &pre_msg.rfc724_mid,
-                    &recipients_chunk,
-                    &pre_msg.message,
-                    msg.id,
-                ))?;
-                row_ids.push(row_id.try_into()?);
-            }
             let row_id = stmt.execute((
                 &rendered_msg.rfc724_mid,
                 &recipients_chunk,
@@ -2986,6 +2977,16 @@ WHERE id=?
                 msg.id,
             ))?;
             row_ids.push(row_id.try_into()?);
+            let Some(pre_msg) = &rendered_pre_msg else {
+                continue;
+            };
+            let row_id = stmt.execute((
+                &pre_msg.rfc724_mid,
+                &recipients_chunk,
+                &pre_msg.message,
+                msg.id,
+            ))?;
+            row_ids.push(row_id.try_into()?);
         }
         Ok(row_ids)
     };

src/download.rs

@@ -10,6 +10,7 @@ use crate::context::Context;
 use crate::imap::session::Session;
 use crate::log::warn;
 use crate::message::{self, Message, MsgId, rfc724_mid_exists};
+use crate::tools;
 use crate::{EventType, chatlist_events};
 
 pub(crate) mod post_msg_metadata;
@@ -320,12 +321,22 @@ pub(crate) async fn download_known_post_messages_without_pre_message(
     context: &Context,
     session: &mut Session,
 ) -> Result<()> {
+    const PRE_MSG_WAIT_TIME: i64 = 30;
+    let now = tools::time();
     let rfc724_mids = context
         .sql
-        .query_map_vec("SELECT rfc724_mid FROM available_post_msgs", (), |row| {
+        .query_map_vec(
+            "
+SELECT rfc724_mid FROM available_post_msgs
+WHERE timestamp<=? OR timestamp>?
+ORDER BY timestamp, rowid
+            ",
+            (now.saturating_sub(PRE_MSG_WAIT_TIME), now),
+            |row| {
                 let rfc724_mid: String = row.get(0)?;
                 Ok(rfc724_mid)
-        })
+            },
+        )
         .await?;
     for rfc724_mid in &rfc724_mids {
         if msg_is_downloaded_for(context, rfc724_mid).await? {

src/imap.rs

@@ -601,7 +601,7 @@ impl Imap {
         let _fetch_msgs_lock_guard = context.fetch_msgs_mutex.lock().await;
 
         let mut uids_fetch: Vec<u32> = Vec::new();
-        let mut available_post_msgs: Vec<String> = Vec::new();
+        let mut available_post_msgs: Vec<(String, i64)> = Vec::new();
         let mut download_later: Vec<String> = Vec::new();
         let mut uid_message_ids = BTreeMap::new();
         let mut largest_uid_skipped = None;
@@ -689,7 +689,7 @@ impl Imap {
                     .is_some()
                 {
                     info!(context, "{message_id:?} is a post-message.");
-                    available_post_msgs.push(message_id.clone());
+                    available_post_msgs.push((message_id.clone(), time()));
 
                     let is_bot = context.get_config_bool(Config::Bot).await?;
                     if is_bot && download_limit.is_none_or(|download_limit| size <= download_limit)
@@ -793,9 +793,10 @@ impl Imap {
                 download_later.len(),
             );
             let trans_fn = |t: &mut rusqlite::Transaction| {
-                let mut stmt = t.prepare("INSERT OR IGNORE INTO available_post_msgs VALUES (?)")?;
+                let mut stmt =
-                for rfc724_mid in available_post_msgs {
+                    t.prepare("INSERT OR IGNORE INTO available_post_msgs VALUES (?,?)")?;
-                    stmt.execute((rfc724_mid,))
+                for entry in available_post_msgs {
+                    stmt.execute(entry)
                         .context("INSERT OR IGNORE INTO available_post_msgs")?;
                 }
                 let mut stmt =

src/receive_imf.rs

@@ -525,18 +525,10 @@ pub(crate) async fn receive_imf_inner(
         "Receiving message {rfc724_mid_orig:?}, seen={seen}...",
     );
 
-    // These checks must be done before processing of SecureJoin and other special messages.
+    let msg_id = message::rfc724_mid_exists(context, rfc724_mid_orig).await?;
-    if mime_parser.pre_message == mimeparser::PreMessageMode::Post {
+    if let Some(msg_id) = msg_id
-        // Post-Message just replaces the attachment and modifies Params, not the whole message.
+        && !mime_parser.incoming
-        // This is done in the `handle_post_message` method.
+    {
-    } else if let Some(msg_id) = message::rfc724_mid_exists(context, rfc724_mid_orig).await? {
-        info!(
-            context,
-            "Message {rfc724_mid} is already in some chat or deleted."
-        );
-        if mime_parser.incoming {
-            return Ok(None);
-        }
         // For the case if we missed a successful SMTP response. Be optimistic that the message is
         // delivered also.
         let self_addr = context.get_primary_self_addr().await?;
@@ -551,6 +543,16 @@ pub(crate) async fn receive_imf_inner(
         if !msg_has_pending_smtp_job(context, msg_id).await? {
             msg_id.set_delivered(context).await?;
         }
+    }
+    // These checks must be done before processing of SecureJoin and other special messages.
+    if mime_parser.pre_message == mimeparser::PreMessageMode::Post {
+        // Post-Message just replaces the attachment and modifies Params, not the whole message.
+        // This is done in the `handle_post_message` method.
+    } else if msg_id.is_some() {
+        info!(
+            context,
+            "Message {rfc724_mid} is already in some chat or deleted."
+        );
         return Ok(None);
     }
 
@@ -2504,7 +2506,10 @@ WHERE id=?
                 part.typ,
                 part.bytes as isize,
                 part.error.as_deref().unwrap_or_default(),
-                state,
+                match mime_parser.incoming {
+                    true => state,
+                    false => MessageState::Undefined,
+                },
                 DownloadState::Done as u32,
                 original_msg.id,
             ),

src/receive_imf/receive_imf_tests.rs

@@ -5592,27 +5592,27 @@ async fn test_mark_message_as_delivered_only_after_sent_out_fully() -> Result<()
         .await
         .unwrap();
 
-    let (pre_msg_id, pre_msg_payload) = first_row_in_smtp_queue(alice).await;
-    assert_eq!(msg_id, pre_msg_id);
-    assert!(pre_msg_payload.len() < file_bytes.len());
-
-    assert_eq!(msg_id.get_state(alice).await?, MessageState::OutPending);
-    // Alice receives her own pre-message because of bcc_self
-    // This should not yet mark the message as delivered,
-    // because not everything was sent,
-    // but it does remove the pre-message from the SMTP queue
-    receive_imf(alice, pre_msg_payload.as_bytes(), false).await?;
-    assert_eq!(msg_id.get_state(alice).await?, MessageState::OutPending);
-
     let (post_msg_id, post_msg_payload) = first_row_in_smtp_queue(alice).await;
     assert_eq!(msg_id, post_msg_id);
     assert!(post_msg_payload.len() > file_bytes.len());
 
     assert_eq!(msg_id.get_state(alice).await?, MessageState::OutPending);
     // Alice receives her own post-message because of bcc_self
+    // This should not yet mark the message as delivered,
+    // because not everything was sent,
+    // but it does remove the post-message from the SMTP queue.
+    receive_imf(alice, post_msg_payload.as_bytes(), false).await?;
+    assert_eq!(msg_id.get_state(alice).await?, MessageState::OutPending);
+
+    let (pre_msg_id, pre_msg_payload) = first_row_in_smtp_queue(alice).await;
+    assert_eq!(msg_id, pre_msg_id);
+    assert!(pre_msg_payload.len() < file_bytes.len());
+
+    assert_eq!(msg_id.get_state(alice).await?, MessageState::OutPending);
+    // Alice receives her own pre-message because of bcc_self
     // This should now mark the message as delivered,
     // because everything was sent by now.
-    receive_imf(alice, post_msg_payload.as_bytes(), false).await?;
+    receive_imf(alice, pre_msg_payload.as_bytes(), false).await?;
     assert_eq!(msg_id.get_state(alice).await?, MessageState::OutDelivered);
 
     Ok(())

src/smtp.rs

@@ -379,7 +379,7 @@ pub(crate) async fn send_msg_to_smtp(
     if retries > 6 {
         context
             .sql
-            .execute("DELETE FROM smtp WHERE id=?", (rowid,))
+            .execute("DELETE FROM smtp WHERE msg_id=?", (msg_id,))
             .await
             .context("Failed to remove message with exceeded retry limit from smtp table")?;
         if let Some(mut msg) = Message::load_from_db_optional(context, msg_id).await? {

src/sql/migrations.rs

@@ -2385,6 +2385,19 @@ UPDATE msgs SET state=19 WHERE state=24; -- Change OutPreparing to OutFailed.
         .await?;
     }
 
+    inc_and_check(&mut migration_version, 153)?;
+    if dbversion < migration_version {
+        sql.execute_migration(
+            "
+CREATE INDEX smtp_index_msg_id ON smtp (msg_id, id);
+ALTER TABLE available_post_msgs ADD COLUMN timestamp INTEGER DEFAULT 0 NOT NULL;
+CREATE INDEX available_post_msgs_timestamp ON available_post_msgs (timestamp);
+            ",
+            migration_version,
+        )
+        .await?;
+    }
+
     let new_version = sql
         .get_raw_config_int(VERSION_CFG)
         .await?

src/test_utils.rs

@@ -722,12 +722,14 @@ ORDER BY id"
         })
     }
 
+    /// Returns `SentMessage` instances representing `smtp` rows for the given message. Returned
+    /// items go in reverse order for historical reasons.
     pub async fn get_smtp_rows_for_msg<'a>(&'a self, msg_id: MsgId) -> Vec<SentMessage<'a>> {
         let sent_msgs = self
             .ctx
             .sql
             .query_map_vec(
-                "SELECT id, msg_id, mime, recipients FROM smtp WHERE msg_id=?",
+                "SELECT id, msg_id, mime, recipients FROM smtp WHERE msg_id=? ORDER BY id DESC",
                 (msg_id,),
                 |row| {
                     let _id: MsgId = row.get(0)?;
@@ -1055,9 +1057,17 @@ ORDER BY id"
     /// This is not hooked up to any SMTP-IMAP pipeline, so the other account must call
     /// [`TestContext::recv_msg`] with the returned [`SentMessage`] if it wants to receive
     /// the message.
+    ///
+    /// Removes SMTP jobs existed before and marks the corresponding messages as delivered, as
+    /// tracking of these jobs is probably already lost by the test code.
     pub async fn send_msg(&self, chat_id: ChatId, msg: &mut Message) -> SentMessage<'_> {
+        while self.pop_sent_msg_opt(Duration::ZERO).await.is_some() {}
         let msg_id = chat::send_msg(self, chat_id, msg).await.unwrap();
-        let res = self.pop_sent_msg().await;
+        let rev_order = false;
+        let res = self
+            .pop_sent_msg_ex(rev_order, Duration::ZERO)
+            .await
+            .unwrap();
         assert_eq!(
             res.sender_msg_id, msg_id,
             "Apparently the message was not actually sent out"

src/tests/pre_messages/forward_and_save.rs

@@ -106,7 +106,7 @@ async fn test_receive_both() -> Result<()> {
     assert_eq!(msg.text, "test".to_owned());
 
     forward_msgs(alice, &[alice_msg_id], alice_chat_id).await?;
-    let rev_order = false;
+    let rev_order = true;
     let msg = bob
         .recv_msg(
             &alice

src/tests/pre_messages/receiving.rs

@@ -547,8 +547,8 @@ async fn test_webxdc_updates_in_post_message_after_pre_message() -> Result<()> {
         .await?;
 
     send_msg(alice, alice_chat_id, &mut alice_instance).await?;
-    let post_message = alice.pop_sent_msg().await;
     let pre_message = alice.pop_sent_msg().await;
+    let post_message = alice.pop_sent_msg().await;
 
     let bob_instance = bob.recv_msg(&pre_message).await;
     assert_eq!(bob_instance.download_state, DownloadState::Available);
@@ -588,8 +588,8 @@ async fn test_webxdc_updates_in_post_message_without_pre_message() -> Result<()>
         .await?;
 
     send_msg(alice, alice_chat_id, &mut alice_instance).await?;
-    let post_message = alice.pop_sent_msg().await;
     let pre_message = alice.pop_sent_msg().await;
+    let post_message = alice.pop_sent_msg().await;
 
     // Bob receives post-message first.
     let bob_instance = bob.recv_msg(&post_message).await;