timeline: when an edit fails on a stale local echo, retry on the matching remote echo

Author: bnjbvr

crates/matrix-sdk-ui/src/timeline/day_dividers.rs

@@ -622,6 +622,7 @@ mod tests {
     fn event_with_ts(timestamp: MilliSecondsSinceUnixEpoch) -> EventTimelineItem {
         let event_kind = EventTimelineItemKind::Remote(RemoteEventTimelineItem {
             event_id: owned_event_id!("$1"),
+            transaction_id: None,
             reactions: Default::default(),
             read_receipts: Default::default(),
             is_own: false,

crates/matrix-sdk-ui/src/timeline/event_handler.rs

@@ -891,7 +891,7 @@ impl<'a, 'o> TimelineEventHandler<'a, 'o> {
             }
             .into(),
 
-            Flow::Remote { event_id, raw_event, position, .. } => {
+            Flow::Remote { event_id, raw_event, position, txn_id, .. } => {
                 // Drop pending reactions if the message is redacted.
                 if let TimelineItemContent::RedactedMessage = content {
                     if !reactions.is_empty() {
@@ -916,6 +916,7 @@ impl<'a, 'o> TimelineEventHandler<'a, 'o> {
 
                 RemoteEventTimelineItem {
                     event_id: event_id.clone(),
+                    transaction_id: txn_id.clone(),
                     reactions,
                     read_receipts: self.ctx.read_receipts.clone(),
                     is_own: self.ctx.is_own_event,

crates/matrix-sdk-ui/src/timeline/event_item/mod.rs

@@ -140,6 +140,7 @@ impl EventTimelineItem {
 
         let event_kind = RemoteEventTimelineItem {
             event_id,
+            transaction_id: None,
             reactions,
             read_receipts,
             is_own,

crates/matrix-sdk-ui/src/timeline/event_item/remote.rs

@@ -19,7 +19,7 @@ use matrix_sdk::deserialized_responses::EncryptionInfo;
 use ruma::{
     events::{receipt::Receipt, AnySyncTimelineEvent},
     serde::Raw,
-    OwnedEventId, OwnedUserId,
+    OwnedEventId, OwnedTransactionId, OwnedUserId,
 };
 
 use super::BundledReactions;
@@ -30,6 +30,9 @@ pub(in crate::timeline) struct RemoteEventTimelineItem {
     /// The event ID.
     pub event_id: OwnedEventId,
 
+    /// If available, the transaction id we've used to send this event.
+    pub transaction_id: Option<OwnedTransactionId>,
+
     /// All bundled reactions about the event.
     pub reactions: BundledReactions,
 
@@ -107,6 +110,7 @@ impl fmt::Debug for RemoteEventTimelineItem {
         // skip raw JSON, too noisy
         let Self {
             event_id,
+            transaction_id,
             reactions,
             read_receipts,
             is_own,
@@ -119,6 +123,7 @@ impl fmt::Debug for RemoteEventTimelineItem {
 
         f.debug_struct("RemoteEventTimelineItem")
             .field("event_id", event_id)
+            .field("transaction_id", transaction_id)
             .field("reactions", reactions)
             .field("read_receipts", read_receipts)
             .field("is_own", is_own)

crates/matrix-sdk-ui/src/timeline/mod.rs

@@ -477,6 +477,22 @@ impl Timeline {
         })
     }
 
+    /// Given a transaction id, try to find a remote echo that used this
+    /// transaction id upon sending.
+    async fn find_remote_by_transaction_id(&self, txn_id: &TransactionId) -> Option<OwnedEventId> {
+        let items = self.inner.items().await;
+
+        let (_, found) = rfind_event_item(&items, |item| {
+            if let Some(remote) = item.as_remote() {
+                remote.transaction_id.as_deref() == Some(txn_id)
+            } else {
+                false
+            }
+        })?;
+
+        Some(found.event_id().expect("remote echoes have event id").to_owned())
+    }
+
     /// Edit an event.
     ///
     /// Only supports events for which [`EventTimelineItem::is_editable()`]
@@ -503,19 +519,38 @@ impl Timeline {
     ) -> Result<bool, RoomSendQueueError> {
         let event_id = match edit_info.id {
             TimelineEventItemId::TransactionId(txn_id) => {
-                let Some(item) = self.item_by_transaction_id(&txn_id).await else {
-                    warn!("Couldn't find the local echo anymore");
-                    return Ok(false);
-                };
+                if let Some(item) = self.item_by_transaction_id(&txn_id).await {
+                    let Some(handle) = item.as_local().and_then(|item| item.send_handle.clone())
+                    else {
+                        warn!("No handle for a local echo; is this a test?");
+                        return Ok(false);
+                    };
 
-                if let Some(handle) = item.as_local().and_then(|item| item.send_handle.clone()) {
                     // Assume no relations, since it's not been sent yet.
-                    let new_content: RoomMessageEventContent = new_content.into();
-                    return Ok(handle.edit(new_content.into()).await?);
+                    let new_content: RoomMessageEventContent = new_content.clone().into();
+
+                    if handle.edit(new_content.into()).await? {
+                        return Ok(true);
+                    }
                 }
 
-                warn!("No handle for a local echo; should only happen in testing situations");
-                return Ok(false);
+                // We end up here in two cases: either there wasn't a local echo with this
+                // transaction id, or the send queue refused to edit the local echo (likely
+                // because it's sent).
+                //
+                // Try to find a matching local echo that now has an event id (it's been sent),
+                // or a remote echo with a matching transaction id, so as to
+                // send an actual edit.
+                if let Some(TimelineEventItemId::EventId(event_id)) =
+                    self.item_by_transaction_id(&txn_id).await.map(|item| item.identifier())
+                {
+                    event_id
+                } else if let Some(event_id) = self.find_remote_by_transaction_id(&txn_id).await {
+                    event_id
+                } else {
+                    warn!("Couldn't find the local echo anymore, nor a matching remote echo");
+                    return Ok(false);
+                }
             }
 
             TimelineEventItemId::EventId(event_id) => event_id,