From 0d9cf7df8510d04a6af6f1693237951ea894ee84 Mon Sep 17 00:00:00 2001
From: Daniel Karzel <daniel@comit.network>
Date: Fri, 15 Oct 2021 13:32:14 +1100
Subject: [PATCH 1/2] Always cleanup order upon rejection

Upon rejection, we always have to remove the order on the maker side, otherwise a taker cannot re-try taking (with e.g. a different amount) because there is already a rejected cfd in the taker database.
---
 daemon/src/maker_cfd.rs | 26 ++++++++++++++++++++------
 1 file changed, 20 insertions(+), 6 deletions(-)

diff --git a/daemon/src/maker_cfd.rs b/daemon/src/maker_cfd.rs
index d2644cd..b74bec2 100644
--- a/daemon/src/maker_cfd.rs
+++ b/daemon/src/maker_cfd.rs
@@ -16,6 +16,8 @@ use bdk::bitcoin::secp256k1::schnorrsig;
 use cfd_protocol::secp256k1_zkp::Signature;
 use futures::channel::mpsc;
 use futures::{future, SinkExt};
+use rocket_db_pools::sqlx::Sqlite;
+use sqlx::pool::PoolConnection;
 use std::collections::HashMap;
 use std::time::SystemTime;
 use tokio::sync::watch;
@@ -513,12 +515,8 @@ impl Actor {
                 current_order.min_quantity,
                 current_order.max_quantity
             );
-            self.takers
-                .do_send_async(maker_inc_connections::TakerMessage {
-                    taker_id,
-                    command: TakerCommand::NotifyOrderRejected { id: order_id },
-                })
-                .await?;
+
+            self.reject_order(taker_id, order_id, conn).await?;
             return Ok(());
         }
 
@@ -654,6 +652,22 @@ impl Actor {
             }
         };
 
+        self.reject_order(taker_id, order_id, conn).await?;
+
+        Ok(())
+    }
+
+    /// Reject an order
+    ///
+    /// Rejection includes removing the order and saving in the db that it was rejected.
+    /// In the current model it is essential to remove the order because a taker
+    /// that received a rejection cannot communicate with the maker until a new order is published.
+    async fn reject_order(
+        &mut self,
+        taker_id: TakerId,
+        order_id: OrderId,
+        mut conn: PoolConnection<Sqlite>,
+    ) -> Result<()> {
         // Update order in db
         insert_new_cfd_state_by_order_id(
             order_id,

From 7355c339a69361b6ba4478f3cabc06c8e02be97d Mon Sep 17 00:00:00 2001
From: Daniel Karzel <daniel@comit.network>
Date: Fri, 15 Oct 2021 13:33:27 +1100
Subject: [PATCH 2/2] Remove todo in favour of warning for awareness

Better log a warning, the assumption is that we rarely see this. Let's see if that is true.
---
 daemon/src/maker_cfd.rs | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/daemon/src/maker_cfd.rs b/daemon/src/maker_cfd.rs
index b74bec2..a6260ef 100644
--- a/daemon/src/maker_cfd.rs
+++ b/daemon/src/maker_cfd.rs
@@ -502,7 +502,13 @@ impl Actor {
                         command: TakerCommand::NotifyInvalidOrderId { id: order_id },
                     })
                     .await?;
-                // TODO: Return an error here?
+
+                // An outdated order on the taker side does not require any state change on the
+                // maker. notifying the taker with a specific message should be sufficient.
+                // Since this is a scenario that we should rarely see we log
+                // a warning to be sure we don't trigger this code path frequently.
+                tracing::warn!("Taker tried to take order with outdated id {}", order_id);
+
                 return Ok(());
             }
         };