fix: store the summed node reward instead of adding it again in SQL

crates/store/src/localdb/node.rs

@@ -164,14 +164,16 @@ impl StorageProcessor<'_> {
         Ok(res.rows_affected())
     }
 
+    /// Stores `reward` as the node's new total; the caller has already added
+    /// the increment.
     // Do not update the `updated_at` field; this field is updated based on heartbeat messages
     // and is used to determine whether a node is alive.
     pub async fn update_node_reward_by_peer_id(
         &mut self,
         peer_id: &str,
         reward: &str,
     ) -> anyhow::Result<()> {
-        sqlx::query!(r#"UPDATE node SET reward = reward + ? WHERE peer_id = ?"#, reward, peer_id)
+        sqlx::query!(r#"UPDATE node SET reward = ? WHERE peer_id = ?"#, reward, peer_id)
             .execute(self.conn())
             .await?;
         Ok(())

node/src/scheduled_tasks/event_watch/gateway.rs

@@ -731,6 +731,24 @@ mod tests {
         }
     }
 
+    #[tokio::test]
+    async fn node_reward_is_added_once() {
+        let (db, _dir) = db().await;
+        let mut storage = db.acquire().await.unwrap();
+        let node = store::Node {
+            peer_id: "operator".into(),
+            goat_addr: "0xabc".into(),
+            ..Default::default()
+        };
+        storage.upsert_node(&node).await.unwrap();
+        for _ in 0..2 {
+            add_node_reward(&mut storage, "0xabc", U256::from(5)).await.unwrap();
+        }
+        let nodes = storage.find_nodes(&NodeQuery::default()).await.unwrap().0;
+        // Adding the increment in SQL as well would give 0 + 5, then 5 + 10.
+        assert_eq!(nodes[0].reward, "10");
+    }
+
     #[tokio::test]
     async fn a_posted_graph_unknown_locally_is_pulled_by_the_watching_roles() {
         let (db, _dir) = db().await;