feat: event emitter will now emit new_txid in-case a tx replaces another

Author: usagi32

stackslib/src/chainstate/stacks/miner.rs

@@ -1406,8 +1406,8 @@ impl<'a> StacksMicroblockBuilder<'a> {
         self.runtime.num_mined = num_txs;
 
         mem_pool.drop_txs(&invalidated_txs)?;
-        event_dispatcher.mempool_txs_dropped(invalidated_txs, MemPoolDropReason::TOO_EXPENSIVE);
-        event_dispatcher.mempool_txs_dropped(to_drop_and_blacklist, MemPoolDropReason::PROBLEMATIC);
+        event_dispatcher.mempool_txs_dropped(invalidated_txs, None, MemPoolDropReason::TOO_EXPENSIVE);
+        event_dispatcher.mempool_txs_dropped(to_drop_and_blacklist, None, MemPoolDropReason::PROBLEMATIC);
 
         if blocked {
             debug!(
@@ -2505,8 +2505,8 @@ impl StacksBlockBuilder {
         mempool.drop_txs(&invalidated_txs)?;
 
         if let Some(observer) = event_observer {
-            observer.mempool_txs_dropped(invalidated_txs, MemPoolDropReason::TOO_EXPENSIVE);
-            observer.mempool_txs_dropped(to_drop_and_blacklist, MemPoolDropReason::PROBLEMATIC);
+            observer.mempool_txs_dropped(invalidated_txs, None, MemPoolDropReason::TOO_EXPENSIVE);
+            observer.mempool_txs_dropped(to_drop_and_blacklist, None, MemPoolDropReason::PROBLEMATIC);
         }
 
         if let Err(e) = result {

stackslib/src/core/mempool.rs

@@ -390,7 +390,7 @@ pub trait ProposalCallbackReceiver: Send {
 
 pub trait MemPoolEventDispatcher {
     fn get_proposal_callback_receiver(&self) -> Option<Box<dyn ProposalCallbackReceiver>>;
-    fn mempool_txs_dropped(&self, txids: Vec<Txid>, reason: MemPoolDropReason);
+    fn mempool_txs_dropped(&self, txids: Vec<Txid>, new_txid: Option<Txid>, reason: MemPoolDropReason);
     fn mined_block_event(
         &self,
         target_burn_height: u64,
@@ -2222,7 +2222,7 @@ impl MemPoolDB {
 
         // broadcast drop event if a tx is being replaced
         if let (Some(prior_tx), Some(event_observer)) = (prior_tx, event_observer) {
-            event_observer.mempool_txs_dropped(vec![prior_tx.txid], replace_reason);
+            event_observer.mempool_txs_dropped(vec![prior_tx.txid], Some(txid), replace_reason);
         };
 
         Ok(())
@@ -2290,7 +2290,7 @@ impl MemPoolDB {
         if let Some(event_observer) = event_observer {
             let sql = "SELECT txid FROM mempool WHERE height < ?1";
             let txids = query_rows(tx, sql, args)?;
-            event_observer.mempool_txs_dropped(txids, MemPoolDropReason::STALE_COLLECT);
+            event_observer.mempool_txs_dropped(txids, None, MemPoolDropReason::STALE_COLLECT);
         }
 
         let sql = "DELETE FROM mempool WHERE height < ?1";

testnet/stacks-node/src/event_dispatcher.rs

@@ -941,9 +941,9 @@ impl ProposalCallbackReceiver for ProposalCallbackHandler {
 }
 
 impl MemPoolEventDispatcher for EventDispatcher {
-    fn mempool_txs_dropped(&self, txids: Vec<Txid>, reason: MemPoolDropReason) {
+    fn mempool_txs_dropped(&self, txids: Vec<Txid>, new_txid: Option<Txid>, reason: MemPoolDropReason) {
         if !txids.is_empty() {
-            self.process_dropped_mempool_txs(txids, reason)
+            self.process_dropped_mempool_txs(txids, new_txid, reason)
         }
     }
 
@@ -1554,7 +1554,7 @@ impl EventDispatcher {
         }
     }
 
-    pub fn process_dropped_mempool_txs(&self, txs: Vec<Txid>, reason: MemPoolDropReason) {
+    pub fn process_dropped_mempool_txs(&self, txs: Vec<Txid>, new_txid: Option<Txid>, reason: MemPoolDropReason) {
         // lazily assemble payload only if we have observers
         let interested_observers = self.filter_observers(&self.mempool_observers_lookup, true);
 
@@ -1566,11 +1566,23 @@ impl EventDispatcher {
             .into_iter()
             .map(|tx| serde_json::Value::String(format!("0x{}", &tx)))
             .collect();
-
-        let payload = json!({
-            "dropped_txids": serde_json::Value::Array(dropped_txids),
-            "reason": reason.to_string(),
-        });
+        
+        let payload = match new_txid{
+            Some(id) => {
+                json!({
+                    "dropped_txids": serde_json::Value::Array(dropped_txids),
+                    "reason": reason.to_string(),
+                    "new_txid": format!("0x{}", &id),
+                })
+            },
+            None => {
+                json!({
+                    "dropped_txids": serde_json::Value::Array(dropped_txids),
+                    "reason": reason.to_string(),
+                    "new_txid": null,
+                })
+            }
+        };
 
         for observer in interested_observers.iter() {
             observer.send_dropped_mempool_txs(&payload);