Duplicate packets on start

.changelog/unreleased/bug-fixes/ibc-relayer/2093-fix-duplicate-packets-on-start.md

@@ -0,0 +1 @@
+- Fix duplicate packets being generated on start. ([#2093](https://github.com/informalsystems/ibc-rs/issues/2093))

relayer/src/worker/packet.rs

@@ -158,10 +158,7 @@ fn handle_packet_cmd<ChainA: ChainHandle, ChainB: ChainHandle>(
 
         // Handle the arrival of an event signaling that the
         // source chain has advanced to a new block.
-        WorkerCmd::NewBlock {
-            height,
-            new_block: _,
-        } => {
+        WorkerCmd::NewBlock { height, .. } => {
             // Decide if packet clearing should be scheduled.
             // Packet clearing may happen once at start,
             // and then at predefined block intervals.
@@ -172,6 +169,9 @@ fn handle_packet_cmd<ChainA: ChainHandle, ChainB: ChainHandle>(
                 clear_interval,
                 height,
             ) {
+                // Decrement the height in order to avoid clearing packets at the same
+                // height at which the packet's events were queried
+                let height = height.decrement().unwrap();
                 link.a_to_b.schedule_packet_clearing(Some(height))
             } else {
                 Ok(())