fix: make retry attempts respect current slot number (#108)

# fix: make retry attempts respect current slot number 

Retry attempts were happening but if the slot changed in the middle of a retry attempt, it wouldn't recognize it and would get into an error loop, exhausting all retry attempts on an obviously incorrect block.

Instead, this PR checks the initial slot number and each retry attempt will only happen if the slot is still valid.

Closes ENG-1127

Author: dylanlott

src/tasks/submit/task.rs

@@ -130,9 +130,9 @@ impl SubmitTask {
         retry_limit: usize,
     ) -> eyre::Result<ControlFlow> {
         let submitting_start_time = Instant::now();
-
-        let (current_slot, start, end) = self.calculate_slot_window();
-        debug!(current_slot, start, end, "calculating target slot window");
+        let now = utils::now();
+        let (expected_slot, start, end) = self.calculate_slot_window();
+        debug!(expected_slot, start, end, now, "calculating target slot window");
 
         let mut req = bumpable.req().clone();
 
@@ -147,6 +147,9 @@ impl SubmitTask {
             let inbound_result = match self.send_transaction(req).instrument(span.clone()).await {
                 Ok(control_flow) => control_flow,
                 Err(error) => {
+                    if let Some(value) = self.slot_still_valid(expected_slot) {
+                        return value;
+                    }
                     // Log error and retry
                     error!(%error, "error handling inbound block");
                     ControlFlow::Retry
@@ -157,6 +160,9 @@ impl SubmitTask {
 
             match inbound_result {
                 ControlFlow::Retry => {
+                    if let Some(value) = self.slot_still_valid(expected_slot) {
+                        return value;
+                    }
                     // bump the req
                     req = bumpable.bumped();
                     if bumpable.bump_count() > retry_limit {
@@ -192,6 +198,19 @@ impl SubmitTask {
         Ok(result)
     }
 
+    /// Checks if a slot is still valid during submission retries.
+    fn slot_still_valid(&self, initial_slot: u64) -> Option<Result<ControlFlow, eyre::Error>> {
+        let (current_slot, _, _) = self.calculate_slot_window();
+        if current_slot != initial_slot {
+            // If the slot has changed, skip the block
+            debug!(current_slot, initial_slot, "slot changed before submission - skipping block");
+            counter!("builder.slot_missed").increment(1);
+            return Some(Ok(ControlFlow::Skip));
+        }
+        debug!(current_slot, "slot still valid - continuing submission");
+        None
+    }
+
     /// Calculates and returns the slot number and its start and end timestamps for the current instant.
     fn calculate_slot_window(&self) -> (u64, u64, u64) {
         let now_ts = utils::now();