feat(engine): set eth_syncing = true if pruner is active (paradigmx…

…yz#4063)

crates/consensus/beacon/src/engine/mod.rs

@@ -1599,13 +1599,18 @@ where
             EnginePruneEvent::Started(tip_block_number) => {
                 trace!(target: "consensus::engine", %tip_block_number, "Pruner started");
                 self.metrics.pruner_runs.increment(1);
+                // Engine can't process any FCU/payload messages from CL while we're pruning, as
+                // pruner needs an exclusive write access to the database. To prevent CL from
+                // sending us unneeded updates, we need to respond `true` on `eth_syncing` request.
+                self.sync_state_updater.update_sync_state(SyncState::Syncing);
             }
             EnginePruneEvent::TaskDropped => {
                 error!(target: "consensus::engine", "Failed to receive spawned pruner");
                 return Some(Err(BeaconConsensusEngineError::PrunerChannelClosed))
             }
             EnginePruneEvent::Finished { result } => {
                 trace!(target: "consensus::engine", ?result, "Pruner finished");
+                self.sync_state_updater.update_sync_state(SyncState::Idle);
                 match result {
                     Ok(_) => {
                         // Update the state and hashes of the blockchain tree if possible.