add event for skipping empty blocks (#493)

Author: frisitano

crates/chain-orchestrator/src/event.rs

@@ -90,6 +90,9 @@ pub enum ChainOrchestratorEvent {
     L2ConsolidatedBlockCommitted(L2BlockInfoWithL1Messages),
     /// A new block has been sequenced by the sequencer.
     BlockSequenced(ScrollBlock),
+    /// Block building was skipped because the built payload was empty and empty blocks are
+    /// disabled.
+    BlockBuildingSkipped,
     /// A new block has been signed by the signer.
     SignedBlock {
         /// The signed block.

crates/chain-orchestrator/src/lib.rs

@@ -313,6 +313,7 @@ impl<
                         .sign_block(block.clone())?;
                     return Ok(Some(ChainOrchestratorEvent::BlockSequenced(block)));
                 }
+                return Ok(Some(ChainOrchestratorEvent::BlockBuildingSkipped));
             }
         }
 

crates/node/src/add_ons/remote_block_source.rs

@@ -214,6 +214,10 @@ where
                             "Block built successfully, proceeding to next");
                         break;
                     }
+                    Some(ChainOrchestratorEvent::BlockBuildingSkipped) => {
+                        tracing::debug!(target: "scroll::remote_source", "Block building skipped (empty block)");
+                        break;
+                    }
                     Some(_) => {
                         // Ignore other events, keep waiting
                     }