fix: signer_coordinator highest block check logic

if the highest block in their tenure is the block the coordinator is waiting on signatures for, just return Ok

Author: kantai

testnet/stacks-node/src/nakamoto_node/signer_coordinator.rs

@@ -28,7 +28,7 @@ use stacks::chainstate::burn::db::sortdb::SortitionDB;
 use stacks::chainstate::burn::{BlockSnapshot, ConsensusHash};
 use stacks::chainstate::nakamoto::{NakamotoBlock, NakamotoChainState};
 use stacks::chainstate::stacks::boot::{RewardSet, MINERS_NAME};
-use stacks::chainstate::stacks::db::StacksChainState;
+use stacks::chainstate::stacks::db::{StacksBlockHeaderTypes, StacksChainState};
 use stacks::chainstate::stacks::Error as ChainstateError;
 use stacks::codec::StacksMessageCodec;
 use stacks::libstackerdb::StackerDBChunkData;
@@ -425,7 +425,17 @@ impl SignerCoordinator {
                             &parent_tenure_header.consensus_hash,
                         )?
                         .ok_or(NakamotoNodeError::UnexpectedChainState)?;
-                    if highest_in_tenure.index_block_hash() != parent_block_id {
+                    let highest_stacks_block_id = highest_in_tenure.index_block_hash();
+                    if &highest_stacks_block_id == block_id {
+                        // the block was included in the chainstate since we last checked!
+                        let StacksBlockHeaderTypes::Nakamoto(stored_block) =
+                            highest_in_tenure.anchored_header
+                        else {
+                            error!("Nakamoto miner produced a non-nakamoto block");
+                            return Err(NakamotoNodeError::UnexpectedChainState);
+                        };
+                        return Ok(stored_block.signer_signature);
+                    } else if highest_stacks_block_id != parent_block_id {
                         info!("SignCoordinator: Exiting due to new stacks tip");
                         return Err(NakamotoNodeError::StacksTipChanged);
                     }