From c63ecd6aba69e1dee2f038dac580bee1943bcea6 Mon Sep 17 00:00:00 2001
From: Daniil Polyakov <arjentix@gmail.com>
Date: Fri, 13 Feb 2026 02:05:55 +0300
Subject: [PATCH] fix: initiate sequencer with chain height from db and not
 from config genesis id

---
 common/src/block.rs       |  1 +
 sequencer_core/src/lib.rs | 54 ++++++++++++++++++++++++++++++++++++++-
 storage/src/lib.rs        |  2 ++
 3 files changed, 56 insertions(+), 1 deletion(-)

diff --git a/common/src/block.rs b/common/src/block.rs
index 91ad1175..90bbe357 100644
--- a/common/src/block.rs
+++ b/common/src/block.rs
@@ -10,6 +10,7 @@ pub type TimeStamp = u64;
 
 #[derive(Debug, Clone, BorshSerialize, BorshDeserialize)]
 pub struct BlockMeta {
+    pub id: BlockId,
     pub hash: BlockHash,
     pub msg_id: MantleMsgId,
 }
diff --git a/sequencer_core/src/lib.rs b/sequencer_core/src/lib.rs
index 31f76a0a..596ac747 100644
--- a/sequencer_core/src/lib.rs
+++ b/sequencer_core/src/lib.rs
@@ -98,6 +98,9 @@ impl<BC: BlockSettlementClientTrait, IC: IndexerClientTrait> SequencerCore<BC, I
             signing_key,
         )
         .unwrap();
+        let latest_block_meta = store
+            .latest_block_meta()
+            .expect("Failed to read latest block meta from store");
 
         #[cfg_attr(not(feature = "testnet"), allow(unused_mut))]
         let mut state = match store.get_nssa_state() {
@@ -143,7 +146,7 @@ impl<BC: BlockSettlementClientTrait, IC: IndexerClientTrait> SequencerCore<BC, I
             state,
             store,
             mempool,
-            chain_height: config.genesis_id,
+            chain_height: latest_block_meta.id,
             sequencer_config: config,
             block_settlement_client,
             indexer_client,
@@ -902,4 +905,53 @@ mod tests {
             "New block should contain the submitted transaction"
         );
     }
+
+    #[tokio::test]
+    async fn test_start_from_config_uses_db_height_not_config_genesis() {
+        let mut config = setup_sequencer_config();
+        let original_genesis_id = config.genesis_id;
+
+        // Step 1: Create initial database and produce some blocks
+        let expected_chain_height = {
+            let (mut sequencer, mempool_handle) =
+                SequencerCoreWithMockClients::start_from_config(config.clone()).await;
+
+            // Verify we start with the genesis_id from config
+            assert_eq!(sequencer.chain_height, original_genesis_id);
+
+            // Produce multiple blocks to advance chain height
+            let tx = common::test_utils::produce_dummy_empty_transaction();
+            mempool_handle.push(tx).await.unwrap();
+            sequencer
+                .produce_new_block_with_mempool_transactions()
+                .unwrap();
+
+            let tx = common::test_utils::produce_dummy_empty_transaction();
+            mempool_handle.push(tx).await.unwrap();
+            sequencer
+                .produce_new_block_with_mempool_transactions()
+                .unwrap();
+
+            // Return the current chain height (should be genesis_id + 2)
+            sequencer.chain_height
+        };
+
+        // Step 2: Modify the config to have a DIFFERENT genesis_id
+        let different_genesis_id = original_genesis_id + 100;
+        config.genesis_id = different_genesis_id;
+
+        // Step 3: Restart sequencer with the modified config (different genesis_id)
+        let (sequencer, _mempool_handle) =
+            SequencerCoreWithMockClients::start_from_config(config.clone()).await;
+
+        // Step 4: Verify chain_height comes from database, NOT from the new config.genesis_id
+        assert_eq!(
+            sequencer.chain_height, expected_chain_height,
+            "Chain height should be loaded from database metadata, not config.genesis_id"
+        );
+        assert_ne!(
+            sequencer.chain_height, different_genesis_id,
+            "Chain height should NOT match the modified config.genesis_id"
+        );
+    }
 }
diff --git a/storage/src/lib.rs b/storage/src/lib.rs
index 4077cc74..c9379e33 100644
--- a/storage/src/lib.rs
+++ b/storage/src/lib.rs
@@ -85,6 +85,7 @@ impl RocksDBIO {
             dbio.put_meta_last_block_in_db(block_id)?;
             dbio.put_meta_last_finalized_block_id(None)?;
             dbio.put_meta_latest_block_meta(&BlockMeta {
+                id: block.header.block_id,
                 hash: block.header.hash,
                 msg_id,
             })?;
@@ -425,6 +426,7 @@ impl RocksDBIO {
                 self.put_meta_last_block_in_db_batch(block.header.block_id, batch)?;
                 self.put_meta_latest_block_meta_batch(
                     &BlockMeta {
+                        id: block.header.block_id,
                         hash: block.header.hash,
                         msg_id,
                     },