fix: TransactionHeader serialization (#1701)

* fix: TransactionHeader db serialization fix

* docs: update changelog

Author: juan518munoz

CHANGELOG.md

@@ -9,6 +9,7 @@
 - Validator now persists validated transactions ([#1614](https://github.com/0xMiden/miden-node/pull/1614)).
 - [BREAKING] Remove `SynState` and introduce `SyncChainMmr` ([#1591](https://github.com/0xMiden/miden-node/issues/1591)).
 - Introduce `SyncChainMmr` RPC endpoint to sync chain MMR deltas within specified block ranges ([#1591](https://github.com/0xMiden/miden-node/issues/1591)).
+- Fixed `TransactionHeader` serialization for row insertion on database & fixed transaction cursor on retrievals ([#1701](https://github.com/0xMiden/miden-node/issues/1701)).
 
 ### Changes
 

crates/store/src/db/models/queries/transactions.rs

@@ -125,11 +125,25 @@ impl TransactionSummaryRowInsert {
     ) -> Self {
         const HEADER_BASE_SIZE: usize = 4 + 32 + 16 + 64; // block_num + tx_id + account_id + commitments
 
-        // Serialize input notes using binary format (store nullifiers)
-        let nullifiers_binary = transaction_header.input_notes().to_bytes();
+        // Extract nullifiers from input notes and serialize them.
+        // We only store the nullifiers (not the full `InputNoteCommitment`) since
+        // that's all that's needed when reading back `TransactionRecords`.
+        let nullifiers: Vec<Nullifier> = transaction_header
+            .input_notes()
+            .iter()
+            .map(miden_protocol::transaction::InputNoteCommitment::nullifier)
+            .collect();
+        let nullifiers_binary = nullifiers.to_bytes();
 
-        // Serialize output notes using binary format (store note IDs)
-        let output_notes_binary = transaction_header.output_notes().to_bytes();
+        // Extract note IDs from output note headers and serialize them.
+        // We only store the `NoteId`s (not the full `NoteHeader` with metadata) since
+        // that's all that's needed when reading back `TransactionRecords`.
+        let output_note_ids: Vec<NoteId> = transaction_header
+            .output_notes()
+            .iter()
+            .map(miden_protocol::note::NoteHeader::id)
+            .collect();
+        let output_notes_binary = output_note_ids.to_bytes();
 
         // Manually calculate the estimated size of the transaction header to avoid
         // the cost of serialization. The size estimation includes:
@@ -269,26 +283,20 @@ pub fn select_transactions_records(
 
         // Add transactions from this chunk one by one until we hit the limit
         let mut added_from_chunk = 0;
-        let mut last_added_tx: Option<TransactionRecordRaw> = None;
 
         for tx in chunk {
             if total_size + tx.size_in_bytes <= max_payload_bytes {
                 total_size += tx.size_in_bytes;
-                last_added_tx = Some(tx);
+                last_block_num = Some(tx.block_num);
+                last_transaction_id = Some(tx.transaction_id.clone());
+                all_transactions.push(tx);
                 added_from_chunk += 1;
             } else {
                 // Can't fit this transaction, stop here
                 break;
             }
         }
 
-        // Update cursor position only for the last transaction that was actually added
-        if let Some(tx) = last_added_tx {
-            last_block_num = Some(tx.block_num);
-            last_transaction_id = Some(tx.transaction_id.clone());
-            all_transactions.push(tx);
-        }
-
         // Break if chunk incomplete (size limit hit or data exhausted)
         if added_from_chunk < NUM_TXS_PER_CHUNK {
             break;

crates/store/src/db/tests.rs

@@ -2398,3 +2398,81 @@ fn test_prune_history() {
         "is_latest=true entry should be retained even if old"
     );
 }
+
+#[test]
+#[miden_node_test_macro::enable_logging]
+fn db_roundtrip_transactions() {
+    let mut conn = create_db();
+    let block_num = BlockNumber::from(1);
+    create_block(&mut conn, block_num);
+
+    let account_id = AccountId::try_from(ACCOUNT_ID_PRIVATE_SENDER).unwrap();
+    queries::upsert_accounts(&mut conn, &[mock_block_account_update(account_id, 0)], block_num)
+        .unwrap();
+
+    // Build two transaction headers with distinct data
+    let tx1 = mock_block_transaction(account_id, 1);
+    let tx2 = mock_block_transaction(account_id, 2);
+    let ordered = OrderedTransactionHeaders::new_unchecked(vec![tx1.clone(), tx2.clone()]);
+
+    // Insert
+    let count = queries::insert_transactions(&mut conn, block_num, &ordered).unwrap();
+    assert_eq!(count, 2, "Should insert 2 transactions");
+
+    // Retrieve
+    let (last_block, records) = queries::select_transactions_records(
+        &mut conn,
+        &[account_id],
+        BlockNumber::GENESIS..=block_num,
+    )
+    .unwrap();
+    assert_eq!(last_block, block_num, "Last block should match");
+    assert_eq!(records.len(), 2, "Should retrieve 2 transactions");
+
+    // Verify each transaction roundtrips correctly.
+    // Records are ordered by (block_num, transaction_id), so match by ID.
+    let originals = [&tx1, &tx2];
+    for record in &records {
+        let original = originals
+            .iter()
+            .find(|tx| tx.id() == record.transaction_id)
+            .expect("Retrieved transaction should match one of the originals");
+        assert_eq!(
+            record.transaction_id,
+            original.id(),
+            "TransactionId DB roundtrip must be symmetric"
+        );
+        assert_eq!(
+            record.account_id,
+            original.account_id(),
+            "AccountId DB roundtrip must be symmetric"
+        );
+        assert_eq!(record.block_num, block_num, "Block number must match");
+        assert_eq!(
+            record.initial_state_commitment,
+            original.initial_state_commitment(),
+            "Initial state commitment DB roundtrip must be symmetric"
+        );
+        assert_eq!(
+            record.final_state_commitment,
+            original.final_state_commitment(),
+            "Final state commitment DB roundtrip must be symmetric"
+        );
+
+        // Input notes are stored as nullifiers only
+        let expected_nullifiers: Vec<Nullifier> =
+            original.input_notes().iter().map(InputNoteCommitment::nullifier).collect();
+        assert_eq!(
+            record.nullifiers, expected_nullifiers,
+            "Nullifiers (from input notes) DB roundtrip must be symmetric"
+        );
+
+        // Output notes are stored as note IDs only
+        let expected_note_ids: Vec<NoteId> =
+            original.output_notes().iter().map(NoteHeader::id).collect();
+        assert_eq!(
+            record.output_notes, expected_note_ids,
+            "Output note IDs DB roundtrip must be symmetric"
+        );
+    }
+}