nitronode/store/database/contract_event.go (1)

20-20: ⚠️ Potential issue | 🟠 Major

Handle nullable block_hash at the model boundary.

The migration allows NULL values in block_hash (line 9: DROP NOT NULL, line 10: UPDATE...SET block_hash = NULL), but ContractEvent.BlockHash remains a non-nullable string type. While GORM converts NULL to empty string during scan, this creates an implicit and unclear contract: getters at lines 89 and 107 both call strings.TrimSpace(ev.BlockHash) without explicit null handling, making it ambiguous whether empty string represents actual empty data or a NULL from the database.

To clarify intent and prevent future bugs, change BlockHash to sql.NullString and update both getters to check Valid before accessing the string value.

Proposed fix (nullable model field + explicit normalization)

+import "database/sql"

 type ContractEvent struct {
@@
-	BlockHash       string    `gorm:"column:block_hash"`
+	BlockHash       sql.NullString `gorm:"column:block_hash"`
@@
 }

 func (s *DBStore) StoreContractEvent(ev core.BlockchainEvent) error {
 	contractEvent := &ContractEvent{
@@
-		BlockHash:       ev.BlockHash,
+		BlockHash:       sql.NullString{String: ev.BlockHash, Valid: true},
@@
 	}
@@
 }

 func (s *DBStore) GetLatestContractEventBlockHashAndNumber(contractAddress string, blockchainID uint64) (uint64, string, error) {
@@
-	return ev.BlockNumber, strings.TrimSpace(ev.BlockHash), nil
+	hash := ""
+	if ev.BlockHash.Valid {
+		hash = strings.TrimSpace(ev.BlockHash.String)
+	}
+	return ev.BlockNumber, hash, nil
 }
@@
 func (s *DBStore) GetPreviousDistinctBlockHash(contractAddress string, blockchainID uint64, belowBlockNumber uint64) (uint64, string, error) {
@@
-	return ev.BlockNumber, strings.TrimSpace(ev.BlockHash), nil
+	hash := ""
+	if ev.BlockHash.Valid {
+		hash = strings.TrimSpace(ev.BlockHash.String)
+	}
+	return ev.BlockNumber, hash, nil
 }

Also applies to lines 32–40 (StoreContractEvent), 78–90 (GetLatestContractEventBlockHashAndNumber), and 95–108 (GetPreviousDistinctBlockHash).

🤖 Prompt for AI Agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

In `@nitronode/store/database/contract_event.go` at line 20, The BlockHash field
in the ContractEvent struct is defined as a non-nullable string type, but the
database migration allows NULL values, creating an implicit and unclear
contract. Change the BlockHash field from string to sql.NullString to explicitly
represent nullable data. Then update all code that accesses BlockHash (including
the getters around lines 89 and 107, the StoreContractEvent struct around lines
32-40, and the GetLatestContractEventBlockHashAndNumber and
GetPreviousDistinctBlockHash functions) to check the Valid field of the
sql.NullString before accessing the string value instead of calling
strings.TrimSpace without null handling.