fix: cast DuckDB HUGEINT to pgtype.Numeric

pgserver/iter.go

@@ -5,6 +5,7 @@ import (
 	"database/sql/driver"
 	"fmt"
 	"io"
+	"math/big"
 	"strings"
 
 	"github.com/dolthub/go-mysql-server/sql"
@@ -87,6 +88,7 @@ type SqlRowIter struct {
 
 	decimals []int
 	lists    []int
+	hugeInts []int
 }
 
 func NewSqlRowIter(rows *stdsql.Rows, schema sql.Schema) (*SqlRowIter, error) {
@@ -116,7 +118,14 @@ func NewSqlRowIter(rows *stdsql.Rows, schema sql.Schema) (*SqlRowIter, error) {
 		}
 	}
 
-	iter := &SqlRowIter{rows, columns, schema, buf, ptrs, decimals, lists}
+	var hugeInts []int
+	for i, t := range columns {
+		if t.DatabaseTypeName() == "HUGEINT" {
+			hugeInts = append(hugeInts, i)
+		}
+	}
+
+	iter := &SqlRowIter{rows, columns, schema, buf, ptrs, decimals, lists, hugeInts}
 	if logrus.GetLevel() >= logrus.DebugLevel {
 		logrus.Debugf("New " + iter.String() + "\n")
 	}
@@ -197,6 +206,21 @@ func (iter *SqlRowIter) Next(ctx *sql.Context) (sql.Row, error) {
 		iter.buffer[idx] = pgtype.FlatArray[any](list)
 	}
 
+	for _, idx := range iter.hugeInts {
+		switch v := iter.buffer[idx].(type) {
+		case nil:
+			continue
+		case *big.Int:
+			var n pgtype.Numeric
+			if err := n.Scan(v.String()); err != nil {
+				return nil, err
+			}
+			iter.buffer[idx] = n
+		default:
+			return nil, fmt.Errorf("unexpected type %T for big.Int value", v)
+		}
+	}
+
 	// Prune or fill the values to match the schema
 	width := len(iter.schema) // the desired width
 	if width == 0 {