fix: make Rows.Close to drain messages

driver/pgdriver/driver.go

@@ -385,7 +385,9 @@ func (r *rows) Close() error {
 
 	for {
 		switch err := r.Next(nil); err {
-		case nil, io.EOF:
+		case nil:
+			// keep going
+		case io.EOF:
 			return nil
 		default: // unexpected error
 			_ = r.cn.Close()
@@ -473,7 +475,7 @@ func (r *rows) readDataRow(rd *reader, dest []driver.Value) error {
 		return err
 	}
 
-	if len(dest) != int(numCol) {
+	if dest != nil && len(dest) != int(numCol) {
 		return fmt.Errorf("pgdriver: query returned %d columns, but Scan dest has %d items",
 			numCol, len(dest))
 	}

driver/pgdriver/driver_test.go

@@ -276,6 +276,18 @@ func TestStatementTimeout(t *testing.T) {
 	require.True(t, pgerr.StatementTimeout())
 }
 
+func TestPartialScan(t *testing.T) {
+	db := sqlDB()
+	defer db.Close()
+
+	for i := 0; i < 10; i++ {
+		var num int
+		err := db.QueryRow("select generate_series(0, 10)").Scan(&num)
+		require.NoError(t, err)
+		require.Equal(t, 0, num)
+	}
+}
+
 func sqlDB() *sql.DB {
 	db, err := sql.Open("pg", dsn())
 	if err != nil {
@@ -287,7 +299,7 @@ func sqlDB() *sql.DB {
 func dsn() string {
 	dsn := os.Getenv("PG")
 	if dsn == "" {
-		dsn = "postgres://postgres:@localhost:5432/test?sslmode=disable"
+		dsn = "postgres://postgres:postgres@localhost:5432/test?sslmode=disable"
 	}
 	return dsn
 }

driver/pgdriver/proto.go

@@ -22,6 +22,7 @@ import (
 )
 
 // https://www.postgresql.org/docs/current/protocol-message-formats.html
+//
 //nolint:deadcode,varcheck,unused
 const (
 	commandCompleteMsg  = 'C'