[Go] [Flightsql Driver] Empty Resultset triggers "Index out of range" error

[miguelpragier]

Describe the bug, including details regarding any error messages, version, and platform.

Description

When having an empty resultset, the driver tries to include an empty record referece, that cannot be scanned.

So, any operation that relies on the returned *Rows will trigger a "Index out of Range" error.

We wrote a patch that prevents empty records to be appended to the resultset.

Further Details

The error is detected here, when r.currentRecord is mistankely 1, when should be zero:

At: /flight/flightsql/driver/driver.go:87

func (r *Rows) Next(dest []driver.Value) error {
	if r.currentRecord >= len(r.records) {
		return io.EOF
	}
	record := r.records[r.currentRecord]

	if int64(r.currentRow) >= record.NumRows() { // IS TRIGGERED HERE
		return ErrOutOfRange
	}

But happens here:

At: /flight/flightsql/driver/driver.go:492

	for reader.Next() {
		record := reader.Record()
		record.Retain()
		records = append(records, record) // BUT HAPPENS HERE
	}

Platform, Arrow/Flight & Go

OS: Linux
Arrow Driver: github.com/apache/arrow/go/v14/arrow/flight/flightsql/driver
Go Version: go1.21.4 linux/amd64

Component(s)

Go