Go panic: extra delimiter at end of line - csv

Question

I'm reading the MaxMind GeoIP Lite City locations CSV file using Go:
csvFile, err := os.Open("/path/GeoLiteCity_20130702/GeoLiteCity-Location.csv")
defer csvFile.Close()
if err != nil {
panic(err)
}
csvf := csv.NewReader(csvFile)
csvf.Read() // skip header row
for {
fields, err := csvf.Read()
if err == io.EOF {
break
} else if err != nil {
panic(err)
}
// does nothing yet
}
The error I'm getting is:
panic: line 2, column 22: extra delimiter at end of line
goroutine 1 [running]: main.main()
/path/myprogram.go:239
+0x108f
goroutine 2 [runnable]: exit status 2
The file is quite long, but starts with these lines:
locId,country,region,city,postalCode,latitude,longitude,metroCode,areaCode
1,O1,,,,0.0000,0.0000,,
2,AP,,,,35.0000,105.0000,,
3,EU,,,,47.0000,8.0000,,
4,AD,,,,42.5000,1.5000,,
5,AE,,,,24.0000,54.0000,,
6,AF,,,,33.0000,65.0000,,
7,AG,,,,17.0500,-61.8000,,
8,AI,,,,18.2500,-63.1667,,
9,AL,,,,41.0000,20.0000,,
It appears to be properly formatted. Each row has 9 fields.
Line 239 is my line invoking the panic, panic(err). As you can see, it's failing on line 2 of the CSV file, which happens in the first iteration of the loop (line 1 is read before the loop, to skip the header row). Column 22 of line 2 is the second-to-last comma.
Am I missing something here? I don't see any trailing comma... (clarification: the commas at the end of each line must be there to indicate empty field values, so they're not trailing, as in, extra.)
UPDATE: The gophers have resolved this issue and the fix ships with Go 1.1.2.

Answer 1

There are even two trailing commas on each line.
Try setting csv.Reader.TrailingComma = true.
It really often helps taking a look at the source or at least the package documentation :-)

Answer 2

Here is a complete example for you. The key is csvf.TrailingComma = true.
package main
import (
"bytes"
"encoding/csv"
"fmt"
"io"
)
var csvData = `locId,country,region,city,postalCode,latitude,longitude,metroCode,areaCode
1,O1,,,,0.0000,0.0000,,
2,AP,,,,35.0000,105.0000,,
3,EU,,,,47.0000,8.0000,,
4,AD,,,,42.5000,1.5000,,
5,AE,,,,24.0000,54.0000,,
6,AF,,,,33.0000,65.0000,,
7,AG,,,,17.0500,-61.8000,,
8,AI,,,,18.2500,-63.1667,,
9,AL,,,,41.0000,20.0000,,
`
func main() {
csvFile := bytes.NewBufferString(csvData)
csvf := csv.NewReader(csvFile)
csvf.TrailingComma = true
csvf.Read() // skip header row
for {
fields, err := csvf.Read()
if err == io.EOF {
break
} else if err != nil {
panic(err)
}
// does nothing yet
fmt.Println(fields)
}
}