Opening a file with os.O_RDWR | os.O_TRUNC produces an empty file after writing.

[gopherbot]

by gauge2:

Before filing a bug, please check whether it has been fixed since
the latest release: run "hg pull -u" and retry what you did to
reproduce the problem.  Thanks.

What steps will reproduce the problem?
1. Have a file with data in it.
2. Open the file with os.O_RDWR | os.O_TRUNC flags.
3. Write some new data to the file.
4. Close the file.
5. Notice that the file is empty.

What is the expected output?
The file will be truncated and then the new data will be written to the blank file.

What do you see instead?
A Blank file with no data in it.

Which compiler are you using (5g, 6g, 8g, gccgo)?
6g

Which operating system are you using?
Ubuntu Unity

Which revision are you using?  (hg identify)
c98449d685d2 weekly/weekly.2011-05-22

[peterGo]

Comment 1:

If you run this program, what is your output?
package main
import (
    "fmt"
    "io/ioutil"
    "os"
)
func write(f *os.File, o string) os.Error {
    fn := f.Name()
    _, err := f.WriteString(fn + " : " + o)
    if err != nil {
        return err
    }
    err = f.Close()
    if err != nil {
        return err
    }
    data, err := ioutil.ReadFile(fn)
    if err != nil {
        return err
    }
    fmt.Println(string(data))
    return nil
}
func main() {
    fn := "2002.txt"
    f, err := os.Create(fn)
    if err != nil {
        fmt.Println(err)
        os.Exit(1)
    }
    err = write(f, "Create")
    if err != nil {
        fmt.Println(err)
    }
    f, err = os.OpenFile(fn, os.O_RDWR|os.O_TRUNC, 0666)
    if err != nil {
        fmt.Println(err)
        os.Exit(1)
    }
    err = write(f, "OpenFile")
    if err != nil {
        fmt.Println(err)
    }
}
Output:
2002.txt : Create
2002.txt : OpenFile

[gopherbot]

Comment 2 by gauge2:

Yes you can close this.  I really thought I had found a bug here.  I applogize deeply
for reporting this.  This works for me.  I must have done something small.

[griesemer]

Comment 3:

Status changed to Invalid.