bytes: Reader.WriteTo returns EOF incorrectly

[rsc]

// WriteTo implements the io.WriterTo interface.
func (r *Reader) WriteTo(w io.Writer) (n int64, err error) {
    r.prevRune = -1
    if r.i >= len(r.s) {
        return 0, io.EOF
    }

The io.EOF should be nil. This breaks:

package main

import (
    "bytes"
    "log"
    "os/exec"
)

func main() {
    cmd := exec.Command("cat")
    cmd.Stdin = bytes.NewReader(nil)
    err := cmd.Run()
    if err != nil {
        log.Fatal(err)
    }
}

Obviously there are simpler tests.

[bradfitz]

Comment 1:

Btw, this isn't related to issue #4403.  I changed this line to a panic and it didn't
panic.

[bradfitz]

Comment 2:

Sent http://golang.org/cl/6855083

Owner changed to @bradfitz.

[bradfitz]

Comment 3:

This issue was closed by revision c8fa7dc.

Status changed to Fixed.