by benlynn:

This program (attached):

package main
import "regexp"
func main() {
  f := func(pattern, s string) {
    switch b, err := regexp.Match(pattern, []byte(s)); err {
    case nil: { println("Got a match?", b) }
    default:  { println("FAIL:", err.String()) }
    }
  }
  f("a+b", "a+b")
  f("a*b", "a*b")
  f("a?b", "a?b")
  f("+b", "+b")
  f("*b", "*b")
  f("?b", "?b")
}

outputs this:

  Got a match? false
  Got a match? true
  Got a match? true
  FAIL: closure applies to nothing
  FAIL: closure applies to nothing
  Got a match? true

but the last case should also trigger an error.

The fix is obvious and trivial. I'll post a CL shortly.

Attachments:

1. bug.go (688 bytes)