null point run smoothly and wrong result

[gopherbot]

by ZhaoChengbing87:

Before filing a bug, please check whether it has been fixed since the
latest release. Search the issue tracker and check that you're running the
latest version of Go:

Run "go version" and compare against
http://golang.org/doc/devel/release.html  If a newer version of Go exists,
install it and retry what you did to reproduce the problem.

Thanks.

What does 'go version' print?

What steps reproduce the problem?
If possible, include a link to a program on play.golang.org.

1. go version go1.2 linux/amd64
2. init the regexp.Regexp with a empty string
3. post the code here


package main

import (
    "fmt"
    "regexp"
)

var (
    //fileRegexp = `chat.log`
    fileRegexp string
    reg        = regexp.MustCompile(fileRegexp)
)

func main() {
    fileRegexp = `chat.log`
    var teststring = []string{"chat.log", "a", "b", "c", "not_match"}
    for _, testcase := range teststring {
        if reg.MatchString(testcase) {
            fmt.Println(testcase, "matches", fileRegexp)
        }
    }

}


What happened?
we get answers like
  chat.log matches chat.log
  a matches chat.log
  b matches chat.log
  c matches chat.log
  not_match matches chat.log
  It is obviously wrong here.
 
What should have happened instead?
  the programme should panic or report a compile error here.
Please provide any additional information below.
  No additional information needed.

[davecheney]

Comment 1:

Everything matches the empty string. 
Thank you for taking an interest in Go, please consider discussing your experiences on
the general golang-nuts mailing list before raising an issue.
Cheers
Dave

Status changed to WorkingAsIntended.

[davecheney]

Comment 2:

Issue #7585 has been merged into this issue.

[gopherbot]

Comment 3 by ZhaoChengbing87:

I get it. I realize this is a tricky place that may lead to unexpected output.
Thank you.