strings.NewReplacer position dependent bug for single substitutions

[gopherbot]

by orthopteroid:

The string replacer appears to have a problem with single replacements that would happen
at the start of a string:

s := "Hello World"
fmt.Println(strings.NewReplacer("Hello","").Replace(s))
fmt.Println(strings.NewReplacer("World","").Replace(s))

Produces:

Hello World
Hello 

Which is incorrect. I would expect:

 World
Hello 

Whereas, when I add another substitution for replacement:

s := "Hello World"
fmt.Println(strings.NewReplacer("Hello","","l","").Replace(s))
fmt.Println(strings.NewReplacer("World","","l","").Replace(s))

Producing a correct result:

 Word
Heo 

Alternatively, if I perform a single replacement which is not at the start of the string:

s := "Hello World"
fmt.Println(strings.NewReplacer("ello","").Replace(s))
fmt.Println(strings.NewReplacer("orld","").Replace(s))

Produces the correct result:

H World
Hello W

So, the problem appears to be with single substitution when the match is at the start of
the string. I have noticed that strings.NewReplacer tries to handle single substitutions
as a special case... perhaps that code has a problem?

--------------
http://play.golang.org/p/Hj1V9d8fAj
go version devel +f4d1cb8d9a91 Thu Sep 19 22:34:33 2013 +1000 linux/386

[robpike]

Comment 1:

Status changed to Duplicate.

Merged into issue #6659.