From efb3af3d5c33dbdbad0fc52e95680843bb77ee72 Mon Sep 17 00:00:00 2001
From: Andrew Gerrand <adg@golang.org>
Date: Fri, 1 Nov 2013 11:18:49 +1100
Subject: [release-branch.go1.2] strings: fix Replacer bug with prefix matches
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««« CL 16880043 / 0eb6508d3e88
strings: fix Replacer bug with prefix matches

singleStringReplacer had a bug where if a string was replaced
at the beginning and no output had yet been produced into the
temp buffer before matching ended, an invalid nil check (used
as a proxy for having matched anything) meant it always
returned its input.

Fixes #6659

R=golang-dev, r
CC=golang-dev
https://golang.org/cl/16880043
»»»

R=golang-dev
CC=golang-dev
https://golang.org/cl/20570044
---
 src/pkg/strings/replace.go | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

(limited to 'src/pkg/strings/replace.go')

diff --git a/src/pkg/strings/replace.go b/src/pkg/strings/replace.go
index f63b1792c5..54c9323e04 100644
--- a/src/pkg/strings/replace.go
+++ b/src/pkg/strings/replace.go
@@ -364,17 +364,18 @@ func makeSingleStringReplacer(pattern string, value string) *singleStringReplace
 
 func (r *singleStringReplacer) Replace(s string) string {
 	var buf []byte
-	i := 0
+	i, matched := 0, false
 	for {
 		match := r.finder.next(s[i:])
 		if match == -1 {
 			break
 		}
+		matched = true
 		buf = append(buf, s[i:i+match]...)
 		buf = append(buf, r.value...)
 		i += match + len(r.finder.pattern)
 	}
-	if buf == nil {
+	if !matched {
 		return s
 	}
 	buf = append(buf, s[i:]...)
-- 
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