regexp: limit the capacity of slices of bytes returned by FindX

This change limits the capacity of the slices of bytes returned by:

- Find
- FindAll
- FindAllSubmatch

to be the same as their length.

Fixes #30169

Change-Id: I07b632757d2bfeab42fce0d42364e2a16c597360
Reviewed-on: https://go-review.googlesource.com/c/161877
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

1 files changed, 4 insertions, 4 deletions

diff --git a/src/regexp/regexp.go b/src/regexp/regexp.go
index 38b3c86d9f..88122d4250 100644
--- a/src/regexp/regexp.go
+++ b/src/regexp/regexp.go
@@ -761,7 +761,7 @@ func (re *Regexp) Find(b []byte) []byte {
 	if a == nil {
 		return nil
 	}
-	return b[a[0]:a[1]]
+	return b[a[0]:a[1]:a[1]]
 }
 
 // FindIndex returns a two-element slice of integers defining the location of
@@ -829,7 +829,7 @@ func (re *Regexp) FindSubmatch(b []byte) [][]byte {
 	ret := make([][]byte, 1+re.numSubexp)
 	for i := range ret {
 		if 2*i < len(a) && a[2*i] >= 0 {
-			ret[i] = b[a[2*i]:a[2*i+1]]
+			ret[i] = b[a[2*i]:a[2*i+1]:a[2*i+1]]
 		}
 	}
 	return ret
@@ -1025,7 +1025,7 @@ func (re *Regexp) FindAll(b []byte, n int) [][]byte {
 		if result == nil {
 			result = make([][]byte, 0, startSize)
 		}
-		result = append(result, b[match[0]:match[1]])
+		result = append(result, b[match[0]:match[1]:match[1]])
 	})
 	return result
 }
@@ -1100,7 +1100,7 @@ func (re *Regexp) FindAllSubmatch(b []byte, n int) [][][]byte {
 		slice := make([][]byte, len(match)/2)
 		for j := range slice {
 			if match[2*j] >= 0 {
-				slice[j] = b[match[2*j]:match[2*j+1]]
+				slice[j] = b[match[2*j]:match[2*j+1]:match[2*j+1]]
 			}
 		}
 		result = append(result, slice)