From: David Mitchell <davem@iabyn.com>
Date: Fri, 7 Sep 2012 12:32:11 +0000 (+0100)
Subject: fix a bug in handling $+[0] and unicode
X-Git-Tag: v5.17.4~130^2
X-Git-Url: https://perl5.git.perl.org/perl5.git/commitdiff_plain/3de645a82921698b4886d748e3a5a5ed98752f42

fix a bug in handling $+[0] and unicode

The code to decide what substring of a pattern target to copy for the
sake of $1, $& etc, would, in the absence of $&, only copy the minimum
range needed to cover $1,$2,...., which might be a shorter range than
what $& covers. This is fine most of the time, but, when calculating
$+[0] on a unicode string, it needs a copy of the whole part of the string
covered by $&, since it needs to convert the byte offest into a char
offset.
So to fix this, always copy as a minimum, the $& range.
I suppose we could be more clever about this: detect the presence
of @+ in the code, only do it for UTF8 etc; but this is simple
and non-fragile.
---

diff --git a/regexec.c b/regexec.c
index fa69a50..2dc2314 100644
--- a/regexec.c
+++ b/regexec.c
@@ -2592,7 +2592,7 @@ got_it:
                     && !(RX_EXTFLAGS(rx) & RXf_PMf_KEEPCOPY) /* //p */
                     && !(PL_sawampersand & SAWAMPERSAND_RIGHT)
                 ) { /* don't copy $' part of string */
-                    U32 n = (PL_sawampersand & SAWAMPERSAND_MIDDLE) ? 0 : 1;
+                    U32 n = 0;
                     max = -1;
                     /* calculate the right-most part of the string covered
                      * by a capture. Due to look-ahead, this may be to
@@ -2613,7 +2613,7 @@ got_it:
                     && !(RX_EXTFLAGS(rx) & RXf_PMf_KEEPCOPY) /* //p */
                     && !(PL_sawampersand & SAWAMPERSAND_LEFT)
                 ) { /* don't copy $` part of string */
-                    U32 n = (PL_sawampersand & SAWAMPERSAND_MIDDLE) ? 0 : 1;
+                    U32 n = 0;
                     min = max;
                     /* calculate the left-most part of the string covered
                      * by a capture. Due to look-behind, this may be to
diff --git a/t/re/re_tests b/t/re/re_tests
index 94b7a38..1aebbe6 100644
--- a/t/re/re_tests
+++ b/t/re/re_tests
@@ -163,6 +163,7 @@ ab|cd	abcd	y	$&	ab
 ()ef	def	y	$&-$1	ef-
 ()ef	def	y	$-[0]	1
 ()ef	def	y	$+[0]	3
+()\x{100}\x{1000}	d\x{100}\x{1000}	y	$+[0]	3
 ()ef	def	y	$-[1]	1
 ()ef	def	y	$+[1]	1
 *a	-	c	-	Quantifier follows nothing