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 (file)
--- 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 (file)
--- 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