From @jimav

Created by @jimav

This is a bug report for perl from james_avera@​yahoo.com,
generated with the help of perlbug 1.39 running under perl 5.12.4.

-----------------------------------------------------------------
If $(?|...) is used in a /\G ... /xsgc pattern then the match fails.
If \G is removed -or- if $(?|...) is changed to $(?​:...) then it works.

(The matched text is at the beginning of the string so \G should not
matter in this case).

#!/usr/bin/perl
use strict; use warnings;

$_ = '{foo{bar}baz}';
if (/\G
  (?| # <--BUG HERE​: fails if (?|...) but works if (?​:...)
  # or if \G is removed
  (SomethingElse)
  | ( \{ (?​: \\. | [^\{\}\\]++ | (?-1))* \} )
  )
  /xsgc)
{
  print "MATCHED​:\n";
  print " 1=$1\n" if defined $1;
  print " 2=$2\n" if defined $2;
} else {
  print "MATCH FAILED\n";
}

Flags:
     category=core
     severity=high

Site configuration information for perl 5.12.4:

Configured by Debian Project at Tue Sep  6 08:08:24 UTC 2011.

Summary of my perl5 (revision 5 version 12 subversion 4) configuration:

   Platform:
     osname=linux, osvers=2.6.24-28-server, 
archname=x86_64-linux-gnu-thread-multi
     uname='linux allspice 2.6.24-28-server #1 smp wed aug 18 21:17:51 
utc 2010 x86_64 x86_64 x86_64 gnulinux '
     config_args='-Dusethreads -Duselargefiles -Dccflags=-DDEBIAN 
-Dcccdlflags=-fPIC -Darchname=x86_64-linux-gnu -Dprefix=/usr 
-Dprivlib=/usr/share/perl/5.12 -Darchlib=/usr/lib/perl/5.12 
-Dvendorprefix=/usr -Dvendorlib=/usr/share/perl5 
-Dvendorarch=/usr/lib/perl5 -Dsiteprefix=/usr/local 
-Dsitelib=/usr/local/share/perl/5.12.4 
-Dsitearch=/usr/local/lib/perl/5.12.4 -Dman1dir=/usr/share/man/man1 
-Dman3dir=/usr/share/man/man3 -Dsiteman1dir=/usr/local/man/man1 
-Dsiteman3dir=/usr/local/man/man3 -Duse64bitint -Dman1ext=1 
-Dman3ext=3perl -Dpager=/usr/bin/sensible-pager -Uafs -Ud_csh -Ud_ualarm 
-Uusesfio -Uusenm -Ui_libutil -DDEBUGGING=-g -Doptimize=-O2 -Duseshrplib 
-Dlibperl=libperl.so.5.12.4 -des'
     hint=recommended, useposix=true, d_sigaction=define
     useithreads=define, usemultiplicity=define
     useperlio=define, d_sfio=undef, uselargefiles=define, usesocks=undef
     use64bitint=define, use64bitall=define, uselongdouble=undef
     usemymalloc=n, bincompat5005=undef
   Compiler:
     cc='cc', ccflags ='-D_REENTRANT -D_GNU_SOURCE -DDEBIAN 
-fno-strict-aliasing -pipe -fstack-protector -I/usr/local/include 
-D_LARGEFILE_SOURCE -D_FILE_OFFSET_BITS=64',
     optimize='-O2 -g',
     cppflags='-D_REENTRANT -D_GNU_SOURCE -DDEBIAN -fno-strict-aliasing 
-pipe -fstack-protector -I/usr/local/include'
     ccversion='', gccversion='4.6.1', gccosandvers=''
     intsize=4, longsize=8, ptrsize=8, doublesize=8, byteorder=12345678
     d_longlong=define, longlongsize=8, d_longdbl=define, longdblsize=16
     ivtype='long', ivsize=8, nvtype='double', nvsize=8, Off_t='off_t', 
lseeksize=8
     alignbytes=8, prototype=define
   Linker and Libraries:
     ld='cc', ldflags =' -fstack-protector -L/usr/local/lib'
     libpth=/usr/local/lib /lib/x86_64-linux-gnu /lib/../lib 
/usr/lib/x86_64-linux-gnu /usr/lib/../lib /lib /usr/lib
     libs=-lgdbm -lgdbm_compat -ldb -ldl -lm -lpthread -lc -lcrypt
     perllibs=-ldl -lm -lpthread -lc -lcrypt
     libc=, so=so, useshrplib=true, libperl=libperl.so.5.12.4
     gnulibc_version='2.13'
   Dynamic Linking:
     dlsrc=dl_dlopen.xs, dlext=so, d_dlsymun=undef, ccdlflags='-Wl,-E'
     cccdlflags='-fPIC', lddlflags='-shared -O2 -g -L/usr/local/lib 
-fstack-protector'

Locally applied patches:



@INC for perl 5.12.4:
     /home/jima/local/share/perl/5.12.4
     /home/jima/local/share/perl
     /home/jima/lib/perl
     /etc/perl
     /usr/local/lib/perl/5.12.4
     /usr/local/share/perl/5.12.4
     /usr/lib/perl5
     /usr/share/perl5
     /usr/lib/perl/5.12
     /usr/share/perl/5.12
     /usr/local/lib/site_perl
     .


Environment for perl 5.12.4:
     HOME=/home/jima
     LANG=en_US.UTF-8
     LANGUAGE (unset)
     LD_LIBRARY_PATH=/home/jima/local/lib
     LOGDIR (unset)
 
PATH=/home/jima/bin:/home/jima/local/bin:/home/jima/jima_tools/linux86_64/bin:/usr/bin:/bin:/usr/sbin:/sbin:/usr/bin/X11:/usr/local/bin:/opt/openoffice.org3/program:/usr/lib/lightdm/lightdm:/usr/local/sbin:/usr/games:.
     PERL5LIB=/home/jima/local/share/perl:/home/jima/lib/perl
     PERL_BADLANG (unset)
     SHELL=/bin/bash

From @demerphq

Hrm, this is an unfortunate side effect of how the implementation of
C< (?|..) > and (?-1) work together. The \G is actually irrelevant as
without it the pattern matches at a different place and does not use (?
-1) to match.

I had hoped that named captures would solve this problem, but they suffer
from the same thing. I will investigate further.

The RT System itself - Status changed from 'new' to 'open'

From @demerphq

On 18 June 2012 19​:53, yves orton via RT <perlbug-followup@​perl.org> wrote​:

Hrm, this is an unfortunate side effect of how the implementation of
C< (?|..) > and (?-1) work together.  The \G is actually irrelevant as
without it the pattern matches at a different place and does not use (?
-1) to match.

I had hoped that named captures would solve this problem, but they suffer
from the same thing. I will investigate further.

I also noticed a weird parse bug if you write the original pattern
with (?&1) which needs to be fixed as well.

Yves

--
perl -Mre=debug -e "/just|another|perl|hacker/"

From @cpansprout

On Mon Jun 18 10​:55​:15 2012, demerphq wrote​:

On 18 June 2012 19​:53, yves orton via RT <perlbug-followup@​perl.org>
wrote​:

Hrm, this is an unfortunate side effect of how the implementation of
C< (?|..) > and (?-1) work together. �The \G is actually irrelevant as
without it the pattern matches at a different place and does not use (?
-1) to match.

I had hoped that named captures would solve this problem, but they
suffer
from the same thing. I will investigate further.

I also noticed a weird parse bug if you write the original pattern
with (?&1) which needs to be fixed as well.

You mean bug #101666?

--

Father Chrysostomos

From @demerphq

On Mon Jun 18 12​:57​:33 2012, sprout wrote​:

On Mon Jun 18 10​:55​:15 2012, demerphq wrote​:

On 18 June 2012 19​:53, yves orton via RT <perlbug-followup@​perl.org>
wrote​:

Hrm, this is an unfortunate side effect of how the implementation
of
C< (?|..) > and (?-1) work together. �The \G is actually
irrelevant as
without it the pattern matches at a different place and does not
use (?
-1) to match.

I had hoped that named captures would solve this problem, but they
suffer
from the same thing. I will investigate further.

I also noticed a weird parse bug if you write the original pattern
with (?&1) which needs to be fixed as well.

You mean bug #101666?

Yes, thanks for the pointer. I have now resolved the problem and closed
that ticket.

cheers,
yves

From @jkeenan

On Sat Jun 23 05​:30​:03 2012, demerphq wrote​:

On Mon Jun 18 12​:57​:33 2012, sprout wrote​:

On Mon Jun 18 10​:55​:15 2012, demerphq wrote​:

On 18 June 2012 19​:53, yves orton via RT <perlbug-followup@​perl.org>
wrote​:

Hrm, this is an unfortunate side effect of how the implementation
of
C< (?|..) > and (?-1) work together. �The \G is actually
irrelevant as
without it the pattern matches at a different place and does not
use (?
-1) to match.

I had hoped that named captures would solve this problem, but they
suffer
from the same thing. I will investigate further.

I also noticed a weird parse bug if you write the original pattern
with (?&1) which needs to be fixed as well.

You mean bug #101666?

Yes, thanks for the pointer. I have now resolved the problem and closed
that ticket.

cheers,
yves

Yves, can we get an update on the status of *this* RT?

Thank you very much.
Jim Keenan