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Postings from June 2019
# New Ticket Created by Jamie Lokier
# Please include the string: [perl #134209]
# in the subject line of all future correspondence about this issue.
# <URL: https://rt.perl.org/Ticket/Display.html?id=134209 >
This is a bug report for perl from jamie@shareable.org,
generated with the help of perlbug 1.41 running under perl 5.28.1.
-----------------------------------------------------------------
[Please describe your issue here]
Hi,
The following short Perl program shows the error:
sub S { "A" =~ /(.)(?{})/; }
"xyz" =~ /(?:(.)(?{say $1;S()}))*/;
Output should be:
x
y
z
Actual output is:
x
A
A
This is because the value stored in $1 is incorrect.
It's not even part of the matched string!
If we change the $1 to $^N, as we might use in better quality code,
the output is wrong in the same way.
As you can imagine, breaking $1 and $^N has a severe impact on any
regex-driven parser which uses code expressions in a regex to collect
data, if the code expressions call anything that happens to do any
pattern matching itself.
Removing the (?{}) from the inner regex in S() stops this bug from
happening.
I've verified this in Perl 5.22.1, Perl 5.26.1 and Perl 5.28.1, hoping
that such a severe error would have been noticed and fixed by a later
version.
Now I am struggling to figure out how to rewrite all my parsers,
knowing that $1 and $^N are subtly unreliable in every Perl version :-/
Any advice on a clean workaround would be welcome.
(The obvious advice to use //g instead of /(...)*/ does work for
simple lists, but thhat doesn't compose as part of a larger regex
where a list of things is one part of a pattern.)
Thanks,
-- Jamie Lokier
[Please do not change anything below this line]
-----------------------------------------------------------------
---
Flags:
category=core
severity=high
---
Site configuration information for perl 5.28.1:
Configured by Ubuntu at Sun Mar 31 11:51:22 UTC 2019.
Summary of my perl5 (revision 5 version 28 subversion 1) configuration:
Platform:
osname=linux
osvers=4.9.0
archname=x86_64-linux-gnu-thread-multi
uname='linux localhost 4.9.0 #1 smp debian 4.9.0 x86_64 gnulinux '
config_args='-Dusethreads -Duselargefiles -Dcc=x86_64-linux-gnu-gcc -Dcpp=x86_64-linux-gnu-cpp -Dld=x86_64-linux-gnu-gcc -Dccflags=-DDEBIAN -Wdate-time -D_FORTIFY_SOURCE=2 -g -O2 -fdebug-prefix-map=/build/perl-IfZKzZ/perl-5.28.1=. -fstack-protector-strong -Wformat -Werror=format-security -Dldflags= -Wl,-Bsymbolic-functions -Wl,-z,relro -Dlddlflags=-shared -Wl,-Bsymbolic-functions -Wl,-z,relro -Dcccdlflags=-fPIC -Darchname=x86_64-linux-gnu -Dprefix=/usr -Dprivlib=/usr/share/perl/5.28 -Darchlib=/usr/lib/x86_64-linux-gnu/perl/5.28 -Dvendorprefix=/usr -Dvendorlib=/usr/share/perl5 -Dvendorarch=/usr/lib/x86_64-linux-gnu/perl5/5.28 -Dsiteprefix=/usr/local -Dsitelib=/usr/local/share/perl/5.28.1 -Dsitearch=/usr/local/lib/x86_64-linux-gnu/perl/5.28.1 -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 -Ui_xlocale -Uversiononly -DDEBUGGING=-g -Doptimize=-O2 -dEs -Duseshrplib -Dlibperl=libperl.so.5.28.1'
hint=recommended
useposix=true
d_sigaction=define
useithreads=define
usemultiplicity=define
use64bitint=define
use64bitall=define
uselongdouble=undef
usemymalloc=n
default_inc_excludes_dot=define
bincompat5005=undef
Compiler:
cc='x86_64-linux-gnu-gcc'
ccflags ='-D_REENTRANT -D_GNU_SOURCE -DDEBIAN -fwrapv -fno-strict-aliasing -pipe -I/usr/local/include -D_LARGEFILE_SOURCE -D_FILE_OFFSET_BITS=64'
optimize='-O2 -g'
cppflags='-D_REENTRANT -D_GNU_SOURCE -DDEBIAN -fwrapv -fno-strict-aliasing -pipe -I/usr/local/include'
ccversion=''
gccversion='8.3.0'
gccosandvers=''
intsize=4
longsize=8
ptrsize=8
doublesize=8
byteorder=12345678
doublekind=3
d_longlong=define
longlongsize=8
d_longdbl=define
longdblsize=16
longdblkind=3
ivtype='long'
ivsize=8
nvtype='double'
nvsize=8
Off_t='off_t'
lseeksize=8
alignbytes=8
prototype=define
Linker and Libraries:
ld='x86_64-linux-gnu-gcc'
ldflags =' -fstack-protector-strong -L/usr/local/lib'
libpth=/usr/local/lib /usr/lib/gcc/x86_64-linux-gnu/8/include-fixed /usr/include/x86_64-linux-gnu /usr/lib /lib/x86_64-linux-gnu /lib/../lib /usr/lib/x86_64-linux-gnu /usr/lib/../lib /lib
libs=-lgdbm -lgdbm_compat -ldb -ldl -lm -lpthread -lc -lcrypt
perllibs=-ldl -lm -lpthread -lc -lcrypt
libc=libc-2.29.so
so=so
useshrplib=true
libperl=libperl.so.5.28
gnulibc_version='2.29'
Dynamic Linking:
dlsrc=dl_dlopen.xs
dlext=so
d_dlsymun=undef
ccdlflags='-Wl,-E'
cccdlflags='-fPIC'
lddlflags='-shared -L/usr/local/lib -fstack-protector-strong'
Locally applied patches:
DEBPKG:debian/cpan_definstalldirs - Provide a sensible INSTALLDIRS default for modules installed from CPAN.
DEBPKG:debian/db_file_ver - https://bugs.debian.org/340047 Remove overly restrictive DB_File version check.
DEBPKG:debian/doc_info - Replace generic man(1) instructions with Debian-specific information.
DEBPKG:debian/enc2xs_inc - https://bugs.debian.org/290336 Tweak enc2xs to follow symlinks and ignore missing @INC directories.
DEBPKG:debian/errno_ver - https://bugs.debian.org/343351 Remove Errno version check due to upgrade problems with long-running processes.
DEBPKG:debian/libperl_embed_doc - https://bugs.debian.org/186778 Note that libperl-dev package is required for embedded linking
DEBPKG:fixes/respect_umask - Respect umask during installation
DEBPKG:debian/writable_site_dirs - Set umask approproately for site install directories
DEBPKG:debian/extutils_set_libperl_path - EU:MM: set location of libperl.a under /usr/lib
DEBPKG:debian/no_packlist_perllocal - Don't install .packlist or perllocal.pod for perl or vendor
DEBPKG:debian/fakeroot - Postpone LD_LIBRARY_PATH evaluation to the binary targets.
DEBPKG:debian/instmodsh_doc - Debian policy doesn't install .packlist files for core or vendor.
DEBPKG:debian/ld_run_path - Remove standard libs from LD_RUN_PATH as per Debian policy.
DEBPKG:debian/libnet_config_path - Set location of libnet.cfg to /etc/perl/Net as /usr may not be writable.
DEBPKG:debian/perlivp - https://bugs.debian.org/510895 Make perlivp skip include directories in /usr/local
DEBPKG:debian/squelch-locale-warnings - https://bugs.debian.org/508764 Squelch locale warnings in Debian package maintainer scripts
DEBPKG:debian/patchlevel - https://bugs.debian.org/567489 List packaged patches for 5.28.1-6 in patchlevel.h
DEBPKG:fixes/document_makemaker_ccflags - https://bugs.debian.org/628522 [rt.cpan.org #68613] Document that CCFLAGS should include $Config{ccflags}
DEBPKG:debian/find_html2text - https://bugs.debian.org/640479 Configure CPAN::Distribution with correct name of html2text
DEBPKG:debian/perl5db-x-terminal-emulator.patch - https://bugs.debian.org/668490 Invoke x-terminal-emulator rather than xterm in perl5db.pl
DEBPKG:debian/cpan-missing-site-dirs - https://bugs.debian.org/688842 Fix CPAN::FirstTime defaults with nonexisting site dirs if a parent is writable
DEBPKG:fixes/memoize_storable_nstore - [rt.cpan.org #77790] https://bugs.debian.org/587650 Memoize::Storable: respect 'nstore' option not respected
DEBPKG:debian/makemaker-pasthru - https://bugs.debian.org/758471 Pass LD settings through to subdirectories
DEBPKG:debian/makemaker-manext - https://bugs.debian.org/247370 Make EU::MakeMaker honour MANnEXT settings in generated manpage headers
DEBPKG:debian/kfreebsd-softupdates - https://bugs.debian.org/796798 Work around Debian Bug#796798
DEBPKG:fixes/autodie-scope - https://bugs.debian.org/798096 Fix a scoping issue with "no autodie" and the "system" sub
DEBPKG:fixes/memoize-pod - [rt.cpan.org #89441] Fix POD errors in Memoize
DEBPKG:debian/hurd-softupdates - https://bugs.debian.org/822735 Fix t/op/stat.t failures on hurd
DEBPKG:fixes/math_complex_doc_great_circle - https://bugs.debian.org/697567 [rt.cpan.org #114104] Math::Trig: clarify definition of great_circle_midpoint
DEBPKG:fixes/math_complex_doc_see_also - https://bugs.debian.org/697568 [rt.cpan.org #114105] Math::Trig: add missing SEE ALSO
DEBPKG:fixes/math_complex_doc_angle_units - https://bugs.debian.org/731505 [rt.cpan.org #114106] Math::Trig: document angle units
DEBPKG:fixes/cpan_web_link - https://bugs.debian.org/367291 CPAN: Add link to main CPAN web site
DEBPKG:debian/hppa_op_optimize_workaround - https://bugs.debian.org/838613 Temporarily lower the optimization of op.c on hppa due to gcc-6 problems
DEBPKG:debian/installman-utf8 - https://bugs.debian.org/840211 Generate man pages with UTF-8 characters
DEBPKG:fixes/getopt-long-4 - https://bugs.debian.org/864544 [rt.cpan.org #122068] Fix issue #122068.
DEBPKG:debian/hppa_opmini_optimize_workaround - https://bugs.debian.org/869122 Lower the optimization level of opmini.c on hppa
DEBPKG:debian/sh4_op_optimize_workaround - https://bugs.debian.org/869373 Also lower the optimization level of op.c and opmini.c on sh4
DEBPKG:debian/perldoc-pager - https://bugs.debian.org/870340 [rt.cpan.org #120229] Fix perldoc terminal escapes when sensible-pager is less
DEBPKG:debian/prune_libs - https://bugs.debian.org/128355 Prune the list of libraries wanted to what we actually need.
DEBPKG:debian/mod_paths - Tweak @INC ordering for Debian
DEBPKG:debian/configure-regen - https://bugs.debian.org/762638 Regenerate Configure et al. after probe unit changes
DEBPKG:debian/deprecate-with-apt - https://bugs.debian.org/747628 Point users to Debian packages of deprecated core modules
DEBPKG:debian/disable-stack-check - https://bugs.debian.org/902779 [perl #133327] Disable debugperl stack extension checks for binary compatibility with perl
DEBPKG:debian/gdbm-fatal - [perl #133295] https://bugs.debian.org/904005 Temporarily skip GDBM_File fatal.t for gdbm >= 1.15 compatibility
DEBPKG:fixes/storable-recursion - https://bugs.debian.org/912900 [perl #133326] [120060c] (perl #133326) fix and clarify handling of recurs_sv.
DEBPKG:fixes/caretx-fallback - https://bugs.debian.org/913347 [perl #133573] [03b94aa] RT#133573: $^X fallback when platform-specific technique fails
DEBPKG:fixes/eumm-usrmerge - https://bugs.debian.org/913637 Avoid mangling /bin non-perl shebangs on merged-/usr systems
DEBPKG:fixes/errno-include-path - [6c5080f] [perl #133662] https://bugs.debian.org/875921 Make Errno_pm.PL compatible with /usr/include/<ARCH>/errno.h
DEBPKG:fixes/kfreebsd-renameat - [a3c63a9] https://bugs.debian.org/912521 [perl #133668] Also work around renameat() kernel bug on GNU/kFreeBSD
DEBPKG:fixes/time-local-2020 - https://bugs.debian.org/915209 [rt.cpan.org #124787] Fix Time::Local tests
DEBPKG:fixes/inplace-editing-bugfix/part1 - https://bugs.debian.org/914651 (perl #133659) move argvout cleanup to a new function
DEBPKG:fixes/inplace-editing-bugfix/part2 - https://bugs.debian.org/914651 (perl #133659) tests for global destruction handling of inplace editing
DEBPKG:fixes/inplace-editing-bugfix/part3 - https://bugs.debian.org/914651 (perl #133659) make an in-place edit successful if the exit status is zero
DEBPKG:fixes/fix-manifest-failures - https://bugs.debian.org/914962 Fix t/porting/manifest.t failures when run in a foreign git checkout
DEBPKG:fixes/pipe-open-bugfix/part1 - [perl #133726] https://bugs.debian.org/916313 Always mark pipe in pipe-open as inherit-on-exec
DEBPKG:fixes/pipe-open-bugfix/part2 - [perl #133726] https://bugs.debian.org/916313 Always mark pipe in list pipe-open as inherit-on-exec
DEBPKG:fixes/storable-probing/prereq1 - [3f4cad1] Storable: fix for strawberry build failures:
DEBPKG:fixes/storable-probing/prereq2 - [perl #133411] [edf639f] (perl #133411) don't try to load Storable with -Dusecrosscompile
DEBPKG:fixes/storable-probing/disable-probing - https://bugs.debian.org/914133 [perl #133708] [2a0bbd3] (perl #133708) remove build-time probing for stack limits for Storable
DEBPKG:debian/perlbug-editor - https://bugs.debian.org/922609 Use "editor" as the default perlbug editor, as per Debian policy
DEBPKG:fixes/posix-mbrlen - [25d7b7a] https://bugs.debian.org/924517 [perl #133928] Fix POSIX::mblen mbstate_t initialization on threaded perls with glibc
---
@INC for perl 5.28.1:
/etc/perl
/usr/local/lib/x86_64-linux-gnu/perl/5.28.1
/usr/local/share/perl/5.28.1
/usr/lib/x86_64-linux-gnu/perl5/5.28
/usr/share/perl5
/usr/lib/x86_64-linux-gnu/perl/5.28
/usr/share/perl/5.28
/usr/local/lib/site_perl
/usr/lib/x86_64-linux-gnu/perl-base
---
Environment for perl 5.28.1:
HOME=/root
LANG=en_GB.UTF-8
LANGUAGE=en_GB:en_US:en
LD_LIBRARY_PATH (unset)
LOGDIR (unset)
PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:/usr/local/games:/snap/bin
PERL_BADLANG (unset)
SHELL=/bin/bash
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