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[perl #22354] s/// flags influence regex use in the replacement body

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From:
perlbug-followup
Date:
May 29, 2003 07:59
Subject:
[perl #22354] s/// flags influence regex use in the replacement body
Message ID:
rt-22354-58318.15.6536873334967@rt.perl.org
# New Ticket Created by  perl-5.8.0@ton.iguana.be 
# Please include the string:  [perl #22354]
# in the subject line of all future correspondence about this issue. 
# <URL: http://rt.perl.org/rt2/Ticket/Display.html?id=22354 >



This is a bug report for perl from perl-5.8.0@ton.iguana.be,
generated with the help of perlbug 1.34 running under perl v5.8.0.


-----------------------------------------------------------------
[Please enter your report here]

This code:
    perl -wle '
sub fun {
    $a = shift;
    print "fun(<$a>)";
    print "unexpectdly matched $& at position @-" if /^de/
}
$_ = "ab\nde";
s/^([\w\W]*)/fun("$1")/e'

outputs (as expected):
fun(<ab
de>)

However, this:

    perl -wle '
sub fun {
    $a = shift;
    print "fun(<$a>)";
    print "unexpectdly matched $& at position @-" if /^de/
}
$_ = "ab\nde";
s/^([\w\W]*)/fun("$1")/em'

outputs:

fun(<ab
de>)
unexpectdly matched de at position 3

The only difference is the m modifier on the s///
I didn't expect the "non-reentrant" regex problems here. Until now I
though the replacement part of a s/// was safe.

Speculation:
It seems that m modifier propagates to the regex that's used in fun() which
gets called from the body.
Presumably one or more modifiers need localizing.

[Please do not change anything below this line]
-----------------------------------------------------------------
---
Flags:
    category=core
    severity=medium
---
Site configuration information for perl v5.8.0:

Configured by ton at Tue Nov 12 01:56:18 CET 2002.

Summary of my perl5 (revision 5.0 version 8 subversion 0) configuration:
  Platform:
    osname=linux, osvers=2.4.19, archname=i686-linux-thread-multi-64int-ld
    uname='linux quasar 2.4.19 #5 wed oct 2 02:34:25 cest 2002 i686 unknown '
    config_args=''
    hint=recommended, useposix=true, d_sigaction=define
    usethreads=define use5005threads=undef useithreads=define usemultiplicity=define
    useperlio=define d_sfio=undef uselargefiles=define usesocks=undef
    use64bitint=define use64bitall=undef uselongdouble=define
    usemymalloc=y, bincompat5005=undef
  Compiler:
    cc='cc', ccflags ='-D_REENTRANT -D_GNU_SOURCE -fno-strict-aliasing -I/usr/local/include -D_LARGEFILE_SOURCE -D_FILE_OFFSET_BITS=64',
    optimize='-O2 -fomit-frame-pointer',
    cppflags='-D_REENTRANT -D_GNU_SOURCE -fno-strict-aliasing -I/usr/local/include'
    ccversion='', gccversion='2.95.3 20010315 (release)', gccosandvers=''
    intsize=4, longsize=4, ptrsize=4, doublesize=8, byteorder=12345678
    d_longlong=define, longlongsize=8, d_longdbl=define, longdblsize=12
    ivtype='long long', ivsize=8, nvtype='long double', nvsize=12, Off_t='off_t', lseeksize=8
    alignbytes=4, prototype=define
  Linker and Libraries:
    ld='cc', ldflags =' -L/usr/local/lib'
    libpth=/usr/local/lib /lib /usr/lib
    libs=-lnsl -lndbm -ldb -ldl -lm -lpthread -lc -lposix -lcrypt -lutil
    perllibs=-lnsl -ldl -lm -lpthread -lc -lposix -lcrypt -lutil
    libc=/lib/libc-2.2.4.so, so=so, useshrplib=false, libperl=libperl.a
    gnulibc_version='2.2.4'
  Dynamic Linking:
    dlsrc=dl_dlopen.xs, dlext=so, d_dlsymun=undef, ccdlflags='-rdynamic'
    cccdlflags='-fpic', lddlflags='-shared -L/usr/local/lib'

Locally applied patches:
    

---
@INC for perl v5.8.0:
    /usr/lib/perl5/5.8.0/i686-linux-thread-multi-64int-ld
    /usr/lib/perl5/5.8.0
    /usr/lib/perl5/site_perl/5.8.0/i686-linux-thread-multi-64int-ld
    /usr/lib/perl5/site_perl/5.8.0
    /usr/lib/perl5/site_perl
    .

---
Environment for perl v5.8.0:
    HOME=/home/ton
    LANG (unset)
    LANGUAGE (unset)
    LD_LIBRARY_PATH (unset)
    LOGDIR (unset)
    PATH=/home/ton/bin.Linux:/home/ton/bin:/home/ton/bin.SampleSetup:/usr/local/bin:/usr/local/sbin:/usr/local/jre/bin:/home/oracle/product/9.0.1/bin:/usr/local/ar/bin:/usr/games/bin:/usr/X11R6/bin:/usr/share/bin:/usr/bin:/usr/sbin:/bin:/sbin:.
    PERL_BADLANG (unset)
    SHELL=/bin/bash


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