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[BUG] warnings causing segfault

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From:
Dan Brook
Date:
May 14, 2003 08:48
Subject:
[BUG] warnings causing segfault
Message ID:
20030514164818.18a92b10.dbrook@easyspace.com
With this simple package (also attached)

package ImportDemo;

use strict;
use warnings;

sub import {
  my $cur  = shift;
  my $dest = caller;

  for(@_) {
    warn qq[\$main::{"${dest}::"}{$_} = \$main::{"${cur}::"}{$_}\n];
    $main::{"${dest}::"}{$_} = $main::{"${cur}::"}{$_};
  }
} 
  
1;

And the running of the below code perl segfaults

$localhost.dan(1.455, "bleadperl") ./perl -Ilib -e 'BEGIN {  
  use ImportDemo; 
  { package foo::bar; @ISA="ImportDemo"; sub baz {} } 
  foo::bar->import("baz")
}'
$main::{"main::"}{baz} = $main::{"foo::bar::"}{baz}
Segmentation fault

Now if this exact code is run after outside a BEGIN *or* the package
doing the importing is not nested (i.e no '::') then the segfault
doesn't
occur e.g

## not in a BEGIN block
$localhost.dan(1.482, "bleadperl") ./perl -Ilib -e '{  
  use ImportDemo; 
  { package foo::bar; @ISA="ImportDemo"; sub baz {} } 
  foo::bar->import("baz")
}'
$main::{"main::"}{baz} = $main::{"foo::bar::"}{baz}

## package name isn't nested
$localhost.dan(1.483, "bleadperl") ./perl -Ilib -e 'BEGIN {  
  use ImportDemo; 
  { package foo; @ISA="ImportDemo"; sub baz {} } 
  foo->import("baz")
}'
$main::{"main::"}{baz} = $main::{"foo::"}{baz}

But if C<use warnings;> is removed from C<ImportDemo> and the first
code example is used then the segfault is nowhere to be seen.

I've found this to occur in 5.6.1, 5.8.0 and bleadperl (-V below).

Dan

### 5.6.1 ###
Summary of my perl5 (revision 5.0 version 6 subversion 1) configuration:
  Platform:
    osname=linux, osvers=2.4.17-0.13smp, archname=i386-linux
    uname='linux daffy.perf.redhat.com 2.4.17-0.13smp #1 smp fri feb 1
10:30:48 est 2002 i686 unknown '
    config_args='-des -Doptimize=-O2 -march=i386 -mcpu=i686 -Dcc=gcc
-Dcf_by=Red Hat, Inc. -Dcccdlflags=-fPIC -Dinstallprefix=/usr
-Dprefix=/usr -Darchname=i386-linux -Dvendorprefix=/usr
-Dsiteprefix=/usr -Uusethreads -Uuseithreads -Uuselargefiles -Dd_dosuid
-Dd_semctl_semun -Di_db -Di_ndbm -Di_gdbm -Di_shadow -Di_syslog
-Dman3ext=3pm'
    hint=recommended, useposix=true, d_sigaction=define
    usethreads=undef use5005threads=undef useithreads=undef
usemultiplicity=undef
    useperlio=undef d_sfio=undef uselargefiles=undef usesocks=undef
    use64bitint=undef use64bitall=undef uselongdouble=undef
  Compiler:
    cc='gcc', ccflags ='-fno-strict-aliasing -I/usr/local/include',
    optimize='-O2 -march=i386 -mcpu=i686',
    cppflags='-fno-strict-aliasing -I/usr/local/include'
    ccversion='', gccversion='2.96 20000731 (Red Hat Linux 7.2
2.96-109)', gccosandvers=''
    intsize=4, longsize=4, ptrsize=4, doublesize=8, byteorder=1234
    d_longlong=define, longlongsize=8, d_longdbl=define, longdblsize=12
    ivtype='long', ivsize=4, nvtype='double', nvsize=8, Off_t='off_t',
lseeksize=4
    alignbytes=4, usemymalloc=n, prototype=define
  Linker and Libraries:
    ld='gcc', ldflags =' -L/usr/local/lib'
    libpth=/usr/local/lib /lib /usr/lib
    libs=-lnsl -ldl -lm -lc -lcrypt -lutil
    perllibs=-lnsl -ldl -lm -lc -lcrypt -lutil
    libc=/lib/libc-2.2.5.so, so=so, useshrplib=false, libperl=libperl.a
  Dynamic Linking:
    dlsrc=dl_dlopen.xs, dlext=so, d_dlsymun=undef, ccdlflags='-rdynamic'
    cccdlflags='-fPIC', lddlflags='-shared -L/usr/local/lib'


Characteristics of this binary (from libperl): 
  Compile-time options:
  Built under linux
  Compiled at Apr  1 2002 12:23:22
  @INC:
    /usr/lib/perl5/5.6.1/i386-linux
    /usr/lib/perl5/5.6.1
    /usr/lib/perl5/site_perl/5.6.1/i386-linux
    /usr/lib/perl5/site_perl/5.6.1
    /usr/lib/perl5/site_perl/5.6.0
    /usr/lib/perl5/site_perl
    /usr/lib/perl5/vendor_perl/5.6.1/i386-linux
    /usr/lib/perl5/vendor_perl/5.6.1
    /usr/lib/perl5/vendor_perl

### 5.8.0 ###
Summary of my perl5 (revision 5.0 version 8 subversion 0) configuration:
  Platform:
    osname=linux, osvers=2.4.18-3, archname=i686-linux-thread-multi
    uname='linux dhcp152.noc.easyspace.net 2.4.18-3 #1 thu apr 18
07:37:53 edt 2002 i686 unknown '
    config_args='-Dusethreads'
    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=undef use64bitall=undef uselongdouble=undef
    usemymalloc=n, 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
-I/usr/include/gdbm',
    optimize='-O2',
    cppflags='-D_REENTRANT -D_GNU_SOURCE -fno-strict-aliasing
-I/usr/local/include -I/usr/include/gdbm'
    ccversion='', gccversion='2.96 20000731 (Red Hat Linux 7.3
2.96-110)', gccosandvers=''
    intsize=4, longsize=4, ptrsize=4, doublesize=8, byteorder=1234
    d_longlong=define, longlongsize=8, d_longdbl=define, longdblsize=12
    ivtype='long', ivsize=4, nvtype='double', nvsize=8, 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 -lgdbm -ldl -lm -lpthread -lc -lcrypt -lutil
    perllibs=-lnsl -ldl -lm -lpthread -lc -lcrypt -lutil
    libc=/lib/libc-2.2.5.so, so=so, useshrplib=true, libperl=libperl.so
    gnulibc_version='2.2.5'
  Dynamic Linking:
    dlsrc=dl_dlopen.xs, dlext=so, d_dlsymun=undef, ccdlflags='-rdynamic
-Wl,-rpath,/usr/local/lib/perl5/5.8.0/i686-linux-thread-multi/CORE'
    cccdlflags='-fpic', lddlflags='-shared -L/usr/local/lib'


Characteristics of this binary (from libperl): 
  Compile-time options: MULTIPLICITY USE_ITHREADS USE_LARGE_FILES
PERL_IMPLICIT_CONTEXT
  Built under linux
  Compiled at Oct 17 2002 13:52:58
  @INC:
    /usr/local/lib/perl5/5.8.0/i686-linux-thread-multi
    /usr/local/lib/perl5/5.8.0
    /usr/local/lib/perl5/site_perl/5.8.0/i686-linux-thread-multi
    /usr/local/lib/perl5/site_perl/5.8.0
    /usr/local/lib/perl5/site_perl
    /home/dan/.perl
    /root/.perl

### bleadperl (not very latest) ###
Summary of my perl5 (revision 5.0 version 9 subversion 0 patch 19143)
configuration:
  Platform:
    osname=linux, osvers=2.4.18-3, archname=i686-linux
    uname='linux dhcp140.noc.easyspace.net 2.4.18-3 #1 thu apr 18
07:37:53 edt 2002 i686 unknown '
    config_args='-d'
    hint=recommended, useposix=true, d_sigaction=define
    usethreads=undef useithreads=undef usemultiplicity=undef
    useperlio=define d_sfio=undef uselargefiles=define usesocks=undef
    use64bitint=undef use64bitall=undef uselongdouble=undef
    usemymalloc=n, bincompat5005=undef
  Compiler:
    cc='cc', ccflags ='-fno-strict-aliasing -I/usr/local/include
-D_LARGEFILE_SOURCE -D_FILE_OFFSET_BITS=64 -I/usr/include/gdbm',
    optimize='-O2',
    cppflags='-fno-strict-aliasing -I/usr/local/include
-I/usr/include/gdbm'
    ccversion='', gccversion='2.96 20000731 (Red Hat Linux 7.3
2.96-110)', gccosandvers=''
    intsize=4, longsize=4, ptrsize=4, doublesize=8, byteorder=1234
    d_longlong=define, longlongsize=8, d_longdbl=define, longdblsize=12
    ivtype='long', ivsize=4, nvtype='double', nvsize=8, 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 -lgdbm -ldl -lm -lc -lcrypt -lutil -lrt
    perllibs=-lnsl -ldl -lm -lc -lcrypt -lutil -lrt
    libc=/lib/libc-2.2.5.so, so=so, useshrplib=false, libperl=libperl.a
    gnulibc_version='2.2.5'
  Dynamic Linking:
    dlsrc=dl_dlopen.xs, dlext=so, d_dlsymun=undef, ccdlflags='-rdynamic'
    cccdlflags='-fpic', lddlflags='-shared -L/usr/local/lib'


Characteristics of this binary (from libperl): 
  Compile-time options: USE_LARGE_FILES
  Locally applied patches:
        DEVEL18374
  Built under linux
  Compiled at Apr  3 2003 14:04:04
  @INC:
    lib
    /usr/local/lib/perl5/5.9.0/i686-linux
    /usr/local/lib/perl5/5.9.0
    /usr/local/lib/perl5/site_perl/5.9.0/i686-linux
    /usr/local/lib/perl5/site_perl/5.9.0
    /usr/local/lib/perl5/site_perl

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