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[perl #25145] Storable segfaults with B::Deparse + overload + cyclic structures

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Sam Vilain
January 19, 2004 19:12
[perl #25145] Storable segfaults with B::Deparse + overload + cyclic structures
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# New Ticket Created by  Sam Vilain 
# Please include the string:  [perl #25145]
# in the subject line of all future correspondence about this issue. 
# <URL: >

This is a bug report for perl from,
generated with the help of perlbug 1.34 running under perl v5.8.1.

[Please enter your report here]

Found a segfault with thawing standard Perl structures with Storable.
This seems to be a bug on all Storable versions I tested, which
includes Perls 5.6.1 - 5.8.3.

Note that it only seems to trigger, if there are back-references to
overloaded objects, *after* something has been deparsed via
B::Deparse - or is that thawed with eval?

The details of the structure don't seem to matter much, but I've made
the simplest structure I could manage that demonstrates the problem.
Which was a *lot* simpler than my original structure ;-).

Here's a test script, which I've tried to make as similar to the ones
in the Storable distribution as possible:


sub BEGIN {
    if ($ENV{PERL_CORE}){
        chdir('t') if -d 't';
        @INC = ('.', '../lib');
    } else {
        unshift @INC, 't';
    require Config; import Config;
    if ($ENV{PERL_CORE} and $Config{'extensions'} !~ /\bStorable\b/) {
        print "1..0 # Skip: Storable was not built\n";
        exit 0;

use strict;
    if (!eval q{
        use Test;
        use B::Deparse 0.61;
        use 5.006;
    }) {
        print "1..0 # skip: tests only work with B::Deparse 0.61 and at least pe
rl 5.6.0\n";
    require File::Spec;
    if ($File::Spec::VERSION < 0.8) {
        print "1..0 # Skip: newer File::Spec needed\n";
        exit 0;

use Storable qw(retrieve store nstore freeze nfreeze thaw dclone);
use Safe;

#$Storable::DEBUGME = 1;

print "1..2\n";
    package Banana;
    use overload   
	'<=>' => \&compare,
	    '==' => \&equal,
		fallback => 1;
    sub compare { return int(rand(3))-1 };
    sub equal { return 1 if rand(1) > 0.5 }

my (@a);

my $nasty =
     foo => sub {
	 print "Hey, there's some code here!\n";
     ($a[0] = bless [ ], "Banana"),
     ($a[1] = [ ]),

# this one segfaults every time.
$a[0]->[0] = $a[0];

# this one only segfaults once in a while.  Other times, it says:
#   Cannot restore overloading on REF(0x815460c) (package <unknown>)
#$a[1]->[0] = $a[0];

print "not " unless $nasty;
print "ok 1\n";

$Storable::Deparse = 1;
$Storable::Eval = 1;

my $schema2 = dclone $nasty;
print "not " unless $nasty;
print "ok 2\n";

[Please do not change anything below this line]
Site configuration information for perl v5.8.1:

Configured by Debian Project at Fri Sep 26 16:57:02 BST 2003.

Summary of my perl5 (revision 5.0 version 8 subversion 1) configuration:
    osname=linux, osvers=2.4.21-c17b, archname=i386-linux-thread-multi
    uname='linux betelgeuse 2.4.21-c17b #2 sat sep 13 01:16:47 bst 2003 i686 unknown '
    config_args='-Dusethreads -Duselargefiles -Dccflags=-DDEBIAN -Dcccdlflags=-fPIC -Darchname=i386-linux -Dprefix=/usr -Dprivlib=/usr/share/perl/5.8.1 -Darchlib=/usr/lib/perl/5.8.1 -Dvendorprefix=/usr -Dvendorlib=/usr/share/perl5 -Dvendorarch=/usr/lib/perl5 -Dsiteprefix=/usr/local -Dsitelib=/usr/local/share/perl/5.8.1 -Dsitearch=/usr/local/lib/perl/5.8.1 -Dman1dir=/usr/share/man/man1 -Dman3dir=/usr/share/man/man3 -Dman1ext=1 -Dman3ext=3perl -Dpager=/usr/bin/sensible-pager -Uafs -Ud_csh -Uusesfio -Uusenm -Duseshrplib -Dd_dosuid -des'
    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
    cc='cc', ccflags ='-D_REENTRANT -D_GNU_SOURCE -DTHREADS_HAVE_PIDS -DDEBIAN -fno-strict-aliasing -I/usr/local/include -D_LARGEFILE_SOURCE -D_FILE_OFFSET_BITS=64',
    cppflags='-D_REENTRANT -D_GNU_SOURCE -DTHREADS_HAVE_PIDS -DDEBIAN -fno-strict-aliasing -I/usr/local/include'
    ccversion='', gccversion='2.95.4 20011002 (Debian prerelease)', 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=-lgdbm -ldb -ldl -lm -lpthread -lc -lcrypt
    perllibs=-ldl -lm -lpthread -lc -lcrypt
    libc=/lib/, so=so, useshrplib=true,
  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 v5.8.1:

Environment for perl v5.8.1:
    LANG (unset)
    LANGUAGE (unset)
    LD_LIBRARY_PATH (unset)
    LOGDIR (unset)
    PERL_BADLANG (unset)

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