Data::Dumper will not correctly create eval-able code for self-referential structures #11780

p5pRT · 2011-11-29T21:25:52Z

Migrated from rt.perl.org#104906 (status was 'open')

Searchable as RT104906$

p5pRT · 2011-11-29T21:25:52Z

From goldstei@ugcs.caltech.edu

Created by goldstei@ugcs.caltech.edu

I've noticed that Data::Dumper does not always create ouput that will eval
correctly for self-referential structures, even if Purity=1.

For example, take this code:

====================
use Data::Dumper;

my $h = {b => 1};
my $m = {c => $h};
$h->{d} = $m;
$h->{a}[0] = $m;
$Data::Dumper::Purity = 1;
print Dumper($h) . "\n";
my $s = Dumper($h);
my $a = eval $s;
print Dumper($a);

This produces the output:

====================
$VAR1 = {
'a' => [
{
'c' => {}
}
],
'b' => 1,
'd' => {}
};
$VAR1->{'a'}[0]{'c'} = $VAR1;
$VAR1->{'d'} = $VAR1->{'a'}[0];

$VAR1 = {
'c' => {
'a' => [
{}
],
'b' => 1,
'd' => {}
}
};
$VAR1->{'c'}{'a'}[0] = $VAR1;
$VAR1->{'c'}{'d'} = $VAR1;

Note that the first outputs $h, while the second outputs $m. This is because,
as the 'eval' function description states:

"In both forms, the value returned is the value of the last expression
evaluated inside the mini-program; a return statement may be also used, just as
with subroutines. The expression providing the return value is evaluated in
void, scalar, or list context, depending on the context of the eval itself."

The correct output could be obtained by adding a '$VAR1' at the end of the
structure, whenever the structure is self-referential.

This issue also appears to be present as late as perl 5.12.4.

Perl Info


Flags:
    category=library
    severity=low
    module=Data::Dumper

Site configuration information for perl 5.10.1:

Configured by Debian Project at Thu Jun 30 22:25:10 UTC 2011.

Summary of my perl5 (revision 5 version 10 subversion 1) configuration:
   
  Platform:
    osname=linux, osvers=2.6.32-5-amd64, archname=x86_64-linux-gnu-thread-multi
    uname='linux brahms 2.6.32-5-amd64 #1 smp tue jun 14 09:42:28 utc 2011 x86_64 gnulinux '
    config_args='-Dusethreads -Duselargefiles -Dccflags=-DDEBIAN -Dcccdlflags=-fPIC -Darchname=x86_64-linux-gnu -Dprefix=/usr -Dprivlib=/usr/share/perl/5.10 -Darchlib=/usr/lib/perl/5.10 -Dvendorprefix=/usr -Dvendorlib=/usr/share/perl5 -Dvendorarch=/usr/lib/perl5 -Dsiteprefix=/usr/local -Dsitelib=/usr/local/share/perl/5.10.1 -Dsitearch=/usr/local/lib/perl/5.10.1 -Dman1dir=/usr/share/man/man1 -Dman3dir=/usr/share/man/man3 -Dsiteman1dir=/usr/local/man/man1 -Dsiteman3dir=/usr/local/man/man3 -Dman1ext=1 -Dman3ext=3perl -Dpager=/usr/bin/sensible-pager -Uafs -Ud_csh -Ud_ualarm -Uusesfio -Uusenm -DDEBUGGING=-g -Doptimize=-O2 -Duseshrplib -Dlibperl=libperl.so.5.10.1 -Dd_dosuid -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='4.4.5', 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 /usr/lib /lib64 /usr/lib64
    libs=-lgdbm -lgdbm_compat -ldb -ldl -lm -lpthread -lc -lcrypt
    perllibs=-ldl -lm -lpthread -lc -lcrypt
    libc=/lib/libc-2.11.2.so, so=so, useshrplib=true, libperl=libperl.so.5.10.1
    gnulibc_version='2.11.2'
  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:
    DEBPKG:debian/arm_thread_stress_timeout - http://bugs.debian.org/501970 Raise the timeout of ext/threads/shared/t/stress.t to accommodate slower build hosts
    DEBPKG:debian/cpan_config_path - Set location of CPAN::Config to /etc/perl as /usr may not be writable.
    DEBPKG:debian/cpan_definstalldirs - Provide a sensible INSTALLDIRS default for modules installed from CPAN.
    DEBPKG:debian/db_file_ver - http://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 - http://bugs.debian.org/290336 Tweak enc2xs to follow symlinks and ignore missing @INC directories.
    DEBPKG:debian/errno_ver - http://bugs.debian.org/343351 Remove Errno version check due to upgrade problems with long-running processes.
    DEBPKG:debian/extutils_hacks - Various debian-specific ExtUtils changes
    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/m68k_thread_stress - http://bugs.debian.org/495826 Disable some threads tests on m68k for now due to missing TLS.
    DEBPKG:debian/mod_paths - Tweak @INC ordering for Debian
    DEBPKG:debian/module_build_man_extensions - http://bugs.debian.org/479460 Adjust Module::Build manual page extensions for the Debian Perl policy
    DEBPKG:debian/perl_synopsis - http://bugs.debian.org/278323 Rearrange perl.pod
    DEBPKG:debian/prune_libs - http://bugs.debian.org/128355 Prune the list of libraries wanted to what we actually need.
    DEBPKG:debian/use_gdbm - Explicitly link against -lgdbm_compat in ODBM_File/NDBM_File. 
    DEBPKG:fixes/assorted_docs - http://bugs.debian.org/443733 [384f06a] Math::BigInt::CalcEmu documentation grammar fix
    DEBPKG:fixes/net_smtp_docs - http://bugs.debian.org/100195 [rt.cpan.org #36038] Document the Net::SMTP 'Port' option
    DEBPKG:fixes/processPL - http://bugs.debian.org/357264 [rt.cpan.org #17224] Always use PERLRUNINST when building perl modules.
    DEBPKG:debian/perlivp - http://bugs.debian.org/510895 Make perlivp skip include directories in /usr/local
    DEBPKG:fixes/pod2man-index-backslash - http://bugs.debian.org/521256 Escape backslashes in .IX entries
    DEBPKG:debian/disable-zlib-bundling - Disable zlib bundling in Compress::Raw::Zlib
    DEBPKG:fixes/kfreebsd_cppsymbols - http://bugs.debian.org/533098 [3b910a0] Add gcc predefined macros to $Config{cppsymbols} on GNU/kFreeBSD.
    DEBPKG:debian/cpanplus_definstalldirs - http://bugs.debian.org/533707 Configure CPANPLUS to use the site directories by default.
    DEBPKG:debian/cpanplus_config_path - Save local versions of CPANPLUS::Config::System into /etc/perl.
    DEBPKG:fixes/kfreebsd-filecopy-pipes - http://bugs.debian.org/537555 [16f708c] Fix File::Copy::copy with pipes on GNU/kFreeBSD
    DEBPKG:fixes/anon-tmpfile-dir - http://bugs.debian.org/528544 [perl #66452] Honor TMPDIR when open()ing an anonymous temporary file
    DEBPKG:fixes/abstract-sockets - http://bugs.debian.org/329291 [89904c0] Add support for Abstract namespace sockets.
    DEBPKG:fixes/hurd_cppsymbols - http://bugs.debian.org/544307 [eeb92b7] Add gcc predefined macros to $Config{cppsymbols} on GNU/Hurd.
    DEBPKG:fixes/autodie-flock - http://bugs.debian.org/543731 Allow for flock returning EAGAIN instead of EWOULDBLOCK on linux/parisc
    DEBPKG:fixes/archive-tar-instance-error - http://bugs.debian.org/539355 [rt.cpan.org #48879] Separate Archive::Tar instance error strings from each other
    DEBPKG:fixes/positive-gpos - http://bugs.debian.org/545234 [perl #69056] [c584a96] Fix \\G crash on first match
    DEBPKG:debian/devel-ppport-ia64-optim - http://bugs.debian.org/548943 Work around an ICE on ia64
    DEBPKG:fixes/trie-logic-match - http://bugs.debian.org/552291 [perl #69973] [0abd0d7] Fix a DoS in Unicode processing [CVE-2009-3626]
    DEBPKG:fixes/hppa-thread-eagain - http://bugs.debian.org/554218 make the threads-shared test suite more robust, fixing failures on hppa
    DEBPKG:fixes/crash-on-undefined-destroy - http://bugs.debian.org/564074 [perl #71952] [1f15e67] Fix a NULL pointer dereference when looking for a DESTROY method
    DEBPKG:fixes/tainted-errno - http://bugs.debian.org/574129 [perl #61976] [be1cf43] fix an errno stringification bug in taint mode
    DEBPKG:fixes/safe-upgrade - http://bugs.debian.org/582978 Upgrade Safe.pm to 2.25, fixing CVE-2010-1974
    DEBPKG:fixes/tell-crash - http://bugs.debian.org/578577 [f4817f3] Fix a tell() crash on bad arguments.
    DEBPKG:fixes/format-write-crash - http://bugs.debian.org/579537 [perl #22977] [421f30e] Fix a crash in format/write
    DEBPKG:fixes/arm-alignment - http://bugs.debian.org/289884 [f1c7503] Prevent gcc from optimizing the alignment test away on armel
    DEBPKG:fixes/fcgi-test - Fix a failure in CGI/t/fast.t when FCGI is installed
    DEBPKG:fixes/hurd-ccflags - http://bugs.debian.org/587901 Make hints/gnu.sh append to $ccflags rather than overriding them
    DEBPKG:debian/squelch-locale-warnings - http://bugs.debian.org/508764 Squelch locale warnings in Debian package maintainer scripts
    DEBPKG:fixes/lc-numeric-docs - http://bugs.debian.org/379329 [perl #78452] [903eb63] LC_NUMERIC documentation fixes
    DEBPKG:fixes/lc-numeric-sprintf - http://bugs.debian.org/601549 [perl #78632] [b3fd614] Fix sprintf not to ignore LC_NUMERIC with constants
    DEBPKG:fixes/concat-stack-corruption - http://bugs.debian.org/596105 [perl #78674] [e3393f5] Fix stack pointer corruption in pp_concat() with 'use encoding'
    DEBPKG:fixes/cgi-multiline-header - http://bugs.debian.org/606995 [CVE-2010-2761 CVE-2010-4410 CVE-2010-4411] CGI.pm MIME boundary and multiline header vulnerabilities
    DEBPKG:fixes/casing-taint-cve-2011-1487 - http://bugs.debian.org/622817 [perl #87336] fix unwanted taint laundering in lc(), uc() et al.
    DEBPKG:fixes/safe-reval-rdo-cve-2010-1447 - [PATCH] Wrap by default coderefs returned by rdo and reval
    DEBPKG:patchlevel - http://bugs.debian.org/567489 List packaged patches for 5.10.1-17squeeze2 in patchlevel.h


@INC for perl 5.10.1:
    /etc/perl
    /usr/local/lib/perl/5.10.1
    /usr/local/share/perl/5.10.1
    /usr/lib/perl5
    /usr/share/perl5
    /usr/lib/perl/5.10
    /usr/share/perl/5.10
    /usr/local/lib/site_perl
    .


Environment for perl 5.10.1:
    HOME=/afs/.ugcs/user/goldstei
    LANG=en_US.UTF-8
    LANGUAGE (unset)
    LD_LIBRARY_PATH (unset)
    LOGDIR (unset)
    PATH=/afs/.ugcs/user/goldstei/ugcs2/scripts:/usr/ug/bin:/usr/ug/sbin:/usr/bin:/bin:/usr/sbin:/sbin:/ug/adm/bin/scripts:/ug/adm/bin/:/usr/X11R6/bin:/afs/.ugcs/user/goldstei/bin:/afs/.ugcs/user/goldstei/maple10/bin:/mnt/cresol/cresol/ufs/egnor/i386-linux2/bin:/usr/ug/share/scripts:/afs/.ugcs/user/goldstei/ugcs2/scripts:/usr/ug/bin:/usr/ug/sbin:/usr/bin:/bin:/usr/sbin:/sbin:/ug/adm/bin/scripts:/ug/adm/bin/:/usr/X11R6/bin:/afs/.ugcs/user/goldstei/bin:/afs/.ugcs/user/goldstei/maple10/bin:/mnt/cresol/cresol/ufs/egnor/i386-linux2/bin:/usr/ug/share/scripts:/usr/local/bin:/usr/bin:/bin:/usr/bin/X11:/usr/games
    PERL_BADLANG (unset)
    SHELL=/bin/zsh

p5pRT · 2011-11-30T11:17:56Z

From zefram@fysh.org

goldstei@ugcs.caltech.edu wrote:

I've noticed that Data::Dumper does not always create ouput that will eval
correctly for self-referential structures, even if Purity=1.
...
my $s = Dumper($h);
my $a = eval $s;

Data::Dumper doesn't actually claim that the eval will return the
structure, only that it will *recreate* it. Which it did: it assigned
it to $VAR1. Try

my $VAR1;
eval $s;
my $a = $VAR1;

The documentation could do with clarification on this point.

-zefram

p5pRT · 2011-11-30T11:17:57Z

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

p5pRT · 2011-11-30T11:19:03Z

From @demerphq

Not a bug. Data::Dumper doesn't say it does this.

You can easily use Data::Dumper in a way it does not matter.

For instance

my $dump= 'do{' . Data::Dumper->new([$x,$y,$z], [qw($x $y
$z)])->Purity(1)->Dump() . ' ($x,$y,$z) }'

cheers,
yves

On 29 November 2011 22:25, goldstei@ugcs.caltech.edu
<perlbug-followup@perl.org> wrote:

# New Ticket Created by goldstei@ugcs.caltech.edu
# Please include the string: [perl #104906]
# in the subject line of all future correspondence about this issue.
# <URL: https://rt-archive.perl.org/perl5/Ticket/Display.html?id=104906 >

This is a bug report for perl from goldstei@ugcs.caltech.edu,
generated with the help of perlbug 1.39 running under perl 5.10.1.

-----------------------------------------------------------------
[Please describe your issue here]

I've noticed that Data::Dumper does not always create ouput that will eval
correctly for self-referential structures, even if Purity=1.

For example, take this code:

====================
use Data::Dumper;

my $h = {b => 1};
my $m = {c => $h};
$h->{d} = $m;
$h->{a}[0] = $m;
$Data::Dumper::Purity = 1;
print Dumper($h) . "\n";
my $s = Dumper($h);
my $a = eval $s;
print Dumper($a);

This produces the output:

====================
$VAR1 = {
'a' => [
{
'c' => {}
}
],
'b' => 1,
'd' => {}
};
$VAR1->{'a'}[0]{'c'} = $VAR1;
$VAR1->{'d'} = $VAR1->{'a'}[0];

$VAR1 = {
'c' => {
'a' => [
{}
],
'b' => 1,
'd' => {}
}
};
$VAR1->{'c'}{'a'}[0] = $VAR1;
$VAR1->{'c'}{'d'} = $VAR1;

Note that the first outputs $h, while the second outputs $m. This is because,
as the 'eval' function description states:

"In both forms, the value returned is the value of the last expression
evaluated inside the mini-program; a return statement may be also used, just as
with subroutines. The expression providing the return value is evaluated in
void, scalar, or list context, depending on the context of the eval itself."

The correct output could be obtained by adding a '$VAR1' at the end of the
structure, whenever the structure is self-referential.

This issue also appears to be present as late as perl 5.12.4.

[Please do not change anything below this line]
-----------------------------------------------------------------
---
Flags:
category=library
severity=low
module=Data::Dumper
---
Site configuration information for perl 5.10.1:

Configured by Debian Project at Thu Jun 30 22:25:10 UTC 2011.

Summary of my perl5 (revision 5 version 10 subversion 1) configuration:

Platform:
osname=linux, osvers=2.6.32-5-amd64, archname=x86_64-linux-gnu-thread-multi
uname='linux brahms 2.6.32-5-amd64 #1 smp tue jun 14 09:42:28 utc 2011 x86_64 gnulinux '
config_args='-Dusethreads -Duselargefiles -Dccflags=-DDEBIAN -Dcccdlflags=-fPIC -Darchname=x86_64-linux-gnu -Dprefix=/usr -Dprivlib=/usr/share/perl/5.10 -Darchlib=/usr/lib/perl/5.10 -Dvendorprefix=/usr -Dvendorlib=/usr/share/perl5 -Dvendorarch=/usr/lib/perl5 -Dsiteprefix=/usr/local -Dsitelib=/usr/local/share/perl/5.10.1 -Dsitearch=/usr/local/lib/perl/5.10.1 -Dman1dir=/usr/share/man/man1 -Dman3dir=/usr/share/man/man3 -Dsiteman1dir=/usr/local/man/man1 -Dsiteman3dir=/usr/local/man/man3 -Dman1ext=1 -Dman3ext=3perl -Dpager=/usr/bin/sensible-pager -Uafs -Ud_csh -Ud_ualarm -Uusesfio -Uusenm -DDEBUGGING=-g -Doptimize=-O2 -Duseshrplib -Dlibperl=libperl.so.5.10.1 -Dd_dosuid -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='4.4.5', 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 /usr/lib /lib64 /usr/lib64
libs=-lgdbm -lgdbm_compat -ldb -ldl -lm -lpthread -lc -lcrypt
perllibs=-ldl -lm -lpthread -lc -lcrypt
libc=/lib/libc-2.11.2.so, so=so, useshrplib=true, libperl=libperl.so.5.10.1
gnulibc_version='2.11.2'
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:
DEBPKG:debian/arm_thread_stress_timeout - http://bugs.debian.org/501970 Raise the timeout of ext/threads/shared/t/stress.t to accommodate slower build hosts
DEBPKG:debian/cpan_config_path - Set location of CPAN::Config to /etc/perl as /usr may not be writable.
DEBPKG:debian/cpan_definstalldirs - Provide a sensible INSTALLDIRS default for modules installed from CPAN.
DEBPKG:debian/db_file_ver - http://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 - http://bugs.debian.org/290336 Tweak enc2xs to follow symlinks and ignore missing @INC directories.
DEBPKG:debian/errno_ver - http://bugs.debian.org/343351 Remove Errno version check due to upgrade problems with long-running processes.
DEBPKG:debian/extutils_hacks - Various debian-specific ExtUtils changes
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/m68k_thread_stress - http://bugs.debian.org/495826 Disable some threads tests on m68k for now due to missing TLS.
DEBPKG:debian/mod_paths - Tweak @INC ordering for Debian
DEBPKG:debian/module_build_man_extensions - http://bugs.debian.org/479460 Adjust Module::Build manual page extensions for the Debian Perl policy
DEBPKG:debian/perl_synopsis - http://bugs.debian.org/278323 Rearrange perl.pod
DEBPKG:debian/prune_libs - http://bugs.debian.org/128355 Prune the list of libraries wanted to what we actually need.
DEBPKG:debian/use_gdbm - Explicitly link against -lgdbm_compat in ODBM_File/NDBM_File.
DEBPKG:fixes/assorted_docs - http://bugs.debian.org/443733 [384f06a] Math::BigInt::CalcEmu documentation grammar fix
DEBPKG:fixes/net_smtp_docs - http://bugs.debian.org/100195 [rt.cpan.org #36038] Document the Net::SMTP 'Port' option
DEBPKG:fixes/processPL - http://bugs.debian.org/357264 [rt.cpan.org #17224] Always use PERLRUNINST when building perl modules.
DEBPKG:debian/perlivp - http://bugs.debian.org/510895 Make perlivp skip include directories in /usr/local
DEBPKG:fixes/pod2man-index-backslash - http://bugs.debian.org/521256 Escape backslashes in .IX entries
DEBPKG:debian/disable-zlib-bundling - Disable zlib bundling in Compress::Raw::Zlib
DEBPKG:fixes/kfreebsd_cppsymbols - http://bugs.debian.org/533098 [3b910a0] Add gcc predefined macros to $Config{cppsymbols} on GNU/kFreeBSD.
DEBPKG:debian/cpanplus_definstalldirs - http://bugs.debian.org/533707 Configure CPANPLUS to use the site directories by default.
DEBPKG:debian/cpanplus_config_path - Save local versions of CPANPLUS::Config::System into /etc/perl.
DEBPKG:fixes/kfreebsd-filecopy-pipes - http://bugs.debian.org/537555 [16f708c] Fix File::Copy::copy with pipes on GNU/kFreeBSD
DEBPKG:fixes/anon-tmpfile-dir - http://bugs.debian.org/528544 [perl #66452] Honor TMPDIR when open()ing an anonymous temporary file
DEBPKG:fixes/abstract-sockets - http://bugs.debian.org/329291 [89904c0] Add support for Abstract namespace sockets.
DEBPKG:fixes/hurd_cppsymbols - http://bugs.debian.org/544307 [eeb92b7] Add gcc predefined macros to $Config{cppsymbols} on GNU/Hurd.
DEBPKG:fixes/autodie-flock - http://bugs.debian.org/543731 Allow for flock returning EAGAIN instead of EWOULDBLOCK on linux/parisc
DEBPKG:fixes/archive-tar-instance-error - http://bugs.debian.org/539355 [rt.cpan.org #48879] Separate Archive::Tar instance error strings from each other
DEBPKG:fixes/positive-gpos - http://bugs.debian.org/545234 [perl #69056] [c584a96] Fix \\G crash on first match
DEBPKG:debian/devel-ppport-ia64-optim - http://bugs.debian.org/548943 Work around an ICE on ia64
DEBPKG:fixes/trie-logic-match - http://bugs.debian.org/552291 [perl #69973] [0abd0d7] Fix a DoS in Unicode processing [CVE-2009-3626]
DEBPKG:fixes/hppa-thread-eagain - http://bugs.debian.org/554218 make the threads-shared test suite more robust, fixing failures on hppa
DEBPKG:fixes/crash-on-undefined-destroy - http://bugs.debian.org/564074 [perl #71952] [1f15e67] Fix a NULL pointer dereference when looking for a DESTROY method
DEBPKG:fixes/tainted-errno - http://bugs.debian.org/574129 [perl #61976] [be1cf43] fix an errno stringification bug in taint mode
DEBPKG:fixes/safe-upgrade - http://bugs.debian.org/582978 Upgrade Safe.pm to 2.25, fixing CVE-2010-1974
DEBPKG:fixes/tell-crash - http://bugs.debian.org/578577 [f4817f3] Fix a tell() crash on bad arguments.
DEBPKG:fixes/format-write-crash - http://bugs.debian.org/579537 [perl #22977] [421f30e] Fix a crash in format/write
DEBPKG:fixes/arm-alignment - http://bugs.debian.org/289884 [f1c7503] Prevent gcc from optimizing the alignment test away on armel
DEBPKG:fixes/fcgi-test - Fix a failure in CGI/t/fast.t when FCGI is installed
DEBPKG:fixes/hurd-ccflags - http://bugs.debian.org/587901 Make hints/gnu.sh append to $ccflags rather than overriding them
DEBPKG:debian/squelch-locale-warnings - http://bugs.debian.org/508764 Squelch locale warnings in Debian package maintainer scripts
DEBPKG:fixes/lc-numeric-docs - http://bugs.debian.org/379329 [perl #78452] [903eb63] LC_NUMERIC documentation fixes
DEBPKG:fixes/lc-numeric-sprintf - http://bugs.debian.org/601549 [perl #78632] [b3fd614] Fix sprintf not to ignore LC_NUMERIC with constants
DEBPKG:fixes/concat-stack-corruption - http://bugs.debian.org/596105 [perl #78674] [e3393f5] Fix stack pointer corruption in pp_concat() with 'use encoding'
DEBPKG:fixes/cgi-multiline-header - http://bugs.debian.org/606995 [CVE-2010-2761 CVE-2010-4410 CVE-2010-4411] CGI.pm MIME boundary and multiline header vulnerabilities
DEBPKG:fixes/casing-taint-cve-2011-1487 - http://bugs.debian.org/622817 [perl #87336] fix unwanted taint laundering in lc(), uc() et al.
DEBPKG:fixes/safe-reval-rdo-cve-2010-1447 - [PATCH] Wrap by default coderefs returned by rdo and reval
DEBPKG:patchlevel - http://bugs.debian.org/567489 List packaged patches for 5.10.1-17squeeze2 in patchlevel.h

---
@INC for perl 5.10.1:
/etc/perl
/usr/local/lib/perl/5.10.1
/usr/local/share/perl/5.10.1
/usr/lib/perl5
/usr/share/perl5
/usr/lib/perl/5.10
/usr/share/perl/5.10
/usr/local/lib/site_perl
.

---
Environment for perl 5.10.1:
HOME=/afs/.ugcs/user/goldstei
LANG=en_US.UTF-8
LANGUAGE (unset)
LD_LIBRARY_PATH (unset)
LOGDIR (unset)
PATH=/afs/.ugcs/user/goldstei/ugcs2/scripts:/usr/ug/bin:/usr/ug/sbin:/usr/bin:/bin:/usr/sbin:/sbin:/ug/adm/bin/scripts:/ug/adm/bin/:/usr/X11R6/bin:/afs/.ugcs/user/goldstei/bin:/afs/.ugcs/user/goldstei/maple10/bin:/mnt/cresol/cresol/ufs/egnor/i386-linux2/bin:/usr/ug/share/scripts:/afs/.ugcs/user/goldstei/ugcs2/scripts:/usr/ug/bin:/usr/ug/sbin:/usr/bin:/bin:/usr/sbin:/sbin:/ug/adm/bin/scripts:/ug/adm/bin/:/usr/X11R6/bin:/afs/.ugcs/user/goldstei/bin:/afs/.ugcs/user/goldstei/maple10/bin:/mnt/cresol/cresol/ufs/egnor/i386-linux2/bin:/usr/ug/share/scripts:/usr/local/bin:/usr/bin:/bin:/usr/bin/X11:/usr/games
PERL_BADLANG (unset)
SHELL=/bin/zsh

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

p5pRT · 2011-12-01T09:40:10Z

From goldstei@ugcs.caltech.edu

I agree that the documentation should be clarified to state that it will
"recreate the variable named in the dump" (such as $VAR1) rather than
recreating an assignable structure. I do think it would be cleaner if
you could simply 'eval' it directly, but I suppose it is the API
designer's call.

Yves: I worked around this by doing exactly what you suggested before I
had even filed this bug.

--
Joshua Goldstein
goldstei@ugcs.caltech.edu
(626)-529-6964

p5pRT · 2011-12-01T13:32:21Z

From @nwc10

On Wed, Nov 30, 2011 at 12:34:59PM -0800, Joshua Goldstein wrote:

I agree that the documentation should be clarified to state that it will
"recreate the variable named in the dump" (such as $VAR1) rather than
recreating an assignable structure. I do think it would be cleaner if
you could simply 'eval' it directly, but I suppose it is the API
designer's call.

I can't actually see what harm would come from changing Data::Dumper to
add 1 statement at the end to return the variable, for the case of nested
structures.

I believe that it wouldn't warn even if eval'd in void context, and the
current result of eval on the output is unspecified (and unclear, hence
this bug report). It's slightly bigger, sure. But in the grand scheme
of things?

It strikes me that with do blocks and appropriate lexicals one could even
make terse output "work" correctly for self referential structures.

Nicholas Clark

p5pRT · 2011-12-01T14:06:20Z

From zefram@fysh.org

Nicholas Clark wrote:

It strikes me that with do blocks and appropriate lexicals one could even
make terse output "work" correctly for self referential structures.

This is what I'd like to see. In terse mode it makes a lot more sense
for eval to return the structure created, because there's no other way
to get at the structure. Currently terse mode just isn't useful on
anything tricky.

-zefram

p5pRT added Wishlist affects-5.10 distro-All type-library labels Oct 19, 2019

jkeenan added dist-Data-Dumper issues in the dual-life blead-first Data-Dumper distribution and removed distro-All labels Jul 5, 2021

xenu removed the affects-5.10 label Nov 19, 2021

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Data::Dumper will not correctly create eval-able code for self-referential structures #11780

Data::Dumper will not correctly create eval-able code for self-referential structures #11780

p5pRT commented Nov 29, 2011

p5pRT commented Nov 29, 2011

p5pRT commented Nov 30, 2011

p5pRT commented Nov 30, 2011

p5pRT commented Nov 30, 2011

my $h = {b => 1};
my $m = {c => $h};
$h->{d} = $m;
$h->{a}[0] = $m;
$Data::Dumper::Purity = 1;
print Dumper($h) . "\n";
my $s = Dumper($h);
my $a = eval $s;
print Dumper($a);

$VAR1 = {
'c' => {
'a' => [
{}
],
'b' => 1,
'd' => {}
}
};
$VAR1->{'c'}{'a'}[0] = $VAR1;
$VAR1->{'c'}{'d'} = $VAR1;

p5pRT commented Dec 1, 2011

p5pRT commented Dec 1, 2011

p5pRT commented Dec 1, 2011

Data::Dumper will not correctly create eval-able code for self-referential structures #11780

Data::Dumper will not correctly create eval-able code for self-referential structures #11780

Comments

p5pRT commented Nov 29, 2011

p5pRT commented Nov 29, 2011

From goldstei@ugcs.caltech.edu

Created by goldstei@ugcs.caltech.edu

my $h = {b => 1}; my $m = {c => $h}; $h->{d} = $m; $h->{a}[0] = $m; $Data​::Dumper​::Purity = 1; print Dumper($h) . "\n"; my $s = Dumper($h); my $a = eval $s; print Dumper($a);

$VAR1 = { 'c' => { 'a' => [ {} ], 'b' => 1, 'd' => {} } }; $VAR1->{'c'}{'a'}[0] = $VAR1; $VAR1->{'c'}{'d'} = $VAR1;

p5pRT commented Nov 30, 2011

From zefram@fysh.org

p5pRT commented Nov 30, 2011

p5pRT commented Nov 30, 2011

From @demerphq

my $h = {b => 1}; my $m = {c => $h}; $h->{d} = $m; $h->{a}[0] = $m; $Data​::Dumper​::Purity = 1; print Dumper($h) . "\n"; my $s = Dumper($h); my $a = eval $s; print Dumper($a);

$VAR1 = { 'c' => { 'a' => [ {} ], 'b' => 1, 'd' => {} } }; $VAR1->{'c'}{'a'}[0] = $VAR1; $VAR1->{'c'}{'d'} = $VAR1;

p5pRT commented Dec 1, 2011

From goldstei@ugcs.caltech.edu

p5pRT commented Dec 1, 2011

From @nwc10

p5pRT commented Dec 1, 2011

From zefram@fysh.org

my $h = {b => 1};
my $m = {c => $h};
$h->{d} = $m;
$h->{a}[0] = $m;
$Data::Dumper::Purity = 1;
print Dumper($h) . "\n";
my $s = Dumper($h);
my $a = eval $s;
print Dumper($a);

$VAR1 = {
'c' => {
'a' => [
{}
],
'b' => 1,
'd' => {}
}
};
$VAR1->{'c'}{'a'}[0] = $VAR1;
$VAR1->{'c'}{'d'} = $VAR1;

my $h = {b => 1};
my $m = {c => $h};
$h->{d} = $m;
$h->{a}[0] = $m;
$Data::Dumper::Purity = 1;
print Dumper($h) . "\n";
my $s = Dumper($h);
my $a = eval $s;
print Dumper($a);

$VAR1 = {
'c' => {
'a' => [
{}
],
'b' => 1,
'd' => {}
}
};
$VAR1->{'c'}{'a'}[0] = $VAR1;
$VAR1->{'c'}{'d'} = $VAR1;