develooper Front page | perl.perl5.porters | Postings from January 2003

[perl #20542] Arrayrefs coerced into hashrefs not handled correctly in some cases

Thread Next
From:
perlbug-followup
Date:
January 25, 2003 18:56
Subject:
[perl #20542] Arrayrefs coerced into hashrefs not handled correctly in some cases
Message ID:
rt-20542-49686.11.3329764220812@bugs6.perl.org
# New Ticket Created by  simonf@cshl.edu 
# Please include the string:  [perl #20542]
# in the subject line of all future correspondence about this issue. 
# <URL: http://rt.perl.org/rt2/Ticket/Display.html?id=20542 >



This is a bug report for perl from simonf@cshl.edu,
generated with the help of perlbug 1.34 running under perl v5.8.0.


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

Here is a simple example of how arrayref to hashref coercion is not handled properly. Consider this script and its output:

***

#!/usr/bin/perl -w

use strict;
use Data::Dumper;

my %hash1 = (1=> 2, 3=>4);
my %hash2 = (1=> 2, 3=>4);
my %hash3 = (1=> 2, 3=>4);
my @array = (\%hash1, \%hash2, \%hash3);
print "Original array\n";
print Dumper @array;

my $ref = \@array;

my @newArray = values %$ref;


print "\nCoerced array\n";
print Dumper @newArray;

my @array1 = (1, 2,3);
my $ref1 = \@array1;
my @newArray1 = values %$ref1;

***

Output:

***

Original array
$VAR1 = {
          '1' => 2,
          '3' => 4
        };
$VAR2 = {
          '1' => 2,
          '3' => 4
        };
$VAR3 = {
          '1' => 2,
          '3' => 4
        };

Coerced array
$VAR1 = {
          '1' => 2,
          '3' => 4
        };
$VAR2 = undef;
Can't coerce array into hash at a.pl line 23.

***

Note that @array1 consisting simply of numbers generates the proper error at the end of the code. However, @array consisting of hashes does not generate an error and returns weird results.

In my code, when an arrayref was erroneously coerced into a hashref, no error message was printed. (The array contained complex objects with several levels of enclosed hashes.)  Instead, perl gobbled up a lot of memory. I have the offending object stored in Storable format if anyone's interested, but I suppose that the bad behavior above could consume too much memory for big objects.

Simon Ilyushchenko

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

Configured by bhcompile at Sun Sep  1 23:55:07 EDT 2002.

Summary of my perl5 (revision 5.0 version 8 subversion 0) configuration:
  Platform:
    osname=linux, osvers=2.4.18-11smp, archname=i386-linux-thread-multi
    uname='linux daffy.perf.redhat.com 2.4.18-11smp #1 smp thu aug 15 06:41:59 edt 2002 i686 i686 i386 gnulinux '
    config_args='-des -Doptimize=-O2 -march=i386 -mcpu=i686 -Dmyhostname=localhost -Dperladmin=root@localhost -Dcc=gcc -Dcf_by=Red Hat, Inc. -Dinstallprefix=/usr -Dprefix=/usr -Darchname=i386-linux -Dvendorprefix=/usr -Dsiteprefix=/usr -Duseshrplib -Dusethreads -Duseithreads -Duselargefiles -Dd_dosuid -Dd_semctl_semun -Di_db -Ui_ndbm -Di_gdbm -Di_shadow -Di_syslog -Dman3ext=3pm -Duseperlio -Dinstallusrbinperl -Ubincompat5005 -Uversiononly -Dpager=/usr/bin/less -isr'
    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='gcc', ccflags ='-D_REENTRANT -D_GNU_SOURCE -fno-strict-aliasing -D_LARGEFILE_SOURCE -D_FILE_OFFSET_BITS=64 -I/usr/include/gdbm',
    optimize='-O2 -march=i386 -mcpu=i686',
    cppflags='-D_REENTRANT -D_GNU_SOURCE -fno-strict-aliasing -I/usr/include/gdbm'
    ccversion='', gccversion='3.2 20020822 (Red Hat Linux Rawhide 3.2-5)', 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='gcc', ldflags =' -L/usr/local/lib'
    libpth=/usr/local/lib /lib /usr/lib
    libs=-lnsl -lgdbm -ldb -ldl -lm -lpthread -lc -lcrypt -lutil
    perllibs=-lnsl -ldl -lm -lpthread -lc -lcrypt -lutil
    libc=/lib/libc-2.2.92.so, so=so, useshrplib=true, libperl=libperl.so
    gnulibc_version='2.2.92'
  Dynamic Linking:
    dlsrc=dl_dlopen.xs, dlext=so, d_dlsymun=undef, ccdlflags='-rdynamic -Wl,-rpath,/usr/lib/perl5/5.8.0/i386-linux-thread-multi/CORE'
    cccdlflags='-fpic', lddlflags='-shared -L/usr/local/lib'

Locally applied patches:
    

---
@INC for perl v5.8.0:
    /usr/lib/perl5/5.8.0/i386-linux-thread-multi
    /usr/lib/perl5/5.8.0
    /usr/lib/perl5/site_perl/5.8.0/i386-linux-thread-multi
    /usr/lib/perl5/site_perl/5.8.0
    /usr/lib/perl5/site_perl
    /usr/lib/perl5/vendor_perl/5.8.0/i386-linux-thread-multi
    /usr/lib/perl5/vendor_perl/5.8.0
    /usr/lib/perl5/vendor_perl/5.6.1
    /usr/lib/perl5/vendor_perl
    .

---
Environment for perl v5.8.0:
    HOME=/home/simonf
    LANG=en_US.iso885915
    LANGUAGE (unset)
    LD_LIBRARY_PATH (unset)
    LOGDIR (unset)
    PATH=/usr/kerberos/bin:/usr/local/bin:/bin:/usr/bin:/usr/X11R6/bin:/sbin:/usr/sbin:/usr/local/bin
    PERL_BADLANG (unset)
    SHELL=/bin/bash


Thread Next


nntp.perl.org: Perl Programming lists via nntp and http.
Comments to Ask Bjørn Hansen at ask@perl.org | Group listing | About