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[perl #55952] Iteration order of hash keys doesn't appear random
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From:
Jonathan Sailor
Date:
June 17, 2008 15:52
Subject:
[perl #55952] Iteration order of hash keys doesn't appear random
Message ID:
rt-3.6.HEAD-6656-1213729087-1874.55952-75-0@perl.org
# New Ticket Created by Jonathan Sailor
# Please include the string: [perl #55952]
# in the subject line of all future correspondence about this issue.
# <URL: http://rt.perl.org/rt3/Ticket/Display.html?id=55952 >
This is a bug report for perl from jsailor@jesnetplus.com,
generated with the help of perlbug 1.35 running under perl v5.8.8.
-----------------------------------------------------------------
[Please enter your report here]
It doesn't seem that the iteration order of hash keys is random. On 5.8.8, I
created a hash with a bunch of key/value pairs, and they are always returned by
the hash's iterator in the same order. I'm not sure if the apparent
lack-of-randomness if actually evidence of a problem or not.
Example:
jsailor@gentoo ~ $ cat hi.pl
#!/usr/bin/perl -l
map { $foo{"key$_"} = "val$_" } 1 .. 10;
map { print "$_ => $foo{$_}" } keys %foo;
jsailor@gentoo ~ $ for ((i=0; i<10; i++)); do
PERL_HASH_SEED_DEBUG=1 perl hi.pl | md5sum
done | sort | uniq -c
HASH_SEED = 4030767996
HASH_SEED = 4231742271
HASH_SEED = 2242964373
HASH_SEED = 1223985970
HASH_SEED = 3159642496
HASH_SEED = 3233708610
HASH_SEED = 1197677821
HASH_SEED = 3042627731
HASH_SEED = 3316032634
HASH_SEED = 3720177465
10 b9610c6717785a4f9e26c9913d1bbb06 -
jsailor@gentoo ~ $
This report if for 10 particular keys inserted in a particular order on a
particular build of Perl, as returned by keys, but the order is just as
constant (for me) for:
- a few different other sets of keys
- iteration with each
- Perl on Debian 5.8.8-7etch3, Perl on OSX 10.4
Thanks!
[Please do not change anything below this line]
-----------------------------------------------------------------
---
Flags:
category=core
severity=medium
---
Site configuration information for perl v5.8.8:
Configured by Gentoo at Mon Nov 19 16:17:34 EST 2007.
Summary of my perl5 (revision 5 version 8 subversion 8) configuration:
Platform:
osname=linux, osvers=2.6.19-gentoo-r5+bsdreiser2_1, archname=i686-linux-thread-multi
uname='linux gentoo.grakker.jesnetplus.com 2.6.19-gentoo-r5+bsdreiser2_1 #4 wed sep 26 23:23:37 edt 2007 i686 amd athlon(tm) xp 2800+ authenticamd gnulinux '
config_args='-des -Darchname=i686-linux-thread -Dcccdlflags=-fPIC -Dccdlflags=-rdynamic -Dcc=i686-pc-linux-gnu-gcc -Dprefix=/usr -Dvendorprefix=/usr -Dsiteprefix=/usr -Dlocincpth= -Doptimize=-march=athlon-xp -O2 -fomit-frame-pointer -pipe -Duselargefiles -Dd_semctl_semun -Dscriptdir=/usr/bin -Dman1dir=/usr/share/man/man1 -Dman3dir=/usr/share/man/man3 -Dinstallman1dir=/usr/share/man/man1 -Dinstallman3dir=/usr/share/man/man3 -Dman1ext=1 -Dman3ext=3pm -Dinc_version_list=5.8.0 5.8.0/i686-linux-thread-multi 5.8.2 5.8.2/i686-linux-thread-multi 5.8.4 5.8.4/i686-linux-thread-multi 5.8.5 5.8.5/i686-linux-thread-multi 5.8.6 5.8.6/i686-linux-thread-multi 5.8.7 5.8.7/i686-linux-thread-multi -Dcf_by=Gentoo -Ud_csh -Dusenm -Dusethreads -Di_ndbm -Di_gdbm -Di_db'
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='i686-pc-linux-gnu-gcc', ccflags ='-D_REENTRANT -D_GNU_SOURCE -DTHREADS_HAVE_PIDS -fno-strict-aliasing -pipe -Wdeclaration-after-statement -D_LARGEFILE_SOURCE -D_FILE_OFFSET_BITS=64',
optimize='-march=athlon-xp -O2 -fomit-frame-pointer -pipe',
cppflags='-D_REENTRANT -D_GNU_SOURCE -DTHREADS_HAVE_PIDS -fno-strict-aliasing -pipe -Wdeclaration-after-statement'
ccversion='', gccversion='3.4.6 (Gentoo 3.4.6-r2, ssp-3.4.6-1.0, pie-8.7.10)', 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='i686-pc-linux-gnu-gcc', ldflags =' -L/usr/local/lib'
libpth=/usr/local/lib /lib /usr/lib
libs=-lpthread -lnsl -lndbm -lgdbm -ldb -ldl -lm -lcrypt -lutil -lc
perllibs=-lpthread -lnsl -ldl -lm -lcrypt -lutil -lc
libc=/lib/libc-2.5.so, so=so, useshrplib=false, libperl=libperl.a
gnulibc_version='2.5'
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 v5.8.8:
/etc/perl
/usr/lib/perl5/vendor_perl/5.8.8/i686-linux-thread-multi
/usr/lib/perl5/vendor_perl/5.8.8
/usr/lib/perl5/vendor_perl/5.8.5
/usr/lib/perl5/vendor_perl/5.8.5/i686-linux-thread-multi
/usr/lib/perl5/vendor_perl/5.8.7
/usr/lib/perl5/vendor_perl/5.8.7/i686-linux-thread-multi
/usr/lib/perl5/vendor_perl
/usr/lib/perl5/site_perl/5.8.8/i686-linux-thread-multi
/usr/lib/perl5/site_perl/5.8.8
/usr/lib/perl5/site_perl/5.8.4
/usr/lib/perl5/site_perl/5.8.4/i686-linux-thread-multi
/usr/lib/perl5/site_perl/5.8.5
/usr/lib/perl5/site_perl/5.8.5/i686-linux-thread-multi
/usr/lib/perl5/site_perl/5.8.6
/usr/lib/perl5/site_perl/5.8.6/i686-linux-thread-multi
/usr/lib/perl5/site_perl/5.8.7
/usr/lib/perl5/site_perl/5.8.7/i686-linux-thread-multi
/usr/lib/perl5/site_perl
/usr/lib/perl5/5.8.8/i686-linux-thread-multi
/usr/lib/perl5/5.8.8
/usr/local/lib/site_perl
.
---
Environment for perl v5.8.8:
HOME=/home/jsailor
LANG (unset)
LANGUAGE (unset)
LD_LIBRARY_PATH (unset)
LOGDIR (unset)
PATH=/usr/local/bin:/usr/bin:/bin:/opt/bin:/usr/i686-pc-linux-gnu/gcc-bin/3.4.6:/opt/blackdown-jdk-1.4.2.03/bin:/opt/blackdown-jdk-1.4.2.03/jre/bin:/usr/games/bin
PERLIO=stdio
PERL_BADLANG (unset)
SHELL=/bin/bash
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[perl #55952] Iteration order of hash keys doesn't appear random
by Jonathan Sailor