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[ID 20010821.004] Pseudo-hash access does not check fornon-numeric indices

From:
Sean McAfee
Date:
August 21, 2001 13:53
Subject:
[ID 20010821.004] Pseudo-hash access does not check fornon-numeric indices
Message ID:
200108212052.NAA32120@artemis.transmeta.com
This is a bug report for perl from mcafee@transmeta.com,
generated with the help of perlbug 1.26 running under perl 5.00503.


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

The following program stalls and causes memory usage to skyrocket:

$column = [ { files => [ ] } ];
push @{ $column->{files} }, "foo";

What I should have written was

push @{ $column->[0]{files} }, "foo";

...but my leaving out of the [0] caused $column to be treated as a
pseudo-hash, causing the index of the "files" member to be the expression
[ ], which, in numeric context, evaulates to the address of the array being
referenced, which is typically a very large number, accounting for the huge
memory usage.  Such, at least, is my theory.


[Please do not change anything below this line]
-----------------------------------------------------------------

---
Site configuration information for perl 5.00503:

Configured by root at Mon Aug 30 23:08:56 EDT 1999.

Summary of my perl5 (5.0 patchlevel 5 subversion 3) configuration:
  Platform:
    osname=linux, osvers=2.2.5-22smp, archname=i386-linux
    uname='linux porky.devel.redhat.com 2.2.5-22smp #1 smp wed jun 2 09:11:51 edt 1999 i686 unknown '
    hint=recommended, useposix=true, d_sigaction=define
    usethreads=undef useperlio=undef d_sfio=undef
  Compiler:
    cc='cc', optimize='-O2', gccversion=egcs-2.91.66 19990314/Linux (egcs-1.1.2 release)
    cppflags='-Dbool=char -DHAS_BOOL -I/usr/local/include'
    ccflags ='-Dbool=char -DHAS_BOOL -I/usr/local/include'
    stdchar='char', d_stdstdio=undef, usevfork=false
    intsize=4, longsize=4, ptrsize=4, doublesize=8
    d_longlong=define, longlongsize=8, d_longdbl=define, longdblsize=12
    alignbytes=4, usemymalloc=n, prototype=define
  Linker and Libraries:
    ld='cc', ldflags =' -L/usr/local/lib'
    libpth=/usr/local/lib /lib /usr/lib
    libs=-lnsl -ldl -lm -lc -lposix -lcrypt
    libc=, 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'

Locally applied patches:
    

---
@INC for perl 5.00503:
    /local/lib/perl5/site_perl/5.005/i386-linux
    /local/lib/perl5/site_perl/5.005
    /usr/lib/perl5/5.00503/i386-linux
    /usr/lib/perl5/5.00503
    /usr/lib/perl5/site_perl/5.005/i386-linux
    /usr/lib/perl5/site_perl/5.005
    .

---
Environment for perl 5.00503:
    HOME=/home/mcafee
    LANG (unset)
    LANGUAGE (unset)
    LD_LIBRARY_PATH (unset)
    LOGDIR (unset)
    PATH=/home/mcafee/perl561/bin:/home/mcafee/perl-5.6.1:/local/bin:/usr/local/bin:/bin:/usr/bin:/usr/X11R6/bin
    PERL5LIB=/local/lib/perl5/site_perl/5.005
    PERL_BADLANG (unset)
    SHELL=/bin/bash




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