[perl #68192] Tied scalar numeric FETCH corruption after STORE()ing a reference

# New Ticket Created by  David Taylor 
# Please include the string:  [perl #68192]
# in the subject line of all future correspondence about this issue. 
# <URL: http://rt.perl.org/rt3/Ticket/Display.html?id=68192 >


With a tied scalar with a FETCH() method that returns a number, if a
reference is STORED()ed in the tied scalar and then a FETCH()ed value
is interpreted in a numeric context, the value that FETCH() returns is
ignored, and instead you get back the STORE()ed reference as an
integer.

5.8.9, 5.10.0 and blead all have the bug, 5.6.2 does not.

Demo:

# BEGIN SCRIPT

sub TIESCALAR { bless {}, __PACKAGE__ };
sub STORE {};
sub FETCH { 123456 };

my $foo;
tie $foo, __PACKAGE__;

my $a = [1234567];

my $x = 0 + $foo;
$foo = $a;
my $y = 0 + $foo;
my $yhex = sprintf '0x%x', $y;

print "x = $x, y = $y, a = $a, yhex = $yhex\n";

# END SCRIPT

Under 5.10.0 this prints:
x = 123456, y = 148755408, a = ARRAY(0x8ddd3d0), yhex = 0x8ddd3d0


$ perl -V
Summary of my perl5 (revision 5 version 10 subversion 0) configuration:
  Platform:
    osname=linux, osvers=2.6.24-23-server, archname=i486-linux-gnu-thread-multi
    uname='linux rothera 2.6.24-23-server #1 smp wed apr 1 22:22:14
utc 2009 i686 gnulinux '
    config_args='-Dusethreads -Duselargefiles -Dccflags=-DDEBIAN
-Dcccdlflags=-fPIC -Darchname=i486-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 -Ds
itelib=/usr/local/share/perl/5.10.0
-Dsitearch=/usr/local/lib/perl/5.10.0 -Dman1dir=/usr/share/man/man1
-Dman3dir=/usr/share/man/man3 -Dsiteman1
dir=/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.5.10.0 -Dd_dosuid -des'
    hint=recommended, useposix=true, d_sigaction=define
    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='cc', ccflags ='-D_REENTRANT -D_GNU_SOURCE -DDEBIAN
-fno-strict-aliasing -pipe -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 -I/usr/local/include'
    ccversion='', gccversion='4.3.2', 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 /usr/lib64
    libs=-lgdbm -lgdbm_compat -ldb -ldl -lm -lpthread -lc -lcrypt
    perllibs=-ldl -lm -lpthread -lc -lcrypt
    libc=/lib/libc-2.8.90.so, so=so, useshrplib=true, libperl=libperl.so.5.10.0
    gnulibc_version='2.8.90'
  Dynamic Linking:
    dlsrc=dl_dlopen.xs, dlext=so, d_dlsymun=undef, ccdlflags='-Wl,-E'
    cccdlflags='-fPIC', lddlflags='-shared -O2 -g -L/usr/local/lib'


Characteristics of this binary (from libperl):
  Compile-time options: MULTIPLICITY PERL_DONT_CREATE_GVSV
                        PERL_IMPLICIT_CONTEXT PERL_MALLOC_WRAP USE_ITHREADS
                        USE_LARGE_FILES USE_PERLIO USE_REENTRANT_API
  Built under linux
  Compiled at Jun 26 2009 19:08:22
  @INC:
    /etc/perl
    /usr/local/lib/perl/5.10.0
    /usr/local/share/perl/5.10.0
    /usr/lib/perl5
    /usr/share/perl5
    /usr/lib/perl/5.10
    /usr/share/perl/5.10
    /usr/local/lib/site_perl
    .

• [perl #68192] Tied scalar numeric FETCH corruption after STORE()ing a reference by David Taylor
• Re: [perl #68192] Tied scalar numeric FETCH corruption after STORE()ing a reference by David Nicol