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Postings from August 2008
On Tue Nov 14 19:02:09 2000, anno4000@lublin.zrz.tu-berlin.de wrote:
>
> This is a bug report for perl from anno4000@lublin.zrz.tu-berlin.de,
> generated with the help of perlbug 1.28 running under perl v5.6.0.
>
>
> -----------------------------------------------------------------
> [Please enter your report here]
>
> The code below demonstrates that under certain circumstances an object
> (a hashref) can turn up n destruction with components missing
> (undefined)
> that were defined before. This happens when a reference to the object
> is
> stored in a package variable.
>
> In the code example, the object that turns up damaged during
> destruction
> is of class Obj in variable $obj. The (only) component of $obj is
> $obj->{ gen}, which is defined throughout the existence of $obj,
> but is found undef during destruction.
>
>
> #!/usr/bin/perl
> use strict; use warnings; $| = 1;
>
> package Gen;
>
> sub new {
> bless {}, shift;
> }
>
> sub obj {
> my $self = shift;
> _new Obj $self; # remember who created you
> }
>
> package Obj;
>
> sub _new {
> my $class = shift;
> my $gen = shift;
> die "Gah!\n" unless defined $gen; # never let an undef gen pass
> bless { gen => $gen}, $class;
> }
>
> sub DESTROY {
> my $self = shift;
> print "destroying $self\n";
> # $self->{ gen} should never be undef at this point
> print "gen undef in destruction\n" unless defined $self->{ gen};
> }
>
> package main;
>
> my $gen = new Gen;
>
> our $obj = $gen->obj; # changing our to my makes the error go away
>
> print "generator defined\n" if defined $obj->{ gen}; # peeking in
> # no warnings; # activating this makes the error go away
> $obj; # commenting this out makes the error go away
>
>
>
> [Please do not change anything below this line]
> -----------------------------------------------------------------
Pay attention to the line: 'gen undef in destruction'
perl-5.6.0 rt-4700.pl
Useless use of a variable in void context at rt-4700.pl line 39.
generator defined
destroying Obj=HASH(0x80ff948)
gen undef in destruction
perl-5.8.0 rt-4700.pl .. perl-5.8.8 rt-4700.pl
Useless use of a variable in void context at rt-4700.pl line 39.
generator defined
destroying Obj=HASH(0x81484a0)
perl-5.8.x rt-4700.pl (MAINT33934)
Useless use of a variable in void context at rt-4700.pl line 39.
generator defined
destroying Obj=HASH(0x8124858)
gen undef in destruction
perl-5.10.0 rt-4700.pl (MAINT33934)
Useless use of a variable in void context at rt-4700.pl line 39.
generator defined
destroying Obj=HASH(0x8169868)
gen undef in destruction
perl-blead rt-4700.pl
Useless use of a variable in void context at rt-4700.pl line 39.
generator defined
destroying Obj=HASH(0x81707e8)
gen undef in destruction
Was the bug gone between 5.8.0 and 5.8.8 or was it just hiding?
Kind regards,
Bram
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