O wise perl monks,
please grant me the benefit of your advice:

Investigating a bizarre problem today, I found some anomalous behaviour in perl. 


use Data::Dumper qw(Dumper);

my $data = {
        args => '',
};

$data->{args}->{stuff} = 'bother';

print Dumper($data);

print "The value is ", $data->{args}->{stuff}, "\n";

[download]

The script outputs: 

$VAR1 = {
          'args' => ''
        };
The value is bother

[download]

Now, "$data->{args}" has been initialised to a scalar empty string. Without using "use strict", perl allows code which treats this like a hashref and stores something in it. The stored data (in this case, a hashref with key stuff and value bother) can't be seen by Data::Dumper but can be retrieved in the same way it was stored.

Is this a perl bug? If I "use strict" then my program emits an error.

Is this a language feature? I have checked this behaviour in perl 5.6, 5.8 and 5.10. Is it something to do with symbolic references ala "use strict refs" ?

In reply to The hidden hashref by nickandrew

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