That's a problem with Perl's absolute minimal OO. People have recognized this, and several solutions are available. For instance, using inside-out objects, you can do this with minimal code changes: 
package FunnyEmail;
use base Email::Simple;
use Hash::Util::FieldHash 'fieldhash';  ### Add this
fieldhash my %JOKE;                     ### Add this
sub new{
    my $class = shift;
    my $text = shift; # assume this gets passed
    my $self=Email::Simple->new($text);
    
    $JOKE{$self} = undef;               ### Change this

    bless $self,$class;

    return $self;

}

[download]
Now your 'JOKE' attribute is in a lexical variable, and not accessable outside of the lexical scope. So, it would not clash with whatever Email::Simple is using, nor will it clash with anything a subclass of FunnyEmail would be doing.

In reply to Re: avoiding overwriting variables in an inherited class by JavaFan
in thread avoiding overwriting variables in an inherited class by whatnext156

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