This will eliminate autovivification: 

my $hash = undef;
print "shouldn't print\n" if $hash; # still prints nothing
if( ref( $hash ) =~ /HASH/ and exists( $hash->{1} ) ) {
    print "Autovivified\n"; # Won't print;
}
print "Still shouldn't print.\n";

[download]

If you don't mind $hash suddenly becoming a hashref (despite being an empty hash), you can eliminate the $ref( $hash ) =~ /HASH/ portion of the check. Do see exists.

You're just getting bitten by autovivification. It's documented behavior.


Dave

In reply to Re: Testing a key creates a hash by davido
in thread Why does testing a key create a hash? by johnnywang

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