APM: Interesting hash side effect

[ezra pagel]

yeah brian, sometimes autovivification is a mixed blessing. this
behavior is discussed in the documentation for exists().

On Thu, 2003-01-09 at 12:45, Brian Michalk wrote:

> I have had a nagging bug that I finally figured out.
> I found that in some cases checking to see if a hash element is defined will
> add to the hash.
> The following line:
>     103     if (defined $self->{keys}{cfg}{$varname}{ref_sub}) {
> will add the hash element, $self->{keys}{cfg}{$varname}.  I had to change my
> code to the following in order to get it to work correctly.
> 
>     102   if (defined $self->{keys}{cfg}{$varname}) {
>     103     if (defined $self->{keys}{cfg}{$varname}{ref_sub}) {
>     104       return $self->{keys}{cfg}{$varname}{ref_sub};
>     105     }
>     106   } else {
>     107     return undef;
>     108   }
> 
> I hope this helps anyone else who cares.
> 
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-- 
======================================================================
Ezra Pagel                                           Software Engineer
Perl/Java/Oracle                                         ezra at jdba.org
Austin Logistics, Inc.                      epagel at austinlogistics.com
Austin, Texas                                           (512)-651-5644
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