in reply to Perl autovivifyies object property when using exists

$ perl -MData::Dump  -E '$fs4={_structure=>{"/Users/dotfiles/perl5/my_
+modules"=>{}}};my $b= $fs4->{_structure}{"/Users/dotfiles/perl5/my_mo
+dules"};say (exists $b->{BLAH} and exists $b->{BLAH}{crap}); say dd( 
+$fs4)'

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output: 
{ _structure => { "/Users/dotfiles/perl5/my_modules" => {} } }
1

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                "If it happens once, it's a bug. If it happens twice, it's a feature. If it happens more than twice, it's a design philosophy."

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Re^2: Perl autovivifyies object property when using exists
by nysus (Parson) on Apr 03, 2024 at 19:12 UTC

    Oh, I see the second exists call in there now. Missed it the first time.

    $PM = "Perl Monk's";
    $MC = "Most Clueless Friar Abbot Bishop Pontiff Deacon Curate Priest Vicar Parson";
    $nysus = $PM . ' ' . $MC;
    Click here if you love Perl Monks

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Re^2: Perl autovivifyies object property when using exists
by nysus (Parson) on Apr 03, 2024 at 18:59 UTC

    This reproduces the problem: 

    perl -MData::Dump -E ' my $fs4 = {'_structure' => {}}; exists $fs4->{_
+structure}{BLAH}{TEST}{Crap}; dd $fs4->{_structure} '

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    Output: { BLAH => { TEST => {} } }

    $PM = "Perl Monk's";
    $MC = "Most Clueless Friar Abbot Bishop Pontiff Deacon Curate Priest Vicar Parson";
    $nysus = $PM . ' ' . $MC;
    Click here if you love Perl Monks

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Re^2: Perl autovivifyies object property when using exists
by nysus (Parson) on Apr 03, 2024 at 18:50 UTC

    I'm at a loss. I get the same as you on the command line. But in my test, running this: 

     my $fs4 = {'_structure' => {}};
 say (exists $fs4->{_structure}{'/Users/dotfiles/perl5/my_modules'}{BL
+AH}{Crap});
 d $fs4->{_structure}, 3;

    [download]

    I get this: 

    $VAR1 = {
  '/Users/dotfiles/perl5/my_modules' => {
    'BLAH' => {}
  }
};

    [download]

    $PM = "Perl Monk's";
    $MC = "Most Clueless Friar Abbot Bishop Pontiff Deacon Curate Priest Vicar Parson";
    $nysus = $PM . ' ' . $MC;
    Click here if you love Perl Monks

[reply]
[d/l]
[select]

In Section Seekers of Perl Wisdom