Hello Perlmonks,

I'm having trouble debugging a heavily random program because I'm unable to force it to repeat its behavior.

After reading perlrun and web-searching a bit I concluded that the following snippet at the top of the program might do the trick: 

#!/usr/bin/env perl
use v5.36;
BEGIN {
    srand(1);                  # rand generator is repeatable
    $ENV{PERL_PERTURB_KEYS}=0; # traversing keys is repeatable
    $ENV{PERL_HASH_SEED}=1;    # hashing is repeatable?
}

[download]
In addition to calling rand() to choose an array index, it also traverses lists of key(%hash). As far as I know, those are the only places where randomness can occur. (No hashes are modified after they're constructed at initialization.)

I gather from perldoc perlrun ("this mode is as close to pre 5.18 behavior as you can get.") that perhaps there are no guarantees anymore?

Can anyone suggest what I might be doing wrong or overlooking?

In reply to Repeatable rand() and keys() for debugging by ibm1620

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