in reply to Help requested to find the cause of an "uninitialized value" message

Slightly different perspective: the error says to me that eval $dumper produces undef. This could be because $dumper is undef, but it could also be because $dumper is something like $VAR1 = undef. You say you check for $VAR1=, but have you checked what is on the right-hand side of the equals sign?

My personal suspicion is that the data are getting lost in the transfer between tasks, but I have no evidence at all to support that. Intermittent failures are hell to diagnose.

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Re^2: Help requested to find the cause of an "uninitialized value" message
by andyok (Novice) on Jan 25, 2022 at 14:30 UTC
    Thank you for your thoughts.

    Following a few smaller-test-cases, and reading through all the comments provided, I think I now understand the nature of the error-message ...
    ... and as you suggest, that the result of eval $dumper is null which when evaluated within %{ .... } is therefore attempting to de-reference a null value.

    So yes, I can check to see if %info = %{ eval $dumper } results in an empty %info which I can then use as a trigger for a break-point or for some printing of some extra information.
    Thank you for your thoughts and time.
    Andrew
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      You might want to check the results of eval $dumper before you try to use them as a hash reference. Something like

      my $hash_ref = eval $dumper;
if ( ! defined $hash_ref ) {
    # You got undef. Handle it as appropriate
} elsif ( 'HASH' eq ref $hash_ref ) {
    # You actually got a hash ref. Handle it.
} else {
    # You got something, but not a hash ref.
    # You don't say this has happened to you, but
    # when troubleshooting, paranoia is justified.
}
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