I simplified the OP example to trap (but only sometimes!!) the bagged behaviour

#!/usr/bin/perl

use Data::Dump;
#https://www.perlmonks.org/index.pl?node_id=11132441
use strict;
use warnings;
use Tk;
use Tk::ProgressBar;

my %pid=(ex1=>{as=>'temp', val=> -21.5});

my $mw=MainWindow->new();
my $tmpbar=$mw->Frame()->pack( -padx=>30 );


my $pbar = $tmpbar->ProgressBar(
        -anchor=>'s',
        -width=>100,
        -length=>500,
        -blocks=>100,
        -gap=>1,
        -resolution=>0.5,
        -variable=>\$pid{ex1}{val}, 
        -from=>-30,
        -to=>70,
    )->pack();

my $repeat;
$repeat = $mw->repeat(500,sub{  

                                $repeat->cancel() if  $pid{ex1}{val} >
+= 65;  
                                unless ( defined $pid{ex1}{val} ){
                                    print "WARNING: \$pid{ex1}{val} NO
+T FOUND!!\n";
                                    dd %pid;
                                }
                                $pid{ex1}{val}+=5;
                                
                            });


$tmpbar->Label( -textvariable => \$pid{ex1}{val} )->pack();


MainLoop;
[download]

L*

I ran this code on v5.24 with good looking GUI, but with run time error:


Use of uninitialized value in numeric ge (>=) at C:\Users\xxxx\Documen
+ts\PerlProjects\Monks\node_id=11132441.pl line 31.
WARNING: $pid{ex1}{val} NOT FOUND!!
("ex1", { as => "temp", val => undef })
[download]

I am a bit perplexed.

Update: I changed:

$repeat->cancel() if  $pid{ex1}{val} >= 65;  # to the following...
$repeat->cancel() if  ($pid{ex1}{val} >= 65); 
and that seems to work better.
[download]

Hello Marshall,

this is exatcly the point: my code show the bug that happens only sometimes. Try to execute the code many times:

>perl tkprogressbar2.pl

Use of uninitialized value in numeric ge (>=) at tkprogressbar2.pl lin
+e 31.
WARNING: $pid{ex1}{val} NOT FOUND!!
("ex1", { as => "temp", val => undef })

>perl tkprogressbar2.pl

>perl tkprogressbar2.pl

>perl tkprogressbar2.pl

>perl tkprogressbar2.pl

Use of uninitialized value in numeric ge (>=) at tkprogressbar2.pl lin
+e 31.
WARNING: $pid{ex1}{val} NOT FOUND!!
("ex1", { as => "temp", val => undef })
[download]

L*

There are no rules, there are no thumbs..
Reinvent the wheel, then learn The Wheel; may be one day you reinvent one of THE WHEELS.

Creating a bug report is always good. But check first the same issue hasn't been reported already.

Also, as a workaround, you can set the value after creating the progress bar, e.g.

    my $value = $$val;
    my $pbar = $$frame->ProgressBar(
        ...
    );
    $$val = $value;
[download]

map{substr$_->[0],$_->[1]||0,1}[\*||{},3],[[]],[ref qr-1,-,-1],[{}],[sub{}^*ARGV,3]