Bizarre copy of ARRAY in leave at ...

Anonymous Monk has asked for the wisdom of the Perl Monks concerning the following question:

Hello,

I run both Linux Mandrake (Perl 5.8.6) and Windows XP (also Perl 5.8.6) and I get the same error (and crash) on both when using the perl debugger. But only when using the perl debugger. Otherwise it runs just fine.

I was trying to use the perl debugger to trace to an unrelated problem in a rather large program. After considerable shuffling I came up with the short script below that brings out the problem on both platforms.

If I can solve this, I can go back to using the debugger with my real program.
Thanks

use Tk;
use Tk::ProgressBar;

my $percent_done = 0;
my $i = 0;

our $mw = MainWindow->new(-title => 'ProgressBar example');

my $progress = $mw->ProgressBar( -variable => \$percent_done )->pack(-
+fill => 'x');

$mw->Button(-text => 'Go!', -command=> sub {
   for ($i = 0; $i < 1000; $i++) { 
     $percent_done = $i/10;
     $mw->update;  # otherwise we don't see how far we are.
  }
 })->pack(-side => 'bottom');

$mw->Button(-text => 'Exit!', -command=> sub {$mw->destroy;}
           )->pack(-side => 'bottom');

MainLoop;
[download]

2005-04-06 Janitored by Arunbear - added code tags, as per Monastery guidelines

Comment on Bizarre copy of ARRAY in leave at ... Download Code

Replies are listed 'Best First'.
Re: Bizarre copy of ARRAY in leave at ... by NateTut (Deacon) on Apr 06, 2005 at 21:01 UTC
Not that it helps much but it crashes for me as well (Perl 5.8 on Win XP): Tk::Error: Can't set -variable to `SCALAR(0x18299b4)' for Tk::ProgressBar=HASH(0 x4e044f4): Bizarre copy of ARRAY in leave at C:/Perl/site/lib/Tk/Trace.pm line 8 9. at C:/Perl/site/lib/Tk/Derived.pm line 294 Tk callback for event Tk callback for . Tk callback for .progressbar Tk::Derived::configure at C:/Perl/site/lib/Tk/Derived.pm line 306 Tk::Widget::new at C:/Perl/site/lib/Tk/Widget.pm line 205 Tk::Widget::__ANON__C:/Perl/site/lib/Tk/Widget.pm:256 at C:/Perl/site/lib/Tk/ Widget.pm line 256 Can't set -variable to `SCALAR(0x18299b4)' for Tk::ProgressBar=HASH(0x4e044f4): Bizarre copy of ARRAY in leave at C:/Perl/site/lib/Tk/Trace.pm line 89. at C:/Perl/site/lib/Tk/Derived.pm line 294 at C:/Perl/site/lib/Tk/Derived.pm line 306 error:Bizarre copy of ARRAY in leave at C:/Perl/site/lib/Tk/Trace.pm line 89.	[reply]
Re^2: Bizarre copy of ARRAY in leave at ... by mnooning (Beadle) on Apr 07, 2005 at 01:42 UTC
I was able to get the thing to at least run ... until I hit the Exit or Go buttons. The problem seems to be that the ProgressBar code works with undefined items, and just ignores the errors, while the debugger does not ignore them. The case in point is ProgressBar::variable I will paste the original, that crashes in the debugger, and my fix. sub variable { my $c = shift; my $oldvarref = $c->{'-variable'}; my $oldval = $$oldvarref if $oldvarref; if(@_) { my $varref = shift; if ($oldvarref) { $c->traceVdelete($oldvarref); } $c->{'-variable'} = $varref; $c->traceVariable($varref, 'w', sub { $c->value($_[1]) }); $$varref = $oldval; _layoutRequest($c,2); } $oldval; } <\code> <br> Here is the fix<br> <br> <code> sub variable { my $c = shift; my $oldvarref = ""; my $oldval = ""; if (defined($c->{'-variable'})) { $oldvarref = $c->{'-variable'}; $oldval = $$oldvarref if $oldvarref; } if(@_) { my $varref = shift; $c->traceVdelete($oldvarref) if (defined($oldvarref) and ($oldvarref ne "")); $c->{'-variable'} = $varref; $c->traceVariable($varref, 'w', sub { $c->value([1]) }); $$varref = $oldval if (defined($oldval) and ($oldval ne "")); _layoutRequest($c,2); } return ($oldval) if (defined($oldval) and ($oldval ne "")); } [download] This took way to long for me to find. Now I have a worse problem (again, only in the debugger). It runs in that it pops up the progress bar, but when I click on either Exit or Go, it bombs. I have traced it down to Tk::MainLoop where it does DoOneEvent(0); but I cannot trace from there. I am getting very nervous that Tk may have such unprotected undefined items sprinkled about. That would spell doom for anyone wanting to use Tk ... and be able to use the Perl debugger. Someone ... please say it isn't so! Thanks	[reply] [d/l]