D'Oh! There were other two interesting posts in the original thread, which settle down the question completely. I'm reporting them here as a reply, else I think the root node may become cluttered as it's late now for such thorough update. To Anno's reply Paul Lalli posted the followup hereafter:

Re: croak/confess from within File::Find (Paul Lalli)

Add this:

push our @CARP_NOT, 'File::Find';

[download]
find(\&wanted, '.'); #line 22
__END__

[download]

Carp has a hard time assigning an error location in callback situations. It climbs the stack, essentially watching for a change in the calling package. When called from a callback it meets that change earlier than intended (from your main to File::Find). The variable @CARP_NOT is checked and a package change is ignored if one of the packages is on the other's @CARP_NOT.

Anno,

Thank you for the information. Annoyingly, it seems that if all the packages are "trusted" (as per Carp's docs), then croak behaves exactly like confess:

#!/opt2/perl/bin/perl
use strict;
use warnings;
use Carp;
use File::Find;

sub err {
    croak ("You did something bad!"); #line 8
}

sub wanted {
  err(); #line 12
}
push our @CARP_NOT, 'File::Find';
find(\&wanted, '.'); #line 15
__END__

[download]
$ ./ff_carp.pl
You did something bad! at ./ff_carp.pl line 8
        main::err() called at ./ff_carp.pl line 12
        main::wanted() called at /opt2/Perl5_8_4/lib/perl5/5.8.4/File/
Find.pm line 810
        File::Find::_find_dir('HASH(0x13e8d4)', ., 2) called at /opt2/
Perl5_8_4/lib/perl5/5.8.4/File/Find.pm line 690
        File::Find::_find_opt('HASH(0x13e8d4)', .) called at /opt2/
Perl5_8_4/lib/perl5/5.8.4/File/Find.pm line 1193
        File::Find::find('CODE(0x15e498)', .) called at ./ff_carp.pl
line 15

[download]

I suppose that's better than nothing. It just bugs me that there doesn't seem to be a way to just have it print where the subroutine was called from. I suppose I could fiddle with caller() to get exactly what I want, but doesn't it seem like carp/croak should be able to do this on its own?

Paul Lalli

Re: croak/confess from within File::Find (Anno)

Add this:

push our @CARP_NOT, 'File::Find';

[download]
find(\&wanted, '.'); #line 22
__END__

[download]

Carp has a hard time assigning an error location in callback situations. It climbs the stack, essentially watching for a change in the calling package. When called from a callback it meets that change earlier than intended (from your main to File::Find). The variable @CARP_NOT is checked and a package change is ignored if one of the packages is on the other's @CARP_NOT.

Anno,

Thank you for the information. Annoyingly, it seems that if all the packages are "trusted" (as per Carp's docs), then croak behaves exactly like confess:

#!/opt2/perl/bin/perl
use strict;
use warnings;
use Carp;
use File::Find;

sub err {
    croak ("You did something bad!"); #line 8
}

sub wanted {
  err(); #line 12
}
push our @CARP_NOT, 'File::Find';
find(\&wanted, '.'); #line 15
__END__

[download]
$ ./ff_carp.pl
You did something bad! at ./ff_carp.pl line 8
        main::err() called at ./ff_carp.pl line 12
        main::wanted() called at /opt2/Perl5_8_4/lib/perl5/5.8.4/File/
Find.pm line 810
        File::Find::_find_dir('HASH(0x13e8d4)', ., 2) called at /opt2/
Perl5_8_4/lib/perl5/5.8.4/File/Find.pm line 690
        File::Find::_find_opt('HASH(0x13e8d4)', .) called at /opt2/
Perl5_8_4/lib/perl5/5.8.4/File/Find.pm line 1193
        File::Find::find('CODE(0x15e498)', .) called at ./ff_carp.pl
line 15

[download]

I suppose that's better than nothing. It just bugs me that there doesn't seem to be a way to just have it print where the subroutine was called from. I suppose I could fiddle with caller() to get exactly what I want, but doesn't it seem like carp/croak should be able to do this on its own?

You can have that if you compile the wanted() function in a package of its own:

{
    package CarpCatcher;
    use Carp;
    sub wanted {
      err(); #line 12
    }

    sub err {
        croak ("You did something bad!");
    }

    push our @CARP_NOT, 'File::Find';
}

use File::Find;

find(\&CarpCatcher::wanted, '.');

__END__

[download]

Anno

In reply to Re: croak/confess from within File::Find by blazar
in thread croak/confess from within File::Find by blazar

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