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

Hi monks,

I was wondering if there's a way to configure the Carp stack backtrace, as printed by longmess or confess, to get a shorter line. For instance, with just the filename + line number, and a shorter, relative path: 

Big error thrown.
Stack:
./lib/Foo.pm:15
./lib/Bar.pm:320
./lib/Base/BarBase.pm:210

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Well, you get the drill.

cheers!

andrea

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Re: Shorter Carp stack backtrace
by almut (Canon) on Apr 16, 2010 at 01:34 UTC

    I don't think this can be configured — at least not without modifying the source :)

    From Carp/Heavy.pm: 

    sub ret_backtrace {
  ...

  my %i = caller_info($i);
  $mess = "$err at $i{file} line $i{line}$tid_msg\n";

  while (my %i = caller_info(++$i)) {
      $mess .= "\t$i{sub_name} called at $i{file} line $i{line}$tid_ms
+g\n";
  }
  
  return $mess;
}

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      I agree. Strangely, it won't let me monkeypatch it, such as in: 

          sub Carp::Heavy::ret_backtrace{ return 'short...' }

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      Don't know why, but it calls its old code. It let's me patch Carp::shortmess though.

      cheers,

      andrea

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      $Carp::CarpLevel?
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        How would that change the line format of the backtrace to file:line, as desired? 

        #!/usr/bin/perl

use Carp 'cluck';

sub foo { bar() }
sub bar { baz() }
sub baz { cluck "big error!" }

foo();

$Carp::CarpLevel = 2;

foo();

__END__
big error! at ./834994.pl line 7
    main::baz() called at ./834994.pl line 6
    main::bar() called at ./834994.pl line 5
    main::foo() called at ./834994.pl line 9
big error! at ./834994.pl line 5
    main::foo() called at ./834994.pl line 13

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