Re: Deep Recursion Limit

[broquaint]

This can be done, but not quite as simply as you had perhaps hoped

use strict;
use warnings;

## disable perl's warning mechanism
no warnings 'recursion';

use B      'svref_2object';
use Symbol 'qualify_to_ref';

sub change_depth_warn {
  my($subname, $limit) = @_;
  my $subref = \&$subname;
  my $gv     = svref_2object($subref)->GV;
  my $lineno = 0;

  no warnings 'redefine';
  *{ qualify_to_ref $subname } = sub {
    if( $gv->CV->DEPTH % $limit == 0 ) {
      $lineno = do {
        my $i = 0;
        1 while caller $i++;
        (caller($i - 2))[2]
      } unless $lineno;

      warn
        sprintf "Deep recursion on subroutine '%s' at %s line %d.\n",
                join('::', $gv->STASH->NAME, $gv->NAME), $0, $lineno;
    }
    &$subref(@_);
  };
}

my $cnt = 0;
sub foo { &foo while $cnt++ < $_[0] }

my $maxdepth = 1000;
my $recdepth = 3000;
change_depth_warn('foo', $maxdepth);

printf "calling foo(), expecting %d warnings ...\n",
       $recdepth / $maxdepth;

foo($recdepth);

__output__

calling foo(), expecting 3 warnings ...
Deep recursion on subroutine 'main::foo' at perlmonks/pmsopw_324564.pl
+ line 43.
Deep recursion on subroutine 'main::foo' at perlmonks/pmsopw_324564.pl
+ line 43.
Deep recursion on subroutine 'main::foo' at perlmonks/pmsopw_324564.pl
+ line 43.

So that disables the recursion warning, and then wraps the foo() in a closure that emits a recursion warning for every $limitth recursion.

[dragonchild]

Post that on CPAN in something - anything. I can see great utility in that. Maybe as a pragma?

use warnings::recursion 1000;