Devel::Cover 0% branch coverage for externally defined methods

accessor_maker.pm

package accessor_maker;
sub import {
  no strict 'refs';
  *{ caller() . '::' . 'foo' } = sub { $_[0]->{ 'foo' } };
}
1;

output.txt

*$ perl -MDevel::Cover=-ignore,accessor_maker.pm whole.pl
Devel::Cover 0.79: Collecting coverage data for branch, condition, pod, statement, subroutine and time.
Selecting packages matching:
Ignoring packages matching:
    accessor_maker.pm
Ignoring packages in:
    .
    /home/rando/perl5/perlbrew/perls/5.14.2-st/lib/5.14.2
    /home/rando/perl5/perlbrew/perls/5.14.2-st/lib/5.14.2/x86_64-linux-thread-multi
    /home/rando/perl5/perlbrew/perls/5.14.2-st/lib/site_perl/5.14.2
    /home/rando/perl5/perlbrew/perls/5.14.2-st/lib/site_perl/5.14.2/x86_64-linux-thread-multi
    /tmp/CPAN-Reporter-lib-d8a6
undefined
undefined
defined
defined
Devel::Cover: Writing coverage database to /tmp/cover/cover_db/runs/1322588867.10128.41268
---------------------------- ------ ------ ------ ------ ------ ------ ------
File                           stmt   bran   cond    sub    pod   time  total
---------------------------- ------ ------ ------ ------ ------ ------ ------
t/whole.pl                    100.0   50.0    n/a  100.0    n/a  100.0   90.0
Total                         100.0   50.0    n/a  100.0    n/a  100.0   90.0
---------------------------- ------ ------ ------ ------ ------ ------ ------

whole.pl

package cm3;
sub new { bless $_[1], $_[0] }

  # comment/uncomment one or the other:
  use accessor_maker;
  #sub foo { $_[0]->{ 'foo' } }

package main;

sub test {
  my $self = shift;

  print 'un' unless defined $self->foo;
  print "defined\n";

  my $foo = $self->foo;
  print 'un' unless defined $foo;
  print "defined\n";
}

test( cm3->new({}) );
test( cm3->new({foo => 1}) );