AFAIK, Perl itself has no problems with a use of circular dependencies between classes (not modules which export stuff at compile time), and circular dependencies are pretty valid design pattern in some cases (ORM)

Now I found problem using it in Moose:

(this one ok)

$ perl -MAA -e 'AA->mysub()'
AA
BB
[download]

(this fails)

perl -MBB -e 'AA->mysub()'
The method 'mysub' was not found in the inheritance hierarchy for AA a
+t /usr/local/lib/perl/5.14.2/Class/MOP/Class.pm line 1053.
    Class::MOP::Class::__ANON__(Moose::Meta::Class=HASH(0x202fc18), "m
+ysub") called at /usr/local/lib/perl/5.14.2/Class/MOP/Class.pm line 1
+098
    Class::MOP::Class::add_around_method_modifier(Moose::Meta::Class=H
+ASH(0x202fc18), "mysub", CODE(0x202b7b0)) called at /usr/local/lib/pe
+rl/5.14.2/Moose/Util.pm line 267
    Moose::Util::add_method_modifier(Moose::Meta::Class=HASH(0x202fc18
+), "around", ARRAY(0x1edb158)) called at /usr/local/lib/perl/5.14.2/M
+oose.pm line 93
    Moose::around(undef, "mysub") called at /usr/local/lib/perl/5.14.2
+/Moose/Exporter.pm line 409
    Moose::around("mysub", CODE(0x202b7b0)) called at AA.pm line 11
    require AA.pm called at CC.pm line 3
    CC::BEGIN() called at AA.pm line 0
    eval {...} called at AA.pm line 0
    require CC.pm called at BB.pm line 4
    BB::BEGIN() called at AA.pm line 0
    eval {...} called at AA.pm line 0
    require BB.pm called at -e line 0
    main::BEGIN() called at AA.pm line 0
    eval {...} called at AA.pm line 0
Compilation failed in require at CC.pm line 3.
BEGIN failed--compilation aborted at CC.pm line 3.
Compilation failed in require at BB.pm line 4.
BEGIN failed--compilation aborted at BB.pm line 4.
Compilation failed in require.
BEGIN failed--compilation aborted.
[download]

AA.pm:

package AA;
use utf8;
use Moose;
use CC;

extends 'BB';

around mysub => sub {
    print "AA\n";
    shift->();
};
[download]

BB.pm:

package BB;
use utf8;
use Moose;
use CC;

sub mysub { print "BB\n";}
[download]

CC.pm:

package CC;

use AA;
1;
[download]

I think that's because Moose tries to find symbols during compile time. Pure perl does not seem to have same problem:

$ perl -MBB -e 'AA->mysub()'
AA
BB
[download]

AA.pm:

package AA;
use utf8;
use CC;

use parent 'BB';

sub mysub {
    print "AA\n";
    shift->SUPER::mysub();
};
[download]

BB.pm:

package BB;
use utf8;
use CC;

sub mysub { print "BB\n";}
1;
[download]

CC.pm:

package CC;

use AA;
1;
[download]

Question is: how to treat this? A bug? Design limitation? What to do in case I want to use circular dependencies? Is there a workaound?