Dear Perl Monks,

I have what appears to be a fairly difficult to solve problem with Attribute::Handlers. When a module that has some attributes defined is required at runtime, the attribute handling code does not run. I've looked through the Attribute::Handlers source and it seems like it only does its thing in a couple of specific compiler phases, namely CHECK and INIT (and END too.) So after those are complete it simply does not do anymore attribute handling.

I put together an example of what I am trying to get to work and posed the question via paste bin on the irc.freenode.net #perl channel. Here is the code for your viewing convenience:

############### SuperClass.pm

package SuperClass;
use strict;
use warnings;
use Attribute::Handlers();

# Keeping this simple for now.
sub WrapSub : ATTR(CODE) {
    my( $class, $typeglob, $referent, ) = @_;
    my( $package_sub ) = sprintf '%s::%s', $class, *{ $typeglob }{NAME
+};

    my $wrap_sub = sub {
        warn 'before';
        $referent->( @_ );
        warn 'after';
    };

 warn 'WrapSub wrapping: ', $package_sub;
    no warnings 'redefine';
    *{ $typeglob } = $wrap_sub;
    return;
}

1;


#################### SubClass.pm
package SubClass;
use strict;
use warnings;
use parent 'SuperClass';

sub foo : WrapSub {
    warn 'fooooo';
}

1;


#!/usr/bin/env perl
#################### test_attribute_handlers_compiletime.pl
use strict;
use warnings;
use SubClass();

SubClass->foo;

__END__

$ ./test_attribute_handlers_compiletime.pl
WrapSub wrapping: SubClass::foo at SuperClass.pm line 17.
before at SuperClass.pm line 12.
fooooo at SubClass.pm line 7.
after at SuperClass.pm line 14.


#!/usr/bin/env perl
#################### test_attribute_handlers_runtime.pl
use strict;
use warnings;
use UNIVERSAL::require();
SubClass->require;

SubClass->foo;

__END__

$ ./test_attribute_handlers_runtime.pl
fooooo at SubClass.pm line 7.

[download]

Is there a simple or not-so-simple solution to this? Such as modifying A::H, using a different handler module, or writing my own MODIFY_CODE_ATTRIBUTES method? Thanks in advance!

In reply to Attribute Handlers don't run when called at run time. by bennymack

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