I agree. I tend to solve this problem by having a namespace just for methods (sometimes one namespace just for class methods and another just for object methods). Then I write my code in an implementation namespace that is not searched for methods where I can write utility subroutines or import stuff with no worries. A simple demonstration might include:

package Cone::Head;
our $VERSION= '1.001_001';
use Cone::Head::code qw< new objectNamespace >;
package Cone::Head::Object;
use Cone::Head::code; # Imports all object methods (by default)
1;
[download]

package Cone::Head::code;
# ...
use Devel::NamedArguments qw< parseMethodArgs >;

sub objectNamespace {
    my( $we )= @_;
    return $we."::Object";
}

sub new {
    my( $we, %args )= parseMethodArgs(@_);
    my $me= init( \%args );
    return bless $me, $we->objectNamespace();
}

# $obj->init() will say: Can't locate object method "init" via package
+...
sub init {
   ...
}
...
[download]

The main drawback I find with this scheme is that caller is woefully inadequate at introspection. A more useful version of caller would be able to tell me that Cone::Head::Beldar->newFromDB() searched for newFromDB() for the class Cone::Head::Beldar and found newFromDB() in parent class Cone::Head where it had been imported from Class::NiftyORM where it was originally called CreateObjectFromDB() but the code inside that method actually considers its default package name to be Class::NiftyORM::code. A situation simulated by the following code:

package Class::NiftyORM::code;
sub Class::NiftyORM::CreateObjectFromDB { ... }

package Cone::Head;
*newFromDB= \&ClassNiftyORM::CreateObjectFromDB;

package Cone::Head::Beldar;
@ISA= qw< Cone::Head >;
[download]

So I'd like to be able to get the following information from something like caller:

• Subroutine (or method) names:
  • Original definition (appears after "sub" keyword), might be undefined
  • Called as (can also be undefined)
• Package names:
  • Default of compiled code (see prior 'package' statement)
  • Of original subroutine name (either above or appears after "sub" keyword)
  • Package (class) where sub was first searched for
  • Package (class) where sub was found (for non-method calls, same as above)

but it's often overly wrong, and not very convenient; thus the fact that you can't safely import subroutines into an OO module feels like a design bug to me.

For convenience; and to solve the problem at coding time rather than burdening your users with runtime solutions, try:

package utils;
use Exporting::Module qw[ utility_sub ];
package Your::OO::Module;
use Exporting::Module ();

...
utils::utility_sub();
...
[download]

That works nicely, as long as I'm the only one using namespace utils; if I'm not, I'll get optional nasty redefinition warnings, or worse silently overriden routines in the utils namespace, which might lead to very hard to debug errors.

namespace::autoclean

(Apologies if this was already mentioned.)