Sometimes you want to remove behavior from your code in a future version, here’s the right way to do it.

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package DeperecatedMethod;
use Moose;
our @CARP_NOT = ( 'Class::MOP::Method::Wrapped', __PACKAGE__ );

has value => (
	isa     => 'Int',
	is      => 'ro',
	lazy    => 1,
	default => &random_generator,
);

has seed_value => (
	isa     => 'Int',
	is      => 'ro',
	lazy    => 1,
	default => &random_generator,
);

before value => sub {
	warnings::warnif('deprecated',
		'attribute `value` is deprecated use `seed_value`'
	);
};

before mymethod => sub {
	warnings::warnif('deprecated',
		'method `mymethod` is deprecated use `random_generator_instead`'
	);
};

sub mymethod {
  return random_generator;
}

sub random_generator {
  return 9;
}

1;

Here’s the quick of how it works, the before has to come after attributes because the methods aren’t yet created. Using before also means it’ll always run with your method, without actually touching your method, insuring no accidental consequences to your method. The @CARP_NOT ensures that the warning thrown doesn’t show a line number in your package, or from within where Method Modifiers are actually run. warnings::warnif( 'deprecated', ..., ensures that these warnings are only emitted if you have the deprecated category enabled. But what if people don’t have warnings enabled? um… oh well? that’s there problem because what if people do and they want to silence these until they can get to them. I highly suggest putting the name of the method being called and it’s successor into the message so that people know how to correct their code.

If you don’t want Moose, just don’t use the method modifier and put warnings:warnif directly in your code. if you’re using a different AOP before, modify @CARP_NOT to have the correct module.