http://www.perlmonks.org?node_id=1015364


in reply to Find out who redefined a subroutine

Ta da!

sub sub::source {
    require Sub::Identify;
    my ($class, $func) = @_;
    my $code = $class->can($func) or return;
    return Sub::Identify::stash_name($code);
}

{
    package MyApp;
    use Time::HiRes qw(time);
    use Carp;
}

# Where do MyApp's subs come from?
#
print MyApp->sub::source('carp'), "\n";
print MyApp->sub::source('time'), "\n";

# Where do Carp's subs come from?
#
print Carp->sub::source('carp'), "\n";
print Carp->sub::source('import'), "\n";

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Though it's worth noting that Sub::Name is able to fool Sub::Identify. Also, Moose/Moo/etc do stringy eval stuff that fools Sub::Identify (deliberately).

package Cow { use Moo; has name => (is => 'lazy', default => sub { 'Mooington' }) } say Cow->new->name

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Re^2: Find out who redefined a subroutine
by Dallaylaen (Chaplain) on Jan 25, 2013 at 15:45 UTC
    Aha, so there *is* a full-blown CPAN module for this. Thanks for noting!

    My code can be fooled, too.

    Just copy original subref to a private variable and it would think the sub is still the original one.

[reply]
      Maybe a way to prevent being fooled is to MD5 the sub, and sign it.
[reply]

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