The problem is, this is sloppy:

ClassName->new

[download]

It will behave differently depending on whether or not there is a sub called ClassName in the current package. This is a pretty hard to debug error, and is not really Moose's fault. The following snippet illustrates the problem and doesn't use Moose anywhere...

use 5.010;
use strict;
use LWP::UserAgent;

{
  package ClassName;
  sub new { bless [@_], $_[0] }
}
{
  package main;
  sub ClassName () { 'LWP::UserAgent' };
  my $obj = ClassName->new;
  say ref $obj;  # says "LWP::UserAgent"  
}

[download]

The solution is to institute a policy of never using the BareWord->method syntax. Better, and unambiguous ways of writing ClassName->new are:

ClassName::->new
# or...
'ClassName'->new

[download]

Update: aliased is also a rather nice solution.

perl -E'sub Monkey::do{say$_,for@_,do{($monkey=[caller(0)]->[3])=~s{::}{ }and$monkey}}"Monkey say"->Monkey::do'

In reply to Re: MooseX obscure error and importance of Unit Testing by tobyink
in thread MooseX obscure error and importance of Unit Testing by greengaroo

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