Hello monks,

I am using Moose for several last projects of mine and I am very happy with it. Only thing is sometimes quite confusing - its error messages. Given this example: 

package Cls;
use Moose;

has an_array => (
    traits  => ['Array'],
    isa     => 'ArrayRef[Str]',
    is      => 'rw',
    # !!! forgotten default to empty array
    handles => {
        list_array => 'elements',
        add_item   => 'push',
    },
);

package main;

func();

sub func {
    my $c = Cls->new();
    $c->add_item('String');
}

[download]

Running code above, the error message is this:

Can't use an undefined value as an ARRAY reference at C:/Perl/site/lib/Moose/Meta/Attribute/Native/MethodProvider/Array.pm line 130.

I am looking for a way how to assume that Moose is always correct and the error is in my code (on add_item in func sub) for the sake of reporting.

I made an attempt to achieve this, but I am not very happy with the solution: 

package MooseX::Silent;

use Carp qw(confess);

$Carp::Internal{$_}++ for qw{
    MooseX::Silent
    MooseX::Method::Signatures::Meta::Method
    Moose::Meta::Attribute::Native::MethodProvider::Hash
    Moose::Meta::Attribute::Native::MethodProvider::Array
    Moose::Meta::Attribute::Native::Trait
};

$SIG{'__DIE__'} = sub { 
    my $msg = shift;
    for($msg) { 
        s/^.*Internal Validation Error is: //; 
        s/MooseX::Types::Structured:://g; 
        s/ at .*? line \d*\.//;
        chomp;
    }
    confess "$msg";
};

1;

[download]

When this module is used in the Cls class, the error message becomes: 

Can't use an undefined value as an ARRAY reference at tst.pl line 22
    main::func() called at tst.pl line 18

[download]

On the other hand this is pretty global and enumeration of packages is also quite inconvenient.

Is there better way to achieve similar results? Any idea or suggestion welcome.

-- thanks, Roman

In reply to Moose warnings by bobr

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