NAME
MooX::StrictConstructor - Make your Moo-based object constructors blow up on unknown attributes
SYNOPSIS
package My::Class;
use Moo;
use MooX::StrictConstructor;
has 'size' => ( is => 'rw');
# then somewhere else, when constructing a new instance
# of My::Class ...
# this blows up because color is not a known attribute
My::Class->new( size => 5, color => 'blue' );DESCRIPTION
Simply loading this module makes your constructors "strict". If your constructor is called with an attribute init argument that your class does not declare, then it dies. This is a great way to catch small typos.
Your application can use Carp::Always to generate stack traces on die. Previously all exceptions contained traces, but this could potentially leak sensitive information, e.g.
My::Sensitive::Class->new( password => $sensitive, extra_value => 'foo' );STANDING ON THE SHOULDERS OF ...
Most of this package was lifted from MooX::InsideOut and most of the Role that implements the strictness was lifted from MooseX::StrictConstructor.
SUBVERTING STRICTNESS
MooseX::StrictConstructor documents two tricks for subverting strictness and avoid having problematic arguments cause an exception: handling them in BUILD or handle them in BUILDARGS.
In MooX::StrictConstructor you can use a BUILDARGS function to handle them, e.g. this will allow you to pass in a parameter called "spy" without raising an exception. Useful? Only you can tell.
sub BUILDARGS {
my ($self, %params) = @_;
my $spy = delete $params{spy};
# do something useful with the spy param
return \%params;
}Because BUILD methods are run after an object has been constructed and this code runs before the object is constructed the BUILD trick will not work.
BUGS/ODDITIES
Inheritance
A class that uses MooX::StrictConstructor but extends another class that does not will not be handled properly. This code hooks into the constructor as it is being strung up (literally) and that happens in the parent class, not the one using strict.
A class that inherits from a Moose based class will discover that the Moose class's attributes are disallowed. Given sufficient Moose meta knowledge it might be possible to work around this. I'd appreciate pull requests and or an outline of a solution.
Subverting strictness
MooseX::StrictConstructor documents a trick for subverting strictness using BUILD. This does not work here because strictness is enforced in the early stage of object construction but the BUILD subs are run after the objects has been built.
Interactions with namespace::clean
MooX::StrictConstructor creates a new method that namespace::clean will over-zealously clean. Workarounds include using MooX::StrictConstructor after namespace::autoclean or telling namespace::clean to ignore new with something like:
use namespace::clean -except => ['new','meta'];SEE ALSO
BUGS
Please report any bugs or feature requests on the bugtracker website https://rt.cpan.org/Public/Dist/Display.html?Name=MooX-StrictConstructor or by email to bug-MooX-StrictConstructor@rt.cpan.org.
When submitting a bug or request, please include a test-file or a patch to an existing test-file that illustrates the bug or desired feature.
AUTHOR
George Hartzell <hartzell@cpan.org>
CONTRIBUTORS
George Hartzell <hartzell@alerce.com>
Graham Knop <haarg@haarg.org>
JJ Merelo <jjmerelo@gmail.com>
jrubinator <jjrs.pam+github@gmail.com>
mohawk2 <mohawk2@users.noreply.github.com>
Samuel Kaufman <samuel.c.kaufman@gmail.com>
Tim Bunce <Tim.Bunce@pobox.com>
COPYRIGHT AND LICENSE
This software is copyright (c) 2013 by George Hartzell.
This is free software; you can redistribute it and/or modify it under the same terms as the Perl 5 programming language system itself.