---
name: "MooseX::StrictConstructor"
section: "3pm"
platform: "linux"
package: "libmoosex-strictconstructor-perl"
version: "0.21-2"
release: "Debian 13 (Trixie)"
platforms: ["linux"]
url: "https://new.carta.tech/MooseX::StrictConstructor"
---

# MooseX::StrictConstructor(3pm)

Make your object constructors blow up on unknown attributes

## NAME

MooseX::StrictConstructor - Make your object constructors blow up on unknown attributes

## VERSION

version 0.21

## SYNOPSIS

```
    package My::Class;
    use Moose;
    use MooseX::StrictConstructor;
    has 'size' => ( is => 'ro' );
    # then later ...
    # 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 calls `"Moose->throw_error()"`. This is a great way to catch small typos.

### Subverting Strictness

You may find yourself wanting to have your constructor accept a parameter which does not correspond to an attribute.

In that case, you'll probably also be writing a `"BUILD()"` or `"BUILDARGS()"` method to deal with that parameter. In a `"BUILDARGS()"` method, you can simply make sure that this parameter is not included in the hash reference you return. Otherwise, in a `"BUILD()"` method, you can delete it from the hash reference of parameters.

```
  sub BUILD {
      my $self   = shift;
      my $params = shift;
      if ( delete $params->{do_something} ) {
          ...
      }
  }
```

## BUGS

Please report any bugs or feature requests to `"bug-moosex-strictconstructor@rt.cpan.org"`, or through the web interface at \<http://rt.cpan.org\>.  I will be notified, and then you'll automatically be notified of progress on your bug as I make changes.

Bugs may be submitted at \<https://github.com/moose/MooseX-StrictConstructor/issues\>.

I am also usually active on IRC as 'autarch' on `"irc://irc.perl.org"`.

## SOURCE

The source code repository for MooseX-StrictConstructor can be found at \<https://github.com/moose/MooseX-StrictConstructor\>.

## DONATIONS

If you'd like to thank me for the work I've done on this module, please consider making a "donation" to me via PayPal. I spend a lot of free time creating free software, and would appreciate any support you'd care to offer.

Please note that **I am not suggesting that you must do this** in order for me to continue working on this particular software. I will continue to do so, inasmuch as I have in the past, for as long as it interests me.

Similarly, a donation made in this way will probably not make me work on this software much more, unless I get so many donations that I can consider working on free software full time (let's all have a chuckle at that together).

To donate, log into PayPal and send money to autarch@urth.org, or use the button at \<http://www.urth.org/~autarch/fs-donation.html\>.

## AUTHOR

Dave Rolsky \<autarch@urth.org\>

## CONTRIBUTORS

- •

  Jesse Luehrs \<doy@tozt.net\>

- •

  Karen Etheridge \<ether@cpan.org\>

- •

  Ricardo Signes \<rjbs@cpan.org\>

## COPYRIGHT AND LICENSE

This software is Copyright (c) 2007 - 2017 by Dave Rolsky.

This is free software, licensed under:

```
  The Artistic License 2.0 (GPL Compatible)
```

The full text of the license can be found in the *LICENSE* file included with this distribution.