# phpman > perldoc > MooseX::StrictConstructor

## NAME
    [MooseX::StrictConstructor](https://www.chedong.com/phpMan.php/perldoc/MooseX%3A%3AStrictConstructor/markdown) - Make your object constructors blow up on unknown attributes

## VERSION
    version 0.21

## SYNOPSIS
        package [My::Class](https://www.chedong.com/phpMan.php/perldoc/My%3A%3AClass/markdown);

        use Moose;
        use [MooseX::StrictConstructor](https://www.chedong.com/phpMan.php/perldoc/MooseX%3A%3AStrictConstructor/markdown);

        has 'size' => ( is => 'ro' );

        # then later ...

        # this blows up because color is not a known attribute
        [My::Class](https://www.chedong.com/phpMan.php/perldoc/My%3A%3AClass/markdown)->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.