MooX::StrictConstructoUsermContributed Perl DocumeMooX::StrictConstructor(3pm)
NAME
MooX::StrictConstructor - Make your Moo-based object constructors blow
up on unknown attributes.
VERSION
version 0.011
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
• MooX::InsideOut
• MooseX::StrictConstructor
AUTHOR
George Hartzell <hartzell@cpan.org>
COPYRIGHT AND LICENSE
This software is copyright (c) 2020 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.
perl v5.30.0 2020-04-01 MooX::StrictConstructor(3pm)
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