| Moose::Manual::Delta - Important Changes in Moose |
Moose::Manual::Delta - Important Changes in Moose
This documents any important or noteworthy changes in Moose, with a focus on backwards. This does duplicate data from the Changes file, but aims to provide more details and when possible workarounds.
Besides helping keep up with changes, you can also use this document for finding the lowest version of Moose that supported a given feature. If you encounter a problem and have a solution but don't see it documented here, or think we missed an important feature, please send us a patch.
use Moose::Exporter; now imports strict and warnings into packages
that use it.
DEMOLISHALL and DEMOLISH now receive an argument indicating whether or
not we are in global destruction.
Type constraints no longer run coercions for a value that already matches the
constraint. This may affect some (arguably buggy) edge case coercions that
rely on side effects in the via clause.
the Moose::Exporter manpage now accepts the -metaclass option for easily
overriding the metaclass (without metaclass). This works for classes
and roles.
Added a duck_type sugar function to the Moose::Util::TypeConstraints manpage
to make integration with non-Moose classes easier. It simply checks if
$obj->can() a list of methods.
A number of methods (mostly inherited from the Class::MOP manpage) have been renamed with a leading underscore to indicate their internal-ness. The old method names will still work for a while, but will warn that the method has been renamed. In a few cases, the method will be removed entirely in the future. This may affect MooseX authors who were using these methods.
Calling subtype with a name as the only argument now throws an
exception. If you want an anonymous subtype do:
my $subtype = subtype as 'Foo';
This is related to the changes in version 0.71_01.
The is_needed method in the Moose::Meta::Method::Destructor manpage is now
only usable as a class method. Previously, it worked as a class or
object method, with a different internal implementation for each
version.
The internals of making a class immutable changed a lot in Class::MOP
0.78_02, and Moose's internals have changed along with it. The
external $metaclass->make_immutable method still works the same
way.
A mutable class accepted Foo->new(undef) without complaint,
while an immutable class would blow up with an unhelpful error. Now,
in both cases we throw a helpful error instead.
This "feature" was originally added to allow for cases such as this:
my $args;
if ( something() ) { $args = {...}; }
return My::Class->new($args);
But we decided this is a bad idea and a little too magical, because it can easily mask real errors.
Calling type or subtype without the sugar helpers (as,
where, message) is now deprecated.
As a side effect, this meant we ended up using Perl prototypes on
as, and code like this will no longer work:
use Moose::Util::TypeConstraints; use Declare::Constraints::Simple -All;
subtype 'ArrayOfInts' => as 'ArrayRef' => IsArrayRef(IsInt);
Instead it must be changed to this:
subtype( 'ArrayOfInts' => { as => 'ArrayRef', where => IsArrayRef(IsInt) } );
If you want to maintain backwards compat with older versions of Moose,
you must explicitly test Moose's VERSION:
if ( Moose->VERSION < 0.71_01 ) { subtype 'ArrayOfInts' => as 'ArrayRef' => IsArrayRef(IsInt); } else { subtype( 'ArrayOfInts' => { as => 'ArrayRef', where => IsArrayRef(IsInt) } ); }
We no longer pass the meta-attribute object as a final argument to triggers. This actually changed for inlined code a while back, but the non-inlined version and the docs were still out of date.
If by some chance you actually used this feature, the workaround is
simple. You fetch the attribute object from out of the $self
that is passed as the first argument to trigger, like so:
has 'foo' => ( is => 'ro', isa => 'Any', trigger => sub { my ( $self, $value ) = @_; my $attr = $self->meta->find_attribute_by_name('foo');
# ...
}
);
If you created a subtype and passed a parent that Moose didn't know about, it simply ignored the parent. Now it automatically creates the parent as a class type. This may not be what you want, but is less broken than before.
You could declare a name with subtype such as "Foo!Bar". Moose would accept this allowed, but if you used it in a parameterized type such as "ArrayRef[Foo!Bar]" it wouldn't work. We now do some vetting on names created via the sugar functions, so that they can only contain alphanumerics, ":", and ".".
Methods created via an attribute can now fulfill a requires
declaration for a role. Honestly we don't know why Stevan didn't make
this work originally, he was just insane or something.
Stack traces from inlined code will now report the line and file as being in your class, as opposed to in Moose guts.
When a class does not provide all of a role's required methods, the error thrown now mentions all of the missing methods, as opposed to just the first missing method.
Moose will no longer inline a constructor for your class unless it
inherits its constructor from Moose::Object, and will warn when it
doesn't inline. If you want to force inlining anyway, pass
"replace_constructor => 1 to make_immutable.
If you want to get rid of the warning, pass inline_constructor =>
0.
Removed the (deprecated) make_immutable keyword.
Removing an attribute from a class now also removes delegation
(handles) methods installed for that attribute. This is correct
behavior, but if you were wrongly relying on it you might get bit.
Roles now add methods by calling add_method, not
alias_method. They make sure to always provide a method object,
which will be cloned internally. This means that it is now possible to
track the source of a method provided by a role, and even follow its
history through intermediate roles. This means that methods added by
a role now show up when looking at a class's method list/map.
Parameter and Union args are now sorted, this makes Int|Str the same constraint as Str|Int. Also, incoming type constraint strings are normalized to remove all whitespace differences. This is mostly for internals and should not affect outside code.
the Moose::Exporter manpage will no longer remove a subroutine that the exporting package re-exports. Moose re-exports the Carp::confess function, among others. The reasoning is that we cannot know whether you have also explicitly imported those functions for your own use, so we err on the safe side and always keep them.
Moose::init_meta should now be called as a method.
New modules for extension writers, the Moose::Exporter manpage and the Moose::Util::MetaRole manpage.
Implemented metaclass traits (and wrote a recipe for it):
use Moose -traits => 'Foo'
This should make writing small Moose extensions a little easier.
Fixed coerce to accept anon types just like subtype can.
So that you can do:
coerce $some_anon_type => from 'Str' => via { ... };
Added BUILDARGS, a new step in Moose::Object->new().
Fixed how the is => (ro|rw) works with custom defined
reader, writer and accessor options. See the below table for
details:
is => ro, writer => _foo # turns into (reader => foo, writer => _foo) is => rw, writer => _foo # turns into (reader => foo, writer => _foo) is => rw, accessor => _foo # turns into (accessor => _foo) is => ro, accessor => _foo # error, accesor is rw
The before/around/after method modifiers now support regexp
matching of method names. NOTE: this only works for classes, it is
currently not supported in roles, but, ... patches welcome.
The has keyword for roles now accepts the same array ref form that
Moose.pm does for classes.
A trigger on a read-only attribute is no longer an error, as it's useful to trigger off of the constructor.
Subtypes of parameterizable types now are parameterizable types themselves.
Fixed issue where DEMOLISHALL was eating the value in $@, and so
not working correctly. It still kind of eats them, but so does vanilla
perl.
Inherited attributes may now be extended without restriction on the type ('isa', 'does').
The entire set of Moose::Meta::TypeConstraint::* classes were refactored in this release. If you were relying on their internals you should test your code carefully.
Documenting the use of '+name' with attributes that come from recently composed roles. It makes sense, people are using it, and so why not just officially support it.
The Moose::Meta::Class->create method now supports roles.
It is now possible to make anonymous enum types by passing enum an
array reference instead of the enum $name => @values.
Added the make_immutable keyword as a shortcut to calling
make_immutable on the meta object. This eventually got removed!
Made init_arg => undef work in Moose. This means "do not accept
a constructor parameter for this attribute".
Type errors now use the provided message. Prior to this release they didn't.
Moose is now a postmodern object system :)
The Role system was completely refactored. It is 100% backwards compat, but the internals were totally changed. If you relied on the internals then you are advised to test carefully.
Added method exclusion and aliasing for Roles in this release.
Added the the Moose::Util::TypeConstraints::OptimizedConstraints manpage module.
Passing a list of values to an accessor (which is only expecting one value) used to be silently ignored, now it throws an error.
Added parameterized types and did a pretty heavy refactoring of the type constraint system.
Better framework extendability and better support for "making your own Moose".
Honestly, you shouldn't be using versions of Moose that are this old, so many bug fixes and speed improvements have been made you would be crazy to not upgrade.
Also, I am tired of going through the Changelog so I am stopping here, if anyone would like to continue this please feel free.
Stevan Little <stevan@iinteractive.com>
Copyright 2009 by Infinity Interactive, Inc.
This library is free software; you can redistribute it and/or modify it under the same terms as Perl itself.
| Moose::Manual::Delta - Important Changes in Moose |