5 Moose::Manual::Delta - Important Changes in Moose
9 This documents any important or noteworthy changes in Moose, with a
10 focus on backwards. This does duplicate data from the F<Changes> file,
11 but aims to provide more details and when possible workarounds.
13 Besides helping keep up with changes, you can also use this document
14 for finding the lowest version of Moose that supported a given
15 feature. If you encounter a problem and have a solution but don't see
16 it documented here, or think we missed an important feature, please
21 L<Moose::Meta::Attribute::Native> has been moved into the Moose core from
22 L<MooseX::AttributeHelpers>. Major changes include:
26 =item C<traits>, not C<metaclass>
28 Method providers are only available via traits.
30 =item C<handles>, not C<provides> or C<curries>
32 The C<provides> syntax was like core Moose C<< handles => HASHREF >>
33 syntax, but with the keys and values reversed. This was confusing,
34 and AttributeHelpers now uses C<< handles => HASHREF >> in a way that
35 should be intuitive to anyone already familiar with how it is used for
38 The C<curries> functionality provided by AttributeHelpers has been
39 generalized to apply to all cases of C<< handles => HASHREF >>, though
40 not every piece of functionality has been ported (currying with a
41 CODEREF is not supported).
43 =item C<empty> now means empty, not non-empty
45 Previously, the C<empty> method provided by Arrays and Hashes returned true if
46 the attribute was B<not> empty (no elements). Now it returns true if the
47 attribute B<is> empty.
51 See L<Moose::Meta::Attribute::Native> for the new documentation.
53 C<< use Moose -metaclass => 'Foo' >> now does alias resolution, just like
54 C<-traits> (and the C<metaclass> and C<traits> options to C<has>).
56 Added two functions C<meta_class_alias> and C<meta_attribute_alias> to
57 L<Moose::Util>, to simplify aliasing metaclasses and metatraits. This is
58 a wrapper around the old
60 package Moose::Meta::Class::Custom::Trait::FooTrait;
61 sub register_implementation { 'My::Meta::Trait' }
67 When an attribute generates I<no> accessors, we now warn. This is to help
68 users who forget the C<is> option. If you really do not want any accessors,
69 you can use C<< is => 'bare' >>. You can maintain back compat with older
70 versions of Moose by using something like:
72 ($Moose::VERSION >= 0.84 ? is => 'bare' : ())
74 When an accessor overwrites an existing method, we now warn. To work around
75 this warning (if you really must have this behavior), you can explicitly
76 remove the method before creating it as an accessor:
80 __PACKAGE__->meta->remove_method('foo');
86 When an unknown option is passed to C<has>, we now warn. You can silence
87 the warning by fixing your code. :)
89 The C<Role> type has been deprecated. On its own, it was useless,
90 since it just checked C<< $object->can('does') >>. If you were using
91 it as a parent type, just call C<role_type('Role::Name')> to create an
92 appropriate type instead.
96 C<use Moose::Exporter;> now imports C<strict> and C<warnings> into packages
101 C<DEMOLISHALL> and C<DEMOLISH> now receive an argument indicating whether or
102 not we are in global destruction.
106 Type constraints no longer run coercions for a value that already matches the
107 constraint. This may affect some (arguably buggy) edge case coercions that
108 rely on side effects in the C<via> clause.
112 L<Moose::Exporter> now accepts the C<-metaclass> option for easily
113 overriding the metaclass (without L<metaclass>). This works for classes
118 Added a C<duck_type> sugar function to L<Moose::Util::TypeConstraints>
119 to make integration with non-Moose classes easier. It simply checks if
120 C<< $obj->can() >> a list of methods.
122 A number of methods (mostly inherited from L<Class::MOP>) have been
123 renamed with a leading underscore to indicate their internal-ness. The
124 old method names will still work for a while, but will warn that the
125 method has been renamed. In a few cases, the method will be removed
126 entirely in the future. This may affect MooseX authors who were using
131 Calling C<subtype> with a name as the only argument now throws an
132 exception. If you want an anonymous subtype do:
134 my $subtype = subtype as 'Foo';
136 This is related to the changes in version 0.71_01.
138 The C<is_needed> method in L<Moose::Meta::Method::Destructor> is now
139 only usable as a class method. Previously, it worked as a class or
140 object method, with a different internal implementation for each
143 The internals of making a class immutable changed a lot in Class::MOP
144 0.78_02, and Moose's internals have changed along with it. The
145 external C<< $metaclass->make_immutable >> method still works the same
150 A mutable class accepted C<< Foo->new(undef) >> without complaint,
151 while an immutable class would blow up with an unhelpful error. Now,
152 in both cases we throw a helpful error instead.
154 This "feature" was originally added to allow for cases such as this:
162 return My::Class->new($args);
164 But we decided this is a bad idea and a little too magical, because it
165 can easily mask real errors.
167 =head1 Version 0.71_01
169 Calling C<type> or C<subtype> without the sugar helpers (C<as>,
170 C<where>, C<message>) is now deprecated.
172 As a side effect, this meant we ended up using Perl prototypes on
173 C<as>, and code like this will no longer work:
175 use Moose::Util::TypeConstraints;
176 use Declare::Constraints::Simple -All;
178 subtype 'ArrayOfInts'
180 => IsArrayRef(IsInt);
182 Instead it must be changed to this:
187 where => IsArrayRef(IsInt)
191 If you want to maintain backwards compat with older versions of Moose,
192 you must explicitly test Moose's C<VERSION>:
194 if ( Moose->VERSION < 0.71_01 ) {
195 subtype 'ArrayOfInts'
197 => IsArrayRef(IsInt);
203 where => IsArrayRef(IsInt)
210 We no longer pass the meta-attribute object as a final argument to
211 triggers. This actually changed for inlined code a while back, but the
212 non-inlined version and the docs were still out of date.
214 If by some chance you actually used this feature, the workaround is
215 simple. You fetch the attribute object from out of the C<$self>
216 that is passed as the first argument to trigger, like so:
222 my ( $self, $value ) = @_;
223 my $attr = $self->meta->find_attribute_by_name('foo');
231 If you created a subtype and passed a parent that Moose didn't know
232 about, it simply ignored the parent. Now it automatically creates the
233 parent as a class type. This may not be what you want, but is less
236 You could declare a name with subtype such as "Foo!Bar". Moose would
237 accept this allowed, but if you used it in a parameterized type such
238 as "ArrayRef[Foo!Bar]" it wouldn't work. We now do some vetting on
239 names created via the sugar functions, so that they can only contain
240 alphanumerics, ":", and ".".
244 Methods created via an attribute can now fulfill a C<requires>
245 declaration for a role. Honestly we don't know why Stevan didn't make
246 this work originally, he was just insane or something.
248 Stack traces from inlined code will now report the line and file as
249 being in your class, as opposed to in Moose guts.
251 =head1 Version 0.62_02
253 When a class does not provide all of a role's required methods, the
254 error thrown now mentions all of the missing methods, as opposed to
255 just the first missing method.
257 Moose will no longer inline a constructor for your class unless it
258 inherits its constructor from Moose::Object, and will warn when it
259 doesn't inline. If you want to force inlining anyway, pass
260 C<< replace_constructor => 1 >> to C<make_immutable>.
262 If you want to get rid of the warning, pass C<< inline_constructor =>
267 Removed the (deprecated) C<make_immutable> keyword.
269 Removing an attribute from a class now also removes delegation
270 (C<handles>) methods installed for that attribute. This is correct
271 behavior, but if you were wrongly relying on it you might get bit.
275 Roles now add methods by calling C<add_method>, not
276 C<alias_method>. They make sure to always provide a method object,
277 which will be cloned internally. This means that it is now possible to
278 track the source of a method provided by a role, and even follow its
279 history through intermediate roles. This means that methods added by
280 a role now show up when looking at a class's method list/map.
282 Parameter and Union args are now sorted, this makes Int|Str the same
283 constraint as Str|Int. Also, incoming type constraint strings are
284 normalized to remove all whitespace differences. This is mostly for
285 internals and should not affect outside code.
287 L<Moose::Exporter> will no longer remove a subroutine that the
288 exporting package re-exports. Moose re-exports the Carp::confess
289 function, among others. The reasoning is that we cannot know whether
290 you have also explicitly imported those functions for your own use, so
291 we err on the safe side and always keep them.
295 C<Moose::init_meta> should now be called as a method.
297 New modules for extension writers, L<Moose::Exporter> and
298 L<Moose::Util::MetaRole>.
300 =head1 Version 0.55_01
302 Implemented metaclass traits (and wrote a recipe for it):
304 use Moose -traits => 'Foo'
306 This should make writing small Moose extensions a little
311 Fixed C<coerce> to accept anon types just like C<subtype> can.
314 coerce $some_anon_type => from 'Str' => via { ... };
318 Added C<BUILDARGS>, a new step in C<< Moose::Object->new() >>.
322 Fixed how the C<< is => (ro|rw) >> works with custom defined
323 C<reader>, C<writer> and C<accessor> options. See the below table for
326 is => ro, writer => _foo # turns into (reader => foo, writer => _foo)
327 is => rw, writer => _foo # turns into (reader => foo, writer => _foo)
328 is => rw, accessor => _foo # turns into (accessor => _foo)
329 is => ro, accessor => _foo # error, accesor is rw
333 The C<before/around/after> method modifiers now support regexp
334 matching of method names. NOTE: this only works for classes, it is
335 currently not supported in roles, but, ... patches welcome.
337 The C<has> keyword for roles now accepts the same array ref form that
338 L<Moose>.pm does for classes.
340 A trigger on a read-only attribute is no longer an error, as it's
341 useful to trigger off of the constructor.
343 Subtypes of parameterizable types now are parameterizable types
348 Fixed issue where C<DEMOLISHALL> was eating the value in C<$@>, and so
349 not working correctly. It still kind of eats them, but so does vanilla
354 Inherited attributes may now be extended without restriction on the
355 type ('isa', 'does').
357 The entire set of Moose::Meta::TypeConstraint::* classes were
358 refactored in this release. If you were relying on their internals you
359 should test your code carefully.
363 Documenting the use of '+name' with attributes that come from recently
364 composed roles. It makes sense, people are using it, and so why not
365 just officially support it.
367 The C<< Moose::Meta::Class->create >> method now supports roles.
369 It is now possible to make anonymous enum types by passing C<enum> an
370 array reference instead of the C<< enum $name => @values >>.
374 Added the C<make_immutable> keyword as a shortcut to calling
375 C<make_immutable> on the meta object. This eventually got removed!
377 Made C<< init_arg => undef >> work in Moose. This means "do not accept
378 a constructor parameter for this attribute".
380 Type errors now use the provided message. Prior to this release they
385 Moose is now a postmodern object system :)
387 The Role system was completely refactored. It is 100% backwards
388 compat, but the internals were totally changed. If you relied on the
389 internals then you are advised to test carefully.
391 Added method exclusion and aliasing for Roles in this release.
393 Added the L<Moose::Util::TypeConstraints::OptimizedConstraints>
396 Passing a list of values to an accessor (which is only expecting one
397 value) used to be silently ignored, now it throws an error.
401 Added parameterized types and did a pretty heavy refactoring of the
402 type constraint system.
404 Better framework extendability and better support for "making your own
407 =head1 Version 0.25 or before
409 Honestly, you shouldn't be using versions of Moose that are this old,
410 so many bug fixes and speed improvements have been made you would be
411 crazy to not upgrade.
413 Also, I am tired of going through the Changelog so I am stopping here,
414 if anyone would like to continue this please feel free.
418 Stevan Little E<lt>stevan@iinteractive.comE<gt>
420 =head1 COPYRIGHT AND LICENSE
422 Copyright 2009 by Infinity Interactive, Inc.
424 L<http://www.iinteractive.com>
426 This library is free software; you can redistribute it and/or modify
427 it under the same terms as Perl itself.