1 package Moose::Manual::Delta;
3 # ABSTRACT: Important Changes in Moose
11 This documents any important or noteworthy changes in Moose, with a
12 focus on backwards. This does duplicate data from the F<Changes> file,
13 but aims to provide more details and when possible workarounds.
15 Besides helping keep up with changes, you can also use this document
16 for finding the lowest version of Moose that supported a given
17 feature. If you encounter a problem and have a solution but don't see
18 it documented here, or think we missed an important feature, please
25 =item Roles have their own default attribute metaclass
27 Previously, when a role was applied to a class, it would use the attribute
28 metaclass defined in the class when copying over the attributes in the role.
29 This was wrong, because for instance, using L<MooseX::FollowPBP> in the class
30 would end up renaming all of the accessors generated by the role, some of which
31 may be being called in the role, causing it to break. Roles now keep track of
32 their own attribute metaclass to use by default when being applied to a class
33 (defaulting to Moose::Meta::Attribute). This is modifiable using
34 L<Moose::Util::MetaRole> by passing the C<applied_attribute> key to the
35 C<role_metaroles> option, as in:
37 Moose::Util::MetaRole::apply_metaroles(
40 attribute => ['My::Meta::Role::Attribute'],
43 applied_attribute => ['My::Meta::Role::Attribute'],
47 =item Class::MOP has been folded into the Moose dist
49 Moose and Class::MOP are tightly related enough that they have always had to be
50 kept pretty closely in step in terms of versions. Making them into a single
51 dist should simplify the upgrade process for users, as it should no longer be
52 possible to upgrade one without the other and potentially cause issues. No
53 functionality has changed, and this should be entirely transparent.
55 =item Moose's conflict checking is more robust and useful
57 There are two parts to this. The most useful one right now is that Moose will
58 ship with a C<moose-outdated> script, which can be run at any point to list the
59 modules which are installed that conflict with the installed version of Moose.
60 After upgrading Moose, running C<moose-outdated | cpanm> should be sufficient
61 to ensure that all of the Moose extensions you use will continue to work.
63 The other part is that Moose's C<META.json> file will also specify the
64 conflicts under the C<x_conflicts> key. We are working with the Perl tool chain
65 developers to try to get conflicts support added to CPAN clients, and if/when
66 that happens, the metadata already exists, and so the conflict checking will
69 =item Most deprecated APIs/features are slated for removal in Moose 2.0200
71 Most of the deprecated APIs and features in Moose will start throwing an error
72 in Moose 2.0200. Some of the features will go away entirely, and some will
73 simply throw an error.
75 The things on the chopping block are:
79 =item * Old public methods in Class::MOP and Moose
81 This includes things like C<< Class::MOP::Class->get_attribute_map >>, C<<
82 Class::MOP::Class->construct_instance >>, and many others. These were
83 deprecated in L<Class::MOP> 0.80_01, release on April 5, 2009.
85 These methods will be removed entirely in Moose 2.0200.
87 =item * Old public functions in Class::MOP
89 This include C<Class::MOP::subname>, C<Class::MOP::in_global_destruction>, and
90 the C<Class::MOP::HAS_ISAREV> constant. The first two were deprecated in 0.84,
91 and the last in 0.80. Class::MOP 0.84 was released on May 12, 2009.
93 These functions will be removed entirely in Moose 2.0200.
95 =item * The C<alias> and C<excludes> option for role composition
97 These were renamed to C<-alias> and C<-excludes> in Moose 0.89, released on
100 Passing these will throw an error in Moose 2.0200.
102 =item * The old L<Moose::Util::MetaRole> API
104 This include the C<apply_metaclass_roles()> function, as well as passing the
105 C<for_class> or any key ending in C<_roles> to C<apply_metaroles()>. This was
106 deprecated in Moose 0.93_01, released on January 4, 2010.
108 These will all throw an error in Moose 2.0200.
110 =item * Passing plain lists to C<type()> or C<subtype()>
112 The old API for these functions allowed you to pass a plain list of parameter,
113 rather than a list of hash references (which is what C<as()>, C<where>,
114 etc. return). This was deprecated in Moose 0.71_01, released on February 22,
117 This will throw an error in Moose 2.0200.
119 =item * The Role subtype
121 This subtype was deprecated in Moose 0.84, released on June 26, 2009.
123 This will be removed entirely in Moose 2.0200.
133 =item * New release policy
135 As of the 2.0 release, Moose now has an official release and support policy,
136 documented in L<Moose::Manual::Support>. All API changes will now go through a
137 deprecation cycle of at least one year, after which the deprecated API can be
138 removed. Deprecations and removals will only happen in major releases.
140 In between major release, we will still make minor releases to add new
141 features, fix bugs, update documentation, etc.
149 =item Configurable stacktraces
151 Classes which use the L<Moose::Error::Default> error class can now have
152 stacktraces disabled by setting the C<MOOSE_ERROR_STYLE> env var to C<croak>.
153 This is experimental, fairly incomplete, and won't work in all cases (because
154 Moose's error system in general is all of these things), but this should allow
155 for reducing at least some of the verbosity in most cases.
163 =item Native Delegations
165 In previous versions of Moose, the Native delegations were created as
166 closures. The generated code was often quite slow compared to doing the same
167 thing by hand. For example, the Array's push delegation ended up doing
170 push @{ $self->$reader() }, @_;
172 If the attribute was created without a reader, the C<$reader> sub reference
173 followed a very slow code path. Even with a reader, this is still slower than
176 Native delegations are now generated as inline code, just like other
177 accessors, so we can access the slot directly.
179 In addition, native traits now do proper constraint checking in all cases. In
180 particular, constraint checking has been improved for array and hash
181 references. Previously, only the I<contained> type (the C<Str> in
182 C<HashRef[Str]>) would be checked when a new value was added to the
183 collection. However, if there was a constraint that applied to the whole
184 value, this was never checked.
186 In addition, coercions are now called on the whole value.
188 The delegation methods now do more argument checking. All of the methods check
189 that a valid number of arguments were passed to the method. In addition, the
190 delegation methods check that the arguments are sane (array indexes, hash
191 keys, numbers, etc.) when applicable. We have tried to emulate the behavior of
192 Perl builtins as much as possible.
194 Finally, triggers are called whenever the value of the attribute is changed by
197 These changes are only likely to break code in a few cases.
199 The inlining code may or may not preserve the original reference when changes
200 are made. In some cases, methods which change the value may replace it
201 entirely. This will break tied values.
203 If you have a typed arrayref or hashref attribute where the type enforces a
204 constraint on the whole collection, this constraint will now be checked. It's
205 possible that code which previously ran without errors will now cause the
206 constraint to fail. However, presumably this is a good thing ;)
208 If you are passing invalid arguments to a delegation which were previously
209 being ignored, these calls will now fail.
211 If your code relied on the trigger only being called for a regular writer,
212 that may cause problems.
214 As always, you are encouraged to test before deploying the latest version of
217 =item Defaults is and default for String, Counter, and Bool
219 A few native traits (String, Counter, Bool) provide default values of "is" and
220 "default" when you created an attribute. Allowing them to provide these values
221 is now deprecated. Supply the value yourself when creating the attribute.
223 =item The C<meta> method
225 Moose and Class::MOP have been cleaned up internally enough to make the
226 C<meta> method that you get by default optional. C<use Moose> and
227 C<use Moose::Role> now can take an additional C<-meta_name> option, which
228 tells Moose what name to use when installing the C<meta> method. Passing
229 C<undef> to this option suppresses generation of the C<meta> method
230 entirely. This should be useful for users of modules which also use a C<meta>
231 method or function, such as L<Curses> or L<Rose::DB::Object>.
239 =item All deprecated features now warn
241 Previously, deprecation mostly consisted of simply saying "X is deprecated" in
242 the Changes file. We were not very consistent about actually warning. Now, all
243 deprecated features still present in Moose actually give a warning. The
244 warning is issued once per calling package. See L<Moose::Deprecated> for more
247 =item You cannot pass C<< coerce => 1 >> unless the attribute's type constraint has a coercion
249 Previously, this was accepted, and it sort of worked, except that if you
250 attempted to set the attribute after the object was created, you would get a
253 Now you will get a warning when you attempt to define the attribute.
255 =item C<no Moose>, C<no Moose::Role>, and C<no Moose::Exporter> no longer unimport strict and warnings
257 This change was made in 1.05, and has now been reverted. We don't know if the
258 user has explicitly loaded strict or warnings on their own, and unimporting
259 them is just broken in that case.
261 =item Reversed logic when defining which options can be changed
263 L<Moose::Meta::Attribute> now allows all options to be changed in an
264 overridden attribute. The previous behaviour required each option to be
265 whitelisted using the C<legal_options_for_inheritance> method. This method has
266 been removed, and there is a new method, C<illegal_options_for_inheritance>,
267 which can now be used to prevent certain options from being changeable.
269 In addition, we only throw an error if the illegal option is actually
270 changed. If the superclass didn't specify this option at all when defining the
271 attribute, the subclass version can still add it as an option.
273 Example of overriding this in an attribute trait:
275 package Bar::Meta::Attribute;
278 has 'my_illegal_option' => (
283 around illegal_options_for_inheritance => sub {
284 return ( shift->(@_), qw/my_illegal_option/ );
293 =item L<Moose::Object/BUILD> methods are now called when calling C<new_object>
295 Previously, C<BUILD> methods would only be called from C<Moose::Object::new>,
296 but now they are also called when constructing an object via
297 C<Moose::Meta::Class::new_object>. C<BUILD> methods are an inherent part of the
298 object construction process, and this should make C<< $meta->new_object >>
299 actually usable without forcing people to use C<< $meta->name->new >>.
301 =item C<no Moose>, C<no Moose::Role>, and C<no Moose::Exporter> now unimport strict and warnings
303 In the interest of having C<no Moose> clean up everything that C<use Moose>
304 does in the calling scope, C<no Moose> (as well as all other
305 L<Moose::Exporter>-using modules) now unimports strict and warnings.
307 =item Metaclass compatibility checking and fixing should be much more robust
309 The L<metaclass compatibility|Moose/METACLASS COMPATIBILITY AND MOOSE> checking
310 and fixing algorithms have been completely rewritten, in both Class::MOP and
311 Moose. This should resolve many confusing errors when dealing with non-Moose
312 inheritance and with custom metaclasses for things like attributes,
313 constructors, etc. For correct code, the only thing that should require a
314 change is that custom error metaclasses must now inherit from
315 L<Moose::Error::Default>.
323 =item Moose::Meta::TypeConstraint::Class is_subtype_of behavior
325 Earlier versions of L<is_subtype_of|Moose::Meta::TypeConstraint::Class/is_subtype_of>
326 would incorrectly return true when called with itself, its own TC name or
327 its class name as an argument. (i.e. $foo_tc->is_subtype_of('Foo') == 1) This
328 behavior was a caused by C<isa> being checked before the class name. The old
329 behavior can be accessed with L<is_type_of|Moose::Meta::TypeConstraint::Class/is_type_of>
337 =item Moose::Meta::Attribute::Native::Trait::Code no longer creates reader methods by default
339 Earlier versions of L<Moose::Meta::Attribute::Native::Trait::Code> created
340 read-only accessors for the attributes it's been applied to, even if you didn't
341 ask for it with C<< is => 'ro' >>. This incorrect behaviour has now been fixed.
349 =item Moose::Util add_method_modifier behavior
351 add_method_modifier (and subsequently the sugar functions Moose::before,
352 Moose::after, and Moose::around) can now accept arrayrefs, with the same
353 behavior as lists. Types other than arrayref and regexp result in an error.
357 =head1 0.93_01 and 0.94
361 =item Moose::Util::MetaRole API has changed
363 The C<apply_metaclass_roles> function is now called C<apply_metaroles>. The
364 way arguments are supplied has been changed to force you to distinguish
365 between metaroles applied to L<Moose::Meta::Class> (and helpers) versus
366 L<Moose::Meta::Role>.
368 The old API still works, but will warn in a future release, and eventually be
371 =item Moose::Meta::Role has real attributes
373 The attributes returned by L<Moose::Meta::Role> are now instances of the
374 L<Moose::Meta::Role::Attribute> class, instead of bare hash references.
376 =item "no Moose" now removes C<blessed> and C<confess>
378 Moose is now smart enough to know exactly what it exported, even when it
379 re-exports functions from other packages. When you unimport Moose, it will
380 remove these functions from your namespace unless you I<also> imported them
381 directly from their respective packages.
383 If you have a C<no Moose> in your code I<before> you call C<blessed> or
384 C<confess>, your code will break. You can either move the C<no Moose> call
385 later in your code, or explicitly import the relevant functions from the
386 packages that provide them.
388 =item L<Moose::Exporter> is smarter about unimporting re-exports
390 The change above comes from a general improvement to L<Moose::Exporter>. It
391 will now unimport any function it exports, even if that function is a
392 re-export from another package.
394 =item Attributes in roles can no longer override class attributes with "+foo"
396 Previously, this worked more or less accidentally, because role attributes
397 weren't objects. This was never documented, but a few MooseX modules took
400 =item The composition_class_roles attribute in L<Moose::Meta::Role> is now a method
402 This was done to make it possible for roles to alter the the list of
403 composition class roles by applying a method modifiers. Previously, this was
404 an attribute and MooseX modules override it. Since that no longer works, this
407 This I<should> be an attribute, so this may switch back to being an attribute
408 in the future if we can figure out how to make this work.
416 =item Calling $object->new() is no longer deprecated
418 We decided to undeprecate this. Now it just works.
420 =item Both C<get_method_map> and C<get_attribute_map> is deprecated
422 These metaclass methods were never meant to be public, and they are both now
423 deprecated. The work around if you still need the functionality they provided
424 is to iterate over the list of names manually.
426 my %fields = map { $_ => $meta->get_attribute($_) } $meta->get_attribute_list;
428 This was actually a change in L<Class::MOP>, but this version of Moose
429 requires a version of L<Class::MOP> that includes said change.
437 =item Added Native delegation for Code refs
439 See L<Moose::Meta::Attribute::Native::Trait::Code> for details.
441 =item Calling $object->new() is deprecated
443 Moose has long supported this, but it's never really been documented, and we
444 don't think this is a good practice. If you want to construct an object from
445 an existing object, you should provide some sort of alternate constructor like
446 C<< $object->clone >>.
448 Calling C<< $object->new >> now issues a warning, and will be an error in a
451 =item Moose no longer warns if you call C<make_immutable> for a class with mutable ancestors
453 While in theory this is a good thing to warn about, we found so many
454 exceptions to this that doing this properly became quite problematic.
462 =item New Native delegation methods from L<List::Util> and L<List::MoreUtils>
464 In particular, we now have C<reduce>, C<shuffle>, C<uniq>, and C<natatime>.
466 =item The Moose::Exporter with_caller feature is now deprecated
468 Use C<with_meta> instead. The C<with_caller> option will start warning in a
471 =item Moose now warns if you call C<make_immutable> for a class with mutable ancestors
473 This is dangerous because modifying a class after a subclass has been
474 immutabilized will lead to incorrect results in the subclass, due to inlining,
475 caching, etc. This occasionally happens accidentally, when a class loads one
476 of its subclasses in the middle of its class definition, so pointing out that
477 this may cause issues should be helpful. Metaclasses (classes that inherit
478 from L<Class::MOP::Object>) are currently exempt from this check, since at the
479 moment we aren't very consistent about which metaclasses we immutabilize.
481 =item C<enum> and C<duck_type> now take arrayrefs for all forms
483 Previously, calling these functions with a list would take the first element of
484 the list as the type constraint name, and use the remainder as the enum values
485 or method names. This makes the interface inconsistent with the anon-type forms
486 of these functions (which must take an arrayref), and a free-form list where
487 the first value is sometimes special is hard to validate (and harder to give
488 reasonable error messages for). These functions have been changed to take
489 arrayrefs in all their forms - so, C<< enum 'My::Type' => [qw(foo bar)] >> is
490 now the preferred way to create an enum type constraint. The old syntax still
491 works for now, but it will hopefully be deprecated and removed in a future
498 L<Moose::Meta::Attribute::Native> has been moved into the Moose core from
499 L<MooseX::AttributeHelpers>. Major changes include:
503 =item C<traits>, not C<metaclass>
505 Method providers are only available via traits.
507 =item C<handles>, not C<provides> or C<curries>
509 The C<provides> syntax was like core Moose C<< handles => HASHREF >>
510 syntax, but with the keys and values reversed. This was confusing,
511 and AttributeHelpers now uses C<< handles => HASHREF >> in a way that
512 should be intuitive to anyone already familiar with how it is used for
515 The C<curries> functionality provided by AttributeHelpers has been
516 generalized to apply to all cases of C<< handles => HASHREF >>, though
517 not every piece of functionality has been ported (currying with a
518 CODEREF is not supported).
520 =item C<empty> is now C<is_empty>, and means empty, not non-empty
522 Previously, the C<empty> method provided by Arrays and Hashes returned true if
523 the attribute was B<not> empty (no elements). Now it returns true if the
524 attribute B<is> empty. It was also renamed to C<is_empty>, to reflect this.
526 =item C<find> was renamed to C<first>, and C<first> and C<last> were removed
528 L<List::Util> refers to the functionality that we used to provide under C<find>
529 as L<first|List::Util/first>, so that will likely be more familiar (and will
530 fit in better if we decide to add more List::Util functions). C<first> and
531 C<last> were removed, since their functionality is easily duplicated with
534 =item Helpers that take a coderef of one argument now use C<$_>
536 Subroutines passed as the first argument to C<first>, C<map>, and C<grep> now
537 receive their argument in C<$_> rather than as a parameter to the subroutine.
538 Helpers that take a coderef of two or more arguments remain using the argument
539 list (there are technical limitations to using C<$a> and C<$b> like C<sort>
542 See L<Moose::Meta::Attribute::Native> for the new documentation.
546 The C<alias> and C<excludes> role parameters have been renamed to C<-alias>
547 and C<-excludes>. The old names still work, but new code should use the new
548 names, and eventually the old ones will be deprecated and removed.
552 C<< use Moose -metaclass => 'Foo' >> now does alias resolution, just like
553 C<-traits> (and the C<metaclass> and C<traits> options to C<has>).
555 Added two functions C<meta_class_alias> and C<meta_attribute_alias> to
556 L<Moose::Util>, to simplify aliasing metaclasses and metatraits. This is
557 a wrapper around the old
559 package Moose::Meta::Class::Custom::Trait::FooTrait;
560 sub register_implementation { 'My::Meta::Trait' }
566 When an attribute generates I<no> accessors, we now warn. This is to help
567 users who forget the C<is> option. If you really do not want any accessors,
568 you can use C<< is => 'bare' >>. You can maintain back compat with older
569 versions of Moose by using something like:
571 ($Moose::VERSION >= 0.84 ? is => 'bare' : ())
573 When an accessor overwrites an existing method, we now warn. To work around
574 this warning (if you really must have this behavior), you can explicitly
575 remove the method before creating it as an accessor:
579 __PACKAGE__->meta->remove_method('foo');
585 When an unknown option is passed to C<has>, we now warn. You can silence
586 the warning by fixing your code. :)
588 The C<Role> type has been deprecated. On its own, it was useless,
589 since it just checked C<< $object->can('does') >>. If you were using
590 it as a parent type, just call C<role_type('Role::Name')> to create an
591 appropriate type instead.
595 C<use Moose::Exporter;> now imports C<strict> and C<warnings> into packages
600 C<DEMOLISHALL> and C<DEMOLISH> now receive an argument indicating whether or
601 not we are in global destruction.
605 Type constraints no longer run coercions for a value that already matches the
606 constraint. This may affect some (arguably buggy) edge case coercions that
607 rely on side effects in the C<via> clause.
611 L<Moose::Exporter> now accepts the C<-metaclass> option for easily
612 overriding the metaclass (without L<metaclass>). This works for classes
617 Added a C<duck_type> sugar function to L<Moose::Util::TypeConstraints>
618 to make integration with non-Moose classes easier. It simply checks if
619 C<< $obj->can() >> a list of methods.
621 A number of methods (mostly inherited from L<Class::MOP>) have been
622 renamed with a leading underscore to indicate their internal-ness. The
623 old method names will still work for a while, but will warn that the
624 method has been renamed. In a few cases, the method will be removed
625 entirely in the future. This may affect MooseX authors who were using
630 Calling C<subtype> with a name as the only argument now throws an
631 exception. If you want an anonymous subtype do:
633 my $subtype = subtype as 'Foo';
635 This is related to the changes in version 0.71_01.
637 The C<is_needed> method in L<Moose::Meta::Method::Destructor> is now
638 only usable as a class method. Previously, it worked as a class or
639 object method, with a different internal implementation for each
642 The internals of making a class immutable changed a lot in Class::MOP
643 0.78_02, and Moose's internals have changed along with it. The
644 external C<< $metaclass->make_immutable >> method still works the same
649 A mutable class accepted C<< Foo->new(undef) >> without complaint,
650 while an immutable class would blow up with an unhelpful error. Now,
651 in both cases we throw a helpful error instead.
653 This "feature" was originally added to allow for cases such as this:
661 return My::Class->new($args);
663 But we decided this is a bad idea and a little too magical, because it
664 can easily mask real errors.
668 Calling C<type> or C<subtype> without the sugar helpers (C<as>,
669 C<where>, C<message>) is now deprecated.
671 As a side effect, this meant we ended up using Perl prototypes on
672 C<as>, and code like this will no longer work:
674 use Moose::Util::TypeConstraints;
675 use Declare::Constraints::Simple -All;
677 subtype 'ArrayOfInts'
679 => IsArrayRef(IsInt);
681 Instead it must be changed to this:
686 where => IsArrayRef(IsInt)
690 If you want to maintain backwards compat with older versions of Moose,
691 you must explicitly test Moose's C<VERSION>:
693 if ( Moose->VERSION < 0.71_01 ) {
694 subtype 'ArrayOfInts'
696 => IsArrayRef(IsInt);
702 where => IsArrayRef(IsInt)
709 We no longer pass the meta-attribute object as a final argument to
710 triggers. This actually changed for inlined code a while back, but the
711 non-inlined version and the docs were still out of date.
713 If by some chance you actually used this feature, the workaround is
714 simple. You fetch the attribute object from out of the C<$self>
715 that is passed as the first argument to trigger, like so:
721 my ( $self, $value ) = @_;
722 my $attr = $self->meta->find_attribute_by_name('foo');
730 If you created a subtype and passed a parent that Moose didn't know
731 about, it simply ignored the parent. Now it automatically creates the
732 parent as a class type. This may not be what you want, but is less
735 You could declare a name with subtype such as "Foo!Bar". Moose would
736 accept this allowed, but if you used it in a parameterized type such
737 as "ArrayRef[Foo!Bar]" it wouldn't work. We now do some vetting on
738 names created via the sugar functions, so that they can only contain
739 alphanumerics, ":", and ".".
743 Methods created via an attribute can now fulfill a C<requires>
744 declaration for a role. Honestly we don't know why Stevan didn't make
745 this work originally, he was just insane or something.
747 Stack traces from inlined code will now report the line and file as
748 being in your class, as opposed to in Moose guts.
752 When a class does not provide all of a role's required methods, the
753 error thrown now mentions all of the missing methods, as opposed to
754 just the first missing method.
756 Moose will no longer inline a constructor for your class unless it
757 inherits its constructor from Moose::Object, and will warn when it
758 doesn't inline. If you want to force inlining anyway, pass
759 C<< replace_constructor => 1 >> to C<make_immutable>.
761 If you want to get rid of the warning, pass C<< inline_constructor =>
766 Removed the (deprecated) C<make_immutable> keyword.
768 Removing an attribute from a class now also removes delegation
769 (C<handles>) methods installed for that attribute. This is correct
770 behavior, but if you were wrongly relying on it you might get bit.
774 Roles now add methods by calling C<add_method>, not
775 C<alias_method>. They make sure to always provide a method object,
776 which will be cloned internally. This means that it is now possible to
777 track the source of a method provided by a role, and even follow its
778 history through intermediate roles. This means that methods added by
779 a role now show up when looking at a class's method list/map.
781 Parameter and Union args are now sorted, this makes Int|Str the same
782 constraint as Str|Int. Also, incoming type constraint strings are
783 normalized to remove all whitespace differences. This is mostly for
784 internals and should not affect outside code.
786 L<Moose::Exporter> will no longer remove a subroutine that the
787 exporting package re-exports. Moose re-exports the Carp::confess
788 function, among others. The reasoning is that we cannot know whether
789 you have also explicitly imported those functions for your own use, so
790 we err on the safe side and always keep them.
794 C<Moose::init_meta> should now be called as a method.
796 New modules for extension writers, L<Moose::Exporter> and
797 L<Moose::Util::MetaRole>.
801 Implemented metaclass traits (and wrote a recipe for it):
803 use Moose -traits => 'Foo'
805 This should make writing small Moose extensions a little
810 Fixed C<coerce> to accept anon types just like C<subtype> can.
813 coerce $some_anon_type => from 'Str' => via { ... };
817 Added C<BUILDARGS>, a new step in C<< Moose::Object->new() >>.
821 Fixed how the C<< is => (ro|rw) >> works with custom defined
822 C<reader>, C<writer> and C<accessor> options. See the below table for
825 is => ro, writer => _foo # turns into (reader => foo, writer => _foo)
826 is => rw, writer => _foo # turns into (reader => foo, writer => _foo)
827 is => rw, accessor => _foo # turns into (accessor => _foo)
828 is => ro, accessor => _foo # error, accesor is rw
832 The C<before/around/after> method modifiers now support regexp
833 matching of method names. NOTE: this only works for classes, it is
834 currently not supported in roles, but, ... patches welcome.
836 The C<has> keyword for roles now accepts the same array ref form that
837 L<Moose>.pm does for classes.
839 A trigger on a read-only attribute is no longer an error, as it's
840 useful to trigger off of the constructor.
842 Subtypes of parameterizable types now are parameterizable types
847 Fixed issue where C<DEMOLISHALL> was eating the value in C<$@>, and so
848 not working correctly. It still kind of eats them, but so does vanilla
853 Inherited attributes may now be extended without restriction on the
854 type ('isa', 'does').
856 The entire set of Moose::Meta::TypeConstraint::* classes were
857 refactored in this release. If you were relying on their internals you
858 should test your code carefully.
862 Documenting the use of '+name' with attributes that come from recently
863 composed roles. It makes sense, people are using it, and so why not
864 just officially support it.
866 The C<< Moose::Meta::Class->create >> method now supports roles.
868 It is now possible to make anonymous enum types by passing C<enum> an
869 array reference instead of the C<< enum $name => @values >>.
873 Added the C<make_immutable> keyword as a shortcut to calling
874 C<make_immutable> on the meta object. This eventually got removed!
876 Made C<< init_arg => undef >> work in Moose. This means "do not accept
877 a constructor parameter for this attribute".
879 Type errors now use the provided message. Prior to this release they
884 Moose is now a postmodern object system :)
886 The Role system was completely refactored. It is 100% backwards
887 compat, but the internals were totally changed. If you relied on the
888 internals then you are advised to test carefully.
890 Added method exclusion and aliasing for Roles in this release.
892 Added the L<Moose::Util::TypeConstraints::OptimizedConstraints>
895 Passing a list of values to an accessor (which is only expecting one
896 value) used to be silently ignored, now it throws an error.
900 Added parameterized types and did a pretty heavy refactoring of the
901 type constraint system.
903 Better framework extensibility and better support for "making your own
906 =head1 0.25 or before
908 Honestly, you shouldn't be using versions of Moose that are this old,
909 so many bug fixes and speed improvements have been made you would be
910 crazy to not upgrade.
912 Also, I am tired of going through the Changelog so I am stopping here,
913 if anyone would like to continue this please feel free.