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moose-outdated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moose-outdated | cpanm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 toolchain
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 Configurable stacktraces
135 Classes which use the L<Moose::Error::Default> error class can now have
136 stacktraces disabled by setting the C<MOOSE_ERROR_STYLE> env var to C<croak>.
137 This is experimental, fairly incomplete, and won't work in all cases (because
138 Moose's error system in general is all of these things), but this should allow
139 for reducing at least some of the verbosity in most cases.
147 =item Native Delegations
149 In previous versions of Moose, the Native delegations were created as
150 closures. The generated code was often quite slow compared to doing the same
151 thing by hand. For example, the Array's push delegation ended up doing
154 push @{ $self->$reader() }, @_;
156 If the attribute was created without a reader, the C<$reader> sub reference
157 followed a very slow code path. Even with a reader, this is still slower than
160 Native delegations are now generated as inline code, just like other
161 accessors, so we can access the slot directly.
163 In addition, native traits now do proper constraint checking in all cases. In
164 particular, constraint checking has been improved for array and hash
165 references. Previously, only the I<contained> type (the C<Str> in
166 C<HashRef[Str]>) would be checked when a new value was added to the
167 collection. However, if there was a constraint that applied to the whole
168 value, this was never checked.
170 In addition, coercions are now called on the whole value.
172 The delegation methods now do more argument checking. All of the methods check
173 that a valid number of arguments were passed to the method. In addition, the
174 delegation methods check that the arguments are sane (array indexes, hash
175 keys, numbers, etc.) when applicable. We have tried to emulate the behavior of
176 Perl builtins as much as possible.
178 Finally, triggers are called whenever the value of the attribute is changed by
181 These changes are only likely to break code in a few cases.
183 The inlining code may or may not preserve the original reference when changes
184 are made. In some cases, methods which change the value may replace it
185 entirely. This will break tied values.
187 If you have a typed arrayref or hashref attribute where the type enforces a
188 constraint on the whole collection, this constraint will now be checked. It's
189 possible that code which previously ran without errors will now cause the
190 constraint to fail. However, presumably this is a good thing ;)
192 If you are passing invalid arguments to a delegation which were previously
193 being ignored, these calls will now fail.
195 If your code relied on the trigger only being called for a regular writer,
196 that may cause problems.
198 As always, you are encouraged to test before deploying the latest version of
201 =item Defaults is and default for String, Counter, and Bool
203 A few native traits (String, Counter, Bool) provide default values of "is" and
204 "default" when you created an attribute. Allowing them to provide these values
205 is now deprecated. Supply the value yourself when creating the attribute.
207 =item The C<meta> method
209 Moose and Class::MOP have been cleaned up internally enough to make the
210 C<meta> method that you get by default optional. C<use Moose> and
211 C<use Moose::Role> now can take an additional C<-meta_name> option, which
212 tells Moose what name to use when installing the C<meta> method. Passing
213 C<undef> to this option suppresses generation of the C<meta> method
214 entirely. This should be useful for users of modules which also use a C<meta>
215 method or function, such as L<Curses> or L<Rose::DB::Object>.
223 =item All deprecated features now warn
225 Previously, deprecation mostly consisted of simply saying "X is deprecated" in
226 the Changes file. We were not very consistent about actually warning. Now, all
227 deprecated features still present in Moose actually give a warning. The
228 warning is issued once per calling package. See L<Moose::Deprecated> for more
231 =item You cannot pass C<< coerce => 1 >> unless the attribute's type constraint has a coercion
233 Previously, this was accepted, and it sort of worked, except that if you
234 attempted to set the attribute after the object was created, you would get a
237 Now you will get a warning when you attempt to define the attribute.
239 =item C<no Moose>, C<no Moose::Role>, and C<no Moose::Exporter> no longer unimport strict and warnings
241 This change was made in 1.05, and has now been reverted. We don't know if the
242 user has explicitly loaded strict or warnings on their own, and unimporting
243 them is just broken in that case.
245 =item Reversed logic when defining which options can be changed
247 L<Moose::Meta::Attribute> now allows all options to be changed in an
248 overridden attribute. The previous behaviour required each option to be
249 whitelisted using the C<legal_options_for_inheritance> method. This method has
250 been removed, and there is a new method, C<illegal_options_for_inheritance>,
251 which can now be used to prevent certain options from being changeable.
253 In addition, we only throw an error if the illegal option is actually
254 changed. If the superclass didn't specify this option at all when defining the
255 attribute, the subclass version can still add it as an option.
257 Example of overriding this in an attribute trait:
259 package Bar::Meta::Attribute;
262 has 'my_illegal_option' => (
267 around illegal_options_for_inheritance => sub {
268 return ( shift->(@_), qw/my_illegal_option/ );
277 =item L<Moose::Object/BUILD> methods are now called when calling C<new_object>
279 Previously, C<BUILD> methods would only be called from C<Moose::Object::new>,
280 but now they are also called when constructing an object via
281 C<Moose::Meta::Class::new_object>. C<BUILD> methods are an inherent part of the
282 object construction process, and this should make C<< $meta->new_object >>
283 actually usable without forcing people to use C<< $meta->name->new >>.
285 =item C<no Moose>, C<no Moose::Role>, and C<no Moose::Exporter> now unimport strict and warnings
287 In the interest of having C<no Moose> clean up everything that C<use Moose>
288 does in the calling scope, C<no Moose> (as well as all other
289 L<Moose::Exporter>-using modules) now unimports strict and warnings.
291 =item Metaclass compatibility checking and fixing should be much more robust
293 The L<metaclass compatibility|Moose/METACLASS COMPATIBILITY AND MOOSE> checking
294 and fixing algorithms have been completely rewritten, in both Class::MOP and
295 Moose. This should resolve many confusing errors when dealing with non-Moose
296 inheritance and with custom metaclasses for things like attributes,
297 constructors, etc. For correct code, the only thing that should require a
298 change is that custom error metaclasses must now inherit from
299 L<Moose::Error::Default>.
307 =item Moose::Meta::TypeConstraint::Class is_subtype_of behavior
309 Earlier versions of L<is_subtype_of|Moose::Meta::TypeConstraint::Class/is_subtype_of>
310 would incorrectly return true when called with itself, its own TC name or
311 its class name as an argument. (i.e. $foo_tc->is_subtype_of('Foo') == 1) This
312 behavior was a caused by C<isa> being checked before the class name. The old
313 behavior can be accessed with L<is_type_of|Moose::Meta::TypeConstraint::Class/is_type_of>
321 =item Moose::Meta::Attribute::Native::Trait::Code no longer creates reader methods by default
323 Earlier versions of L<Moose::Meta::Attribute::Native::Trait::Code> created
324 read-only accessors for the attributes it's been applied to, even if you didn't
325 ask for it with C<< is => 'ro' >>. This incorrect behaviour has now been fixed.
333 =item Moose::Util add_method_modifier behavior
335 add_method_modifier (and subsequently the sugar functions Moose::before,
336 Moose::after, and Moose::around) can now accept arrayrefs, with the same
337 behavior as lists. Types other than arrayref and regexp result in an error.
341 =head1 0.93_01 and 0.94
345 =item Moose::Util::MetaRole API has changed
347 The C<apply_metaclass_roles> function is now called C<apply_metaroles>. The
348 way arguments are supplied has been changed to force you to distinguish
349 between metaroles applied to L<Moose::Meta::Class> (and helpers) versus
350 L<Moose::Meta::Role>.
352 The old API still works, but will warn in a future release, and eventually be
355 =item Moose::Meta::Role has real attributes
357 The attributes returned by L<Moose::Meta::Role> are now instances of the
358 L<Moose::Meta::Role::Attribute> class, instead of bare hash references.
360 =item "no Moose" now removes C<blessed> and C<confess>
362 Moose is now smart enough to know exactly what it exported, even when it
363 re-exports functions from other packages. When you unimport Moose, it will
364 remove these functions from your namespace unless you I<also> imported them
365 directly from their respective packages.
367 If you have a C<no Moose> in your code I<before> you call C<blessed> or
368 C<confess>, your code will break. You can either move the C<no Moose> call
369 later in your code, or explicitly import the relevant functions from the
370 packages that provide them.
372 =item L<Moose::Exporter> is smarter about unimporting re-exports
374 The change above comes from a general improvement to L<Moose::Exporter>. It
375 will now unimport any function it exports, even if that function is a
376 re-export from another package.
378 =item Attributes in roles can no longer override class attributes with "+foo"
380 Previously, this worked more or less accidentally, because role attributes
381 weren't objects. This was never documented, but a few MooseX modules took
384 =item The composition_class_roles attribute in L<Moose::Meta::Role> is now a method
386 This was done to make it possible for roles to alter the the list of
387 composition class roles by applying a method modifiers. Previously, this was
388 an attribute and MooseX modules override it. Since that no longer works, this
391 This I<should> be an attribute, so this may switch back to being an attribute
392 in the future if we can figure out how to make this work.
400 =item Calling $object->new() is no longer deprecated
402 We decided to undeprecate this. Now it just works.
404 =item Both C<get_method_map> and C<get_attribute_map> is deprecated
406 These metaclass methods were never meant to be public, and they are both now
407 deprecated. The work around if you still need the functionality they provided
408 is to iterate over the list of names manually.
410 my %fields = map { $_ => $meta->get_attribute($_) } $meta->get_attribute_list;
412 This was actually a change in L<Class::MOP>, but this version of Moose
413 requires a version of L<Class::MOP> that includes said change.
421 =item Added Native delegation for Code refs
423 See L<Moose::Meta::Attribute::Native::Trait::Code> for details.
425 =item Calling $object->new() is deprecated
427 Moose has long supported this, but it's never really been documented, and we
428 don't think this is a good practice. If you want to construct an object from
429 an existing object, you should provide some sort of alternate constructor like
430 C<< $object->clone >>.
432 Calling C<< $object->new >> now issues a warning, and will be an error in a
435 =item Moose no longer warns if you call C<make_immutable> for a class with mutable ancestors
437 While in theory this is a good thing to warn about, we found so many
438 exceptions to this that doing this properly became quite problematic.
446 =item New Native delegation methods from L<List::Util> and L<List::MoreUtils>
448 In particular, we now have C<reduce>, C<shuffle>, C<uniq>, and C<natatime>.
450 =item The Moose::Exporter with_caller feature is now deprecated
452 Use C<with_meta> instead. The C<with_caller> option will start warning in a
455 =item Moose now warns if you call C<make_immutable> for a class with mutable ancestors
457 This is dangerous because modifying a class after a subclass has been
458 immutabilized will lead to incorrect results in the subclass, due to inlining,
459 caching, etc. This occasionally happens accidentally, when a class loads one
460 of its subclasses in the middle of its class definition, so pointing out that
461 this may cause issues should be helpful. Metaclasses (classes that inherit
462 from L<Class::MOP::Object>) are currently exempt from this check, since at the
463 moment we aren't very consistent about which metaclasses we immutabilize.
465 =item C<enum> and C<duck_type> now take arrayrefs for all forms
467 Previously, calling these functions with a list would take the first element of
468 the list as the type constraint name, and use the remainder as the enum values
469 or method names. This makes the interface inconsistent with the anon-type forms
470 of these functions (which must take an arrayref), and a free-form list where
471 the first value is sometimes special is hard to validate (and harder to give
472 reasonable error messages for). These functions have been changed to take
473 arrayrefs in all their forms - so, C<< enum 'My::Type' => [qw(foo bar)] >> is
474 now the preferred way to create an enum type constraint. The old syntax still
475 works for now, but it will hopefully be deprecated and removed in a future
482 L<Moose::Meta::Attribute::Native> has been moved into the Moose core from
483 L<MooseX::AttributeHelpers>. Major changes include:
487 =item C<traits>, not C<metaclass>
489 Method providers are only available via traits.
491 =item C<handles>, not C<provides> or C<curries>
493 The C<provides> syntax was like core Moose C<< handles => HASHREF >>
494 syntax, but with the keys and values reversed. This was confusing,
495 and AttributeHelpers now uses C<< handles => HASHREF >> in a way that
496 should be intuitive to anyone already familiar with how it is used for
499 The C<curries> functionality provided by AttributeHelpers has been
500 generalized to apply to all cases of C<< handles => HASHREF >>, though
501 not every piece of functionality has been ported (currying with a
502 CODEREF is not supported).
504 =item C<empty> is now C<is_empty>, and means empty, not non-empty
506 Previously, the C<empty> method provided by Arrays and Hashes returned true if
507 the attribute was B<not> empty (no elements). Now it returns true if the
508 attribute B<is> empty. It was also renamed to C<is_empty>, to reflect this.
510 =item C<find> was renamed to C<first>, and C<first> and C<last> were removed
512 L<List::Util> refers to the functionality that we used to provide under C<find>
513 as L<first|List::Util/first>, so that will likely be more familiar (and will
514 fit in better if we decide to add more List::Util functions). C<first> and
515 C<last> were removed, since their functionality is easily duplicated with
518 =item Helpers that take a coderef of one argument now use C<$_>
520 Subroutines passed as the first argument to C<first>, C<map>, and C<grep> now
521 receive their argument in C<$_> rather than as a parameter to the subroutine.
522 Helpers that take a coderef of two or more arguments remain using the argument
523 list (there are technical limitations to using C<$a> and C<$b> like C<sort>
526 See L<Moose::Meta::Attribute::Native> for the new documentation.
530 The C<alias> and C<excludes> role parameters have been renamed to C<-alias>
531 and C<-excludes>. The old names still work, but new code should use the new
532 names, and eventually the old ones will be deprecated and removed.
536 C<< use Moose -metaclass => 'Foo' >> now does alias resolution, just like
537 C<-traits> (and the C<metaclass> and C<traits> options to C<has>).
539 Added two functions C<meta_class_alias> and C<meta_attribute_alias> to
540 L<Moose::Util>, to simplify aliasing metaclasses and metatraits. This is
541 a wrapper around the old
543 package Moose::Meta::Class::Custom::Trait::FooTrait;
544 sub register_implementation { 'My::Meta::Trait' }
550 When an attribute generates I<no> accessors, we now warn. This is to help
551 users who forget the C<is> option. If you really do not want any accessors,
552 you can use C<< is => 'bare' >>. You can maintain back compat with older
553 versions of Moose by using something like:
555 ($Moose::VERSION >= 0.84 ? is => 'bare' : ())
557 When an accessor overwrites an existing method, we now warn. To work around
558 this warning (if you really must have this behavior), you can explicitly
559 remove the method before creating it as an accessor:
563 __PACKAGE__->meta->remove_method('foo');
569 When an unknown option is passed to C<has>, we now warn. You can silence
570 the warning by fixing your code. :)
572 The C<Role> type has been deprecated. On its own, it was useless,
573 since it just checked C<< $object->can('does') >>. If you were using
574 it as a parent type, just call C<role_type('Role::Name')> to create an
575 appropriate type instead.
579 C<use Moose::Exporter;> now imports C<strict> and C<warnings> into packages
584 C<DEMOLISHALL> and C<DEMOLISH> now receive an argument indicating whether or
585 not we are in global destruction.
589 Type constraints no longer run coercions for a value that already matches the
590 constraint. This may affect some (arguably buggy) edge case coercions that
591 rely on side effects in the C<via> clause.
595 L<Moose::Exporter> now accepts the C<-metaclass> option for easily
596 overriding the metaclass (without L<metaclass>). This works for classes
601 Added a C<duck_type> sugar function to L<Moose::Util::TypeConstraints>
602 to make integration with non-Moose classes easier. It simply checks if
603 C<< $obj->can() >> a list of methods.
605 A number of methods (mostly inherited from L<Class::MOP>) have been
606 renamed with a leading underscore to indicate their internal-ness. The
607 old method names will still work for a while, but will warn that the
608 method has been renamed. In a few cases, the method will be removed
609 entirely in the future. This may affect MooseX authors who were using
614 Calling C<subtype> with a name as the only argument now throws an
615 exception. If you want an anonymous subtype do:
617 my $subtype = subtype as 'Foo';
619 This is related to the changes in version 0.71_01.
621 The C<is_needed> method in L<Moose::Meta::Method::Destructor> is now
622 only usable as a class method. Previously, it worked as a class or
623 object method, with a different internal implementation for each
626 The internals of making a class immutable changed a lot in Class::MOP
627 0.78_02, and Moose's internals have changed along with it. The
628 external C<< $metaclass->make_immutable >> method still works the same
633 A mutable class accepted C<< Foo->new(undef) >> without complaint,
634 while an immutable class would blow up with an unhelpful error. Now,
635 in both cases we throw a helpful error instead.
637 This "feature" was originally added to allow for cases such as this:
645 return My::Class->new($args);
647 But we decided this is a bad idea and a little too magical, because it
648 can easily mask real errors.
652 Calling C<type> or C<subtype> without the sugar helpers (C<as>,
653 C<where>, C<message>) is now deprecated.
655 As a side effect, this meant we ended up using Perl prototypes on
656 C<as>, and code like this will no longer work:
658 use Moose::Util::TypeConstraints;
659 use Declare::Constraints::Simple -All;
661 subtype 'ArrayOfInts'
663 => IsArrayRef(IsInt);
665 Instead it must be changed to this:
670 where => IsArrayRef(IsInt)
674 If you want to maintain backwards compat with older versions of Moose,
675 you must explicitly test Moose's C<VERSION>:
677 if ( Moose->VERSION < 0.71_01 ) {
678 subtype 'ArrayOfInts'
680 => IsArrayRef(IsInt);
686 where => IsArrayRef(IsInt)
693 We no longer pass the meta-attribute object as a final argument to
694 triggers. This actually changed for inlined code a while back, but the
695 non-inlined version and the docs were still out of date.
697 If by some chance you actually used this feature, the workaround is
698 simple. You fetch the attribute object from out of the C<$self>
699 that is passed as the first argument to trigger, like so:
705 my ( $self, $value ) = @_;
706 my $attr = $self->meta->find_attribute_by_name('foo');
714 If you created a subtype and passed a parent that Moose didn't know
715 about, it simply ignored the parent. Now it automatically creates the
716 parent as a class type. This may not be what you want, but is less
719 You could declare a name with subtype such as "Foo!Bar". Moose would
720 accept this allowed, but if you used it in a parameterized type such
721 as "ArrayRef[Foo!Bar]" it wouldn't work. We now do some vetting on
722 names created via the sugar functions, so that they can only contain
723 alphanumerics, ":", and ".".
727 Methods created via an attribute can now fulfill a C<requires>
728 declaration for a role. Honestly we don't know why Stevan didn't make
729 this work originally, he was just insane or something.
731 Stack traces from inlined code will now report the line and file as
732 being in your class, as opposed to in Moose guts.
736 When a class does not provide all of a role's required methods, the
737 error thrown now mentions all of the missing methods, as opposed to
738 just the first missing method.
740 Moose will no longer inline a constructor for your class unless it
741 inherits its constructor from Moose::Object, and will warn when it
742 doesn't inline. If you want to force inlining anyway, pass
743 C<< replace_constructor => 1 >> to C<make_immutable>.
745 If you want to get rid of the warning, pass C<< inline_constructor =>
750 Removed the (deprecated) C<make_immutable> keyword.
752 Removing an attribute from a class now also removes delegation
753 (C<handles>) methods installed for that attribute. This is correct
754 behavior, but if you were wrongly relying on it you might get bit.
758 Roles now add methods by calling C<add_method>, not
759 C<alias_method>. They make sure to always provide a method object,
760 which will be cloned internally. This means that it is now possible to
761 track the source of a method provided by a role, and even follow its
762 history through intermediate roles. This means that methods added by
763 a role now show up when looking at a class's method list/map.
765 Parameter and Union args are now sorted, this makes Int|Str the same
766 constraint as Str|Int. Also, incoming type constraint strings are
767 normalized to remove all whitespace differences. This is mostly for
768 internals and should not affect outside code.
770 L<Moose::Exporter> will no longer remove a subroutine that the
771 exporting package re-exports. Moose re-exports the Carp::confess
772 function, among others. The reasoning is that we cannot know whether
773 you have also explicitly imported those functions for your own use, so
774 we err on the safe side and always keep them.
778 C<Moose::init_meta> should now be called as a method.
780 New modules for extension writers, L<Moose::Exporter> and
781 L<Moose::Util::MetaRole>.
785 Implemented metaclass traits (and wrote a recipe for it):
787 use Moose -traits => 'Foo'
789 This should make writing small Moose extensions a little
794 Fixed C<coerce> to accept anon types just like C<subtype> can.
797 coerce $some_anon_type => from 'Str' => via { ... };
801 Added C<BUILDARGS>, a new step in C<< Moose::Object->new() >>.
805 Fixed how the C<< is => (ro|rw) >> works with custom defined
806 C<reader>, C<writer> and C<accessor> options. See the below table for
809 is => ro, writer => _foo # turns into (reader => foo, writer => _foo)
810 is => rw, writer => _foo # turns into (reader => foo, writer => _foo)
811 is => rw, accessor => _foo # turns into (accessor => _foo)
812 is => ro, accessor => _foo # error, accesor is rw
816 The C<before/around/after> method modifiers now support regexp
817 matching of method names. NOTE: this only works for classes, it is
818 currently not supported in roles, but, ... patches welcome.
820 The C<has> keyword for roles now accepts the same array ref form that
821 L<Moose>.pm does for classes.
823 A trigger on a read-only attribute is no longer an error, as it's
824 useful to trigger off of the constructor.
826 Subtypes of parameterizable types now are parameterizable types
831 Fixed issue where C<DEMOLISHALL> was eating the value in C<$@>, and so
832 not working correctly. It still kind of eats them, but so does vanilla
837 Inherited attributes may now be extended without restriction on the
838 type ('isa', 'does').
840 The entire set of Moose::Meta::TypeConstraint::* classes were
841 refactored in this release. If you were relying on their internals you
842 should test your code carefully.
846 Documenting the use of '+name' with attributes that come from recently
847 composed roles. It makes sense, people are using it, and so why not
848 just officially support it.
850 The C<< Moose::Meta::Class->create >> method now supports roles.
852 It is now possible to make anonymous enum types by passing C<enum> an
853 array reference instead of the C<< enum $name => @values >>.
857 Added the C<make_immutable> keyword as a shortcut to calling
858 C<make_immutable> on the meta object. This eventually got removed!
860 Made C<< init_arg => undef >> work in Moose. This means "do not accept
861 a constructor parameter for this attribute".
863 Type errors now use the provided message. Prior to this release they
868 Moose is now a postmodern object system :)
870 The Role system was completely refactored. It is 100% backwards
871 compat, but the internals were totally changed. If you relied on the
872 internals then you are advised to test carefully.
874 Added method exclusion and aliasing for Roles in this release.
876 Added the L<Moose::Util::TypeConstraints::OptimizedConstraints>
879 Passing a list of values to an accessor (which is only expecting one
880 value) used to be silently ignored, now it throws an error.
884 Added parameterized types and did a pretty heavy refactoring of the
885 type constraint system.
887 Better framework extensibility and better support for "making your own
890 =head1 0.25 or before
892 Honestly, you shouldn't be using versions of Moose that are this old,
893 so many bug fixes and speed improvements have been made you would be
894 crazy to not upgrade.
896 Also, I am tired of going through the Changelog so I am stopping here,
897 if anyone would like to continue this please feel free.