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 things that affect backwards compatibility. This does duplicate data
13 from the F<Changes> file, but aims to provide more details and when possible
16 Besides helping keep up with changes, you can also use this document
17 for finding the lowest version of Moose that supported a given
18 feature. If you encounter a problem and have a solution but don't see
19 it documented here, or think we missed an important feature, please
26 =item C<< ->init_meta >> is even less reliable at loading extensions
28 Previously, calling C<< MooseX::Foo->init_meta(@_) >> (and nothing else) from
29 within your own C<init_meta> had a decent chance of doing something useful.
30 This was never supported behavior, and didn't always work anyway. Due to some
31 implementation adjustments, this now has a smaller chance of doing something
32 useful, which could break code that was expecting it to continue doing useful
33 things. Code that does this should instead just call
34 C<< MooseX::Foo->import({ into => $into }) >>.
36 =item All the Cookbook recipes have been renamed
38 We've given them all descriptive names, rather than numbers. This makes it
39 easier to talk about them, and eliminates the need to renumber recipes in
40 order to reorder them or delete one.
48 =item The parent of a union type is its components' nearest common ancestor
50 Previously, union types considered all of their component types their parent
51 types. This was incorrect because parent types are defined as types that must
52 be satisfied in order for the child type to be satisfied, but in a union,
53 validating as any parent type will validate against the entire union. This has
54 been changed to find the nearest common ancestor for all of its components. For
55 example, a union of "Int|ArrayRef[Int]" now has a parent of "Defined".
57 =item Union types consider all members in the C<is_subtype_of> and C<is_a_type_of> methods
59 Previously, a union type would report itself as being of a subtype of a type if
60 I<any> of its member types were subtypes of that type. This was incorrect
61 because any value that passes a subtype constraint must also pass a parent
62 constraint. This has changed so that I<all> of its member types must be a
63 subtype of the specified type.
65 =item Enum types now work with just one value
67 Previously, an C<enum> type needed to have two or more values. Nobody knew
70 =item Methods defined in UNIVERSAL now appear in the MOP
72 Any method introspection methods that look at methods from parent classes now
73 find methods defined in UNIVERSAL. This includes methods like C<<
74 $class->get_all_methods >> and C<< $class->find_method_by_name >>.
76 This also means that you can now apply method modifiers to these methods.
78 =item Hand-optimized type constraint code causes a deprecation warning
80 If you provide an optimized sub ref for a type constraint, this now causes a
81 deprecation warning. Typically, this comes from passing an C<optimize_as>
82 parameter to C<subtype>, but it could also happen if you create a
83 L<Moose::Meta::TypeConstraint> object directly.
85 Use the inlining feature (C<inline_as>) added in 2.0100 instead.
87 =item C<Class::Load::load_class> and C<is_class_loaded> have been removed
89 The C<Class::MOP::load_class> and C<Class::MOP::is_class_loaded> subroutines
90 are no longer documented, and will cause a deprecation warning in the
91 future. Moose now uses L<Class::Load> to provide this functionality, and you
100 =item Array and Hash native traits provide a C<shallow_clone> method
102 The Array and Hash native traits now provide a "shallow_clone" method, which
103 will return a reference to a new container with the same contents as the
104 attribute's reference.
112 =item Hand-optimized type constraint code is deprecated in favor of inlining
114 Moose allows you to provide a hand-optimized version of a type constraint's
115 subroutine reference. This version allows type constraints to generate inline
116 code, and you should use this inlining instead of providing a hand-optimized
117 subroutine reference.
119 This affects the C<optimize_as> sub exported by
120 L<Moose::Util::TypeConstraints>. Use C<inline_as> instead.
122 This will start warning in the 2.0300 release.
130 =item More useful type constraint error messages
132 If you have L<Devel::PartialDump> version 0.14 or higher installed, Moose's
133 type constraint error messages will use it to display the invalid value, rather
134 than just displaying it directly. This will generally be much more useful. For
135 instance, instead of this:
137 Attribute (foo) does not pass the type constraint because: Validation failed for 'ArrayRef[Int]' with value ARRAY(0x275eed8)
139 the error message will instead look like
141 Attribute (foo) does not pass the type constraint because: Validation failed for 'ArrayRef[Int]' with value [ "a" ]
143 Note that L<Devel::PartialDump> can't be made a direct dependency at the
144 moment, because it uses Moose itself, but we're considering options to make
153 =item Roles have their own default attribute metaclass
155 Previously, when a role was applied to a class, it would use the attribute
156 metaclass defined in the class when copying over the attributes in the role.
157 This was wrong, because for instance, using L<MooseX::FollowPBP> in the class
158 would end up renaming all of the accessors generated by the role, some of which
159 may be being called in the role, causing it to break. Roles now keep track of
160 their own attribute metaclass to use by default when being applied to a class
161 (defaulting to Moose::Meta::Attribute). This is modifiable using
162 L<Moose::Util::MetaRole> by passing the C<applied_attribute> key to the
163 C<role_metaroles> option, as in:
165 Moose::Util::MetaRole::apply_metaroles(
168 attribute => ['My::Meta::Role::Attribute'],
171 applied_attribute => ['My::Meta::Role::Attribute'],
175 =item Class::MOP has been folded into the Moose dist
177 Moose and Class::MOP are tightly related enough that they have always had to be
178 kept pretty closely in step in terms of versions. Making them into a single
179 dist should simplify the upgrade process for users, as it should no longer be
180 possible to upgrade one without the other and potentially cause issues. No
181 functionality has changed, and this should be entirely transparent.
183 =item Moose's conflict checking is more robust and useful
185 There are two parts to this. The most useful one right now is that Moose will
186 ship with a C<moose-outdated> script, which can be run at any point to list the
187 modules which are installed that conflict with the installed version of Moose.
188 After upgrading Moose, running C<moose-outdated | cpanm> should be sufficient
189 to ensure that all of the Moose extensions you use will continue to work.
191 The other part is that Moose's C<META.json> file will also specify the
192 conflicts under the C<x_conflicts> key. We are working with the Perl tool chain
193 developers to try to get conflicts support added to CPAN clients, and if/when
194 that happens, the metadata already exists, and so the conflict checking will
197 =item Most deprecated APIs/features are slated for removal in Moose 2.0200
199 Most of the deprecated APIs and features in Moose will start throwing an error
200 in Moose 2.0200. Some of the features will go away entirely, and some will
201 simply throw an error.
203 The things on the chopping block are:
207 =item * Old public methods in Class::MOP and Moose
209 This includes things like C<< Class::MOP::Class->get_attribute_map >>, C<<
210 Class::MOP::Class->construct_instance >>, and many others. These were
211 deprecated in L<Class::MOP> 0.80_01, released on April 5, 2009.
213 These methods will be removed entirely in Moose 2.0200.
215 =item * Old public functions in Class::MOP
217 This include C<Class::MOP::subname>, C<Class::MOP::in_global_destruction>, and
218 the C<Class::MOP::HAS_ISAREV> constant. The first two were deprecated in 0.84,
219 and the last in 0.80. Class::MOP 0.84 was released on May 12, 2009.
221 These functions will be removed entirely in Moose 2.0200.
223 =item * The C<alias> and C<excludes> option for role composition
225 These were renamed to C<-alias> and C<-excludes> in Moose 0.89, released on
228 Passing these will throw an error in Moose 2.0200.
230 =item * The old L<Moose::Util::MetaRole> API
232 This include the C<apply_metaclass_roles()> function, as well as passing the
233 C<for_class> or any key ending in C<_roles> to C<apply_metaroles()>. This was
234 deprecated in Moose 0.93_01, released on January 4, 2010.
236 These will all throw an error in Moose 2.0200.
238 =item * Passing plain lists to C<type()> or C<subtype()>
240 The old API for these functions allowed you to pass a plain list of parameter,
241 rather than a list of hash references (which is what C<as()>, C<where>,
242 etc. return). This was deprecated in Moose 0.71_01, released on February 22,
245 This will throw an error in Moose 2.0200.
247 =item * The Role subtype
249 This subtype was deprecated in Moose 0.84, released on June 26, 2009.
251 This will be removed entirely in Moose 2.0200.
261 =item * New release policy
263 As of the 2.0 release, Moose now has an official release and support policy,
264 documented in L<Moose::Manual::Support>. All API changes will now go through a
265 deprecation cycle of at least one year, after which the deprecated API can be
266 removed. Deprecations and removals will only happen in major releases.
268 In between major releases, we will still make minor releases to add new
269 features, fix bugs, update documentation, etc.
277 =item Configurable stacktraces
279 Classes which use the L<Moose::Error::Default> error class can now have
280 stacktraces disabled by setting the C<MOOSE_ERROR_STYLE> env var to C<croak>.
281 This is experimental, fairly incomplete, and won't work in all cases (because
282 Moose's error system in general is all of these things), but this should allow
283 for reducing at least some of the verbosity in most cases.
291 =item Native Delegations
293 In previous versions of Moose, the Native delegations were created as
294 closures. The generated code was often quite slow compared to doing the same
295 thing by hand. For example, the Array's push delegation ended up doing
298 push @{ $self->$reader() }, @_;
300 If the attribute was created without a reader, the C<$reader> sub reference
301 followed a very slow code path. Even with a reader, this is still slower than
304 Native delegations are now generated as inline code, just like other
305 accessors, so we can access the slot directly.
307 In addition, native traits now do proper constraint checking in all cases. In
308 particular, constraint checking has been improved for array and hash
309 references. Previously, only the I<contained> type (the C<Str> in
310 C<HashRef[Str]>) would be checked when a new value was added to the
311 collection. However, if there was a constraint that applied to the whole
312 value, this was never checked.
314 In addition, coercions are now called on the whole value.
316 The delegation methods now do more argument checking. All of the methods check
317 that a valid number of arguments were passed to the method. In addition, the
318 delegation methods check that the arguments are sane (array indexes, hash
319 keys, numbers, etc.) when applicable. We have tried to emulate the behavior of
320 Perl builtins as much as possible.
322 Finally, triggers are called whenever the value of the attribute is changed by
325 These changes are only likely to break code in a few cases.
327 The inlining code may or may not preserve the original reference when changes
328 are made. In some cases, methods which change the value may replace it
329 entirely. This will break tied values.
331 If you have a typed arrayref or hashref attribute where the type enforces a
332 constraint on the whole collection, this constraint will now be checked. It's
333 possible that code which previously ran without errors will now cause the
334 constraint to fail. However, presumably this is a good thing ;)
336 If you are passing invalid arguments to a delegation which were previously
337 being ignored, these calls will now fail.
339 If your code relied on the trigger only being called for a regular writer,
340 that may cause problems.
342 As always, you are encouraged to test before deploying the latest version of
345 =item Defaults is and default for String, Counter, and Bool
347 A few native traits (String, Counter, Bool) provide default values of "is" and
348 "default" when you created an attribute. Allowing them to provide these values
349 is now deprecated. Supply the value yourself when creating the attribute.
351 =item The C<meta> method
353 Moose and Class::MOP have been cleaned up internally enough to make the
354 C<meta> method that you get by default optional. C<use Moose> and
355 C<use Moose::Role> now can take an additional C<-meta_name> option, which
356 tells Moose what name to use when installing the C<meta> method. Passing
357 C<undef> to this option suppresses generation of the C<meta> method
358 entirely. This should be useful for users of modules which also use a C<meta>
359 method or function, such as L<Curses> or L<Rose::DB::Object>.
367 =item All deprecated features now warn
369 Previously, deprecation mostly consisted of simply saying "X is deprecated" in
370 the Changes file. We were not very consistent about actually warning. Now, all
371 deprecated features still present in Moose actually give a warning. The
372 warning is issued once per calling package. See L<Moose::Deprecated> for more
375 =item You cannot pass C<< coerce => 1 >> unless the attribute's type constraint has a coercion
377 Previously, this was accepted, and it sort of worked, except that if you
378 attempted to set the attribute after the object was created, you would get a
381 Now you will get a warning when you attempt to define the attribute.
383 =item C<no Moose>, C<no Moose::Role>, and C<no Moose::Exporter> no longer unimport strict and warnings
385 This change was made in 1.05, and has now been reverted. We don't know if the
386 user has explicitly loaded strict or warnings on their own, and unimporting
387 them is just broken in that case.
389 =item Reversed logic when defining which options can be changed
391 L<Moose::Meta::Attribute> now allows all options to be changed in an
392 overridden attribute. The previous behaviour required each option to be
393 whitelisted using the C<legal_options_for_inheritance> method. This method has
394 been removed, and there is a new method, C<illegal_options_for_inheritance>,
395 which can now be used to prevent certain options from being changeable.
397 In addition, we only throw an error if the illegal option is actually
398 changed. If the superclass didn't specify this option at all when defining the
399 attribute, the subclass version can still add it as an option.
401 Example of overriding this in an attribute trait:
403 package Bar::Meta::Attribute;
406 has 'my_illegal_option' => (
411 around illegal_options_for_inheritance => sub {
412 return ( shift->(@_), qw/my_illegal_option/ );
421 =item L<Moose::Object/BUILD> methods are now called when calling C<new_object>
423 Previously, C<BUILD> methods would only be called from C<Moose::Object::new>,
424 but now they are also called when constructing an object via
425 C<Moose::Meta::Class::new_object>. C<BUILD> methods are an inherent part of the
426 object construction process, and this should make C<< $meta->new_object >>
427 actually usable without forcing people to use C<< $meta->name->new >>.
429 =item C<no Moose>, C<no Moose::Role>, and C<no Moose::Exporter> now unimport strict and warnings
431 In the interest of having C<no Moose> clean up everything that C<use Moose>
432 does in the calling scope, C<no Moose> (as well as all other
433 L<Moose::Exporter>-using modules) now unimports strict and warnings.
435 =item Metaclass compatibility checking and fixing should be much more robust
437 The L<metaclass compatibility|Moose/METACLASS COMPATIBILITY AND MOOSE> checking
438 and fixing algorithms have been completely rewritten, in both Class::MOP and
439 Moose. This should resolve many confusing errors when dealing with non-Moose
440 inheritance and with custom metaclasses for things like attributes,
441 constructors, etc. For correct code, the only thing that should require a
442 change is that custom error metaclasses must now inherit from
443 L<Moose::Error::Default>.
451 =item Moose::Meta::TypeConstraint::Class is_subtype_of behavior
453 Earlier versions of L<is_subtype_of|Moose::Meta::TypeConstraint::Class/is_subtype_of>
454 would incorrectly return true when called with itself, its own TC name or
455 its class name as an argument. (i.e. $foo_tc->is_subtype_of('Foo') == 1) This
456 behavior was a caused by C<isa> being checked before the class name. The old
457 behavior can be accessed with L<is_type_of|Moose::Meta::TypeConstraint::Class/is_type_of>
465 =item Moose::Meta::Attribute::Native::Trait::Code no longer creates reader methods by default
467 Earlier versions of L<Moose::Meta::Attribute::Native::Trait::Code> created
468 read-only accessors for the attributes it's been applied to, even if you didn't
469 ask for it with C<< is => 'ro' >>. This incorrect behaviour has now been fixed.
477 =item Moose::Util add_method_modifier behavior
479 add_method_modifier (and subsequently the sugar functions Moose::before,
480 Moose::after, and Moose::around) can now accept arrayrefs, with the same
481 behavior as lists. Types other than arrayref and regexp result in an error.
485 =head1 0.93_01 and 0.94
489 =item Moose::Util::MetaRole API has changed
491 The C<apply_metaclass_roles> function is now called C<apply_metaroles>. The
492 way arguments are supplied has been changed to force you to distinguish
493 between metaroles applied to L<Moose::Meta::Class> (and helpers) versus
494 L<Moose::Meta::Role>.
496 The old API still works, but will warn in a future release, and eventually be
499 =item Moose::Meta::Role has real attributes
501 The attributes returned by L<Moose::Meta::Role> are now instances of the
502 L<Moose::Meta::Role::Attribute> class, instead of bare hash references.
504 =item "no Moose" now removes C<blessed> and C<confess>
506 Moose is now smart enough to know exactly what it exported, even when it
507 re-exports functions from other packages. When you unimport Moose, it will
508 remove these functions from your namespace unless you I<also> imported them
509 directly from their respective packages.
511 If you have a C<no Moose> in your code I<before> you call C<blessed> or
512 C<confess>, your code will break. You can either move the C<no Moose> call
513 later in your code, or explicitly import the relevant functions from the
514 packages that provide them.
516 =item L<Moose::Exporter> is smarter about unimporting re-exports
518 The change above comes from a general improvement to L<Moose::Exporter>. It
519 will now unimport any function it exports, even if that function is a
520 re-export from another package.
522 =item Attributes in roles can no longer override class attributes with "+foo"
524 Previously, this worked more or less accidentally, because role attributes
525 weren't objects. This was never documented, but a few MooseX modules took
528 =item The composition_class_roles attribute in L<Moose::Meta::Role> is now a method
530 This was done to make it possible for roles to alter the the list of
531 composition class roles by applying a method modifiers. Previously, this was
532 an attribute and MooseX modules override it. Since that no longer works, this
535 This I<should> be an attribute, so this may switch back to being an attribute
536 in the future if we can figure out how to make this work.
544 =item Calling $object->new() is no longer deprecated
546 We decided to undeprecate this. Now it just works.
548 =item Both C<get_method_map> and C<get_attribute_map> is deprecated
550 These metaclass methods were never meant to be public, and they are both now
551 deprecated. The work around if you still need the functionality they provided
552 is to iterate over the list of names manually.
554 my %fields = map { $_ => $meta->get_attribute($_) } $meta->get_attribute_list;
556 This was actually a change in L<Class::MOP>, but this version of Moose
557 requires a version of L<Class::MOP> that includes said change.
565 =item Added Native delegation for Code refs
567 See L<Moose::Meta::Attribute::Native::Trait::Code> for details.
569 =item Calling $object->new() is deprecated
571 Moose has long supported this, but it's never really been documented, and we
572 don't think this is a good practice. If you want to construct an object from
573 an existing object, you should provide some sort of alternate constructor like
574 C<< $object->clone >>.
576 Calling C<< $object->new >> now issues a warning, and will be an error in a
579 =item Moose no longer warns if you call C<make_immutable> for a class with mutable ancestors
581 While in theory this is a good thing to warn about, we found so many
582 exceptions to this that doing this properly became quite problematic.
590 =item New Native delegation methods from L<List::Util> and L<List::MoreUtils>
592 In particular, we now have C<reduce>, C<shuffle>, C<uniq>, and C<natatime>.
594 =item The Moose::Exporter with_caller feature is now deprecated
596 Use C<with_meta> instead. The C<with_caller> option will start warning in a
599 =item Moose now warns if you call C<make_immutable> for a class with mutable ancestors
601 This is dangerous because modifying a class after a subclass has been
602 immutabilized will lead to incorrect results in the subclass, due to inlining,
603 caching, etc. This occasionally happens accidentally, when a class loads one
604 of its subclasses in the middle of its class definition, so pointing out that
605 this may cause issues should be helpful. Metaclasses (classes that inherit
606 from L<Class::MOP::Object>) are currently exempt from this check, since at the
607 moment we aren't very consistent about which metaclasses we immutabilize.
609 =item C<enum> and C<duck_type> now take arrayrefs for all forms
611 Previously, calling these functions with a list would take the first element of
612 the list as the type constraint name, and use the remainder as the enum values
613 or method names. This makes the interface inconsistent with the anon-type forms
614 of these functions (which must take an arrayref), and a free-form list where
615 the first value is sometimes special is hard to validate (and harder to give
616 reasonable error messages for). These functions have been changed to take
617 arrayrefs in all their forms - so, C<< enum 'My::Type' => [qw(foo bar)] >> is
618 now the preferred way to create an enum type constraint. The old syntax still
619 works for now, but it will hopefully be deprecated and removed in a future
626 L<Moose::Meta::Attribute::Native> has been moved into the Moose core from
627 L<MooseX::AttributeHelpers>. Major changes include:
631 =item C<traits>, not C<metaclass>
633 Method providers are only available via traits.
635 =item C<handles>, not C<provides> or C<curries>
637 The C<provides> syntax was like core Moose C<< handles => HASHREF >>
638 syntax, but with the keys and values reversed. This was confusing,
639 and AttributeHelpers now uses C<< handles => HASHREF >> in a way that
640 should be intuitive to anyone already familiar with how it is used for
643 The C<curries> functionality provided by AttributeHelpers has been
644 generalized to apply to all cases of C<< handles => HASHREF >>, though
645 not every piece of functionality has been ported (currying with a
646 CODEREF is not supported).
648 =item C<empty> is now C<is_empty>, and means empty, not non-empty
650 Previously, the C<empty> method provided by Arrays and Hashes returned true if
651 the attribute was B<not> empty (no elements). Now it returns true if the
652 attribute B<is> empty. It was also renamed to C<is_empty>, to reflect this.
654 =item C<find> was renamed to C<first>, and C<first> and C<last> were removed
656 L<List::Util> refers to the functionality that we used to provide under C<find>
657 as L<first|List::Util/first>, so that will likely be more familiar (and will
658 fit in better if we decide to add more List::Util functions). C<first> and
659 C<last> were removed, since their functionality is easily duplicated with
662 =item Helpers that take a coderef of one argument now use C<$_>
664 Subroutines passed as the first argument to C<first>, C<map>, and C<grep> now
665 receive their argument in C<$_> rather than as a parameter to the subroutine.
666 Helpers that take a coderef of two or more arguments remain using the argument
667 list (there are technical limitations to using C<$a> and C<$b> like C<sort>
670 See L<Moose::Meta::Attribute::Native> for the new documentation.
674 The C<alias> and C<excludes> role parameters have been renamed to C<-alias>
675 and C<-excludes>. The old names still work, but new code should use the new
676 names, and eventually the old ones will be deprecated and removed.
680 C<< use Moose -metaclass => 'Foo' >> now does alias resolution, just like
681 C<-traits> (and the C<metaclass> and C<traits> options to C<has>).
683 Added two functions C<meta_class_alias> and C<meta_attribute_alias> to
684 L<Moose::Util>, to simplify aliasing metaclasses and metatraits. This is
685 a wrapper around the old
687 package Moose::Meta::Class::Custom::Trait::FooTrait;
688 sub register_implementation { 'My::Meta::Trait' }
694 When an attribute generates I<no> accessors, we now warn. This is to help
695 users who forget the C<is> option. If you really do not want any accessors,
696 you can use C<< is => 'bare' >>. You can maintain back compat with older
697 versions of Moose by using something like:
699 ($Moose::VERSION >= 0.84 ? is => 'bare' : ())
701 When an accessor overwrites an existing method, we now warn. To work around
702 this warning (if you really must have this behavior), you can explicitly
703 remove the method before creating it as an accessor:
707 __PACKAGE__->meta->remove_method('foo');
713 When an unknown option is passed to C<has>, we now warn. You can silence
714 the warning by fixing your code. :)
716 The C<Role> type has been deprecated. On its own, it was useless,
717 since it just checked C<< $object->can('does') >>. If you were using
718 it as a parent type, just call C<role_type('Role::Name')> to create an
719 appropriate type instead.
723 C<use Moose::Exporter;> now imports C<strict> and C<warnings> into packages
728 C<DEMOLISHALL> and C<DEMOLISH> now receive an argument indicating whether or
729 not we are in global destruction.
733 Type constraints no longer run coercions for a value that already matches the
734 constraint. This may affect some (arguably buggy) edge case coercions that
735 rely on side effects in the C<via> clause.
739 L<Moose::Exporter> now accepts the C<-metaclass> option for easily
740 overriding the metaclass (without L<metaclass>). This works for classes
745 Added a C<duck_type> sugar function to L<Moose::Util::TypeConstraints>
746 to make integration with non-Moose classes easier. It simply checks if
747 C<< $obj->can() >> a list of methods.
749 A number of methods (mostly inherited from L<Class::MOP>) have been
750 renamed with a leading underscore to indicate their internal-ness. The
751 old method names will still work for a while, but will warn that the
752 method has been renamed. In a few cases, the method will be removed
753 entirely in the future. This may affect MooseX authors who were using
758 Calling C<subtype> with a name as the only argument now throws an
759 exception. If you want an anonymous subtype do:
761 my $subtype = subtype as 'Foo';
763 This is related to the changes in version 0.71_01.
765 The C<is_needed> method in L<Moose::Meta::Method::Destructor> is now
766 only usable as a class method. Previously, it worked as a class or
767 object method, with a different internal implementation for each
770 The internals of making a class immutable changed a lot in Class::MOP
771 0.78_02, and Moose's internals have changed along with it. The
772 external C<< $metaclass->make_immutable >> method still works the same
777 A mutable class accepted C<< Foo->new(undef) >> without complaint,
778 while an immutable class would blow up with an unhelpful error. Now,
779 in both cases we throw a helpful error instead.
781 This "feature" was originally added to allow for cases such as this:
789 return My::Class->new($args);
791 But we decided this is a bad idea and a little too magical, because it
792 can easily mask real errors.
796 Calling C<type> or C<subtype> without the sugar helpers (C<as>,
797 C<where>, C<message>) is now deprecated.
799 As a side effect, this meant we ended up using Perl prototypes on
800 C<as>, and code like this will no longer work:
802 use Moose::Util::TypeConstraints;
803 use Declare::Constraints::Simple -All;
805 subtype 'ArrayOfInts'
807 => IsArrayRef(IsInt);
809 Instead it must be changed to this:
814 where => IsArrayRef(IsInt)
818 If you want to maintain backwards compat with older versions of Moose,
819 you must explicitly test Moose's C<VERSION>:
821 if ( Moose->VERSION < 0.71_01 ) {
822 subtype 'ArrayOfInts'
824 => IsArrayRef(IsInt);
830 where => IsArrayRef(IsInt)
837 We no longer pass the meta-attribute object as a final argument to
838 triggers. This actually changed for inlined code a while back, but the
839 non-inlined version and the docs were still out of date.
841 If by some chance you actually used this feature, the workaround is
842 simple. You fetch the attribute object from out of the C<$self>
843 that is passed as the first argument to trigger, like so:
849 my ( $self, $value ) = @_;
850 my $attr = $self->meta->find_attribute_by_name('foo');
858 If you created a subtype and passed a parent that Moose didn't know
859 about, it simply ignored the parent. Now it automatically creates the
860 parent as a class type. This may not be what you want, but is less
863 You could declare a name with subtype such as "Foo!Bar". Moose would
864 accept this allowed, but if you used it in a parameterized type such
865 as "ArrayRef[Foo!Bar]" it wouldn't work. We now do some vetting on
866 names created via the sugar functions, so that they can only contain
867 alphanumerics, ":", and ".".
871 Methods created via an attribute can now fulfill a C<requires>
872 declaration for a role. Honestly we don't know why Stevan didn't make
873 this work originally, he was just insane or something.
875 Stack traces from inlined code will now report the line and file as
876 being in your class, as opposed to in Moose guts.
880 When a class does not provide all of a role's required methods, the
881 error thrown now mentions all of the missing methods, as opposed to
882 just the first missing method.
884 Moose will no longer inline a constructor for your class unless it
885 inherits its constructor from Moose::Object, and will warn when it
886 doesn't inline. If you want to force inlining anyway, pass
887 C<< replace_constructor => 1 >> to C<make_immutable>.
889 If you want to get rid of the warning, pass C<< inline_constructor =>
894 Removed the (deprecated) C<make_immutable> keyword.
896 Removing an attribute from a class now also removes delegation
897 (C<handles>) methods installed for that attribute. This is correct
898 behavior, but if you were wrongly relying on it you might get bit.
902 Roles now add methods by calling C<add_method>, not
903 C<alias_method>. They make sure to always provide a method object,
904 which will be cloned internally. This means that it is now possible to
905 track the source of a method provided by a role, and even follow its
906 history through intermediate roles. This means that methods added by
907 a role now show up when looking at a class's method list/map.
909 Parameter and Union args are now sorted, this makes Int|Str the same
910 constraint as Str|Int. Also, incoming type constraint strings are
911 normalized to remove all whitespace differences. This is mostly for
912 internals and should not affect outside code.
914 L<Moose::Exporter> will no longer remove a subroutine that the
915 exporting package re-exports. Moose re-exports the Carp::confess
916 function, among others. The reasoning is that we cannot know whether
917 you have also explicitly imported those functions for your own use, so
918 we err on the safe side and always keep them.
922 C<Moose::init_meta> should now be called as a method.
924 New modules for extension writers, L<Moose::Exporter> and
925 L<Moose::Util::MetaRole>.
929 Implemented metaclass traits (and wrote a recipe for it):
931 use Moose -traits => 'Foo'
933 This should make writing small Moose extensions a little
938 Fixed C<coerce> to accept anon types just like C<subtype> can.
941 coerce $some_anon_type => from 'Str' => via { ... };
945 Added C<BUILDARGS>, a new step in C<< Moose::Object->new() >>.
949 Fixed how the C<< is => (ro|rw) >> works with custom defined
950 C<reader>, C<writer> and C<accessor> options. See the below table for
953 is => ro, writer => _foo # turns into (reader => foo, writer => _foo)
954 is => rw, writer => _foo # turns into (reader => foo, writer => _foo)
955 is => rw, accessor => _foo # turns into (accessor => _foo)
956 is => ro, accessor => _foo # error, accesor is rw
960 The C<before/around/after> method modifiers now support regexp
961 matching of method names. NOTE: this only works for classes, it is
962 currently not supported in roles, but, ... patches welcome.
964 The C<has> keyword for roles now accepts the same array ref form that
965 L<Moose>.pm does for classes.
967 A trigger on a read-only attribute is no longer an error, as it's
968 useful to trigger off of the constructor.
970 Subtypes of parameterizable types now are parameterizable types
975 Fixed issue where C<DEMOLISHALL> was eating the value in C<$@>, and so
976 not working correctly. It still kind of eats them, but so does vanilla
981 Inherited attributes may now be extended without restriction on the
982 type ('isa', 'does').
984 The entire set of Moose::Meta::TypeConstraint::* classes were
985 refactored in this release. If you were relying on their internals you
986 should test your code carefully.
990 Documenting the use of '+name' with attributes that come from recently
991 composed roles. It makes sense, people are using it, and so why not
992 just officially support it.
994 The C<< Moose::Meta::Class->create >> method now supports roles.
996 It is now possible to make anonymous enum types by passing C<enum> an
997 array reference instead of the C<< enum $name => @values >>.
1001 Added the C<make_immutable> keyword as a shortcut to calling
1002 C<make_immutable> on the meta object. This eventually got removed!
1004 Made C<< init_arg => undef >> work in Moose. This means "do not accept
1005 a constructor parameter for this attribute".
1007 Type errors now use the provided message. Prior to this release they
1012 Moose is now a postmodern object system :)
1014 The Role system was completely refactored. It is 100% backwards
1015 compat, but the internals were totally changed. If you relied on the
1016 internals then you are advised to test carefully.
1018 Added method exclusion and aliasing for Roles in this release.
1020 Added the L<Moose::Util::TypeConstraints::OptimizedConstraints>
1023 Passing a list of values to an accessor (which is only expecting one
1024 value) used to be silently ignored, now it throws an error.
1028 Added parameterized types and did a pretty heavy refactoring of the
1029 type constraint system.
1031 Better framework extensibility and better support for "making your own
1034 =head1 0.25 or before
1036 Honestly, you shouldn't be using versions of Moose that are this old,
1037 so many bug fixes and speed improvements have been made you would be
1038 crazy to not upgrade.
1040 Also, I am tired of going through the Changelog so I am stopping here,
1041 if anyone would like to continue this please feel free.