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 The parent of a union type is its components' nearest common ancestor
28 Previously, union types considered all of their component types their parent
29 types. This was incorrect because parent types are defined as types that must
30 be satisfied in order for the child type to be satisfied, but in a union,
31 validating as any parent type will validate against the entire union. This has
32 been changed to find the nearest common ancestor for all of its components. For
33 example, a union of "Int|ArrayRef[Int]" now has a parent of "Defined".
35 =item Union types consider all members in the C<is_subtype_of> and C<is_a_type_of> methods
37 Previously, a union type would report itself as being of a subtype of a type if
38 I<any> of its member types were subtypes of that type. This was incorrect
39 because any value that passes a subtype constraint must also pass a parent
40 constraint. This has changed so that I<all> of its member types must be a
41 subtype of the specified type.
43 =item Enum types now work with just one value
45 Previously, an C<enum> type needed to have two or more values. Nobody knew
48 =item Methods defined in UNIVERSAL now appear in the MOP
50 Any method introspection methods that look at methods from parent classes now
51 find methods defined in UNIVERSAL. This includes methods like C<<
52 $class->get_all_methods >> and C<< $class->find_method_by_name >>.
54 This also means that you can now apply method modifiers to these methods.
56 =item Hand-optimized type constraint code causes a deprecation warning
58 If you provide an optimized sub ref for a type constraint, this now causes a
59 deprecation warning. Typically, this comes from passing an C<optimize_as>
60 parameter to C<subtype>, but it could also happen if you create a
61 L<Moose::Meta::TypeConstraint> object directly.
63 Use the inlining feature (C<inline_as>) added in 2.0100 instead.
71 =item Array and Hash native traits provide a C<shallow_clone> method
73 The Array and Hash native traits now provide a "shallow_clone" method, which
74 will return a reference to a new container with the same contents as the
75 attribute's reference.
83 =item Hand-optimized type constraint code is deprecated in favor of inlining
85 Moose allows you to provide a hand-optimized version of a type constraint's
86 subroutine reference. This version allows type constraints to generate inline
87 code, and you should use this inlining instead of providing a hand-optimized
90 This affects the C<optimize_as> sub exported by
91 L<Moose::Util::TypeConstraints>. Use C<inline_as> instead.
93 This will start warning in the 2.0300 release.
101 =item More useful type constraint error messages
103 If you have L<Devel::PartialDump> version 0.14 or higher installed, Moose's
104 type constraint error messages will use it to display the invalid value, rather
105 than just displaying it directly. This will generally be much more useful. For
106 instance, instead of this:
108 Attribute (foo) does not pass the type constraint because: Validation failed for 'ArrayRef[Int]' with value ARRAY(0x275eed8)
110 the error message will instead look like
112 Attribute (foo) does not pass the type constraint because: Validation failed for 'ArrayRef[Int]' with value [ "a" ]
114 Note that L<Devel::PartialDump> can't be made a direct dependency at the
115 moment, because it uses Moose itself, but we're considering options to make
124 =item Roles have their own default attribute metaclass
126 Previously, when a role was applied to a class, it would use the attribute
127 metaclass defined in the class when copying over the attributes in the role.
128 This was wrong, because for instance, using L<MooseX::FollowPBP> in the class
129 would end up renaming all of the accessors generated by the role, some of which
130 may be being called in the role, causing it to break. Roles now keep track of
131 their own attribute metaclass to use by default when being applied to a class
132 (defaulting to Moose::Meta::Attribute). This is modifiable using
133 L<Moose::Util::MetaRole> by passing the C<applied_attribute> key to the
134 C<role_metaroles> option, as in:
136 Moose::Util::MetaRole::apply_metaroles(
139 attribute => ['My::Meta::Role::Attribute'],
142 applied_attribute => ['My::Meta::Role::Attribute'],
146 =item Class::MOP has been folded into the Moose dist
148 Moose and Class::MOP are tightly related enough that they have always had to be
149 kept pretty closely in step in terms of versions. Making them into a single
150 dist should simplify the upgrade process for users, as it should no longer be
151 possible to upgrade one without the other and potentially cause issues. No
152 functionality has changed, and this should be entirely transparent.
154 =item Moose's conflict checking is more robust and useful
156 There are two parts to this. The most useful one right now is that Moose will
157 ship with a C<moose-outdated> script, which can be run at any point to list the
158 modules which are installed that conflict with the installed version of Moose.
159 After upgrading Moose, running C<moose-outdated | cpanm> should be sufficient
160 to ensure that all of the Moose extensions you use will continue to work.
162 The other part is that Moose's C<META.json> file will also specify the
163 conflicts under the C<x_conflicts> key. We are working with the Perl tool chain
164 developers to try to get conflicts support added to CPAN clients, and if/when
165 that happens, the metadata already exists, and so the conflict checking will
168 =item Most deprecated APIs/features are slated for removal in Moose 2.0200
170 Most of the deprecated APIs and features in Moose will start throwing an error
171 in Moose 2.0200. Some of the features will go away entirely, and some will
172 simply throw an error.
174 The things on the chopping block are:
178 =item * Old public methods in Class::MOP and Moose
180 This includes things like C<< Class::MOP::Class->get_attribute_map >>, C<<
181 Class::MOP::Class->construct_instance >>, and many others. These were
182 deprecated in L<Class::MOP> 0.80_01, released on April 5, 2009.
184 These methods will be removed entirely in Moose 2.0200.
186 =item * Old public functions in Class::MOP
188 This include C<Class::MOP::subname>, C<Class::MOP::in_global_destruction>, and
189 the C<Class::MOP::HAS_ISAREV> constant. The first two were deprecated in 0.84,
190 and the last in 0.80. Class::MOP 0.84 was released on May 12, 2009.
192 These functions will be removed entirely in Moose 2.0200.
194 =item * The C<alias> and C<excludes> option for role composition
196 These were renamed to C<-alias> and C<-excludes> in Moose 0.89, released on
199 Passing these will throw an error in Moose 2.0200.
201 =item * The old L<Moose::Util::MetaRole> API
203 This include the C<apply_metaclass_roles()> function, as well as passing the
204 C<for_class> or any key ending in C<_roles> to C<apply_metaroles()>. This was
205 deprecated in Moose 0.93_01, released on January 4, 2010.
207 These will all throw an error in Moose 2.0200.
209 =item * Passing plain lists to C<type()> or C<subtype()>
211 The old API for these functions allowed you to pass a plain list of parameter,
212 rather than a list of hash references (which is what C<as()>, C<where>,
213 etc. return). This was deprecated in Moose 0.71_01, released on February 22,
216 This will throw an error in Moose 2.0200.
218 =item * The Role subtype
220 This subtype was deprecated in Moose 0.84, released on June 26, 2009.
222 This will be removed entirely in Moose 2.0200.
232 =item * New release policy
234 As of the 2.0 release, Moose now has an official release and support policy,
235 documented in L<Moose::Manual::Support>. All API changes will now go through a
236 deprecation cycle of at least one year, after which the deprecated API can be
237 removed. Deprecations and removals will only happen in major releases.
239 In between major releases, we will still make minor releases to add new
240 features, fix bugs, update documentation, etc.
248 =item Configurable stacktraces
250 Classes which use the L<Moose::Error::Default> error class can now have
251 stacktraces disabled by setting the C<MOOSE_ERROR_STYLE> env var to C<croak>.
252 This is experimental, fairly incomplete, and won't work in all cases (because
253 Moose's error system in general is all of these things), but this should allow
254 for reducing at least some of the verbosity in most cases.
262 =item Native Delegations
264 In previous versions of Moose, the Native delegations were created as
265 closures. The generated code was often quite slow compared to doing the same
266 thing by hand. For example, the Array's push delegation ended up doing
269 push @{ $self->$reader() }, @_;
271 If the attribute was created without a reader, the C<$reader> sub reference
272 followed a very slow code path. Even with a reader, this is still slower than
275 Native delegations are now generated as inline code, just like other
276 accessors, so we can access the slot directly.
278 In addition, native traits now do proper constraint checking in all cases. In
279 particular, constraint checking has been improved for array and hash
280 references. Previously, only the I<contained> type (the C<Str> in
281 C<HashRef[Str]>) would be checked when a new value was added to the
282 collection. However, if there was a constraint that applied to the whole
283 value, this was never checked.
285 In addition, coercions are now called on the whole value.
287 The delegation methods now do more argument checking. All of the methods check
288 that a valid number of arguments were passed to the method. In addition, the
289 delegation methods check that the arguments are sane (array indexes, hash
290 keys, numbers, etc.) when applicable. We have tried to emulate the behavior of
291 Perl builtins as much as possible.
293 Finally, triggers are called whenever the value of the attribute is changed by
296 These changes are only likely to break code in a few cases.
298 The inlining code may or may not preserve the original reference when changes
299 are made. In some cases, methods which change the value may replace it
300 entirely. This will break tied values.
302 If you have a typed arrayref or hashref attribute where the type enforces a
303 constraint on the whole collection, this constraint will now be checked. It's
304 possible that code which previously ran without errors will now cause the
305 constraint to fail. However, presumably this is a good thing ;)
307 If you are passing invalid arguments to a delegation which were previously
308 being ignored, these calls will now fail.
310 If your code relied on the trigger only being called for a regular writer,
311 that may cause problems.
313 As always, you are encouraged to test before deploying the latest version of
316 =item Defaults is and default for String, Counter, and Bool
318 A few native traits (String, Counter, Bool) provide default values of "is" and
319 "default" when you created an attribute. Allowing them to provide these values
320 is now deprecated. Supply the value yourself when creating the attribute.
322 =item The C<meta> method
324 Moose and Class::MOP have been cleaned up internally enough to make the
325 C<meta> method that you get by default optional. C<use Moose> and
326 C<use Moose::Role> now can take an additional C<-meta_name> option, which
327 tells Moose what name to use when installing the C<meta> method. Passing
328 C<undef> to this option suppresses generation of the C<meta> method
329 entirely. This should be useful for users of modules which also use a C<meta>
330 method or function, such as L<Curses> or L<Rose::DB::Object>.
338 =item All deprecated features now warn
340 Previously, deprecation mostly consisted of simply saying "X is deprecated" in
341 the Changes file. We were not very consistent about actually warning. Now, all
342 deprecated features still present in Moose actually give a warning. The
343 warning is issued once per calling package. See L<Moose::Deprecated> for more
346 =item You cannot pass C<< coerce => 1 >> unless the attribute's type constraint has a coercion
348 Previously, this was accepted, and it sort of worked, except that if you
349 attempted to set the attribute after the object was created, you would get a
352 Now you will get a warning when you attempt to define the attribute.
354 =item C<no Moose>, C<no Moose::Role>, and C<no Moose::Exporter> no longer unimport strict and warnings
356 This change was made in 1.05, and has now been reverted. We don't know if the
357 user has explicitly loaded strict or warnings on their own, and unimporting
358 them is just broken in that case.
360 =item Reversed logic when defining which options can be changed
362 L<Moose::Meta::Attribute> now allows all options to be changed in an
363 overridden attribute. The previous behaviour required each option to be
364 whitelisted using the C<legal_options_for_inheritance> method. This method has
365 been removed, and there is a new method, C<illegal_options_for_inheritance>,
366 which can now be used to prevent certain options from being changeable.
368 In addition, we only throw an error if the illegal option is actually
369 changed. If the superclass didn't specify this option at all when defining the
370 attribute, the subclass version can still add it as an option.
372 Example of overriding this in an attribute trait:
374 package Bar::Meta::Attribute;
377 has 'my_illegal_option' => (
382 around illegal_options_for_inheritance => sub {
383 return ( shift->(@_), qw/my_illegal_option/ );
392 =item L<Moose::Object/BUILD> methods are now called when calling C<new_object>
394 Previously, C<BUILD> methods would only be called from C<Moose::Object::new>,
395 but now they are also called when constructing an object via
396 C<Moose::Meta::Class::new_object>. C<BUILD> methods are an inherent part of the
397 object construction process, and this should make C<< $meta->new_object >>
398 actually usable without forcing people to use C<< $meta->name->new >>.
400 =item C<no Moose>, C<no Moose::Role>, and C<no Moose::Exporter> now unimport strict and warnings
402 In the interest of having C<no Moose> clean up everything that C<use Moose>
403 does in the calling scope, C<no Moose> (as well as all other
404 L<Moose::Exporter>-using modules) now unimports strict and warnings.
406 =item Metaclass compatibility checking and fixing should be much more robust
408 The L<metaclass compatibility|Moose/METACLASS COMPATIBILITY AND MOOSE> checking
409 and fixing algorithms have been completely rewritten, in both Class::MOP and
410 Moose. This should resolve many confusing errors when dealing with non-Moose
411 inheritance and with custom metaclasses for things like attributes,
412 constructors, etc. For correct code, the only thing that should require a
413 change is that custom error metaclasses must now inherit from
414 L<Moose::Error::Default>.
422 =item Moose::Meta::TypeConstraint::Class is_subtype_of behavior
424 Earlier versions of L<is_subtype_of|Moose::Meta::TypeConstraint::Class/is_subtype_of>
425 would incorrectly return true when called with itself, its own TC name or
426 its class name as an argument. (i.e. $foo_tc->is_subtype_of('Foo') == 1) This
427 behavior was a caused by C<isa> being checked before the class name. The old
428 behavior can be accessed with L<is_type_of|Moose::Meta::TypeConstraint::Class/is_type_of>
436 =item Moose::Meta::Attribute::Native::Trait::Code no longer creates reader methods by default
438 Earlier versions of L<Moose::Meta::Attribute::Native::Trait::Code> created
439 read-only accessors for the attributes it's been applied to, even if you didn't
440 ask for it with C<< is => 'ro' >>. This incorrect behaviour has now been fixed.
448 =item Moose::Util add_method_modifier behavior
450 add_method_modifier (and subsequently the sugar functions Moose::before,
451 Moose::after, and Moose::around) can now accept arrayrefs, with the same
452 behavior as lists. Types other than arrayref and regexp result in an error.
456 =head1 0.93_01 and 0.94
460 =item Moose::Util::MetaRole API has changed
462 The C<apply_metaclass_roles> function is now called C<apply_metaroles>. The
463 way arguments are supplied has been changed to force you to distinguish
464 between metaroles applied to L<Moose::Meta::Class> (and helpers) versus
465 L<Moose::Meta::Role>.
467 The old API still works, but will warn in a future release, and eventually be
470 =item Moose::Meta::Role has real attributes
472 The attributes returned by L<Moose::Meta::Role> are now instances of the
473 L<Moose::Meta::Role::Attribute> class, instead of bare hash references.
475 =item "no Moose" now removes C<blessed> and C<confess>
477 Moose is now smart enough to know exactly what it exported, even when it
478 re-exports functions from other packages. When you unimport Moose, it will
479 remove these functions from your namespace unless you I<also> imported them
480 directly from their respective packages.
482 If you have a C<no Moose> in your code I<before> you call C<blessed> or
483 C<confess>, your code will break. You can either move the C<no Moose> call
484 later in your code, or explicitly import the relevant functions from the
485 packages that provide them.
487 =item L<Moose::Exporter> is smarter about unimporting re-exports
489 The change above comes from a general improvement to L<Moose::Exporter>. It
490 will now unimport any function it exports, even if that function is a
491 re-export from another package.
493 =item Attributes in roles can no longer override class attributes with "+foo"
495 Previously, this worked more or less accidentally, because role attributes
496 weren't objects. This was never documented, but a few MooseX modules took
499 =item The composition_class_roles attribute in L<Moose::Meta::Role> is now a method
501 This was done to make it possible for roles to alter the the list of
502 composition class roles by applying a method modifiers. Previously, this was
503 an attribute and MooseX modules override it. Since that no longer works, this
506 This I<should> be an attribute, so this may switch back to being an attribute
507 in the future if we can figure out how to make this work.
515 =item Calling $object->new() is no longer deprecated
517 We decided to undeprecate this. Now it just works.
519 =item Both C<get_method_map> and C<get_attribute_map> is deprecated
521 These metaclass methods were never meant to be public, and they are both now
522 deprecated. The work around if you still need the functionality they provided
523 is to iterate over the list of names manually.
525 my %fields = map { $_ => $meta->get_attribute($_) } $meta->get_attribute_list;
527 This was actually a change in L<Class::MOP>, but this version of Moose
528 requires a version of L<Class::MOP> that includes said change.
536 =item Added Native delegation for Code refs
538 See L<Moose::Meta::Attribute::Native::Trait::Code> for details.
540 =item Calling $object->new() is deprecated
542 Moose has long supported this, but it's never really been documented, and we
543 don't think this is a good practice. If you want to construct an object from
544 an existing object, you should provide some sort of alternate constructor like
545 C<< $object->clone >>.
547 Calling C<< $object->new >> now issues a warning, and will be an error in a
550 =item Moose no longer warns if you call C<make_immutable> for a class with mutable ancestors
552 While in theory this is a good thing to warn about, we found so many
553 exceptions to this that doing this properly became quite problematic.
561 =item New Native delegation methods from L<List::Util> and L<List::MoreUtils>
563 In particular, we now have C<reduce>, C<shuffle>, C<uniq>, and C<natatime>.
565 =item The Moose::Exporter with_caller feature is now deprecated
567 Use C<with_meta> instead. The C<with_caller> option will start warning in a
570 =item Moose now warns if you call C<make_immutable> for a class with mutable ancestors
572 This is dangerous because modifying a class after a subclass has been
573 immutabilized will lead to incorrect results in the subclass, due to inlining,
574 caching, etc. This occasionally happens accidentally, when a class loads one
575 of its subclasses in the middle of its class definition, so pointing out that
576 this may cause issues should be helpful. Metaclasses (classes that inherit
577 from L<Class::MOP::Object>) are currently exempt from this check, since at the
578 moment we aren't very consistent about which metaclasses we immutabilize.
580 =item C<enum> and C<duck_type> now take arrayrefs for all forms
582 Previously, calling these functions with a list would take the first element of
583 the list as the type constraint name, and use the remainder as the enum values
584 or method names. This makes the interface inconsistent with the anon-type forms
585 of these functions (which must take an arrayref), and a free-form list where
586 the first value is sometimes special is hard to validate (and harder to give
587 reasonable error messages for). These functions have been changed to take
588 arrayrefs in all their forms - so, C<< enum 'My::Type' => [qw(foo bar)] >> is
589 now the preferred way to create an enum type constraint. The old syntax still
590 works for now, but it will hopefully be deprecated and removed in a future
597 L<Moose::Meta::Attribute::Native> has been moved into the Moose core from
598 L<MooseX::AttributeHelpers>. Major changes include:
602 =item C<traits>, not C<metaclass>
604 Method providers are only available via traits.
606 =item C<handles>, not C<provides> or C<curries>
608 The C<provides> syntax was like core Moose C<< handles => HASHREF >>
609 syntax, but with the keys and values reversed. This was confusing,
610 and AttributeHelpers now uses C<< handles => HASHREF >> in a way that
611 should be intuitive to anyone already familiar with how it is used for
614 The C<curries> functionality provided by AttributeHelpers has been
615 generalized to apply to all cases of C<< handles => HASHREF >>, though
616 not every piece of functionality has been ported (currying with a
617 CODEREF is not supported).
619 =item C<empty> is now C<is_empty>, and means empty, not non-empty
621 Previously, the C<empty> method provided by Arrays and Hashes returned true if
622 the attribute was B<not> empty (no elements). Now it returns true if the
623 attribute B<is> empty. It was also renamed to C<is_empty>, to reflect this.
625 =item C<find> was renamed to C<first>, and C<first> and C<last> were removed
627 L<List::Util> refers to the functionality that we used to provide under C<find>
628 as L<first|List::Util/first>, so that will likely be more familiar (and will
629 fit in better if we decide to add more List::Util functions). C<first> and
630 C<last> were removed, since their functionality is easily duplicated with
633 =item Helpers that take a coderef of one argument now use C<$_>
635 Subroutines passed as the first argument to C<first>, C<map>, and C<grep> now
636 receive their argument in C<$_> rather than as a parameter to the subroutine.
637 Helpers that take a coderef of two or more arguments remain using the argument
638 list (there are technical limitations to using C<$a> and C<$b> like C<sort>
641 See L<Moose::Meta::Attribute::Native> for the new documentation.
645 The C<alias> and C<excludes> role parameters have been renamed to C<-alias>
646 and C<-excludes>. The old names still work, but new code should use the new
647 names, and eventually the old ones will be deprecated and removed.
651 C<< use Moose -metaclass => 'Foo' >> now does alias resolution, just like
652 C<-traits> (and the C<metaclass> and C<traits> options to C<has>).
654 Added two functions C<meta_class_alias> and C<meta_attribute_alias> to
655 L<Moose::Util>, to simplify aliasing metaclasses and metatraits. This is
656 a wrapper around the old
658 package Moose::Meta::Class::Custom::Trait::FooTrait;
659 sub register_implementation { 'My::Meta::Trait' }
665 When an attribute generates I<no> accessors, we now warn. This is to help
666 users who forget the C<is> option. If you really do not want any accessors,
667 you can use C<< is => 'bare' >>. You can maintain back compat with older
668 versions of Moose by using something like:
670 ($Moose::VERSION >= 0.84 ? is => 'bare' : ())
672 When an accessor overwrites an existing method, we now warn. To work around
673 this warning (if you really must have this behavior), you can explicitly
674 remove the method before creating it as an accessor:
678 __PACKAGE__->meta->remove_method('foo');
684 When an unknown option is passed to C<has>, we now warn. You can silence
685 the warning by fixing your code. :)
687 The C<Role> type has been deprecated. On its own, it was useless,
688 since it just checked C<< $object->can('does') >>. If you were using
689 it as a parent type, just call C<role_type('Role::Name')> to create an
690 appropriate type instead.
694 C<use Moose::Exporter;> now imports C<strict> and C<warnings> into packages
699 C<DEMOLISHALL> and C<DEMOLISH> now receive an argument indicating whether or
700 not we are in global destruction.
704 Type constraints no longer run coercions for a value that already matches the
705 constraint. This may affect some (arguably buggy) edge case coercions that
706 rely on side effects in the C<via> clause.
710 L<Moose::Exporter> now accepts the C<-metaclass> option for easily
711 overriding the metaclass (without L<metaclass>). This works for classes
716 Added a C<duck_type> sugar function to L<Moose::Util::TypeConstraints>
717 to make integration with non-Moose classes easier. It simply checks if
718 C<< $obj->can() >> a list of methods.
720 A number of methods (mostly inherited from L<Class::MOP>) have been
721 renamed with a leading underscore to indicate their internal-ness. The
722 old method names will still work for a while, but will warn that the
723 method has been renamed. In a few cases, the method will be removed
724 entirely in the future. This may affect MooseX authors who were using
729 Calling C<subtype> with a name as the only argument now throws an
730 exception. If you want an anonymous subtype do:
732 my $subtype = subtype as 'Foo';
734 This is related to the changes in version 0.71_01.
736 The C<is_needed> method in L<Moose::Meta::Method::Destructor> is now
737 only usable as a class method. Previously, it worked as a class or
738 object method, with a different internal implementation for each
741 The internals of making a class immutable changed a lot in Class::MOP
742 0.78_02, and Moose's internals have changed along with it. The
743 external C<< $metaclass->make_immutable >> method still works the same
748 A mutable class accepted C<< Foo->new(undef) >> without complaint,
749 while an immutable class would blow up with an unhelpful error. Now,
750 in both cases we throw a helpful error instead.
752 This "feature" was originally added to allow for cases such as this:
760 return My::Class->new($args);
762 But we decided this is a bad idea and a little too magical, because it
763 can easily mask real errors.
767 Calling C<type> or C<subtype> without the sugar helpers (C<as>,
768 C<where>, C<message>) is now deprecated.
770 As a side effect, this meant we ended up using Perl prototypes on
771 C<as>, and code like this will no longer work:
773 use Moose::Util::TypeConstraints;
774 use Declare::Constraints::Simple -All;
776 subtype 'ArrayOfInts'
778 => IsArrayRef(IsInt);
780 Instead it must be changed to this:
785 where => IsArrayRef(IsInt)
789 If you want to maintain backwards compat with older versions of Moose,
790 you must explicitly test Moose's C<VERSION>:
792 if ( Moose->VERSION < 0.71_01 ) {
793 subtype 'ArrayOfInts'
795 => IsArrayRef(IsInt);
801 where => IsArrayRef(IsInt)
808 We no longer pass the meta-attribute object as a final argument to
809 triggers. This actually changed for inlined code a while back, but the
810 non-inlined version and the docs were still out of date.
812 If by some chance you actually used this feature, the workaround is
813 simple. You fetch the attribute object from out of the C<$self>
814 that is passed as the first argument to trigger, like so:
820 my ( $self, $value ) = @_;
821 my $attr = $self->meta->find_attribute_by_name('foo');
829 If you created a subtype and passed a parent that Moose didn't know
830 about, it simply ignored the parent. Now it automatically creates the
831 parent as a class type. This may not be what you want, but is less
834 You could declare a name with subtype such as "Foo!Bar". Moose would
835 accept this allowed, but if you used it in a parameterized type such
836 as "ArrayRef[Foo!Bar]" it wouldn't work. We now do some vetting on
837 names created via the sugar functions, so that they can only contain
838 alphanumerics, ":", and ".".
842 Methods created via an attribute can now fulfill a C<requires>
843 declaration for a role. Honestly we don't know why Stevan didn't make
844 this work originally, he was just insane or something.
846 Stack traces from inlined code will now report the line and file as
847 being in your class, as opposed to in Moose guts.
851 When a class does not provide all of a role's required methods, the
852 error thrown now mentions all of the missing methods, as opposed to
853 just the first missing method.
855 Moose will no longer inline a constructor for your class unless it
856 inherits its constructor from Moose::Object, and will warn when it
857 doesn't inline. If you want to force inlining anyway, pass
858 C<< replace_constructor => 1 >> to C<make_immutable>.
860 If you want to get rid of the warning, pass C<< inline_constructor =>
865 Removed the (deprecated) C<make_immutable> keyword.
867 Removing an attribute from a class now also removes delegation
868 (C<handles>) methods installed for that attribute. This is correct
869 behavior, but if you were wrongly relying on it you might get bit.
873 Roles now add methods by calling C<add_method>, not
874 C<alias_method>. They make sure to always provide a method object,
875 which will be cloned internally. This means that it is now possible to
876 track the source of a method provided by a role, and even follow its
877 history through intermediate roles. This means that methods added by
878 a role now show up when looking at a class's method list/map.
880 Parameter and Union args are now sorted, this makes Int|Str the same
881 constraint as Str|Int. Also, incoming type constraint strings are
882 normalized to remove all whitespace differences. This is mostly for
883 internals and should not affect outside code.
885 L<Moose::Exporter> will no longer remove a subroutine that the
886 exporting package re-exports. Moose re-exports the Carp::confess
887 function, among others. The reasoning is that we cannot know whether
888 you have also explicitly imported those functions for your own use, so
889 we err on the safe side and always keep them.
893 C<Moose::init_meta> should now be called as a method.
895 New modules for extension writers, L<Moose::Exporter> and
896 L<Moose::Util::MetaRole>.
900 Implemented metaclass traits (and wrote a recipe for it):
902 use Moose -traits => 'Foo'
904 This should make writing small Moose extensions a little
909 Fixed C<coerce> to accept anon types just like C<subtype> can.
912 coerce $some_anon_type => from 'Str' => via { ... };
916 Added C<BUILDARGS>, a new step in C<< Moose::Object->new() >>.
920 Fixed how the C<< is => (ro|rw) >> works with custom defined
921 C<reader>, C<writer> and C<accessor> options. See the below table for
924 is => ro, writer => _foo # turns into (reader => foo, writer => _foo)
925 is => rw, writer => _foo # turns into (reader => foo, writer => _foo)
926 is => rw, accessor => _foo # turns into (accessor => _foo)
927 is => ro, accessor => _foo # error, accesor is rw
931 The C<before/around/after> method modifiers now support regexp
932 matching of method names. NOTE: this only works for classes, it is
933 currently not supported in roles, but, ... patches welcome.
935 The C<has> keyword for roles now accepts the same array ref form that
936 L<Moose>.pm does for classes.
938 A trigger on a read-only attribute is no longer an error, as it's
939 useful to trigger off of the constructor.
941 Subtypes of parameterizable types now are parameterizable types
946 Fixed issue where C<DEMOLISHALL> was eating the value in C<$@>, and so
947 not working correctly. It still kind of eats them, but so does vanilla
952 Inherited attributes may now be extended without restriction on the
953 type ('isa', 'does').
955 The entire set of Moose::Meta::TypeConstraint::* classes were
956 refactored in this release. If you were relying on their internals you
957 should test your code carefully.
961 Documenting the use of '+name' with attributes that come from recently
962 composed roles. It makes sense, people are using it, and so why not
963 just officially support it.
965 The C<< Moose::Meta::Class->create >> method now supports roles.
967 It is now possible to make anonymous enum types by passing C<enum> an
968 array reference instead of the C<< enum $name => @values >>.
972 Added the C<make_immutable> keyword as a shortcut to calling
973 C<make_immutable> on the meta object. This eventually got removed!
975 Made C<< init_arg => undef >> work in Moose. This means "do not accept
976 a constructor parameter for this attribute".
978 Type errors now use the provided message. Prior to this release they
983 Moose is now a postmodern object system :)
985 The Role system was completely refactored. It is 100% backwards
986 compat, but the internals were totally changed. If you relied on the
987 internals then you are advised to test carefully.
989 Added method exclusion and aliasing for Roles in this release.
991 Added the L<Moose::Util::TypeConstraints::OptimizedConstraints>
994 Passing a list of values to an accessor (which is only expecting one
995 value) used to be silently ignored, now it throws an error.
999 Added parameterized types and did a pretty heavy refactoring of the
1000 type constraint system.
1002 Better framework extensibility and better support for "making your own
1005 =head1 0.25 or before
1007 Honestly, you shouldn't be using versions of Moose that are this old,
1008 so many bug fixes and speed improvements have been made you would be
1009 crazy to not upgrade.
1011 Also, I am tired of going through the Changelog so I am stopping here,
1012 if anyone would like to continue this please feel free.