5 Moose::Manual::Delta - Important Changes in Moose
9 This documents any important or noteworthy changes in Moose, with a
10 focus on backwards. This does duplicate data from the F<Changes> file,
11 but aims to provide more details and when possible workarounds.
13 Besides helping keep up with changes, you can also use this document
14 for finding the lowest version of Moose that supported a given
15 feature. If you encounter a problem and have a solution but don't see
16 it documented here, or think we missed an important feature, please
21 =item L<Moose::Object/BUILD> methods are now called when calling C<new_object>
23 Previously, C<BUILD> methods would only be called from C<Moose::Object::new>,
24 but now they are also called when constructing an object via
25 C<Moose::Meta::Class::new_object>. C<BUILD> methods are an inherent part of the
26 object construction process, and this should make C<< $meta->new_object >>
27 actually usable without forcing people to use C<< $meta->name->new >>.
29 =item C<no Moose>, C<no Moose::Role>, and C<no Moose::Exporter> now unimport strict and warnings
31 In the interest of having C<no Moose> clean up everything that C<use Moose>
32 does in the calling scope, C<no Moose> (as well as all other
33 L<Moose::Exporter>-using modules) now unimports strict and warnings.
41 =item Moose::Meta::TypeConstraint::Class is_subtype_of behavior
43 Earlier versions of L<is_subtype_of|Moose::Meta::TypeConstraint::Class/is_subtype_of>
44 would incorrectly return true when called with itself, its own TC name or
45 its class name as an argument. (i.e. $foo_tc->is_subtype_of('Foo') == 1) This
46 behavior was a caused by C<isa> being checked before the class name. The old
47 behavior can be accessed with L<is_type_of|Moose::Meta::TypeConstraint::Class/is_type_of>
55 =item Moose::Meta::Attribute::Native::Trait::Code no longer creates reader methods by default
57 Earlier versions of L<Moose::Meta::Attribute::Native::Trait::Code> created
58 read-only accessors for the attributes it's been applied to, even if you didn't
59 ask for it with C<< is => 'ro' >>. This incorrect behaviour has now been fixed.
67 =item Moose::Util add_method_modifier behavior
69 add_method_modifier (and subsequently the sugar functions Moose::before,
70 Moose::after, and Moose::around) can now accept arrayrefs, with the same
71 behavior as lists. Types other than arrayref and regexp result in an error.
75 =head1 0.93_01 and 0.94
79 =item Moose::Util::MetaRole API has changed
81 The C<apply_metaclass_roles> function is now called C<apply_metaroles>. The
82 way arguments are supplied has been changed to force you to distinguish
83 between metaroles applied to L<Moose::Meta::Class> (and helpers) versus
86 The old API still works, but will warn in a future release, and eventually be
89 =item Moose::Meta::Role has real attributes
91 The attributes returned by L<Moose::Meta::Role> are now instances of the
92 L<Moose::Meta::Role::Attribute> class, instead of bare hash references.
94 =item "no Moose" now removes C<blessed> and C<confess>
96 Moose is now smart enough to know exactly what it exported, even when it
97 re-exports functions from other packages. When you unimport Moose, it will
98 remove these functions from your namespace unless you I<also> imported them
99 directly from their respective packages.
101 If you have a C<no Moose> in your code I<before> you call C<blessed> or
102 C<confess>, your code will break. You can either move the C<no Moose> call
103 later in your code, or explicitly import the relevant functions from the
104 packages that provide them.
106 =item L<Moose::Exporter> is smarter about unimporting re-exports
108 The change above comes from a general improvement to L<Moose::Exporter>. It
109 will now unimport any function it exports, even if that function is a
110 re-export from another package.
112 =item Attributes in roles can no longer override class attributes with "+foo"
114 Previously, this worked more or less accidentally, because role attributes
115 weren't objects. This was never documented, but a few MooseX modules took
118 =item The composition_class_roles attribute in L<Moose::Meta::Role> is now a method
120 This was done to make it possible for roles to alter the the list of
121 composition class roles by applying a method modifiers. Previously, this was
122 an attribute and MooseX modules override it. Since that no longer works, this
125 This I<should> be an attribute, so this may switch back to being an attribute
126 in the future if we can figure out how to make this work.
134 =item Calling $object->new() is no longer deprecated
136 We decided to undeprecate this. Now it just works.
138 =item Both C<get_method_map> and C<get_attribute_map> is deprecated
140 These metaclass methods were never meant to be public, and they are both now
141 deprecated. The work around if you still need the functionality they provided
142 is to iterate over the list of names manually.
144 my %fields = map { $_ => $meta->get_attribute($_) } $meta->get_attribute_list;
146 This was actually a change in L<Class::MOP>, but this version of Moose
147 requires a version of L<Class::MOP> that includes said change.
155 =item Added Native delegation for Code refs
157 See L<Moose::Meta::Attribute::Native::Trait::Code> for details.
159 =item Calling $object->new() is deprecated
161 Moose has long supported this, but it's never really been documented, and we
162 don't think this is a good practice. If you want to construct an object from
163 an existing object, you should provide some sort of alternate constructor like
164 C<< $object->clone >>.
166 Calling C<< $object->new >> now issues a warning, and will be an error in a
169 =item Moose no longer warns if you call C<make_immutable> for a class with mutable ancestors
171 While in theory this is a good thing to warn about, we found so many
172 exceptions to this that doing this properly became quite problematic.
176 =head1 Version 0.89_02
180 =item New Native delegation methods from L<List::Util> and L<List::MoreUtils>
182 In particular, we now have C<reduce>, C<shuffle>, C<uniq>, and C<natatime>.
184 =item The Moose::Exporter with_caller feature is now deprecated
186 Use C<with_meta> instead. The C<with_caller> option will start warning in a
189 =item Moose now warns if you call C<make_immutable> for a class with mutable ancestors
191 This is dangerous because modifying a class after a subclass has been
192 immutabilized will lead to incorrect results in the subclass, due to inlining,
193 caching, etc. This occasionally happens accidentally, when a class loads one
194 of its subclasses in the middle of its class definition, so pointing out that
195 this may cause issues should be helpful. Metaclasses (classes that inherit
196 from L<Class::MOP::Object>) are currently exempt from this check, since at the
197 moment we aren't very consistent about which metaclasses we immutabilize.
199 =item C<enum> and C<duck_type> now take arrayrefs for all forms
201 Previously, calling these functions with a list would take the first element of
202 the list as the type constraint name, and use the remainder as the enum values
203 or method names. This makes the interface inconsistent with the anon-type forms
204 of these functions (which must take an arrayref), and a free-form list where
205 the first value is sometimes special is hard to validate (and harder to give
206 reasonable error messages for). These functions have been changed to take
207 arrayrefs in all their forms - so, C<< enum 'My::Type' => [qw(foo bar)] >> is
208 now the preferred way to create an enum type constraint. The old syntax still
209 works for now, but it will hopefully be deprecated and removed in a future
214 =head1 Version 0.89_01
216 L<Moose::Meta::Attribute::Native> has been moved into the Moose core from
217 L<MooseX::AttributeHelpers>. Major changes include:
221 =item C<traits>, not C<metaclass>
223 Method providers are only available via traits.
225 =item C<handles>, not C<provides> or C<curries>
227 The C<provides> syntax was like core Moose C<< handles => HASHREF >>
228 syntax, but with the keys and values reversed. This was confusing,
229 and AttributeHelpers now uses C<< handles => HASHREF >> in a way that
230 should be intuitive to anyone already familiar with how it is used for
233 The C<curries> functionality provided by AttributeHelpers has been
234 generalized to apply to all cases of C<< handles => HASHREF >>, though
235 not every piece of functionality has been ported (currying with a
236 CODEREF is not supported).
238 =item C<empty> is now C<is_empty>, and means empty, not non-empty
240 Previously, the C<empty> method provided by Arrays and Hashes returned true if
241 the attribute was B<not> empty (no elements). Now it returns true if the
242 attribute B<is> empty. It was also renamed to C<is_empty>, to reflect this.
244 =item C<find> was renamed to C<first>, and C<first> and C<last> were removed
246 L<List::Util> refers to the functionality that we used to provide under C<find>
247 as L<first|List::Util/first>, so that will likely be more familiar (and will
248 fit in better if we decide to add more List::Util functions). C<first> and
249 C<last> were removed, since their functionality is easily duplicated with
252 =item Helpers that take a coderef of one argument now use C<$_>
254 Subroutines passed as the first argument to C<first>, C<map>, and C<grep> now
255 receive their argument in C<$_> rather than as a parameter to the subroutine.
256 Helpers that take a coderef of two or more arguments remain using the argument
257 list (there are technical limitations to using C<$a> and C<$b> like C<sort>
260 See L<Moose::Meta::Attribute::Native> for the new documentation.
264 The C<alias> and C<excludes> role parameters have been renamed to C<-alias>
265 and C<-excludes>. The old names still work, but new code should use the new
266 names, and eventually the old ones will be deprecated and removed.
270 C<< use Moose -metaclass => 'Foo' >> now does alias resolution, just like
271 C<-traits> (and the C<metaclass> and C<traits> options to C<has>).
273 Added two functions C<meta_class_alias> and C<meta_attribute_alias> to
274 L<Moose::Util>, to simplify aliasing metaclasses and metatraits. This is
275 a wrapper around the old
277 package Moose::Meta::Class::Custom::Trait::FooTrait;
278 sub register_implementation { 'My::Meta::Trait' }
284 When an attribute generates I<no> accessors, we now warn. This is to help
285 users who forget the C<is> option. If you really do not want any accessors,
286 you can use C<< is => 'bare' >>. You can maintain back compat with older
287 versions of Moose by using something like:
289 ($Moose::VERSION >= 0.84 ? is => 'bare' : ())
291 When an accessor overwrites an existing method, we now warn. To work around
292 this warning (if you really must have this behavior), you can explicitly
293 remove the method before creating it as an accessor:
297 __PACKAGE__->meta->remove_method('foo');
303 When an unknown option is passed to C<has>, we now warn. You can silence
304 the warning by fixing your code. :)
306 The C<Role> type has been deprecated. On its own, it was useless,
307 since it just checked C<< $object->can('does') >>. If you were using
308 it as a parent type, just call C<role_type('Role::Name')> to create an
309 appropriate type instead.
313 C<use Moose::Exporter;> now imports C<strict> and C<warnings> into packages
318 C<DEMOLISHALL> and C<DEMOLISH> now receive an argument indicating whether or
319 not we are in global destruction.
323 Type constraints no longer run coercions for a value that already matches the
324 constraint. This may affect some (arguably buggy) edge case coercions that
325 rely on side effects in the C<via> clause.
329 L<Moose::Exporter> now accepts the C<-metaclass> option for easily
330 overriding the metaclass (without L<metaclass>). This works for classes
335 Added a C<duck_type> sugar function to L<Moose::Util::TypeConstraints>
336 to make integration with non-Moose classes easier. It simply checks if
337 C<< $obj->can() >> a list of methods.
339 A number of methods (mostly inherited from L<Class::MOP>) have been
340 renamed with a leading underscore to indicate their internal-ness. The
341 old method names will still work for a while, but will warn that the
342 method has been renamed. In a few cases, the method will be removed
343 entirely in the future. This may affect MooseX authors who were using
348 Calling C<subtype> with a name as the only argument now throws an
349 exception. If you want an anonymous subtype do:
351 my $subtype = subtype as 'Foo';
353 This is related to the changes in version 0.71_01.
355 The C<is_needed> method in L<Moose::Meta::Method::Destructor> is now
356 only usable as a class method. Previously, it worked as a class or
357 object method, with a different internal implementation for each
360 The internals of making a class immutable changed a lot in Class::MOP
361 0.78_02, and Moose's internals have changed along with it. The
362 external C<< $metaclass->make_immutable >> method still works the same
367 A mutable class accepted C<< Foo->new(undef) >> without complaint,
368 while an immutable class would blow up with an unhelpful error. Now,
369 in both cases we throw a helpful error instead.
371 This "feature" was originally added to allow for cases such as this:
379 return My::Class->new($args);
381 But we decided this is a bad idea and a little too magical, because it
382 can easily mask real errors.
384 =head1 Version 0.71_01
386 Calling C<type> or C<subtype> without the sugar helpers (C<as>,
387 C<where>, C<message>) is now deprecated.
389 As a side effect, this meant we ended up using Perl prototypes on
390 C<as>, and code like this will no longer work:
392 use Moose::Util::TypeConstraints;
393 use Declare::Constraints::Simple -All;
395 subtype 'ArrayOfInts'
397 => IsArrayRef(IsInt);
399 Instead it must be changed to this:
404 where => IsArrayRef(IsInt)
408 If you want to maintain backwards compat with older versions of Moose,
409 you must explicitly test Moose's C<VERSION>:
411 if ( Moose->VERSION < 0.71_01 ) {
412 subtype 'ArrayOfInts'
414 => IsArrayRef(IsInt);
420 where => IsArrayRef(IsInt)
427 We no longer pass the meta-attribute object as a final argument to
428 triggers. This actually changed for inlined code a while back, but the
429 non-inlined version and the docs were still out of date.
431 If by some chance you actually used this feature, the workaround is
432 simple. You fetch the attribute object from out of the C<$self>
433 that is passed as the first argument to trigger, like so:
439 my ( $self, $value ) = @_;
440 my $attr = $self->meta->find_attribute_by_name('foo');
448 If you created a subtype and passed a parent that Moose didn't know
449 about, it simply ignored the parent. Now it automatically creates the
450 parent as a class type. This may not be what you want, but is less
453 You could declare a name with subtype such as "Foo!Bar". Moose would
454 accept this allowed, but if you used it in a parameterized type such
455 as "ArrayRef[Foo!Bar]" it wouldn't work. We now do some vetting on
456 names created via the sugar functions, so that they can only contain
457 alphanumerics, ":", and ".".
461 Methods created via an attribute can now fulfill a C<requires>
462 declaration for a role. Honestly we don't know why Stevan didn't make
463 this work originally, he was just insane or something.
465 Stack traces from inlined code will now report the line and file as
466 being in your class, as opposed to in Moose guts.
468 =head1 Version 0.62_02
470 When a class does not provide all of a role's required methods, the
471 error thrown now mentions all of the missing methods, as opposed to
472 just the first missing method.
474 Moose will no longer inline a constructor for your class unless it
475 inherits its constructor from Moose::Object, and will warn when it
476 doesn't inline. If you want to force inlining anyway, pass
477 C<< replace_constructor => 1 >> to C<make_immutable>.
479 If you want to get rid of the warning, pass C<< inline_constructor =>
484 Removed the (deprecated) C<make_immutable> keyword.
486 Removing an attribute from a class now also removes delegation
487 (C<handles>) methods installed for that attribute. This is correct
488 behavior, but if you were wrongly relying on it you might get bit.
492 Roles now add methods by calling C<add_method>, not
493 C<alias_method>. They make sure to always provide a method object,
494 which will be cloned internally. This means that it is now possible to
495 track the source of a method provided by a role, and even follow its
496 history through intermediate roles. This means that methods added by
497 a role now show up when looking at a class's method list/map.
499 Parameter and Union args are now sorted, this makes Int|Str the same
500 constraint as Str|Int. Also, incoming type constraint strings are
501 normalized to remove all whitespace differences. This is mostly for
502 internals and should not affect outside code.
504 L<Moose::Exporter> will no longer remove a subroutine that the
505 exporting package re-exports. Moose re-exports the Carp::confess
506 function, among others. The reasoning is that we cannot know whether
507 you have also explicitly imported those functions for your own use, so
508 we err on the safe side and always keep them.
512 C<Moose::init_meta> should now be called as a method.
514 New modules for extension writers, L<Moose::Exporter> and
515 L<Moose::Util::MetaRole>.
517 =head1 Version 0.55_01
519 Implemented metaclass traits (and wrote a recipe for it):
521 use Moose -traits => 'Foo'
523 This should make writing small Moose extensions a little
528 Fixed C<coerce> to accept anon types just like C<subtype> can.
531 coerce $some_anon_type => from 'Str' => via { ... };
535 Added C<BUILDARGS>, a new step in C<< Moose::Object->new() >>.
539 Fixed how the C<< is => (ro|rw) >> works with custom defined
540 C<reader>, C<writer> and C<accessor> options. See the below table for
543 is => ro, writer => _foo # turns into (reader => foo, writer => _foo)
544 is => rw, writer => _foo # turns into (reader => foo, writer => _foo)
545 is => rw, accessor => _foo # turns into (accessor => _foo)
546 is => ro, accessor => _foo # error, accesor is rw
550 The C<before/around/after> method modifiers now support regexp
551 matching of method names. NOTE: this only works for classes, it is
552 currently not supported in roles, but, ... patches welcome.
554 The C<has> keyword for roles now accepts the same array ref form that
555 L<Moose>.pm does for classes.
557 A trigger on a read-only attribute is no longer an error, as it's
558 useful to trigger off of the constructor.
560 Subtypes of parameterizable types now are parameterizable types
565 Fixed issue where C<DEMOLISHALL> was eating the value in C<$@>, and so
566 not working correctly. It still kind of eats them, but so does vanilla
571 Inherited attributes may now be extended without restriction on the
572 type ('isa', 'does').
574 The entire set of Moose::Meta::TypeConstraint::* classes were
575 refactored in this release. If you were relying on their internals you
576 should test your code carefully.
580 Documenting the use of '+name' with attributes that come from recently
581 composed roles. It makes sense, people are using it, and so why not
582 just officially support it.
584 The C<< Moose::Meta::Class->create >> method now supports roles.
586 It is now possible to make anonymous enum types by passing C<enum> an
587 array reference instead of the C<< enum $name => @values >>.
591 Added the C<make_immutable> keyword as a shortcut to calling
592 C<make_immutable> on the meta object. This eventually got removed!
594 Made C<< init_arg => undef >> work in Moose. This means "do not accept
595 a constructor parameter for this attribute".
597 Type errors now use the provided message. Prior to this release they
602 Moose is now a postmodern object system :)
604 The Role system was completely refactored. It is 100% backwards
605 compat, but the internals were totally changed. If you relied on the
606 internals then you are advised to test carefully.
608 Added method exclusion and aliasing for Roles in this release.
610 Added the L<Moose::Util::TypeConstraints::OptimizedConstraints>
613 Passing a list of values to an accessor (which is only expecting one
614 value) used to be silently ignored, now it throws an error.
618 Added parameterized types and did a pretty heavy refactoring of the
619 type constraint system.
621 Better framework extendability and better support for "making your own
624 =head1 Version 0.25 or before
626 Honestly, you shouldn't be using versions of Moose that are this old,
627 so many bug fixes and speed improvements have been made you would be
628 crazy to not upgrade.
630 Also, I am tired of going through the Changelog so I am stopping here,
631 if anyone would like to continue this please feel free.
635 Stevan Little E<lt>stevan@iinteractive.comE<gt>
637 =head1 COPYRIGHT AND LICENSE
639 Copyright 2009 by Infinity Interactive, Inc.
641 L<http://www.iinteractive.com>
643 This library is free software; you can redistribute it and/or modify
644 it under the same terms as Perl itself.