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
23 =item Moose::Meta::Attribute::Native::Trait::Code no longer creates reader methods by default
25 Earlier versions of L<Moose::Meta::Attribute::Native::Trait::Code> created
26 read-only accessors for the attributes it's been applied to, even if you didn't
27 ask for it with C<< is => 'ro' >>. This incorrect behaviour has now been fixed.
35 =item Moose::Util add_method_modifier behavior
37 add_method_modifier (and subsequently the sugar functions Moose::before,
38 Moose::after, and Moose::around) can now accept arrayrefs, with the same
39 behavior as lists. Types other than arrayref and regexp result in an error.
43 =head1 0.93_01 and 0.94
47 =item Moose::Util::MetaRole API has changed
49 The C<apply_metaclass_roles> function is now called C<apply_metaroles>. The
50 way arguments are supplied has been changed to force you to distinguish
51 between metaroles applied to L<Moose::Meta::Class> (and helpers) versus
54 The old API still works, but will warn in a future release, and eventually be
57 =item Moose::Meta::Role has real attributes
59 The attributes returned by L<Moose::Meta::Role> are now instances of the
60 L<Moose::Meta::Role::Attribute> class, instead of bare hash references.
62 =item "no Moose" now removes C<blessed> and C<confess>
64 Moose is now smart enough to know exactly what it exported, even when it
65 re-exports functions from other packages. When you unimport Moose, it will
66 remove these functions from your namespace unless you I<also> imported them
67 directly from their respective packages.
69 If you have a C<no Moose> in your code I<before> you call C<blessed> or
70 C<confess>, your code will break. You can either move the C<no Moose> call
71 later in your code, or explicitly import the relevant functions from the
72 packages that provide them.
74 =item L<Moose::Exporter> is smarter about unimporting re-exports
76 The change above comes from a general improvement to L<Moose::Exporter>. It
77 will now unimport any function it exports, even if that function is a
78 re-export from another package.
80 =item Attributes in roles can no longer override class attributes with "+foo"
82 Previously, this worked more or less accidentally, because role attributes
83 weren't objects. This was never documented, but a few MooseX modules took
86 =item The composition_class_roles attribute in L<Moose::Meta::Role> is now a method
88 This was done to make it possible for roles to alter the the list of
89 composition class roles by applying a method modifiers. Previously, this was
90 an attribute and MooseX modules override it. Since that no longer works, this
93 This I<should> be an attribute, so this may switch back to being an attribute
94 in the future if we can figure out how to make this work.
102 =item Calling $object->new() is no longer deprecated
104 We decided to undeprecate this. Now it just works.
106 =item Both C<get_method_map> and C<get_attribute_map> is deprecated
108 These metaclass methods were never meant to be public, and they are both now
109 deprecated. The work around if you still need the functionality they provided
110 is to iterate over the list of names manually.
112 my %fields = map { $_ => $meta->get_attribute($_) } $meta->get_attribute_list;
114 This was actually a change in L<Class::MOP>, but this version of Moose
115 requires a version of L<Class::MOP> that includes said change.
123 =item Added Native delegation for Code refs
125 See L<Moose::Meta::Attribute::Native::Trait::Code> for details.
127 =item Calling $object->new() is deprecated
129 Moose has long supported this, but it's never really been documented, and we
130 don't think this is a good practice. If you want to construct an object from
131 an existing object, you should provide some sort of alternate constructor like
132 C<< $object->clone >>.
134 Calling C<< $object->new >> now issues a warning, and will be an error in a
137 =item Moose no longer warns if you call C<make_immutable> for a class with mutable ancestors
139 While in theory this is a good thing to warn about, we found so many
140 exceptions to this that doing this properly became quite problematic.
144 =head1 Version 0.89_02
148 =item New Native delegation methods from L<List::Util> and L<List::MoreUtils>
150 In particular, we now have C<reduce>, C<shuffle>, C<uniq>, and C<natatime>.
152 =item The Moose::Exporter with_caller feature is now deprecated
154 Use C<with_meta> instead. The C<with_caller> option will start warning in a
157 =item Moose now warns if you call C<make_immutable> for a class with mutable ancestors
159 This is dangerous because modifying a class after a subclass has been
160 immutabilized will lead to incorrect results in the subclass, due to inlining,
161 caching, etc. This occasionally happens accidentally, when a class loads one
162 of its subclasses in the middle of its class definition, so pointing out that
163 this may cause issues should be helpful. Metaclasses (classes that inherit
164 from L<Class::MOP::Object>) are currently exempt from this check, since at the
165 moment we aren't very consistent about which metaclasses we immutabilize.
167 =item C<enum> and C<duck_type> now take arrayrefs for all forms
169 Previously, calling these functions with a list would take the first element of
170 the list as the type constraint name, and use the remainder as the enum values
171 or method names. This makes the interface inconsistent with the anon-type forms
172 of these functions (which must take an arrayref), and a free-form list where
173 the first value is sometimes special is hard to validate (and harder to give
174 reasonable error messages for). These functions have been changed to take
175 arrayrefs in all their forms - so, C<< enum 'My::Type' => [qw(foo bar)] >> is
176 now the preferred way to create an enum type constraint. The old syntax still
177 works for now, but it will hopefully be deprecated and removed in a future
182 =head1 Version 0.89_01
184 L<Moose::Meta::Attribute::Native> has been moved into the Moose core from
185 L<MooseX::AttributeHelpers>. Major changes include:
189 =item C<traits>, not C<metaclass>
191 Method providers are only available via traits.
193 =item C<handles>, not C<provides> or C<curries>
195 The C<provides> syntax was like core Moose C<< handles => HASHREF >>
196 syntax, but with the keys and values reversed. This was confusing,
197 and AttributeHelpers now uses C<< handles => HASHREF >> in a way that
198 should be intuitive to anyone already familiar with how it is used for
201 The C<curries> functionality provided by AttributeHelpers has been
202 generalized to apply to all cases of C<< handles => HASHREF >>, though
203 not every piece of functionality has been ported (currying with a
204 CODEREF is not supported).
206 =item C<empty> is now C<is_empty>, and means empty, not non-empty
208 Previously, the C<empty> method provided by Arrays and Hashes returned true if
209 the attribute was B<not> empty (no elements). Now it returns true if the
210 attribute B<is> empty. It was also renamed to C<is_empty>, to reflect this.
212 =item C<find> was renamed to C<first>, and C<first> and C<last> were removed
214 L<List::Util> refers to the functionality that we used to provide under C<find>
215 as L<first|List::Util/first>, so that will likely be more familiar (and will
216 fit in better if we decide to add more List::Util functions). C<first> and
217 C<last> were removed, since their functionality is easily duplicated with
220 =item Helpers that take a coderef of one argument now use C<$_>
222 Subroutines passed as the first argument to C<first>, C<map>, and C<grep> now
223 receive their argument in C<$_> rather than as a parameter to the subroutine.
224 Helpers that take a coderef of two or more arguments remain using the argument
225 list (there are technical limitations to using C<$a> and C<$b> like C<sort>
228 See L<Moose::Meta::Attribute::Native> for the new documentation.
232 The C<alias> and C<excludes> role parameters have been renamed to C<-alias>
233 and C<-excludes>. The old names still work, but new code should use the new
234 names, and eventually the old ones will be deprecated and removed.
238 C<< use Moose -metaclass => 'Foo' >> now does alias resolution, just like
239 C<-traits> (and the C<metaclass> and C<traits> options to C<has>).
241 Added two functions C<meta_class_alias> and C<meta_attribute_alias> to
242 L<Moose::Util>, to simplify aliasing metaclasses and metatraits. This is
243 a wrapper around the old
245 package Moose::Meta::Class::Custom::Trait::FooTrait;
246 sub register_implementation { 'My::Meta::Trait' }
252 When an attribute generates I<no> accessors, we now warn. This is to help
253 users who forget the C<is> option. If you really do not want any accessors,
254 you can use C<< is => 'bare' >>. You can maintain back compat with older
255 versions of Moose by using something like:
257 ($Moose::VERSION >= 0.84 ? is => 'bare' : ())
259 When an accessor overwrites an existing method, we now warn. To work around
260 this warning (if you really must have this behavior), you can explicitly
261 remove the method before creating it as an accessor:
265 __PACKAGE__->meta->remove_method('foo');
271 When an unknown option is passed to C<has>, we now warn. You can silence
272 the warning by fixing your code. :)
274 The C<Role> type has been deprecated. On its own, it was useless,
275 since it just checked C<< $object->can('does') >>. If you were using
276 it as a parent type, just call C<role_type('Role::Name')> to create an
277 appropriate type instead.
281 C<use Moose::Exporter;> now imports C<strict> and C<warnings> into packages
286 C<DEMOLISHALL> and C<DEMOLISH> now receive an argument indicating whether or
287 not we are in global destruction.
291 Type constraints no longer run coercions for a value that already matches the
292 constraint. This may affect some (arguably buggy) edge case coercions that
293 rely on side effects in the C<via> clause.
297 L<Moose::Exporter> now accepts the C<-metaclass> option for easily
298 overriding the metaclass (without L<metaclass>). This works for classes
303 Added a C<duck_type> sugar function to L<Moose::Util::TypeConstraints>
304 to make integration with non-Moose classes easier. It simply checks if
305 C<< $obj->can() >> a list of methods.
307 A number of methods (mostly inherited from L<Class::MOP>) have been
308 renamed with a leading underscore to indicate their internal-ness. The
309 old method names will still work for a while, but will warn that the
310 method has been renamed. In a few cases, the method will be removed
311 entirely in the future. This may affect MooseX authors who were using
316 Calling C<subtype> with a name as the only argument now throws an
317 exception. If you want an anonymous subtype do:
319 my $subtype = subtype as 'Foo';
321 This is related to the changes in version 0.71_01.
323 The C<is_needed> method in L<Moose::Meta::Method::Destructor> is now
324 only usable as a class method. Previously, it worked as a class or
325 object method, with a different internal implementation for each
328 The internals of making a class immutable changed a lot in Class::MOP
329 0.78_02, and Moose's internals have changed along with it. The
330 external C<< $metaclass->make_immutable >> method still works the same
335 A mutable class accepted C<< Foo->new(undef) >> without complaint,
336 while an immutable class would blow up with an unhelpful error. Now,
337 in both cases we throw a helpful error instead.
339 This "feature" was originally added to allow for cases such as this:
347 return My::Class->new($args);
349 But we decided this is a bad idea and a little too magical, because it
350 can easily mask real errors.
352 =head1 Version 0.71_01
354 Calling C<type> or C<subtype> without the sugar helpers (C<as>,
355 C<where>, C<message>) is now deprecated.
357 As a side effect, this meant we ended up using Perl prototypes on
358 C<as>, and code like this will no longer work:
360 use Moose::Util::TypeConstraints;
361 use Declare::Constraints::Simple -All;
363 subtype 'ArrayOfInts'
365 => IsArrayRef(IsInt);
367 Instead it must be changed to this:
372 where => IsArrayRef(IsInt)
376 If you want to maintain backwards compat with older versions of Moose,
377 you must explicitly test Moose's C<VERSION>:
379 if ( Moose->VERSION < 0.71_01 ) {
380 subtype 'ArrayOfInts'
382 => IsArrayRef(IsInt);
388 where => IsArrayRef(IsInt)
395 We no longer pass the meta-attribute object as a final argument to
396 triggers. This actually changed for inlined code a while back, but the
397 non-inlined version and the docs were still out of date.
399 If by some chance you actually used this feature, the workaround is
400 simple. You fetch the attribute object from out of the C<$self>
401 that is passed as the first argument to trigger, like so:
407 my ( $self, $value ) = @_;
408 my $attr = $self->meta->find_attribute_by_name('foo');
416 If you created a subtype and passed a parent that Moose didn't know
417 about, it simply ignored the parent. Now it automatically creates the
418 parent as a class type. This may not be what you want, but is less
421 You could declare a name with subtype such as "Foo!Bar". Moose would
422 accept this allowed, but if you used it in a parameterized type such
423 as "ArrayRef[Foo!Bar]" it wouldn't work. We now do some vetting on
424 names created via the sugar functions, so that they can only contain
425 alphanumerics, ":", and ".".
429 Methods created via an attribute can now fulfill a C<requires>
430 declaration for a role. Honestly we don't know why Stevan didn't make
431 this work originally, he was just insane or something.
433 Stack traces from inlined code will now report the line and file as
434 being in your class, as opposed to in Moose guts.
436 =head1 Version 0.62_02
438 When a class does not provide all of a role's required methods, the
439 error thrown now mentions all of the missing methods, as opposed to
440 just the first missing method.
442 Moose will no longer inline a constructor for your class unless it
443 inherits its constructor from Moose::Object, and will warn when it
444 doesn't inline. If you want to force inlining anyway, pass
445 C<< replace_constructor => 1 >> to C<make_immutable>.
447 If you want to get rid of the warning, pass C<< inline_constructor =>
452 Removed the (deprecated) C<make_immutable> keyword.
454 Removing an attribute from a class now also removes delegation
455 (C<handles>) methods installed for that attribute. This is correct
456 behavior, but if you were wrongly relying on it you might get bit.
460 Roles now add methods by calling C<add_method>, not
461 C<alias_method>. They make sure to always provide a method object,
462 which will be cloned internally. This means that it is now possible to
463 track the source of a method provided by a role, and even follow its
464 history through intermediate roles. This means that methods added by
465 a role now show up when looking at a class's method list/map.
467 Parameter and Union args are now sorted, this makes Int|Str the same
468 constraint as Str|Int. Also, incoming type constraint strings are
469 normalized to remove all whitespace differences. This is mostly for
470 internals and should not affect outside code.
472 L<Moose::Exporter> will no longer remove a subroutine that the
473 exporting package re-exports. Moose re-exports the Carp::confess
474 function, among others. The reasoning is that we cannot know whether
475 you have also explicitly imported those functions for your own use, so
476 we err on the safe side and always keep them.
480 C<Moose::init_meta> should now be called as a method.
482 New modules for extension writers, L<Moose::Exporter> and
483 L<Moose::Util::MetaRole>.
485 =head1 Version 0.55_01
487 Implemented metaclass traits (and wrote a recipe for it):
489 use Moose -traits => 'Foo'
491 This should make writing small Moose extensions a little
496 Fixed C<coerce> to accept anon types just like C<subtype> can.
499 coerce $some_anon_type => from 'Str' => via { ... };
503 Added C<BUILDARGS>, a new step in C<< Moose::Object->new() >>.
507 Fixed how the C<< is => (ro|rw) >> works with custom defined
508 C<reader>, C<writer> and C<accessor> options. See the below table for
511 is => ro, writer => _foo # turns into (reader => foo, writer => _foo)
512 is => rw, writer => _foo # turns into (reader => foo, writer => _foo)
513 is => rw, accessor => _foo # turns into (accessor => _foo)
514 is => ro, accessor => _foo # error, accesor is rw
518 The C<before/around/after> method modifiers now support regexp
519 matching of method names. NOTE: this only works for classes, it is
520 currently not supported in roles, but, ... patches welcome.
522 The C<has> keyword for roles now accepts the same array ref form that
523 L<Moose>.pm does for classes.
525 A trigger on a read-only attribute is no longer an error, as it's
526 useful to trigger off of the constructor.
528 Subtypes of parameterizable types now are parameterizable types
533 Fixed issue where C<DEMOLISHALL> was eating the value in C<$@>, and so
534 not working correctly. It still kind of eats them, but so does vanilla
539 Inherited attributes may now be extended without restriction on the
540 type ('isa', 'does').
542 The entire set of Moose::Meta::TypeConstraint::* classes were
543 refactored in this release. If you were relying on their internals you
544 should test your code carefully.
548 Documenting the use of '+name' with attributes that come from recently
549 composed roles. It makes sense, people are using it, and so why not
550 just officially support it.
552 The C<< Moose::Meta::Class->create >> method now supports roles.
554 It is now possible to make anonymous enum types by passing C<enum> an
555 array reference instead of the C<< enum $name => @values >>.
559 Added the C<make_immutable> keyword as a shortcut to calling
560 C<make_immutable> on the meta object. This eventually got removed!
562 Made C<< init_arg => undef >> work in Moose. This means "do not accept
563 a constructor parameter for this attribute".
565 Type errors now use the provided message. Prior to this release they
570 Moose is now a postmodern object system :)
572 The Role system was completely refactored. It is 100% backwards
573 compat, but the internals were totally changed. If you relied on the
574 internals then you are advised to test carefully.
576 Added method exclusion and aliasing for Roles in this release.
578 Added the L<Moose::Util::TypeConstraints::OptimizedConstraints>
581 Passing a list of values to an accessor (which is only expecting one
582 value) used to be silently ignored, now it throws an error.
586 Added parameterized types and did a pretty heavy refactoring of the
587 type constraint system.
589 Better framework extendability and better support for "making your own
592 =head1 Version 0.25 or before
594 Honestly, you shouldn't be using versions of Moose that are this old,
595 so many bug fixes and speed improvements have been made you would be
596 crazy to not upgrade.
598 Also, I am tired of going through the Changelog so I am stopping here,
599 if anyone would like to continue this please feel free.
603 Stevan Little E<lt>stevan@iinteractive.comE<gt>
605 =head1 COPYRIGHT AND LICENSE
607 Copyright 2009 by Infinity Interactive, Inc.
609 L<http://www.iinteractive.com>
611 This library is free software; you can redistribute it and/or modify
612 it under the same terms as Perl itself.