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
19 =head1 0.93_01 and 0.94
23 =item Moose::Util::MetaRole API has changed
25 The C<apply_metaclass_roles> function is now called C<apply_metaroles>. The
26 way arguments are supplied has been changed to force you to distinguish
27 between metaroles applied to L<Moose::Meta::Class> (and helpers) versus
30 The old API still works, but will warn in a future release, and eventually be
33 =item Moose::Meta::Role has real attributes
35 The attributes returned by L<Moose::Meta::Role> are now instances of the
36 L<Moose::Meta::Role::Attribute> class, instead of bare hash references.
38 =item "no Moose" now removes C<blessed> and C<confess>
40 Moose is now smart enough to know exactly what it exported, even when it
41 re-exports functions from other packages. When you unimport Moose, it will
42 remove these functions from your namespace unless you I<also> imported them
43 directly from their respective packages.
45 If you have a C<no Moose> in your code I<before> you call C<blessed> or
46 C<confess>, your code will break. You can either move the C<no Moose> call
47 later in your code, or explicitly import the relevant functions from the
48 packages that provide them.
50 =item L<Moose::Exporter> is smarter about unimporting re-exports
52 The change above comes from a general improvement to L<Moose::Exporter>. It
53 will now unimport any function it exports, even if that function is a
54 re-export from another package.
56 =item Attributes in roles can no longer override class attributes with "+foo"
58 Previously, this worked more or less accidentally, because role attributes
59 weren't objects. This was never documented, but a few MooseX modules took
62 =item The composition_class_roles attribute in L<Moose::Meta::Role> is now a method
64 This was done to make it possible for roles to alter the the list of
65 composition class roles by applying a method modifiers. Previously, this was
66 an attribute and MooseX modules override it. Since that no longer works, this
69 This I<should> be an attribute, so this may switch back to being an attribute
70 in the future if we can figure out how to make this work.
78 =item Calling $object->new() is no longer deprecated
80 We decided to undeprecate this. Now it just works.
82 =item Both C<get_method_map> and C<get_attribute_map> is deprecated
84 These metaclass methods were never meant to be public, and they are both now
85 deprecated. The work around if you still need the functionality they provided
86 is to iterate over the list of names manually.
88 my %fields = map { $_ => $meta->get_attribute($_) } $meta->get_attribute_list;
90 This was actually a change in L<Class::MOP>, but this version of Moose
91 requires a version of L<Class::MOP> that includes said change.
99 =item Added Native delegation for Code refs
101 See L<Moose::Meta::Attribute::Native::Trait::Code> for details.
103 =item Calling $object->new() is deprecated
105 Moose has long supported this, but it's never really been documented, and we
106 don't think this is a good practice. If you want to construct an object from
107 an existing object, you should provide some sort of alternate constructor like
108 C<< $object->clone >>.
110 Calling C<< $object->new >> now issues a warning, and will be an error in a
113 =item Moose no longer warns if you call C<make_immutable> for a class with mutable ancestors
115 While in theory this is a good thing to warn about, we found so many
116 exceptions to this that doing this properly became quite problematic.
120 =head1 Version 0.89_02
124 =item New Native delegation methods from L<List::Util> and L<List::MoreUtils>
126 In particular, we now have C<reduce>, C<shuffle>, C<uniq>, and C<natatime>.
128 =item The Moose::Exporter with_caller feature is now deprecated
130 Use C<with_meta> instead. The C<with_caller> option will start warning in a
133 =item Moose now warns if you call C<make_immutable> for a class with mutable ancestors
135 This is dangerous because modifying a class after a subclass has been
136 immutabilized will lead to incorrect results in the subclass, due to inlining,
137 caching, etc. This occasionally happens accidentally, when a class loads one
138 of its subclasses in the middle of its class definition, so pointing out that
139 this may cause issues should be helpful. Metaclasses (classes that inherit
140 from L<Class::MOP::Object>) are currently exempt from this check, since at the
141 moment we aren't very consistent about which metaclasses we immutabilize.
143 =item C<enum> and C<duck_type> now take arrayrefs for all forms
145 Previously, calling these functions with a list would take the first element of
146 the list as the type constraint name, and use the remainder as the enum values
147 or method names. This makes the interface inconsistent with the anon-type forms
148 of these functions (which must take an arrayref), and a free-form list where
149 the first value is sometimes special is hard to validate (and harder to give
150 reasonable error messages for). These functions have been changed to take
151 arrayrefs in all their forms - so, C<< enum 'My::Type' => [qw(foo bar)] >> is
152 now the preferred way to create an enum type constraint. The old syntax still
153 works for now, but it will hopefully be deprecated and removed in a future
158 =head1 Version 0.89_01
160 L<Moose::Meta::Attribute::Native> has been moved into the Moose core from
161 L<MooseX::AttributeHelpers>. Major changes include:
165 =item C<traits>, not C<metaclass>
167 Method providers are only available via traits.
169 =item C<handles>, not C<provides> or C<curries>
171 The C<provides> syntax was like core Moose C<< handles => HASHREF >>
172 syntax, but with the keys and values reversed. This was confusing,
173 and AttributeHelpers now uses C<< handles => HASHREF >> in a way that
174 should be intuitive to anyone already familiar with how it is used for
177 The C<curries> functionality provided by AttributeHelpers has been
178 generalized to apply to all cases of C<< handles => HASHREF >>, though
179 not every piece of functionality has been ported (currying with a
180 CODEREF is not supported).
182 =item C<empty> is now C<is_empty>, and means empty, not non-empty
184 Previously, the C<empty> method provided by Arrays and Hashes returned true if
185 the attribute was B<not> empty (no elements). Now it returns true if the
186 attribute B<is> empty. It was also renamed to C<is_empty>, to reflect this.
188 =item C<find> was renamed to C<first>, and C<first> and C<last> were removed
190 L<List::Util> refers to the functionality that we used to provide under C<find>
191 as L<first|List::Util/first>, so that will likely be more familiar (and will
192 fit in better if we decide to add more List::Util functions). C<first> and
193 C<last> were removed, since their functionality is easily duplicated with
196 =item Helpers that take a coderef of one argument now use C<$_>
198 Subroutines passed as the first argument to C<first>, C<map>, and C<grep> now
199 receive their argument in C<$_> rather than as a parameter to the subroutine.
200 Helpers that take a coderef of two or more arguments remain using the argument
201 list (there are technical limitations to using C<$a> and C<$b> like C<sort>
204 See L<Moose::Meta::Attribute::Native> for the new documentation.
208 The C<alias> and C<excludes> role parameters have been renamed to C<-alias>
209 and C<-excludes>. The old names still work, but new code should use the new
210 names, and eventually the old ones will be deprecated and removed.
214 C<< use Moose -metaclass => 'Foo' >> now does alias resolution, just like
215 C<-traits> (and the C<metaclass> and C<traits> options to C<has>).
217 Added two functions C<meta_class_alias> and C<meta_attribute_alias> to
218 L<Moose::Util>, to simplify aliasing metaclasses and metatraits. This is
219 a wrapper around the old
221 package Moose::Meta::Class::Custom::Trait::FooTrait;
222 sub register_implementation { 'My::Meta::Trait' }
228 When an attribute generates I<no> accessors, we now warn. This is to help
229 users who forget the C<is> option. If you really do not want any accessors,
230 you can use C<< is => 'bare' >>. You can maintain back compat with older
231 versions of Moose by using something like:
233 ($Moose::VERSION >= 0.84 ? is => 'bare' : ())
235 When an accessor overwrites an existing method, we now warn. To work around
236 this warning (if you really must have this behavior), you can explicitly
237 remove the method before creating it as an accessor:
241 __PACKAGE__->meta->remove_method('foo');
247 When an unknown option is passed to C<has>, we now warn. You can silence
248 the warning by fixing your code. :)
250 The C<Role> type has been deprecated. On its own, it was useless,
251 since it just checked C<< $object->can('does') >>. If you were using
252 it as a parent type, just call C<role_type('Role::Name')> to create an
253 appropriate type instead.
257 C<use Moose::Exporter;> now imports C<strict> and C<warnings> into packages
262 C<DEMOLISHALL> and C<DEMOLISH> now receive an argument indicating whether or
263 not we are in global destruction.
267 Type constraints no longer run coercions for a value that already matches the
268 constraint. This may affect some (arguably buggy) edge case coercions that
269 rely on side effects in the C<via> clause.
273 L<Moose::Exporter> now accepts the C<-metaclass> option for easily
274 overriding the metaclass (without L<metaclass>). This works for classes
279 Added a C<duck_type> sugar function to L<Moose::Util::TypeConstraints>
280 to make integration with non-Moose classes easier. It simply checks if
281 C<< $obj->can() >> a list of methods.
283 A number of methods (mostly inherited from L<Class::MOP>) have been
284 renamed with a leading underscore to indicate their internal-ness. The
285 old method names will still work for a while, but will warn that the
286 method has been renamed. In a few cases, the method will be removed
287 entirely in the future. This may affect MooseX authors who were using
292 Calling C<subtype> with a name as the only argument now throws an
293 exception. If you want an anonymous subtype do:
295 my $subtype = subtype as 'Foo';
297 This is related to the changes in version 0.71_01.
299 The C<is_needed> method in L<Moose::Meta::Method::Destructor> is now
300 only usable as a class method. Previously, it worked as a class or
301 object method, with a different internal implementation for each
304 The internals of making a class immutable changed a lot in Class::MOP
305 0.78_02, and Moose's internals have changed along with it. The
306 external C<< $metaclass->make_immutable >> method still works the same
311 A mutable class accepted C<< Foo->new(undef) >> without complaint,
312 while an immutable class would blow up with an unhelpful error. Now,
313 in both cases we throw a helpful error instead.
315 This "feature" was originally added to allow for cases such as this:
323 return My::Class->new($args);
325 But we decided this is a bad idea and a little too magical, because it
326 can easily mask real errors.
328 =head1 Version 0.71_01
330 Calling C<type> or C<subtype> without the sugar helpers (C<as>,
331 C<where>, C<message>) is now deprecated.
333 As a side effect, this meant we ended up using Perl prototypes on
334 C<as>, and code like this will no longer work:
336 use Moose::Util::TypeConstraints;
337 use Declare::Constraints::Simple -All;
339 subtype 'ArrayOfInts'
341 => IsArrayRef(IsInt);
343 Instead it must be changed to this:
348 where => IsArrayRef(IsInt)
352 If you want to maintain backwards compat with older versions of Moose,
353 you must explicitly test Moose's C<VERSION>:
355 if ( Moose->VERSION < 0.71_01 ) {
356 subtype 'ArrayOfInts'
358 => IsArrayRef(IsInt);
364 where => IsArrayRef(IsInt)
371 We no longer pass the meta-attribute object as a final argument to
372 triggers. This actually changed for inlined code a while back, but the
373 non-inlined version and the docs were still out of date.
375 If by some chance you actually used this feature, the workaround is
376 simple. You fetch the attribute object from out of the C<$self>
377 that is passed as the first argument to trigger, like so:
383 my ( $self, $value ) = @_;
384 my $attr = $self->meta->find_attribute_by_name('foo');
392 If you created a subtype and passed a parent that Moose didn't know
393 about, it simply ignored the parent. Now it automatically creates the
394 parent as a class type. This may not be what you want, but is less
397 You could declare a name with subtype such as "Foo!Bar". Moose would
398 accept this allowed, but if you used it in a parameterized type such
399 as "ArrayRef[Foo!Bar]" it wouldn't work. We now do some vetting on
400 names created via the sugar functions, so that they can only contain
401 alphanumerics, ":", and ".".
405 Methods created via an attribute can now fulfill a C<requires>
406 declaration for a role. Honestly we don't know why Stevan didn't make
407 this work originally, he was just insane or something.
409 Stack traces from inlined code will now report the line and file as
410 being in your class, as opposed to in Moose guts.
412 =head1 Version 0.62_02
414 When a class does not provide all of a role's required methods, the
415 error thrown now mentions all of the missing methods, as opposed to
416 just the first missing method.
418 Moose will no longer inline a constructor for your class unless it
419 inherits its constructor from Moose::Object, and will warn when it
420 doesn't inline. If you want to force inlining anyway, pass
421 C<< replace_constructor => 1 >> to C<make_immutable>.
423 If you want to get rid of the warning, pass C<< inline_constructor =>
428 Removed the (deprecated) C<make_immutable> keyword.
430 Removing an attribute from a class now also removes delegation
431 (C<handles>) methods installed for that attribute. This is correct
432 behavior, but if you were wrongly relying on it you might get bit.
436 Roles now add methods by calling C<add_method>, not
437 C<alias_method>. They make sure to always provide a method object,
438 which will be cloned internally. This means that it is now possible to
439 track the source of a method provided by a role, and even follow its
440 history through intermediate roles. This means that methods added by
441 a role now show up when looking at a class's method list/map.
443 Parameter and Union args are now sorted, this makes Int|Str the same
444 constraint as Str|Int. Also, incoming type constraint strings are
445 normalized to remove all whitespace differences. This is mostly for
446 internals and should not affect outside code.
448 L<Moose::Exporter> will no longer remove a subroutine that the
449 exporting package re-exports. Moose re-exports the Carp::confess
450 function, among others. The reasoning is that we cannot know whether
451 you have also explicitly imported those functions for your own use, so
452 we err on the safe side and always keep them.
456 C<Moose::init_meta> should now be called as a method.
458 New modules for extension writers, L<Moose::Exporter> and
459 L<Moose::Util::MetaRole>.
461 =head1 Version 0.55_01
463 Implemented metaclass traits (and wrote a recipe for it):
465 use Moose -traits => 'Foo'
467 This should make writing small Moose extensions a little
472 Fixed C<coerce> to accept anon types just like C<subtype> can.
475 coerce $some_anon_type => from 'Str' => via { ... };
479 Added C<BUILDARGS>, a new step in C<< Moose::Object->new() >>.
483 Fixed how the C<< is => (ro|rw) >> works with custom defined
484 C<reader>, C<writer> and C<accessor> options. See the below table for
487 is => ro, writer => _foo # turns into (reader => foo, writer => _foo)
488 is => rw, writer => _foo # turns into (reader => foo, writer => _foo)
489 is => rw, accessor => _foo # turns into (accessor => _foo)
490 is => ro, accessor => _foo # error, accesor is rw
494 The C<before/around/after> method modifiers now support regexp
495 matching of method names. NOTE: this only works for classes, it is
496 currently not supported in roles, but, ... patches welcome.
498 The C<has> keyword for roles now accepts the same array ref form that
499 L<Moose>.pm does for classes.
501 A trigger on a read-only attribute is no longer an error, as it's
502 useful to trigger off of the constructor.
504 Subtypes of parameterizable types now are parameterizable types
509 Fixed issue where C<DEMOLISHALL> was eating the value in C<$@>, and so
510 not working correctly. It still kind of eats them, but so does vanilla
515 Inherited attributes may now be extended without restriction on the
516 type ('isa', 'does').
518 The entire set of Moose::Meta::TypeConstraint::* classes were
519 refactored in this release. If you were relying on their internals you
520 should test your code carefully.
524 Documenting the use of '+name' with attributes that come from recently
525 composed roles. It makes sense, people are using it, and so why not
526 just officially support it.
528 The C<< Moose::Meta::Class->create >> method now supports roles.
530 It is now possible to make anonymous enum types by passing C<enum> an
531 array reference instead of the C<< enum $name => @values >>.
535 Added the C<make_immutable> keyword as a shortcut to calling
536 C<make_immutable> on the meta object. This eventually got removed!
538 Made C<< init_arg => undef >> work in Moose. This means "do not accept
539 a constructor parameter for this attribute".
541 Type errors now use the provided message. Prior to this release they
546 Moose is now a postmodern object system :)
548 The Role system was completely refactored. It is 100% backwards
549 compat, but the internals were totally changed. If you relied on the
550 internals then you are advised to test carefully.
552 Added method exclusion and aliasing for Roles in this release.
554 Added the L<Moose::Util::TypeConstraints::OptimizedConstraints>
557 Passing a list of values to an accessor (which is only expecting one
558 value) used to be silently ignored, now it throws an error.
562 Added parameterized types and did a pretty heavy refactoring of the
563 type constraint system.
565 Better framework extendability and better support for "making your own
568 =head1 Version 0.25 or before
570 Honestly, you shouldn't be using versions of Moose that are this old,
571 so many bug fixes and speed improvements have been made you would be
572 crazy to not upgrade.
574 Also, I am tired of going through the Changelog so I am stopping here,
575 if anyone would like to continue this please feel free.
579 Stevan Little E<lt>stevan@iinteractive.comE<gt>
581 =head1 COPYRIGHT AND LICENSE
583 Copyright 2009 by Infinity Interactive, Inc.
585 L<http://www.iinteractive.com>
587 This library is free software; you can redistribute it and/or modify
588 it under the same terms as Perl itself.