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::Util add_method_modifier behavior
25 add_method_modifier (and subsequently the sugar functions Moose::before,
26 Moose::after, and Moose::around) can now accept arrayrefs, with the same
27 behavior as lists. Types other than arrayref and regexp result in an error.
31 =head1 0.93_01 and 0.94
35 =item Moose::Util::MetaRole API has changed
37 The C<apply_metaclass_roles> function is now called C<apply_metaroles>. The
38 way arguments are supplied has been changed to force you to distinguish
39 between metaroles applied to L<Moose::Meta::Class> (and helpers) versus
42 The old API still works, but will warn in a future release, and eventually be
45 =item Moose::Meta::Role has real attributes
47 The attributes returned by L<Moose::Meta::Role> are now instances of the
48 L<Moose::Meta::Role::Attribute> class, instead of bare hash references.
50 =item "no Moose" now removes C<blessed> and C<confess>
52 Moose is now smart enough to know exactly what it exported, even when it
53 re-exports functions from other packages. When you unimport Moose, it will
54 remove these functions from your namespace unless you I<also> imported them
55 directly from their respective packages.
57 If you have a C<no Moose> in your code I<before> you call C<blessed> or
58 C<confess>, your code will break. You can either move the C<no Moose> call
59 later in your code, or explicitly import the relevant functions from the
60 packages that provide them.
62 =item L<Moose::Exporter> is smarter about unimporting re-exports
64 The change above comes from a general improvement to L<Moose::Exporter>. It
65 will now unimport any function it exports, even if that function is a
66 re-export from another package.
68 =item Attributes in roles can no longer override class attributes with "+foo"
70 Previously, this worked more or less accidentally, because role attributes
71 weren't objects. This was never documented, but a few MooseX modules took
74 =item The composition_class_roles attribute in L<Moose::Meta::Role> is now a method
76 This was done to make it possible for roles to alter the the list of
77 composition class roles by applying a method modifiers. Previously, this was
78 an attribute and MooseX modules override it. Since that no longer works, this
81 This I<should> be an attribute, so this may switch back to being an attribute
82 in the future if we can figure out how to make this work.
90 =item Calling $object->new() is no longer deprecated
92 We decided to undeprecate this. Now it just works.
94 =item Both C<get_method_map> and C<get_attribute_map> is deprecated
96 These metaclass methods were never meant to be public, and they are both now
97 deprecated. The work around if you still need the functionality they provided
98 is to iterate over the list of names manually.
100 my %fields = map { $_ => $meta->get_attribute($_) } $meta->get_attribute_list;
102 This was actually a change in L<Class::MOP>, but this version of Moose
103 requires a version of L<Class::MOP> that includes said change.
111 =item Added Native delegation for Code refs
113 See L<Moose::Meta::Attribute::Native::Trait::Code> for details.
115 =item Calling $object->new() is deprecated
117 Moose has long supported this, but it's never really been documented, and we
118 don't think this is a good practice. If you want to construct an object from
119 an existing object, you should provide some sort of alternate constructor like
120 C<< $object->clone >>.
122 Calling C<< $object->new >> now issues a warning, and will be an error in a
125 =item Moose no longer warns if you call C<make_immutable> for a class with mutable ancestors
127 While in theory this is a good thing to warn about, we found so many
128 exceptions to this that doing this properly became quite problematic.
132 =head1 Version 0.89_02
136 =item New Native delegation methods from L<List::Util> and L<List::MoreUtils>
138 In particular, we now have C<reduce>, C<shuffle>, C<uniq>, and C<natatime>.
140 =item The Moose::Exporter with_caller feature is now deprecated
142 Use C<with_meta> instead. The C<with_caller> option will start warning in a
145 =item Moose now warns if you call C<make_immutable> for a class with mutable ancestors
147 This is dangerous because modifying a class after a subclass has been
148 immutabilized will lead to incorrect results in the subclass, due to inlining,
149 caching, etc. This occasionally happens accidentally, when a class loads one
150 of its subclasses in the middle of its class definition, so pointing out that
151 this may cause issues should be helpful. Metaclasses (classes that inherit
152 from L<Class::MOP::Object>) are currently exempt from this check, since at the
153 moment we aren't very consistent about which metaclasses we immutabilize.
155 =item C<enum> and C<duck_type> now take arrayrefs for all forms
157 Previously, calling these functions with a list would take the first element of
158 the list as the type constraint name, and use the remainder as the enum values
159 or method names. This makes the interface inconsistent with the anon-type forms
160 of these functions (which must take an arrayref), and a free-form list where
161 the first value is sometimes special is hard to validate (and harder to give
162 reasonable error messages for). These functions have been changed to take
163 arrayrefs in all their forms - so, C<< enum 'My::Type' => [qw(foo bar)] >> is
164 now the preferred way to create an enum type constraint. The old syntax still
165 works for now, but it will hopefully be deprecated and removed in a future
170 =head1 Version 0.89_01
172 L<Moose::Meta::Attribute::Native> has been moved into the Moose core from
173 L<MooseX::AttributeHelpers>. Major changes include:
177 =item C<traits>, not C<metaclass>
179 Method providers are only available via traits.
181 =item C<handles>, not C<provides> or C<curries>
183 The C<provides> syntax was like core Moose C<< handles => HASHREF >>
184 syntax, but with the keys and values reversed. This was confusing,
185 and AttributeHelpers now uses C<< handles => HASHREF >> in a way that
186 should be intuitive to anyone already familiar with how it is used for
189 The C<curries> functionality provided by AttributeHelpers has been
190 generalized to apply to all cases of C<< handles => HASHREF >>, though
191 not every piece of functionality has been ported (currying with a
192 CODEREF is not supported).
194 =item C<empty> is now C<is_empty>, and means empty, not non-empty
196 Previously, the C<empty> method provided by Arrays and Hashes returned true if
197 the attribute was B<not> empty (no elements). Now it returns true if the
198 attribute B<is> empty. It was also renamed to C<is_empty>, to reflect this.
200 =item C<find> was renamed to C<first>, and C<first> and C<last> were removed
202 L<List::Util> refers to the functionality that we used to provide under C<find>
203 as L<first|List::Util/first>, so that will likely be more familiar (and will
204 fit in better if we decide to add more List::Util functions). C<first> and
205 C<last> were removed, since their functionality is easily duplicated with
208 =item Helpers that take a coderef of one argument now use C<$_>
210 Subroutines passed as the first argument to C<first>, C<map>, and C<grep> now
211 receive their argument in C<$_> rather than as a parameter to the subroutine.
212 Helpers that take a coderef of two or more arguments remain using the argument
213 list (there are technical limitations to using C<$a> and C<$b> like C<sort>
216 See L<Moose::Meta::Attribute::Native> for the new documentation.
220 The C<alias> and C<excludes> role parameters have been renamed to C<-alias>
221 and C<-excludes>. The old names still work, but new code should use the new
222 names, and eventually the old ones will be deprecated and removed.
226 C<< use Moose -metaclass => 'Foo' >> now does alias resolution, just like
227 C<-traits> (and the C<metaclass> and C<traits> options to C<has>).
229 Added two functions C<meta_class_alias> and C<meta_attribute_alias> to
230 L<Moose::Util>, to simplify aliasing metaclasses and metatraits. This is
231 a wrapper around the old
233 package Moose::Meta::Class::Custom::Trait::FooTrait;
234 sub register_implementation { 'My::Meta::Trait' }
240 When an attribute generates I<no> accessors, we now warn. This is to help
241 users who forget the C<is> option. If you really do not want any accessors,
242 you can use C<< is => 'bare' >>. You can maintain back compat with older
243 versions of Moose by using something like:
245 ($Moose::VERSION >= 0.84 ? is => 'bare' : ())
247 When an accessor overwrites an existing method, we now warn. To work around
248 this warning (if you really must have this behavior), you can explicitly
249 remove the method before creating it as an accessor:
253 __PACKAGE__->meta->remove_method('foo');
259 When an unknown option is passed to C<has>, we now warn. You can silence
260 the warning by fixing your code. :)
262 The C<Role> type has been deprecated. On its own, it was useless,
263 since it just checked C<< $object->can('does') >>. If you were using
264 it as a parent type, just call C<role_type('Role::Name')> to create an
265 appropriate type instead.
269 C<use Moose::Exporter;> now imports C<strict> and C<warnings> into packages
274 C<DEMOLISHALL> and C<DEMOLISH> now receive an argument indicating whether or
275 not we are in global destruction.
279 Type constraints no longer run coercions for a value that already matches the
280 constraint. This may affect some (arguably buggy) edge case coercions that
281 rely on side effects in the C<via> clause.
285 L<Moose::Exporter> now accepts the C<-metaclass> option for easily
286 overriding the metaclass (without L<metaclass>). This works for classes
291 Added a C<duck_type> sugar function to L<Moose::Util::TypeConstraints>
292 to make integration with non-Moose classes easier. It simply checks if
293 C<< $obj->can() >> a list of methods.
295 A number of methods (mostly inherited from L<Class::MOP>) have been
296 renamed with a leading underscore to indicate their internal-ness. The
297 old method names will still work for a while, but will warn that the
298 method has been renamed. In a few cases, the method will be removed
299 entirely in the future. This may affect MooseX authors who were using
304 Calling C<subtype> with a name as the only argument now throws an
305 exception. If you want an anonymous subtype do:
307 my $subtype = subtype as 'Foo';
309 This is related to the changes in version 0.71_01.
311 The C<is_needed> method in L<Moose::Meta::Method::Destructor> is now
312 only usable as a class method. Previously, it worked as a class or
313 object method, with a different internal implementation for each
316 The internals of making a class immutable changed a lot in Class::MOP
317 0.78_02, and Moose's internals have changed along with it. The
318 external C<< $metaclass->make_immutable >> method still works the same
323 A mutable class accepted C<< Foo->new(undef) >> without complaint,
324 while an immutable class would blow up with an unhelpful error. Now,
325 in both cases we throw a helpful error instead.
327 This "feature" was originally added to allow for cases such as this:
335 return My::Class->new($args);
337 But we decided this is a bad idea and a little too magical, because it
338 can easily mask real errors.
340 =head1 Version 0.71_01
342 Calling C<type> or C<subtype> without the sugar helpers (C<as>,
343 C<where>, C<message>) is now deprecated.
345 As a side effect, this meant we ended up using Perl prototypes on
346 C<as>, and code like this will no longer work:
348 use Moose::Util::TypeConstraints;
349 use Declare::Constraints::Simple -All;
351 subtype 'ArrayOfInts'
353 => IsArrayRef(IsInt);
355 Instead it must be changed to this:
360 where => IsArrayRef(IsInt)
364 If you want to maintain backwards compat with older versions of Moose,
365 you must explicitly test Moose's C<VERSION>:
367 if ( Moose->VERSION < 0.71_01 ) {
368 subtype 'ArrayOfInts'
370 => IsArrayRef(IsInt);
376 where => IsArrayRef(IsInt)
383 We no longer pass the meta-attribute object as a final argument to
384 triggers. This actually changed for inlined code a while back, but the
385 non-inlined version and the docs were still out of date.
387 If by some chance you actually used this feature, the workaround is
388 simple. You fetch the attribute object from out of the C<$self>
389 that is passed as the first argument to trigger, like so:
395 my ( $self, $value ) = @_;
396 my $attr = $self->meta->find_attribute_by_name('foo');
404 If you created a subtype and passed a parent that Moose didn't know
405 about, it simply ignored the parent. Now it automatically creates the
406 parent as a class type. This may not be what you want, but is less
409 You could declare a name with subtype such as "Foo!Bar". Moose would
410 accept this allowed, but if you used it in a parameterized type such
411 as "ArrayRef[Foo!Bar]" it wouldn't work. We now do some vetting on
412 names created via the sugar functions, so that they can only contain
413 alphanumerics, ":", and ".".
417 Methods created via an attribute can now fulfill a C<requires>
418 declaration for a role. Honestly we don't know why Stevan didn't make
419 this work originally, he was just insane or something.
421 Stack traces from inlined code will now report the line and file as
422 being in your class, as opposed to in Moose guts.
424 =head1 Version 0.62_02
426 When a class does not provide all of a role's required methods, the
427 error thrown now mentions all of the missing methods, as opposed to
428 just the first missing method.
430 Moose will no longer inline a constructor for your class unless it
431 inherits its constructor from Moose::Object, and will warn when it
432 doesn't inline. If you want to force inlining anyway, pass
433 C<< replace_constructor => 1 >> to C<make_immutable>.
435 If you want to get rid of the warning, pass C<< inline_constructor =>
440 Removed the (deprecated) C<make_immutable> keyword.
442 Removing an attribute from a class now also removes delegation
443 (C<handles>) methods installed for that attribute. This is correct
444 behavior, but if you were wrongly relying on it you might get bit.
448 Roles now add methods by calling C<add_method>, not
449 C<alias_method>. They make sure to always provide a method object,
450 which will be cloned internally. This means that it is now possible to
451 track the source of a method provided by a role, and even follow its
452 history through intermediate roles. This means that methods added by
453 a role now show up when looking at a class's method list/map.
455 Parameter and Union args are now sorted, this makes Int|Str the same
456 constraint as Str|Int. Also, incoming type constraint strings are
457 normalized to remove all whitespace differences. This is mostly for
458 internals and should not affect outside code.
460 L<Moose::Exporter> will no longer remove a subroutine that the
461 exporting package re-exports. Moose re-exports the Carp::confess
462 function, among others. The reasoning is that we cannot know whether
463 you have also explicitly imported those functions for your own use, so
464 we err on the safe side and always keep them.
468 C<Moose::init_meta> should now be called as a method.
470 New modules for extension writers, L<Moose::Exporter> and
471 L<Moose::Util::MetaRole>.
473 =head1 Version 0.55_01
475 Implemented metaclass traits (and wrote a recipe for it):
477 use Moose -traits => 'Foo'
479 This should make writing small Moose extensions a little
484 Fixed C<coerce> to accept anon types just like C<subtype> can.
487 coerce $some_anon_type => from 'Str' => via { ... };
491 Added C<BUILDARGS>, a new step in C<< Moose::Object->new() >>.
495 Fixed how the C<< is => (ro|rw) >> works with custom defined
496 C<reader>, C<writer> and C<accessor> options. See the below table for
499 is => ro, writer => _foo # turns into (reader => foo, writer => _foo)
500 is => rw, writer => _foo # turns into (reader => foo, writer => _foo)
501 is => rw, accessor => _foo # turns into (accessor => _foo)
502 is => ro, accessor => _foo # error, accesor is rw
506 The C<before/around/after> method modifiers now support regexp
507 matching of method names. NOTE: this only works for classes, it is
508 currently not supported in roles, but, ... patches welcome.
510 The C<has> keyword for roles now accepts the same array ref form that
511 L<Moose>.pm does for classes.
513 A trigger on a read-only attribute is no longer an error, as it's
514 useful to trigger off of the constructor.
516 Subtypes of parameterizable types now are parameterizable types
521 Fixed issue where C<DEMOLISHALL> was eating the value in C<$@>, and so
522 not working correctly. It still kind of eats them, but so does vanilla
527 Inherited attributes may now be extended without restriction on the
528 type ('isa', 'does').
530 The entire set of Moose::Meta::TypeConstraint::* classes were
531 refactored in this release. If you were relying on their internals you
532 should test your code carefully.
536 Documenting the use of '+name' with attributes that come from recently
537 composed roles. It makes sense, people are using it, and so why not
538 just officially support it.
540 The C<< Moose::Meta::Class->create >> method now supports roles.
542 It is now possible to make anonymous enum types by passing C<enum> an
543 array reference instead of the C<< enum $name => @values >>.
547 Added the C<make_immutable> keyword as a shortcut to calling
548 C<make_immutable> on the meta object. This eventually got removed!
550 Made C<< init_arg => undef >> work in Moose. This means "do not accept
551 a constructor parameter for this attribute".
553 Type errors now use the provided message. Prior to this release they
558 Moose is now a postmodern object system :)
560 The Role system was completely refactored. It is 100% backwards
561 compat, but the internals were totally changed. If you relied on the
562 internals then you are advised to test carefully.
564 Added method exclusion and aliasing for Roles in this release.
566 Added the L<Moose::Util::TypeConstraints::OptimizedConstraints>
569 Passing a list of values to an accessor (which is only expecting one
570 value) used to be silently ignored, now it throws an error.
574 Added parameterized types and did a pretty heavy refactoring of the
575 type constraint system.
577 Better framework extendability and better support for "making your own
580 =head1 Version 0.25 or before
582 Honestly, you shouldn't be using versions of Moose that are this old,
583 so many bug fixes and speed improvements have been made you would be
584 crazy to not upgrade.
586 Also, I am tired of going through the Changelog so I am stopping here,
587 if anyone would like to continue this please feel free.
591 Stevan Little E<lt>stevan@iinteractive.comE<gt>
593 =head1 COPYRIGHT AND LICENSE
595 Copyright 2009 by Infinity Interactive, Inc.
597 L<http://www.iinteractive.com>
599 This library is free software; you can redistribute it and/or modify
600 it under the same terms as Perl itself.