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 Added Native delegation for Code refs
25 See L<Moose::Meta::Attribute::Native::Trait::Code> for details.
29 =head1 Version 0.89_02
33 =item New Native delegation methods from L<List::Util> and L<List::MoreUtils>
35 In particular, we now have C<reduce>, C<shuffle>, C<uniq>, and C<natatime>.
37 =item The Moose::Exporter with_caller feature is now deprecated
39 Use C<with_meta> instead. The C<with_caller> option will start warning in a
42 =item Moose now warns if you call C<make_immutable> for a class with mutable ancestors
44 This is dangerous because modifying a class after a subclass has been
45 immutabilized will lead to incorrect results in the subclass, due to inlining,
46 caching, etc. This occasionally happens accidentally, when a class loads one
47 of its subclasses in the middle of its class definition, so pointing out that
48 this may cause issues should be helpful. Metaclasses (classes that inherit
49 from L<Class::MOP::Object>) are currently exempt from this check, since at the
50 moment we aren't very consistent about which metaclasses we immutabilize.
51 Anonymous classes are also exempt, since they are often created automatically,
52 and the user is never given a choice about whether or not to make them
53 immutable. If you're sure you know what you're doing, you also can pass the
54 C<allow_mutable_ancestors> option to make_immutable to silence the warning
55 (but be aware that modifying those mutable ancestors can still lead to
56 incorrect behavior in your subclass).
60 =head1 Version 0.89_01
62 L<Moose::Meta::Attribute::Native> has been moved into the Moose core from
63 L<MooseX::AttributeHelpers>. Major changes include:
67 =item C<traits>, not C<metaclass>
69 Method providers are only available via traits.
71 =item C<handles>, not C<provides> or C<curries>
73 The C<provides> syntax was like core Moose C<< handles => HASHREF >>
74 syntax, but with the keys and values reversed. This was confusing,
75 and AttributeHelpers now uses C<< handles => HASHREF >> in a way that
76 should be intuitive to anyone already familiar with how it is used for
79 The C<curries> functionality provided by AttributeHelpers has been
80 generalized to apply to all cases of C<< handles => HASHREF >>, though
81 not every piece of functionality has been ported (currying with a
82 CODEREF is not supported).
84 =item C<empty> is now C<is_empty>, and means empty, not non-empty
86 Previously, the C<empty> method provided by Arrays and Hashes returned true if
87 the attribute was B<not> empty (no elements). Now it returns true if the
88 attribute B<is> empty. It was also renamed to C<is_empty>, to reflect this.
90 =item C<find> was renamed to C<first>, and C<first> and C<last> were removed
92 L<List::Util> refers to the functionality that we used to provide under C<find>
93 as L<first|List::Util/first>, so that will likely be more familiar (and will
94 fit in better if we decide to add more List::Util functions). C<first> and
95 C<last> were removed, since their functionality is easily duplicated with
98 =item Helpers that take a coderef of one argument now use C<$_>
100 Subroutines passed as the first argument to C<first>, C<map>, and C<grep> now
101 receive their argument in C<$_> rather than as a parameter to the subroutine.
102 Helpers that take a coderef of two or more arguments remain using the argument
103 list (there are technical limitations to using C<$a> and C<$b> like C<sort>
106 See L<Moose::Meta::Attribute::Native> for the new documentation.
110 The C<alias> and C<excludes> role parameters have been renamed to C<-alias>
111 and C<-excludes>. The old names still work, but new code should use the new
112 names, and eventually the old ones will be deprecated and removed.
116 C<< use Moose -metaclass => 'Foo' >> now does alias resolution, just like
117 C<-traits> (and the C<metaclass> and C<traits> options to C<has>).
119 Added two functions C<meta_class_alias> and C<meta_attribute_alias> to
120 L<Moose::Util>, to simplify aliasing metaclasses and metatraits. This is
121 a wrapper around the old
123 package Moose::Meta::Class::Custom::Trait::FooTrait;
124 sub register_implementation { 'My::Meta::Trait' }
130 When an attribute generates I<no> accessors, we now warn. This is to help
131 users who forget the C<is> option. If you really do not want any accessors,
132 you can use C<< is => 'bare' >>. You can maintain back compat with older
133 versions of Moose by using something like:
135 ($Moose::VERSION >= 0.84 ? is => 'bare' : ())
137 When an accessor overwrites an existing method, we now warn. To work around
138 this warning (if you really must have this behavior), you can explicitly
139 remove the method before creating it as an accessor:
143 __PACKAGE__->meta->remove_method('foo');
149 When an unknown option is passed to C<has>, we now warn. You can silence
150 the warning by fixing your code. :)
152 The C<Role> type has been deprecated. On its own, it was useless,
153 since it just checked C<< $object->can('does') >>. If you were using
154 it as a parent type, just call C<role_type('Role::Name')> to create an
155 appropriate type instead.
159 C<use Moose::Exporter;> now imports C<strict> and C<warnings> into packages
164 C<DEMOLISHALL> and C<DEMOLISH> now receive an argument indicating whether or
165 not we are in global destruction.
169 Type constraints no longer run coercions for a value that already matches the
170 constraint. This may affect some (arguably buggy) edge case coercions that
171 rely on side effects in the C<via> clause.
175 L<Moose::Exporter> now accepts the C<-metaclass> option for easily
176 overriding the metaclass (without L<metaclass>). This works for classes
181 Added a C<duck_type> sugar function to L<Moose::Util::TypeConstraints>
182 to make integration with non-Moose classes easier. It simply checks if
183 C<< $obj->can() >> a list of methods.
185 A number of methods (mostly inherited from L<Class::MOP>) have been
186 renamed with a leading underscore to indicate their internal-ness. The
187 old method names will still work for a while, but will warn that the
188 method has been renamed. In a few cases, the method will be removed
189 entirely in the future. This may affect MooseX authors who were using
194 Calling C<subtype> with a name as the only argument now throws an
195 exception. If you want an anonymous subtype do:
197 my $subtype = subtype as 'Foo';
199 This is related to the changes in version 0.71_01.
201 The C<is_needed> method in L<Moose::Meta::Method::Destructor> is now
202 only usable as a class method. Previously, it worked as a class or
203 object method, with a different internal implementation for each
206 The internals of making a class immutable changed a lot in Class::MOP
207 0.78_02, and Moose's internals have changed along with it. The
208 external C<< $metaclass->make_immutable >> method still works the same
213 A mutable class accepted C<< Foo->new(undef) >> without complaint,
214 while an immutable class would blow up with an unhelpful error. Now,
215 in both cases we throw a helpful error instead.
217 This "feature" was originally added to allow for cases such as this:
225 return My::Class->new($args);
227 But we decided this is a bad idea and a little too magical, because it
228 can easily mask real errors.
230 =head1 Version 0.71_01
232 Calling C<type> or C<subtype> without the sugar helpers (C<as>,
233 C<where>, C<message>) is now deprecated.
235 As a side effect, this meant we ended up using Perl prototypes on
236 C<as>, and code like this will no longer work:
238 use Moose::Util::TypeConstraints;
239 use Declare::Constraints::Simple -All;
241 subtype 'ArrayOfInts'
243 => IsArrayRef(IsInt);
245 Instead it must be changed to this:
250 where => IsArrayRef(IsInt)
254 If you want to maintain backwards compat with older versions of Moose,
255 you must explicitly test Moose's C<VERSION>:
257 if ( Moose->VERSION < 0.71_01 ) {
258 subtype 'ArrayOfInts'
260 => IsArrayRef(IsInt);
266 where => IsArrayRef(IsInt)
273 We no longer pass the meta-attribute object as a final argument to
274 triggers. This actually changed for inlined code a while back, but the
275 non-inlined version and the docs were still out of date.
277 If by some chance you actually used this feature, the workaround is
278 simple. You fetch the attribute object from out of the C<$self>
279 that is passed as the first argument to trigger, like so:
285 my ( $self, $value ) = @_;
286 my $attr = $self->meta->find_attribute_by_name('foo');
294 If you created a subtype and passed a parent that Moose didn't know
295 about, it simply ignored the parent. Now it automatically creates the
296 parent as a class type. This may not be what you want, but is less
299 You could declare a name with subtype such as "Foo!Bar". Moose would
300 accept this allowed, but if you used it in a parameterized type such
301 as "ArrayRef[Foo!Bar]" it wouldn't work. We now do some vetting on
302 names created via the sugar functions, so that they can only contain
303 alphanumerics, ":", and ".".
307 Methods created via an attribute can now fulfill a C<requires>
308 declaration for a role. Honestly we don't know why Stevan didn't make
309 this work originally, he was just insane or something.
311 Stack traces from inlined code will now report the line and file as
312 being in your class, as opposed to in Moose guts.
314 =head1 Version 0.62_02
316 When a class does not provide all of a role's required methods, the
317 error thrown now mentions all of the missing methods, as opposed to
318 just the first missing method.
320 Moose will no longer inline a constructor for your class unless it
321 inherits its constructor from Moose::Object, and will warn when it
322 doesn't inline. If you want to force inlining anyway, pass
323 C<< replace_constructor => 1 >> to C<make_immutable>.
325 If you want to get rid of the warning, pass C<< inline_constructor =>
330 Removed the (deprecated) C<make_immutable> keyword.
332 Removing an attribute from a class now also removes delegation
333 (C<handles>) methods installed for that attribute. This is correct
334 behavior, but if you were wrongly relying on it you might get bit.
338 Roles now add methods by calling C<add_method>, not
339 C<alias_method>. They make sure to always provide a method object,
340 which will be cloned internally. This means that it is now possible to
341 track the source of a method provided by a role, and even follow its
342 history through intermediate roles. This means that methods added by
343 a role now show up when looking at a class's method list/map.
345 Parameter and Union args are now sorted, this makes Int|Str the same
346 constraint as Str|Int. Also, incoming type constraint strings are
347 normalized to remove all whitespace differences. This is mostly for
348 internals and should not affect outside code.
350 L<Moose::Exporter> will no longer remove a subroutine that the
351 exporting package re-exports. Moose re-exports the Carp::confess
352 function, among others. The reasoning is that we cannot know whether
353 you have also explicitly imported those functions for your own use, so
354 we err on the safe side and always keep them.
358 C<Moose::init_meta> should now be called as a method.
360 New modules for extension writers, L<Moose::Exporter> and
361 L<Moose::Util::MetaRole>.
363 =head1 Version 0.55_01
365 Implemented metaclass traits (and wrote a recipe for it):
367 use Moose -traits => 'Foo'
369 This should make writing small Moose extensions a little
374 Fixed C<coerce> to accept anon types just like C<subtype> can.
377 coerce $some_anon_type => from 'Str' => via { ... };
381 Added C<BUILDARGS>, a new step in C<< Moose::Object->new() >>.
385 Fixed how the C<< is => (ro|rw) >> works with custom defined
386 C<reader>, C<writer> and C<accessor> options. See the below table for
389 is => ro, writer => _foo # turns into (reader => foo, writer => _foo)
390 is => rw, writer => _foo # turns into (reader => foo, writer => _foo)
391 is => rw, accessor => _foo # turns into (accessor => _foo)
392 is => ro, accessor => _foo # error, accesor is rw
396 The C<before/around/after> method modifiers now support regexp
397 matching of method names. NOTE: this only works for classes, it is
398 currently not supported in roles, but, ... patches welcome.
400 The C<has> keyword for roles now accepts the same array ref form that
401 L<Moose>.pm does for classes.
403 A trigger on a read-only attribute is no longer an error, as it's
404 useful to trigger off of the constructor.
406 Subtypes of parameterizable types now are parameterizable types
411 Fixed issue where C<DEMOLISHALL> was eating the value in C<$@>, and so
412 not working correctly. It still kind of eats them, but so does vanilla
417 Inherited attributes may now be extended without restriction on the
418 type ('isa', 'does').
420 The entire set of Moose::Meta::TypeConstraint::* classes were
421 refactored in this release. If you were relying on their internals you
422 should test your code carefully.
426 Documenting the use of '+name' with attributes that come from recently
427 composed roles. It makes sense, people are using it, and so why not
428 just officially support it.
430 The C<< Moose::Meta::Class->create >> method now supports roles.
432 It is now possible to make anonymous enum types by passing C<enum> an
433 array reference instead of the C<< enum $name => @values >>.
437 Added the C<make_immutable> keyword as a shortcut to calling
438 C<make_immutable> on the meta object. This eventually got removed!
440 Made C<< init_arg => undef >> work in Moose. This means "do not accept
441 a constructor parameter for this attribute".
443 Type errors now use the provided message. Prior to this release they
448 Moose is now a postmodern object system :)
450 The Role system was completely refactored. It is 100% backwards
451 compat, but the internals were totally changed. If you relied on the
452 internals then you are advised to test carefully.
454 Added method exclusion and aliasing for Roles in this release.
456 Added the L<Moose::Util::TypeConstraints::OptimizedConstraints>
459 Passing a list of values to an accessor (which is only expecting one
460 value) used to be silently ignored, now it throws an error.
464 Added parameterized types and did a pretty heavy refactoring of the
465 type constraint system.
467 Better framework extendability and better support for "making your own
470 =head1 Version 0.25 or before
472 Honestly, you shouldn't be using versions of Moose that are this old,
473 so many bug fixes and speed improvements have been made you would be
474 crazy to not upgrade.
476 Also, I am tired of going through the Changelog so I am stopping here,
477 if anyone would like to continue this please feel free.
481 Stevan Little E<lt>stevan@iinteractive.comE<gt>
483 =head1 COPYRIGHT AND LICENSE
485 Copyright 2009 by Infinity Interactive, Inc.
487 L<http://www.iinteractive.com>
489 This library is free software; you can redistribute it and/or modify
490 it under the same terms as Perl itself.