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 L<Moose::Meta::Attribute::Native> has been moved into the Moose core from
22 L<MooseX::AttributeHelpers>. Major changes include:
26 =item C<traits>, not C<metaclass>
28 Method providers are only available via traits.
30 =item C<handles>, not C<provides> or C<curries>
32 The C<provides> syntax was like core Moose C<< handles => HASHREF >>
33 syntax, but with the keys and values reversed. This was confusing,
34 and AttributeHelpers now uses C<< handles => HASHREF >> in a way that
35 should be intuitive to anyone already familiar with how it is used for
38 The C<curries> functionality provided by AttributeHelpers has been
39 generalized to apply to all cases of C<< handles => HASHREF >>, though
40 not every piece of functionality has been ported (currying with a
41 CODEREF is not supported).
43 =item C<empty> is now C<is_empty>, and means empty, not non-empty
45 Previously, the C<empty> method provided by Arrays and Hashes returned true if
46 the attribute was B<not> empty (no elements). Now it returns true if the
47 attribute B<is> empty. It was also renamed to C<is_empty>, to reflect this.
49 =item C<find> was renamed to C<first>, and C<first> and C<last> were removed
51 L<List::Util> refers to the functionality that we used to provide under C<find>
52 as L<first|List::Util/first>, so that will likely be more familiar (and will
53 fit in better if we decide to add more List::Util functions). C<first> and
54 C<last> were removed, since their functionality is easily duplicated with
57 =item Helpers that take a coderef of one argument now use C<$_>
59 Subroutines passed as the first argument to C<first>, C<map>, and C<grep> now
60 receive their argument in C<$_> rather than as a parameter to the subroutine.
61 Helpers that take a coderef of two or more arguments remain using the argument
62 list (there are technical limitations to using C<$a> and C<$b> like C<sort>
67 See L<Moose::Meta::Attribute::Native> for the new documentation.
69 C<< use Moose -metaclass => 'Foo' >> now does alias resolution, just like
70 C<-traits> (and the C<metaclass> and C<traits> options to C<has>).
72 Added two functions C<meta_class_alias> and C<meta_attribute_alias> to
73 L<Moose::Util>, to simplify aliasing metaclasses and metatraits. This is
74 a wrapper around the old
76 package Moose::Meta::Class::Custom::Trait::FooTrait;
77 sub register_implementation { 'My::Meta::Trait' }
81 The C<alias> and C<excludes> role parameters have been renamed to C<-alias>
82 and C<-excludes>. The old names still work, but new code should use the new
83 names, and eventually the old ones will be deprecated and removed.
87 When an attribute generates I<no> accessors, we now warn. This is to help
88 users who forget the C<is> option. If you really do not want any accessors,
89 you can use C<< is => 'bare' >>. You can maintain back compat with older
90 versions of Moose by using something like:
92 ($Moose::VERSION >= 0.84 ? is => 'bare' : ())
94 When an accessor overwrites an existing method, we now warn. To work around
95 this warning (if you really must have this behavior), you can explicitly
96 remove the method before creating it as an accessor:
100 __PACKAGE__->meta->remove_method('foo');
106 When an unknown option is passed to C<has>, we now warn. You can silence
107 the warning by fixing your code. :)
109 The C<Role> type has been deprecated. On its own, it was useless,
110 since it just checked C<< $object->can('does') >>. If you were using
111 it as a parent type, just call C<role_type('Role::Name')> to create an
112 appropriate type instead.
116 C<use Moose::Exporter;> now imports C<strict> and C<warnings> into packages
121 C<DEMOLISHALL> and C<DEMOLISH> now receive an argument indicating whether or
122 not we are in global destruction.
126 Type constraints no longer run coercions for a value that already matches the
127 constraint. This may affect some (arguably buggy) edge case coercions that
128 rely on side effects in the C<via> clause.
132 L<Moose::Exporter> now accepts the C<-metaclass> option for easily
133 overriding the metaclass (without L<metaclass>). This works for classes
138 Added a C<duck_type> sugar function to L<Moose::Util::TypeConstraints>
139 to make integration with non-Moose classes easier. It simply checks if
140 C<< $obj->can() >> a list of methods.
142 A number of methods (mostly inherited from L<Class::MOP>) have been
143 renamed with a leading underscore to indicate their internal-ness. The
144 old method names will still work for a while, but will warn that the
145 method has been renamed. In a few cases, the method will be removed
146 entirely in the future. This may affect MooseX authors who were using
151 Calling C<subtype> with a name as the only argument now throws an
152 exception. If you want an anonymous subtype do:
154 my $subtype = subtype as 'Foo';
156 This is related to the changes in version 0.71_01.
158 The C<is_needed> method in L<Moose::Meta::Method::Destructor> is now
159 only usable as a class method. Previously, it worked as a class or
160 object method, with a different internal implementation for each
163 The internals of making a class immutable changed a lot in Class::MOP
164 0.78_02, and Moose's internals have changed along with it. The
165 external C<< $metaclass->make_immutable >> method still works the same
170 A mutable class accepted C<< Foo->new(undef) >> without complaint,
171 while an immutable class would blow up with an unhelpful error. Now,
172 in both cases we throw a helpful error instead.
174 This "feature" was originally added to allow for cases such as this:
182 return My::Class->new($args);
184 But we decided this is a bad idea and a little too magical, because it
185 can easily mask real errors.
187 =head1 Version 0.71_01
189 Calling C<type> or C<subtype> without the sugar helpers (C<as>,
190 C<where>, C<message>) is now deprecated.
192 As a side effect, this meant we ended up using Perl prototypes on
193 C<as>, and code like this will no longer work:
195 use Moose::Util::TypeConstraints;
196 use Declare::Constraints::Simple -All;
198 subtype 'ArrayOfInts'
200 => IsArrayRef(IsInt);
202 Instead it must be changed to this:
207 where => IsArrayRef(IsInt)
211 If you want to maintain backwards compat with older versions of Moose,
212 you must explicitly test Moose's C<VERSION>:
214 if ( Moose->VERSION < 0.71_01 ) {
215 subtype 'ArrayOfInts'
217 => IsArrayRef(IsInt);
223 where => IsArrayRef(IsInt)
230 We no longer pass the meta-attribute object as a final argument to
231 triggers. This actually changed for inlined code a while back, but the
232 non-inlined version and the docs were still out of date.
234 If by some chance you actually used this feature, the workaround is
235 simple. You fetch the attribute object from out of the C<$self>
236 that is passed as the first argument to trigger, like so:
242 my ( $self, $value ) = @_;
243 my $attr = $self->meta->find_attribute_by_name('foo');
251 If you created a subtype and passed a parent that Moose didn't know
252 about, it simply ignored the parent. Now it automatically creates the
253 parent as a class type. This may not be what you want, but is less
256 You could declare a name with subtype such as "Foo!Bar". Moose would
257 accept this allowed, but if you used it in a parameterized type such
258 as "ArrayRef[Foo!Bar]" it wouldn't work. We now do some vetting on
259 names created via the sugar functions, so that they can only contain
260 alphanumerics, ":", and ".".
264 Methods created via an attribute can now fulfill a C<requires>
265 declaration for a role. Honestly we don't know why Stevan didn't make
266 this work originally, he was just insane or something.
268 Stack traces from inlined code will now report the line and file as
269 being in your class, as opposed to in Moose guts.
271 =head1 Version 0.62_02
273 When a class does not provide all of a role's required methods, the
274 error thrown now mentions all of the missing methods, as opposed to
275 just the first missing method.
277 Moose will no longer inline a constructor for your class unless it
278 inherits its constructor from Moose::Object, and will warn when it
279 doesn't inline. If you want to force inlining anyway, pass
280 C<< replace_constructor => 1 >> to C<make_immutable>.
282 If you want to get rid of the warning, pass C<< inline_constructor =>
287 Removed the (deprecated) C<make_immutable> keyword.
289 Removing an attribute from a class now also removes delegation
290 (C<handles>) methods installed for that attribute. This is correct
291 behavior, but if you were wrongly relying on it you might get bit.
295 Roles now add methods by calling C<add_method>, not
296 C<alias_method>. They make sure to always provide a method object,
297 which will be cloned internally. This means that it is now possible to
298 track the source of a method provided by a role, and even follow its
299 history through intermediate roles. This means that methods added by
300 a role now show up when looking at a class's method list/map.
302 Parameter and Union args are now sorted, this makes Int|Str the same
303 constraint as Str|Int. Also, incoming type constraint strings are
304 normalized to remove all whitespace differences. This is mostly for
305 internals and should not affect outside code.
307 L<Moose::Exporter> will no longer remove a subroutine that the
308 exporting package re-exports. Moose re-exports the Carp::confess
309 function, among others. The reasoning is that we cannot know whether
310 you have also explicitly imported those functions for your own use, so
311 we err on the safe side and always keep them.
315 C<Moose::init_meta> should now be called as a method.
317 New modules for extension writers, L<Moose::Exporter> and
318 L<Moose::Util::MetaRole>.
320 =head1 Version 0.55_01
322 Implemented metaclass traits (and wrote a recipe for it):
324 use Moose -traits => 'Foo'
326 This should make writing small Moose extensions a little
331 Fixed C<coerce> to accept anon types just like C<subtype> can.
334 coerce $some_anon_type => from 'Str' => via { ... };
338 Added C<BUILDARGS>, a new step in C<< Moose::Object->new() >>.
342 Fixed how the C<< is => (ro|rw) >> works with custom defined
343 C<reader>, C<writer> and C<accessor> options. See the below table for
346 is => ro, writer => _foo # turns into (reader => foo, writer => _foo)
347 is => rw, writer => _foo # turns into (reader => foo, writer => _foo)
348 is => rw, accessor => _foo # turns into (accessor => _foo)
349 is => ro, accessor => _foo # error, accesor is rw
353 The C<before/around/after> method modifiers now support regexp
354 matching of method names. NOTE: this only works for classes, it is
355 currently not supported in roles, but, ... patches welcome.
357 The C<has> keyword for roles now accepts the same array ref form that
358 L<Moose>.pm does for classes.
360 A trigger on a read-only attribute is no longer an error, as it's
361 useful to trigger off of the constructor.
363 Subtypes of parameterizable types now are parameterizable types
368 Fixed issue where C<DEMOLISHALL> was eating the value in C<$@>, and so
369 not working correctly. It still kind of eats them, but so does vanilla
374 Inherited attributes may now be extended without restriction on the
375 type ('isa', 'does').
377 The entire set of Moose::Meta::TypeConstraint::* classes were
378 refactored in this release. If you were relying on their internals you
379 should test your code carefully.
383 Documenting the use of '+name' with attributes that come from recently
384 composed roles. It makes sense, people are using it, and so why not
385 just officially support it.
387 The C<< Moose::Meta::Class->create >> method now supports roles.
389 It is now possible to make anonymous enum types by passing C<enum> an
390 array reference instead of the C<< enum $name => @values >>.
394 Added the C<make_immutable> keyword as a shortcut to calling
395 C<make_immutable> on the meta object. This eventually got removed!
397 Made C<< init_arg => undef >> work in Moose. This means "do not accept
398 a constructor parameter for this attribute".
400 Type errors now use the provided message. Prior to this release they
405 Moose is now a postmodern object system :)
407 The Role system was completely refactored. It is 100% backwards
408 compat, but the internals were totally changed. If you relied on the
409 internals then you are advised to test carefully.
411 Added method exclusion and aliasing for Roles in this release.
413 Added the L<Moose::Util::TypeConstraints::OptimizedConstraints>
416 Passing a list of values to an accessor (which is only expecting one
417 value) used to be silently ignored, now it throws an error.
421 Added parameterized types and did a pretty heavy refactoring of the
422 type constraint system.
424 Better framework extendability and better support for "making your own
427 =head1 Version 0.25 or before
429 Honestly, you shouldn't be using versions of Moose that are this old,
430 so many bug fixes and speed improvements have been made you would be
431 crazy to not upgrade.
433 Also, I am tired of going through the Changelog so I am stopping here,
434 if anyone would like to continue this please feel free.
438 Stevan Little E<lt>stevan@iinteractive.comE<gt>
440 =head1 COPYRIGHT AND LICENSE
442 Copyright 2009 by Infinity Interactive, Inc.
444 L<http://www.iinteractive.com>
446 This library is free software; you can redistribute it and/or modify
447 it under the same terms as Perl itself.