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 New Native delegation methods from L<List::Util> and L<List::MoreUtils>
25 In particular, we now have C<reduce>, C<shuffle>, C<uniq>, and C<natatime>.
29 =head1 Version 0.89_01
31 L<Moose::Meta::Attribute::Native> has been moved into the Moose core from
32 L<MooseX::AttributeHelpers>. Major changes include:
36 =item C<traits>, not C<metaclass>
38 Method providers are only available via traits.
40 =item C<handles>, not C<provides> or C<curries>
42 The C<provides> syntax was like core Moose C<< handles => HASHREF >>
43 syntax, but with the keys and values reversed. This was confusing,
44 and AttributeHelpers now uses C<< handles => HASHREF >> in a way that
45 should be intuitive to anyone already familiar with how it is used for
48 The C<curries> functionality provided by AttributeHelpers has been
49 generalized to apply to all cases of C<< handles => HASHREF >>, though
50 not every piece of functionality has been ported (currying with a
51 CODEREF is not supported).
53 =item C<empty> is now C<is_empty>, and means empty, not non-empty
55 Previously, the C<empty> method provided by Arrays and Hashes returned true if
56 the attribute was B<not> empty (no elements). Now it returns true if the
57 attribute B<is> empty. It was also renamed to C<is_empty>, to reflect this.
59 =item C<find> was renamed to C<first>, and C<first> and C<last> were removed
61 L<List::Util> refers to the functionality that we used to provide under C<find>
62 as L<first|List::Util/first>, so that will likely be more familiar (and will
63 fit in better if we decide to add more List::Util functions). C<first> and
64 C<last> were removed, since their functionality is easily duplicated with
67 =item Helpers that take a coderef of one argument now use C<$_>
69 Subroutines passed as the first argument to C<first>, C<map>, and C<grep> now
70 receive their argument in C<$_> rather than as a parameter to the subroutine.
71 Helpers that take a coderef of two or more arguments remain using the argument
72 list (there are technical limitations to using C<$a> and C<$b> like C<sort>
75 See L<Moose::Meta::Attribute::Native> for the new documentation.
81 C<< use Moose -metaclass => 'Foo' >> now does alias resolution, just like
82 C<-traits> (and the C<metaclass> and C<traits> options to C<has>).
84 Added two functions C<meta_class_alias> and C<meta_attribute_alias> to
85 L<Moose::Util>, to simplify aliasing metaclasses and metatraits. This is
86 a wrapper around the old
88 package Moose::Meta::Class::Custom::Trait::FooTrait;
89 sub register_implementation { 'My::Meta::Trait' }
93 The C<alias> and C<excludes> role parameters have been renamed to C<-alias>
94 and C<-excludes>. The old names still work, but new code should use the new
95 names, and eventually the old ones will be deprecated and removed.
99 When an attribute generates I<no> accessors, we now warn. This is to help
100 users who forget the C<is> option. If you really do not want any accessors,
101 you can use C<< is => 'bare' >>. You can maintain back compat with older
102 versions of Moose by using something like:
104 ($Moose::VERSION >= 0.84 ? is => 'bare' : ())
106 When an accessor overwrites an existing method, we now warn. To work around
107 this warning (if you really must have this behavior), you can explicitly
108 remove the method before creating it as an accessor:
112 __PACKAGE__->meta->remove_method('foo');
118 When an unknown option is passed to C<has>, we now warn. You can silence
119 the warning by fixing your code. :)
121 The C<Role> type has been deprecated. On its own, it was useless,
122 since it just checked C<< $object->can('does') >>. If you were using
123 it as a parent type, just call C<role_type('Role::Name')> to create an
124 appropriate type instead.
128 C<use Moose::Exporter;> now imports C<strict> and C<warnings> into packages
133 C<DEMOLISHALL> and C<DEMOLISH> now receive an argument indicating whether or
134 not we are in global destruction.
138 Type constraints no longer run coercions for a value that already matches the
139 constraint. This may affect some (arguably buggy) edge case coercions that
140 rely on side effects in the C<via> clause.
144 L<Moose::Exporter> now accepts the C<-metaclass> option for easily
145 overriding the metaclass (without L<metaclass>). This works for classes
150 Added a C<duck_type> sugar function to L<Moose::Util::TypeConstraints>
151 to make integration with non-Moose classes easier. It simply checks if
152 C<< $obj->can() >> a list of methods.
154 A number of methods (mostly inherited from L<Class::MOP>) have been
155 renamed with a leading underscore to indicate their internal-ness. The
156 old method names will still work for a while, but will warn that the
157 method has been renamed. In a few cases, the method will be removed
158 entirely in the future. This may affect MooseX authors who were using
163 Calling C<subtype> with a name as the only argument now throws an
164 exception. If you want an anonymous subtype do:
166 my $subtype = subtype as 'Foo';
168 This is related to the changes in version 0.71_01.
170 The C<is_needed> method in L<Moose::Meta::Method::Destructor> is now
171 only usable as a class method. Previously, it worked as a class or
172 object method, with a different internal implementation for each
175 The internals of making a class immutable changed a lot in Class::MOP
176 0.78_02, and Moose's internals have changed along with it. The
177 external C<< $metaclass->make_immutable >> method still works the same
182 A mutable class accepted C<< Foo->new(undef) >> without complaint,
183 while an immutable class would blow up with an unhelpful error. Now,
184 in both cases we throw a helpful error instead.
186 This "feature" was originally added to allow for cases such as this:
194 return My::Class->new($args);
196 But we decided this is a bad idea and a little too magical, because it
197 can easily mask real errors.
199 =head1 Version 0.71_01
201 Calling C<type> or C<subtype> without the sugar helpers (C<as>,
202 C<where>, C<message>) is now deprecated.
204 As a side effect, this meant we ended up using Perl prototypes on
205 C<as>, and code like this will no longer work:
207 use Moose::Util::TypeConstraints;
208 use Declare::Constraints::Simple -All;
210 subtype 'ArrayOfInts'
212 => IsArrayRef(IsInt);
214 Instead it must be changed to this:
219 where => IsArrayRef(IsInt)
223 If you want to maintain backwards compat with older versions of Moose,
224 you must explicitly test Moose's C<VERSION>:
226 if ( Moose->VERSION < 0.71_01 ) {
227 subtype 'ArrayOfInts'
229 => IsArrayRef(IsInt);
235 where => IsArrayRef(IsInt)
242 We no longer pass the meta-attribute object as a final argument to
243 triggers. This actually changed for inlined code a while back, but the
244 non-inlined version and the docs were still out of date.
246 If by some chance you actually used this feature, the workaround is
247 simple. You fetch the attribute object from out of the C<$self>
248 that is passed as the first argument to trigger, like so:
254 my ( $self, $value ) = @_;
255 my $attr = $self->meta->find_attribute_by_name('foo');
263 If you created a subtype and passed a parent that Moose didn't know
264 about, it simply ignored the parent. Now it automatically creates the
265 parent as a class type. This may not be what you want, but is less
268 You could declare a name with subtype such as "Foo!Bar". Moose would
269 accept this allowed, but if you used it in a parameterized type such
270 as "ArrayRef[Foo!Bar]" it wouldn't work. We now do some vetting on
271 names created via the sugar functions, so that they can only contain
272 alphanumerics, ":", and ".".
276 Methods created via an attribute can now fulfill a C<requires>
277 declaration for a role. Honestly we don't know why Stevan didn't make
278 this work originally, he was just insane or something.
280 Stack traces from inlined code will now report the line and file as
281 being in your class, as opposed to in Moose guts.
283 =head1 Version 0.62_02
285 When a class does not provide all of a role's required methods, the
286 error thrown now mentions all of the missing methods, as opposed to
287 just the first missing method.
289 Moose will no longer inline a constructor for your class unless it
290 inherits its constructor from Moose::Object, and will warn when it
291 doesn't inline. If you want to force inlining anyway, pass
292 C<< replace_constructor => 1 >> to C<make_immutable>.
294 If you want to get rid of the warning, pass C<< inline_constructor =>
299 Removed the (deprecated) C<make_immutable> keyword.
301 Removing an attribute from a class now also removes delegation
302 (C<handles>) methods installed for that attribute. This is correct
303 behavior, but if you were wrongly relying on it you might get bit.
307 Roles now add methods by calling C<add_method>, not
308 C<alias_method>. They make sure to always provide a method object,
309 which will be cloned internally. This means that it is now possible to
310 track the source of a method provided by a role, and even follow its
311 history through intermediate roles. This means that methods added by
312 a role now show up when looking at a class's method list/map.
314 Parameter and Union args are now sorted, this makes Int|Str the same
315 constraint as Str|Int. Also, incoming type constraint strings are
316 normalized to remove all whitespace differences. This is mostly for
317 internals and should not affect outside code.
319 L<Moose::Exporter> will no longer remove a subroutine that the
320 exporting package re-exports. Moose re-exports the Carp::confess
321 function, among others. The reasoning is that we cannot know whether
322 you have also explicitly imported those functions for your own use, so
323 we err on the safe side and always keep them.
327 C<Moose::init_meta> should now be called as a method.
329 New modules for extension writers, L<Moose::Exporter> and
330 L<Moose::Util::MetaRole>.
332 =head1 Version 0.55_01
334 Implemented metaclass traits (and wrote a recipe for it):
336 use Moose -traits => 'Foo'
338 This should make writing small Moose extensions a little
343 Fixed C<coerce> to accept anon types just like C<subtype> can.
346 coerce $some_anon_type => from 'Str' => via { ... };
350 Added C<BUILDARGS>, a new step in C<< Moose::Object->new() >>.
354 Fixed how the C<< is => (ro|rw) >> works with custom defined
355 C<reader>, C<writer> and C<accessor> options. See the below table for
358 is => ro, writer => _foo # turns into (reader => foo, writer => _foo)
359 is => rw, writer => _foo # turns into (reader => foo, writer => _foo)
360 is => rw, accessor => _foo # turns into (accessor => _foo)
361 is => ro, accessor => _foo # error, accesor is rw
365 The C<before/around/after> method modifiers now support regexp
366 matching of method names. NOTE: this only works for classes, it is
367 currently not supported in roles, but, ... patches welcome.
369 The C<has> keyword for roles now accepts the same array ref form that
370 L<Moose>.pm does for classes.
372 A trigger on a read-only attribute is no longer an error, as it's
373 useful to trigger off of the constructor.
375 Subtypes of parameterizable types now are parameterizable types
380 Fixed issue where C<DEMOLISHALL> was eating the value in C<$@>, and so
381 not working correctly. It still kind of eats them, but so does vanilla
386 Inherited attributes may now be extended without restriction on the
387 type ('isa', 'does').
389 The entire set of Moose::Meta::TypeConstraint::* classes were
390 refactored in this release. If you were relying on their internals you
391 should test your code carefully.
395 Documenting the use of '+name' with attributes that come from recently
396 composed roles. It makes sense, people are using it, and so why not
397 just officially support it.
399 The C<< Moose::Meta::Class->create >> method now supports roles.
401 It is now possible to make anonymous enum types by passing C<enum> an
402 array reference instead of the C<< enum $name => @values >>.
406 Added the C<make_immutable> keyword as a shortcut to calling
407 C<make_immutable> on the meta object. This eventually got removed!
409 Made C<< init_arg => undef >> work in Moose. This means "do not accept
410 a constructor parameter for this attribute".
412 Type errors now use the provided message. Prior to this release they
417 Moose is now a postmodern object system :)
419 The Role system was completely refactored. It is 100% backwards
420 compat, but the internals were totally changed. If you relied on the
421 internals then you are advised to test carefully.
423 Added method exclusion and aliasing for Roles in this release.
425 Added the L<Moose::Util::TypeConstraints::OptimizedConstraints>
428 Passing a list of values to an accessor (which is only expecting one
429 value) used to be silently ignored, now it throws an error.
433 Added parameterized types and did a pretty heavy refactoring of the
434 type constraint system.
436 Better framework extendability and better support for "making your own
439 =head1 Version 0.25 or before
441 Honestly, you shouldn't be using versions of Moose that are this old,
442 so many bug fixes and speed improvements have been made you would be
443 crazy to not upgrade.
445 Also, I am tired of going through the Changelog so I am stopping here,
446 if anyone would like to continue this please feel free.
450 Stevan Little E<lt>stevan@iinteractive.comE<gt>
452 =head1 COPYRIGHT AND LICENSE
454 Copyright 2009 by Infinity Interactive, Inc.
456 L<http://www.iinteractive.com>
458 This library is free software; you can redistribute it and/or modify
459 it under the same terms as Perl itself.