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> now 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.
51 See L<Moose::Meta::Attribute::Native> for the new documentation.
53 C<< use Moose -metaclass => 'Foo' >> now does alias resolution, just like
54 C<-traits> (and the C<metaclass> and C<traits> options to C<has>).
56 Added two functions C<meta_class_alias> and C<meta_attribute_alias> to
57 L<Moose::Util>, to simplify aliasing metaclasses and metatraits. This is
58 a wrapper around the old
60 package Moose::Meta::Class::Custom::Trait::FooTrait;
61 sub register_implementation { 'My::Meta::Trait' }
65 The C<alias> and C<excludes> role parameters have been renamed to C<-alias>
66 and C<-excludes>. The old names still work, but new code should use the new
67 names, and eventually the old ones will be deprecated and removed.
71 When an attribute generates I<no> accessors, we now warn. This is to help
72 users who forget the C<is> option. If you really do not want any accessors,
73 you can use C<< is => 'bare' >>. You can maintain back compat with older
74 versions of Moose by using something like:
76 ($Moose::VERSION >= 0.84 ? is => 'bare' : ())
78 When an accessor overwrites an existing method, we now warn. To work around
79 this warning (if you really must have this behavior), you can explicitly
80 remove the method before creating it as an accessor:
84 __PACKAGE__->meta->remove_method('foo');
90 When an unknown option is passed to C<has>, we now warn. You can silence
91 the warning by fixing your code. :)
93 The C<Role> type has been deprecated. On its own, it was useless,
94 since it just checked C<< $object->can('does') >>. If you were using
95 it as a parent type, just call C<role_type('Role::Name')> to create an
96 appropriate type instead.
100 C<use Moose::Exporter;> now imports C<strict> and C<warnings> into packages
105 C<DEMOLISHALL> and C<DEMOLISH> now receive an argument indicating whether or
106 not we are in global destruction.
110 Type constraints no longer run coercions for a value that already matches the
111 constraint. This may affect some (arguably buggy) edge case coercions that
112 rely on side effects in the C<via> clause.
116 L<Moose::Exporter> now accepts the C<-metaclass> option for easily
117 overriding the metaclass (without L<metaclass>). This works for classes
122 Added a C<duck_type> sugar function to L<Moose::Util::TypeConstraints>
123 to make integration with non-Moose classes easier. It simply checks if
124 C<< $obj->can() >> a list of methods.
126 A number of methods (mostly inherited from L<Class::MOP>) have been
127 renamed with a leading underscore to indicate their internal-ness. The
128 old method names will still work for a while, but will warn that the
129 method has been renamed. In a few cases, the method will be removed
130 entirely in the future. This may affect MooseX authors who were using
135 Calling C<subtype> with a name as the only argument now throws an
136 exception. If you want an anonymous subtype do:
138 my $subtype = subtype as 'Foo';
140 This is related to the changes in version 0.71_01.
142 The C<is_needed> method in L<Moose::Meta::Method::Destructor> is now
143 only usable as a class method. Previously, it worked as a class or
144 object method, with a different internal implementation for each
147 The internals of making a class immutable changed a lot in Class::MOP
148 0.78_02, and Moose's internals have changed along with it. The
149 external C<< $metaclass->make_immutable >> method still works the same
154 A mutable class accepted C<< Foo->new(undef) >> without complaint,
155 while an immutable class would blow up with an unhelpful error. Now,
156 in both cases we throw a helpful error instead.
158 This "feature" was originally added to allow for cases such as this:
166 return My::Class->new($args);
168 But we decided this is a bad idea and a little too magical, because it
169 can easily mask real errors.
171 =head1 Version 0.71_01
173 Calling C<type> or C<subtype> without the sugar helpers (C<as>,
174 C<where>, C<message>) is now deprecated.
176 As a side effect, this meant we ended up using Perl prototypes on
177 C<as>, and code like this will no longer work:
179 use Moose::Util::TypeConstraints;
180 use Declare::Constraints::Simple -All;
182 subtype 'ArrayOfInts'
184 => IsArrayRef(IsInt);
186 Instead it must be changed to this:
191 where => IsArrayRef(IsInt)
195 If you want to maintain backwards compat with older versions of Moose,
196 you must explicitly test Moose's C<VERSION>:
198 if ( Moose->VERSION < 0.71_01 ) {
199 subtype 'ArrayOfInts'
201 => IsArrayRef(IsInt);
207 where => IsArrayRef(IsInt)
214 We no longer pass the meta-attribute object as a final argument to
215 triggers. This actually changed for inlined code a while back, but the
216 non-inlined version and the docs were still out of date.
218 If by some chance you actually used this feature, the workaround is
219 simple. You fetch the attribute object from out of the C<$self>
220 that is passed as the first argument to trigger, like so:
226 my ( $self, $value ) = @_;
227 my $attr = $self->meta->find_attribute_by_name('foo');
235 If you created a subtype and passed a parent that Moose didn't know
236 about, it simply ignored the parent. Now it automatically creates the
237 parent as a class type. This may not be what you want, but is less
240 You could declare a name with subtype such as "Foo!Bar". Moose would
241 accept this allowed, but if you used it in a parameterized type such
242 as "ArrayRef[Foo!Bar]" it wouldn't work. We now do some vetting on
243 names created via the sugar functions, so that they can only contain
244 alphanumerics, ":", and ".".
248 Methods created via an attribute can now fulfill a C<requires>
249 declaration for a role. Honestly we don't know why Stevan didn't make
250 this work originally, he was just insane or something.
252 Stack traces from inlined code will now report the line and file as
253 being in your class, as opposed to in Moose guts.
255 =head1 Version 0.62_02
257 When a class does not provide all of a role's required methods, the
258 error thrown now mentions all of the missing methods, as opposed to
259 just the first missing method.
261 Moose will no longer inline a constructor for your class unless it
262 inherits its constructor from Moose::Object, and will warn when it
263 doesn't inline. If you want to force inlining anyway, pass
264 C<< replace_constructor => 1 >> to C<make_immutable>.
266 If you want to get rid of the warning, pass C<< inline_constructor =>
271 Removed the (deprecated) C<make_immutable> keyword.
273 Removing an attribute from a class now also removes delegation
274 (C<handles>) methods installed for that attribute. This is correct
275 behavior, but if you were wrongly relying on it you might get bit.
279 Roles now add methods by calling C<add_method>, not
280 C<alias_method>. They make sure to always provide a method object,
281 which will be cloned internally. This means that it is now possible to
282 track the source of a method provided by a role, and even follow its
283 history through intermediate roles. This means that methods added by
284 a role now show up when looking at a class's method list/map.
286 Parameter and Union args are now sorted, this makes Int|Str the same
287 constraint as Str|Int. Also, incoming type constraint strings are
288 normalized to remove all whitespace differences. This is mostly for
289 internals and should not affect outside code.
291 L<Moose::Exporter> will no longer remove a subroutine that the
292 exporting package re-exports. Moose re-exports the Carp::confess
293 function, among others. The reasoning is that we cannot know whether
294 you have also explicitly imported those functions for your own use, so
295 we err on the safe side and always keep them.
299 C<Moose::init_meta> should now be called as a method.
301 New modules for extension writers, L<Moose::Exporter> and
302 L<Moose::Util::MetaRole>.
304 =head1 Version 0.55_01
306 Implemented metaclass traits (and wrote a recipe for it):
308 use Moose -traits => 'Foo'
310 This should make writing small Moose extensions a little
315 Fixed C<coerce> to accept anon types just like C<subtype> can.
318 coerce $some_anon_type => from 'Str' => via { ... };
322 Added C<BUILDARGS>, a new step in C<< Moose::Object->new() >>.
326 Fixed how the C<< is => (ro|rw) >> works with custom defined
327 C<reader>, C<writer> and C<accessor> options. See the below table for
330 is => ro, writer => _foo # turns into (reader => foo, writer => _foo)
331 is => rw, writer => _foo # turns into (reader => foo, writer => _foo)
332 is => rw, accessor => _foo # turns into (accessor => _foo)
333 is => ro, accessor => _foo # error, accesor is rw
337 The C<before/around/after> method modifiers now support regexp
338 matching of method names. NOTE: this only works for classes, it is
339 currently not supported in roles, but, ... patches welcome.
341 The C<has> keyword for roles now accepts the same array ref form that
342 L<Moose>.pm does for classes.
344 A trigger on a read-only attribute is no longer an error, as it's
345 useful to trigger off of the constructor.
347 Subtypes of parameterizable types now are parameterizable types
352 Fixed issue where C<DEMOLISHALL> was eating the value in C<$@>, and so
353 not working correctly. It still kind of eats them, but so does vanilla
358 Inherited attributes may now be extended without restriction on the
359 type ('isa', 'does').
361 The entire set of Moose::Meta::TypeConstraint::* classes were
362 refactored in this release. If you were relying on their internals you
363 should test your code carefully.
367 Documenting the use of '+name' with attributes that come from recently
368 composed roles. It makes sense, people are using it, and so why not
369 just officially support it.
371 The C<< Moose::Meta::Class->create >> method now supports roles.
373 It is now possible to make anonymous enum types by passing C<enum> an
374 array reference instead of the C<< enum $name => @values >>.
378 Added the C<make_immutable> keyword as a shortcut to calling
379 C<make_immutable> on the meta object. This eventually got removed!
381 Made C<< init_arg => undef >> work in Moose. This means "do not accept
382 a constructor parameter for this attribute".
384 Type errors now use the provided message. Prior to this release they
389 Moose is now a postmodern object system :)
391 The Role system was completely refactored. It is 100% backwards
392 compat, but the internals were totally changed. If you relied on the
393 internals then you are advised to test carefully.
395 Added method exclusion and aliasing for Roles in this release.
397 Added the L<Moose::Util::TypeConstraints::OptimizedConstraints>
400 Passing a list of values to an accessor (which is only expecting one
401 value) used to be silently ignored, now it throws an error.
405 Added parameterized types and did a pretty heavy refactoring of the
406 type constraint system.
408 Better framework extendability and better support for "making your own
411 =head1 Version 0.25 or before
413 Honestly, you shouldn't be using versions of Moose that are this old,
414 so many bug fixes and speed improvements have been made you would be
415 crazy to not upgrade.
417 Also, I am tired of going through the Changelog so I am stopping here,
418 if anyone would like to continue this please feel free.
422 Stevan Little E<lt>stevan@iinteractive.comE<gt>
424 =head1 COPYRIGHT AND LICENSE
426 Copyright 2009 by Infinity Interactive, Inc.
428 L<http://www.iinteractive.com>
430 This library is free software; you can redistribute it and/or modify
431 it under the same terms as Perl itself.