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>
65 =item Several new helpers from L<List::Util> and L<List::MoreUtils> were added
67 In particular, we now have C<reduce>, C<shuffle>, C<uniq>, and C<natatime>.
71 See L<Moose::Meta::Attribute::Native> for the new documentation.
73 C<< use Moose -metaclass => 'Foo' >> now does alias resolution, just like
74 C<-traits> (and the C<metaclass> and C<traits> options to C<has>).
76 Added two functions C<meta_class_alias> and C<meta_attribute_alias> to
77 L<Moose::Util>, to simplify aliasing metaclasses and metatraits. This is
78 a wrapper around the old
80 package Moose::Meta::Class::Custom::Trait::FooTrait;
81 sub register_implementation { 'My::Meta::Trait' }
85 The C<alias> and C<excludes> role parameters have been renamed to C<-alias>
86 and C<-excludes>. The old names still work, but new code should use the new
87 names, and eventually the old ones will be deprecated and removed.
91 When an attribute generates I<no> accessors, we now warn. This is to help
92 users who forget the C<is> option. If you really do not want any accessors,
93 you can use C<< is => 'bare' >>. You can maintain back compat with older
94 versions of Moose by using something like:
96 ($Moose::VERSION >= 0.84 ? is => 'bare' : ())
98 When an accessor overwrites an existing method, we now warn. To work around
99 this warning (if you really must have this behavior), you can explicitly
100 remove the method before creating it as an accessor:
104 __PACKAGE__->meta->remove_method('foo');
110 When an unknown option is passed to C<has>, we now warn. You can silence
111 the warning by fixing your code. :)
113 The C<Role> type has been deprecated. On its own, it was useless,
114 since it just checked C<< $object->can('does') >>. If you were using
115 it as a parent type, just call C<role_type('Role::Name')> to create an
116 appropriate type instead.
120 C<use Moose::Exporter;> now imports C<strict> and C<warnings> into packages
125 C<DEMOLISHALL> and C<DEMOLISH> now receive an argument indicating whether or
126 not we are in global destruction.
130 Type constraints no longer run coercions for a value that already matches the
131 constraint. This may affect some (arguably buggy) edge case coercions that
132 rely on side effects in the C<via> clause.
136 L<Moose::Exporter> now accepts the C<-metaclass> option for easily
137 overriding the metaclass (without L<metaclass>). This works for classes
142 Added a C<duck_type> sugar function to L<Moose::Util::TypeConstraints>
143 to make integration with non-Moose classes easier. It simply checks if
144 C<< $obj->can() >> a list of methods.
146 A number of methods (mostly inherited from L<Class::MOP>) have been
147 renamed with a leading underscore to indicate their internal-ness. The
148 old method names will still work for a while, but will warn that the
149 method has been renamed. In a few cases, the method will be removed
150 entirely in the future. This may affect MooseX authors who were using
155 Calling C<subtype> with a name as the only argument now throws an
156 exception. If you want an anonymous subtype do:
158 my $subtype = subtype as 'Foo';
160 This is related to the changes in version 0.71_01.
162 The C<is_needed> method in L<Moose::Meta::Method::Destructor> is now
163 only usable as a class method. Previously, it worked as a class or
164 object method, with a different internal implementation for each
167 The internals of making a class immutable changed a lot in Class::MOP
168 0.78_02, and Moose's internals have changed along with it. The
169 external C<< $metaclass->make_immutable >> method still works the same
174 A mutable class accepted C<< Foo->new(undef) >> without complaint,
175 while an immutable class would blow up with an unhelpful error. Now,
176 in both cases we throw a helpful error instead.
178 This "feature" was originally added to allow for cases such as this:
186 return My::Class->new($args);
188 But we decided this is a bad idea and a little too magical, because it
189 can easily mask real errors.
191 =head1 Version 0.71_01
193 Calling C<type> or C<subtype> without the sugar helpers (C<as>,
194 C<where>, C<message>) is now deprecated.
196 As a side effect, this meant we ended up using Perl prototypes on
197 C<as>, and code like this will no longer work:
199 use Moose::Util::TypeConstraints;
200 use Declare::Constraints::Simple -All;
202 subtype 'ArrayOfInts'
204 => IsArrayRef(IsInt);
206 Instead it must be changed to this:
211 where => IsArrayRef(IsInt)
215 If you want to maintain backwards compat with older versions of Moose,
216 you must explicitly test Moose's C<VERSION>:
218 if ( Moose->VERSION < 0.71_01 ) {
219 subtype 'ArrayOfInts'
221 => IsArrayRef(IsInt);
227 where => IsArrayRef(IsInt)
234 We no longer pass the meta-attribute object as a final argument to
235 triggers. This actually changed for inlined code a while back, but the
236 non-inlined version and the docs were still out of date.
238 If by some chance you actually used this feature, the workaround is
239 simple. You fetch the attribute object from out of the C<$self>
240 that is passed as the first argument to trigger, like so:
246 my ( $self, $value ) = @_;
247 my $attr = $self->meta->find_attribute_by_name('foo');
255 If you created a subtype and passed a parent that Moose didn't know
256 about, it simply ignored the parent. Now it automatically creates the
257 parent as a class type. This may not be what you want, but is less
260 You could declare a name with subtype such as "Foo!Bar". Moose would
261 accept this allowed, but if you used it in a parameterized type such
262 as "ArrayRef[Foo!Bar]" it wouldn't work. We now do some vetting on
263 names created via the sugar functions, so that they can only contain
264 alphanumerics, ":", and ".".
268 Methods created via an attribute can now fulfill a C<requires>
269 declaration for a role. Honestly we don't know why Stevan didn't make
270 this work originally, he was just insane or something.
272 Stack traces from inlined code will now report the line and file as
273 being in your class, as opposed to in Moose guts.
275 =head1 Version 0.62_02
277 When a class does not provide all of a role's required methods, the
278 error thrown now mentions all of the missing methods, as opposed to
279 just the first missing method.
281 Moose will no longer inline a constructor for your class unless it
282 inherits its constructor from Moose::Object, and will warn when it
283 doesn't inline. If you want to force inlining anyway, pass
284 C<< replace_constructor => 1 >> to C<make_immutable>.
286 If you want to get rid of the warning, pass C<< inline_constructor =>
291 Removed the (deprecated) C<make_immutable> keyword.
293 Removing an attribute from a class now also removes delegation
294 (C<handles>) methods installed for that attribute. This is correct
295 behavior, but if you were wrongly relying on it you might get bit.
299 Roles now add methods by calling C<add_method>, not
300 C<alias_method>. They make sure to always provide a method object,
301 which will be cloned internally. This means that it is now possible to
302 track the source of a method provided by a role, and even follow its
303 history through intermediate roles. This means that methods added by
304 a role now show up when looking at a class's method list/map.
306 Parameter and Union args are now sorted, this makes Int|Str the same
307 constraint as Str|Int. Also, incoming type constraint strings are
308 normalized to remove all whitespace differences. This is mostly for
309 internals and should not affect outside code.
311 L<Moose::Exporter> will no longer remove a subroutine that the
312 exporting package re-exports. Moose re-exports the Carp::confess
313 function, among others. The reasoning is that we cannot know whether
314 you have also explicitly imported those functions for your own use, so
315 we err on the safe side and always keep them.
319 C<Moose::init_meta> should now be called as a method.
321 New modules for extension writers, L<Moose::Exporter> and
322 L<Moose::Util::MetaRole>.
324 =head1 Version 0.55_01
326 Implemented metaclass traits (and wrote a recipe for it):
328 use Moose -traits => 'Foo'
330 This should make writing small Moose extensions a little
335 Fixed C<coerce> to accept anon types just like C<subtype> can.
338 coerce $some_anon_type => from 'Str' => via { ... };
342 Added C<BUILDARGS>, a new step in C<< Moose::Object->new() >>.
346 Fixed how the C<< is => (ro|rw) >> works with custom defined
347 C<reader>, C<writer> and C<accessor> options. See the below table for
350 is => ro, writer => _foo # turns into (reader => foo, writer => _foo)
351 is => rw, writer => _foo # turns into (reader => foo, writer => _foo)
352 is => rw, accessor => _foo # turns into (accessor => _foo)
353 is => ro, accessor => _foo # error, accesor is rw
357 The C<before/around/after> method modifiers now support regexp
358 matching of method names. NOTE: this only works for classes, it is
359 currently not supported in roles, but, ... patches welcome.
361 The C<has> keyword for roles now accepts the same array ref form that
362 L<Moose>.pm does for classes.
364 A trigger on a read-only attribute is no longer an error, as it's
365 useful to trigger off of the constructor.
367 Subtypes of parameterizable types now are parameterizable types
372 Fixed issue where C<DEMOLISHALL> was eating the value in C<$@>, and so
373 not working correctly. It still kind of eats them, but so does vanilla
378 Inherited attributes may now be extended without restriction on the
379 type ('isa', 'does').
381 The entire set of Moose::Meta::TypeConstraint::* classes were
382 refactored in this release. If you were relying on their internals you
383 should test your code carefully.
387 Documenting the use of '+name' with attributes that come from recently
388 composed roles. It makes sense, people are using it, and so why not
389 just officially support it.
391 The C<< Moose::Meta::Class->create >> method now supports roles.
393 It is now possible to make anonymous enum types by passing C<enum> an
394 array reference instead of the C<< enum $name => @values >>.
398 Added the C<make_immutable> keyword as a shortcut to calling
399 C<make_immutable> on the meta object. This eventually got removed!
401 Made C<< init_arg => undef >> work in Moose. This means "do not accept
402 a constructor parameter for this attribute".
404 Type errors now use the provided message. Prior to this release they
409 Moose is now a postmodern object system :)
411 The Role system was completely refactored. It is 100% backwards
412 compat, but the internals were totally changed. If you relied on the
413 internals then you are advised to test carefully.
415 Added method exclusion and aliasing for Roles in this release.
417 Added the L<Moose::Util::TypeConstraints::OptimizedConstraints>
420 Passing a list of values to an accessor (which is only expecting one
421 value) used to be silently ignored, now it throws an error.
425 Added parameterized types and did a pretty heavy refactoring of the
426 type constraint system.
428 Better framework extendability and better support for "making your own
431 =head1 Version 0.25 or before
433 Honestly, you shouldn't be using versions of Moose that are this old,
434 so many bug fixes and speed improvements have been made you would be
435 crazy to not upgrade.
437 Also, I am tired of going through the Changelog so I am stopping here,
438 if anyone would like to continue this please feel free.
442 Stevan Little E<lt>stevan@iinteractive.comE<gt>
444 =head1 COPYRIGHT AND LICENSE
446 Copyright 2009 by Infinity Interactive, Inc.
448 L<http://www.iinteractive.com>
450 This library is free software; you can redistribute it and/or modify
451 it under the same terms as Perl itself.