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
19 =head1 Version 0.89_01
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.
75 C<< use Moose -metaclass => 'Foo' >> now does alias resolution, just like
76 C<-traits> (and the C<metaclass> and C<traits> options to C<has>).
78 Added two functions C<meta_class_alias> and C<meta_attribute_alias> to
79 L<Moose::Util>, to simplify aliasing metaclasses and metatraits. This is
80 a wrapper around the old
82 package Moose::Meta::Class::Custom::Trait::FooTrait;
83 sub register_implementation { 'My::Meta::Trait' }
87 The C<alias> and C<excludes> role parameters have been renamed to C<-alias>
88 and C<-excludes>. The old names still work, but new code should use the new
89 names, and eventually the old ones will be deprecated and removed.
93 When an attribute generates I<no> accessors, we now warn. This is to help
94 users who forget the C<is> option. If you really do not want any accessors,
95 you can use C<< is => 'bare' >>. You can maintain back compat with older
96 versions of Moose by using something like:
98 ($Moose::VERSION >= 0.84 ? is => 'bare' : ())
100 When an accessor overwrites an existing method, we now warn. To work around
101 this warning (if you really must have this behavior), you can explicitly
102 remove the method before creating it as an accessor:
106 __PACKAGE__->meta->remove_method('foo');
112 When an unknown option is passed to C<has>, we now warn. You can silence
113 the warning by fixing your code. :)
115 The C<Role> type has been deprecated. On its own, it was useless,
116 since it just checked C<< $object->can('does') >>. If you were using
117 it as a parent type, just call C<role_type('Role::Name')> to create an
118 appropriate type instead.
122 C<use Moose::Exporter;> now imports C<strict> and C<warnings> into packages
127 C<DEMOLISHALL> and C<DEMOLISH> now receive an argument indicating whether or
128 not we are in global destruction.
132 Type constraints no longer run coercions for a value that already matches the
133 constraint. This may affect some (arguably buggy) edge case coercions that
134 rely on side effects in the C<via> clause.
138 L<Moose::Exporter> now accepts the C<-metaclass> option for easily
139 overriding the metaclass (without L<metaclass>). This works for classes
144 Added a C<duck_type> sugar function to L<Moose::Util::TypeConstraints>
145 to make integration with non-Moose classes easier. It simply checks if
146 C<< $obj->can() >> a list of methods.
148 A number of methods (mostly inherited from L<Class::MOP>) have been
149 renamed with a leading underscore to indicate their internal-ness. The
150 old method names will still work for a while, but will warn that the
151 method has been renamed. In a few cases, the method will be removed
152 entirely in the future. This may affect MooseX authors who were using
157 Calling C<subtype> with a name as the only argument now throws an
158 exception. If you want an anonymous subtype do:
160 my $subtype = subtype as 'Foo';
162 This is related to the changes in version 0.71_01.
164 The C<is_needed> method in L<Moose::Meta::Method::Destructor> is now
165 only usable as a class method. Previously, it worked as a class or
166 object method, with a different internal implementation for each
169 The internals of making a class immutable changed a lot in Class::MOP
170 0.78_02, and Moose's internals have changed along with it. The
171 external C<< $metaclass->make_immutable >> method still works the same
176 A mutable class accepted C<< Foo->new(undef) >> without complaint,
177 while an immutable class would blow up with an unhelpful error. Now,
178 in both cases we throw a helpful error instead.
180 This "feature" was originally added to allow for cases such as this:
188 return My::Class->new($args);
190 But we decided this is a bad idea and a little too magical, because it
191 can easily mask real errors.
193 =head1 Version 0.71_01
195 Calling C<type> or C<subtype> without the sugar helpers (C<as>,
196 C<where>, C<message>) is now deprecated.
198 As a side effect, this meant we ended up using Perl prototypes on
199 C<as>, and code like this will no longer work:
201 use Moose::Util::TypeConstraints;
202 use Declare::Constraints::Simple -All;
204 subtype 'ArrayOfInts'
206 => IsArrayRef(IsInt);
208 Instead it must be changed to this:
213 where => IsArrayRef(IsInt)
217 If you want to maintain backwards compat with older versions of Moose,
218 you must explicitly test Moose's C<VERSION>:
220 if ( Moose->VERSION < 0.71_01 ) {
221 subtype 'ArrayOfInts'
223 => IsArrayRef(IsInt);
229 where => IsArrayRef(IsInt)
236 We no longer pass the meta-attribute object as a final argument to
237 triggers. This actually changed for inlined code a while back, but the
238 non-inlined version and the docs were still out of date.
240 If by some chance you actually used this feature, the workaround is
241 simple. You fetch the attribute object from out of the C<$self>
242 that is passed as the first argument to trigger, like so:
248 my ( $self, $value ) = @_;
249 my $attr = $self->meta->find_attribute_by_name('foo');
257 If you created a subtype and passed a parent that Moose didn't know
258 about, it simply ignored the parent. Now it automatically creates the
259 parent as a class type. This may not be what you want, but is less
262 You could declare a name with subtype such as "Foo!Bar". Moose would
263 accept this allowed, but if you used it in a parameterized type such
264 as "ArrayRef[Foo!Bar]" it wouldn't work. We now do some vetting on
265 names created via the sugar functions, so that they can only contain
266 alphanumerics, ":", and ".".
270 Methods created via an attribute can now fulfill a C<requires>
271 declaration for a role. Honestly we don't know why Stevan didn't make
272 this work originally, he was just insane or something.
274 Stack traces from inlined code will now report the line and file as
275 being in your class, as opposed to in Moose guts.
277 =head1 Version 0.62_02
279 When a class does not provide all of a role's required methods, the
280 error thrown now mentions all of the missing methods, as opposed to
281 just the first missing method.
283 Moose will no longer inline a constructor for your class unless it
284 inherits its constructor from Moose::Object, and will warn when it
285 doesn't inline. If you want to force inlining anyway, pass
286 C<< replace_constructor => 1 >> to C<make_immutable>.
288 If you want to get rid of the warning, pass C<< inline_constructor =>
293 Removed the (deprecated) C<make_immutable> keyword.
295 Removing an attribute from a class now also removes delegation
296 (C<handles>) methods installed for that attribute. This is correct
297 behavior, but if you were wrongly relying on it you might get bit.
301 Roles now add methods by calling C<add_method>, not
302 C<alias_method>. They make sure to always provide a method object,
303 which will be cloned internally. This means that it is now possible to
304 track the source of a method provided by a role, and even follow its
305 history through intermediate roles. This means that methods added by
306 a role now show up when looking at a class's method list/map.
308 Parameter and Union args are now sorted, this makes Int|Str the same
309 constraint as Str|Int. Also, incoming type constraint strings are
310 normalized to remove all whitespace differences. This is mostly for
311 internals and should not affect outside code.
313 L<Moose::Exporter> will no longer remove a subroutine that the
314 exporting package re-exports. Moose re-exports the Carp::confess
315 function, among others. The reasoning is that we cannot know whether
316 you have also explicitly imported those functions for your own use, so
317 we err on the safe side and always keep them.
321 C<Moose::init_meta> should now be called as a method.
323 New modules for extension writers, L<Moose::Exporter> and
324 L<Moose::Util::MetaRole>.
326 =head1 Version 0.55_01
328 Implemented metaclass traits (and wrote a recipe for it):
330 use Moose -traits => 'Foo'
332 This should make writing small Moose extensions a little
337 Fixed C<coerce> to accept anon types just like C<subtype> can.
340 coerce $some_anon_type => from 'Str' => via { ... };
344 Added C<BUILDARGS>, a new step in C<< Moose::Object->new() >>.
348 Fixed how the C<< is => (ro|rw) >> works with custom defined
349 C<reader>, C<writer> and C<accessor> options. See the below table for
352 is => ro, writer => _foo # turns into (reader => foo, writer => _foo)
353 is => rw, writer => _foo # turns into (reader => foo, writer => _foo)
354 is => rw, accessor => _foo # turns into (accessor => _foo)
355 is => ro, accessor => _foo # error, accesor is rw
359 The C<before/around/after> method modifiers now support regexp
360 matching of method names. NOTE: this only works for classes, it is
361 currently not supported in roles, but, ... patches welcome.
363 The C<has> keyword for roles now accepts the same array ref form that
364 L<Moose>.pm does for classes.
366 A trigger on a read-only attribute is no longer an error, as it's
367 useful to trigger off of the constructor.
369 Subtypes of parameterizable types now are parameterizable types
374 Fixed issue where C<DEMOLISHALL> was eating the value in C<$@>, and so
375 not working correctly. It still kind of eats them, but so does vanilla
380 Inherited attributes may now be extended without restriction on the
381 type ('isa', 'does').
383 The entire set of Moose::Meta::TypeConstraint::* classes were
384 refactored in this release. If you were relying on their internals you
385 should test your code carefully.
389 Documenting the use of '+name' with attributes that come from recently
390 composed roles. It makes sense, people are using it, and so why not
391 just officially support it.
393 The C<< Moose::Meta::Class->create >> method now supports roles.
395 It is now possible to make anonymous enum types by passing C<enum> an
396 array reference instead of the C<< enum $name => @values >>.
400 Added the C<make_immutable> keyword as a shortcut to calling
401 C<make_immutable> on the meta object. This eventually got removed!
403 Made C<< init_arg => undef >> work in Moose. This means "do not accept
404 a constructor parameter for this attribute".
406 Type errors now use the provided message. Prior to this release they
411 Moose is now a postmodern object system :)
413 The Role system was completely refactored. It is 100% backwards
414 compat, but the internals were totally changed. If you relied on the
415 internals then you are advised to test carefully.
417 Added method exclusion and aliasing for Roles in this release.
419 Added the L<Moose::Util::TypeConstraints::OptimizedConstraints>
422 Passing a list of values to an accessor (which is only expecting one
423 value) used to be silently ignored, now it throws an error.
427 Added parameterized types and did a pretty heavy refactoring of the
428 type constraint system.
430 Better framework extendability and better support for "making your own
433 =head1 Version 0.25 or before
435 Honestly, you shouldn't be using versions of Moose that are this old,
436 so many bug fixes and speed improvements have been made you would be
437 crazy to not upgrade.
439 Also, I am tired of going through the Changelog so I am stopping here,
440 if anyone would like to continue this please feel free.
444 Stevan Little E<lt>stevan@iinteractive.comE<gt>
446 =head1 COPYRIGHT AND LICENSE
448 Copyright 2009 by Infinity Interactive, Inc.
450 L<http://www.iinteractive.com>
452 This library is free software; you can redistribute it and/or modify
453 it under the same terms as Perl itself.