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>
67 See L<Moose::Meta::Attribute::Native> for the new documentation.
71 C<< use Moose -metaclass => 'Foo' >> now does alias resolution, just like
72 C<-traits> (and the C<metaclass> and C<traits> options to C<has>).
74 Added two functions C<meta_class_alias> and C<meta_attribute_alias> to
75 L<Moose::Util>, to simplify aliasing metaclasses and metatraits. This is
76 a wrapper around the old
78 package Moose::Meta::Class::Custom::Trait::FooTrait;
79 sub register_implementation { 'My::Meta::Trait' }
83 The C<alias> and C<excludes> role parameters have been renamed to C<-alias>
84 and C<-excludes>. The old names still work, but new code should use the new
85 names, and eventually the old ones will be deprecated and removed.
89 When an attribute generates I<no> accessors, we now warn. This is to help
90 users who forget the C<is> option. If you really do not want any accessors,
91 you can use C<< is => 'bare' >>. You can maintain back compat with older
92 versions of Moose by using something like:
94 ($Moose::VERSION >= 0.84 ? is => 'bare' : ())
96 When an accessor overwrites an existing method, we now warn. To work around
97 this warning (if you really must have this behavior), you can explicitly
98 remove the method before creating it as an accessor:
102 __PACKAGE__->meta->remove_method('foo');
108 When an unknown option is passed to C<has>, we now warn. You can silence
109 the warning by fixing your code. :)
111 The C<Role> type has been deprecated. On its own, it was useless,
112 since it just checked C<< $object->can('does') >>. If you were using
113 it as a parent type, just call C<role_type('Role::Name')> to create an
114 appropriate type instead.
118 C<use Moose::Exporter;> now imports C<strict> and C<warnings> into packages
123 C<DEMOLISHALL> and C<DEMOLISH> now receive an argument indicating whether or
124 not we are in global destruction.
128 Type constraints no longer run coercions for a value that already matches the
129 constraint. This may affect some (arguably buggy) edge case coercions that
130 rely on side effects in the C<via> clause.
134 L<Moose::Exporter> now accepts the C<-metaclass> option for easily
135 overriding the metaclass (without L<metaclass>). This works for classes
140 Added a C<duck_type> sugar function to L<Moose::Util::TypeConstraints>
141 to make integration with non-Moose classes easier. It simply checks if
142 C<< $obj->can() >> a list of methods.
144 A number of methods (mostly inherited from L<Class::MOP>) have been
145 renamed with a leading underscore to indicate their internal-ness. The
146 old method names will still work for a while, but will warn that the
147 method has been renamed. In a few cases, the method will be removed
148 entirely in the future. This may affect MooseX authors who were using
153 Calling C<subtype> with a name as the only argument now throws an
154 exception. If you want an anonymous subtype do:
156 my $subtype = subtype as 'Foo';
158 This is related to the changes in version 0.71_01.
160 The C<is_needed> method in L<Moose::Meta::Method::Destructor> is now
161 only usable as a class method. Previously, it worked as a class or
162 object method, with a different internal implementation for each
165 The internals of making a class immutable changed a lot in Class::MOP
166 0.78_02, and Moose's internals have changed along with it. The
167 external C<< $metaclass->make_immutable >> method still works the same
172 A mutable class accepted C<< Foo->new(undef) >> without complaint,
173 while an immutable class would blow up with an unhelpful error. Now,
174 in both cases we throw a helpful error instead.
176 This "feature" was originally added to allow for cases such as this:
184 return My::Class->new($args);
186 But we decided this is a bad idea and a little too magical, because it
187 can easily mask real errors.
189 =head1 Version 0.71_01
191 Calling C<type> or C<subtype> without the sugar helpers (C<as>,
192 C<where>, C<message>) is now deprecated.
194 As a side effect, this meant we ended up using Perl prototypes on
195 C<as>, and code like this will no longer work:
197 use Moose::Util::TypeConstraints;
198 use Declare::Constraints::Simple -All;
200 subtype 'ArrayOfInts'
202 => IsArrayRef(IsInt);
204 Instead it must be changed to this:
209 where => IsArrayRef(IsInt)
213 If you want to maintain backwards compat with older versions of Moose,
214 you must explicitly test Moose's C<VERSION>:
216 if ( Moose->VERSION < 0.71_01 ) {
217 subtype 'ArrayOfInts'
219 => IsArrayRef(IsInt);
225 where => IsArrayRef(IsInt)
232 We no longer pass the meta-attribute object as a final argument to
233 triggers. This actually changed for inlined code a while back, but the
234 non-inlined version and the docs were still out of date.
236 If by some chance you actually used this feature, the workaround is
237 simple. You fetch the attribute object from out of the C<$self>
238 that is passed as the first argument to trigger, like so:
244 my ( $self, $value ) = @_;
245 my $attr = $self->meta->find_attribute_by_name('foo');
253 If you created a subtype and passed a parent that Moose didn't know
254 about, it simply ignored the parent. Now it automatically creates the
255 parent as a class type. This may not be what you want, but is less
258 You could declare a name with subtype such as "Foo!Bar". Moose would
259 accept this allowed, but if you used it in a parameterized type such
260 as "ArrayRef[Foo!Bar]" it wouldn't work. We now do some vetting on
261 names created via the sugar functions, so that they can only contain
262 alphanumerics, ":", and ".".
266 Methods created via an attribute can now fulfill a C<requires>
267 declaration for a role. Honestly we don't know why Stevan didn't make
268 this work originally, he was just insane or something.
270 Stack traces from inlined code will now report the line and file as
271 being in your class, as opposed to in Moose guts.
273 =head1 Version 0.62_02
275 When a class does not provide all of a role's required methods, the
276 error thrown now mentions all of the missing methods, as opposed to
277 just the first missing method.
279 Moose will no longer inline a constructor for your class unless it
280 inherits its constructor from Moose::Object, and will warn when it
281 doesn't inline. If you want to force inlining anyway, pass
282 C<< replace_constructor => 1 >> to C<make_immutable>.
284 If you want to get rid of the warning, pass C<< inline_constructor =>
289 Removed the (deprecated) C<make_immutable> keyword.
291 Removing an attribute from a class now also removes delegation
292 (C<handles>) methods installed for that attribute. This is correct
293 behavior, but if you were wrongly relying on it you might get bit.
297 Roles now add methods by calling C<add_method>, not
298 C<alias_method>. They make sure to always provide a method object,
299 which will be cloned internally. This means that it is now possible to
300 track the source of a method provided by a role, and even follow its
301 history through intermediate roles. This means that methods added by
302 a role now show up when looking at a class's method list/map.
304 Parameter and Union args are now sorted, this makes Int|Str the same
305 constraint as Str|Int. Also, incoming type constraint strings are
306 normalized to remove all whitespace differences. This is mostly for
307 internals and should not affect outside code.
309 L<Moose::Exporter> will no longer remove a subroutine that the
310 exporting package re-exports. Moose re-exports the Carp::confess
311 function, among others. The reasoning is that we cannot know whether
312 you have also explicitly imported those functions for your own use, so
313 we err on the safe side and always keep them.
317 C<Moose::init_meta> should now be called as a method.
319 New modules for extension writers, L<Moose::Exporter> and
320 L<Moose::Util::MetaRole>.
322 =head1 Version 0.55_01
324 Implemented metaclass traits (and wrote a recipe for it):
326 use Moose -traits => 'Foo'
328 This should make writing small Moose extensions a little
333 Fixed C<coerce> to accept anon types just like C<subtype> can.
336 coerce $some_anon_type => from 'Str' => via { ... };
340 Added C<BUILDARGS>, a new step in C<< Moose::Object->new() >>.
344 Fixed how the C<< is => (ro|rw) >> works with custom defined
345 C<reader>, C<writer> and C<accessor> options. See the below table for
348 is => ro, writer => _foo # turns into (reader => foo, writer => _foo)
349 is => rw, writer => _foo # turns into (reader => foo, writer => _foo)
350 is => rw, accessor => _foo # turns into (accessor => _foo)
351 is => ro, accessor => _foo # error, accesor is rw
355 The C<before/around/after> method modifiers now support regexp
356 matching of method names. NOTE: this only works for classes, it is
357 currently not supported in roles, but, ... patches welcome.
359 The C<has> keyword for roles now accepts the same array ref form that
360 L<Moose>.pm does for classes.
362 A trigger on a read-only attribute is no longer an error, as it's
363 useful to trigger off of the constructor.
365 Subtypes of parameterizable types now are parameterizable types
370 Fixed issue where C<DEMOLISHALL> was eating the value in C<$@>, and so
371 not working correctly. It still kind of eats them, but so does vanilla
376 Inherited attributes may now be extended without restriction on the
377 type ('isa', 'does').
379 The entire set of Moose::Meta::TypeConstraint::* classes were
380 refactored in this release. If you were relying on their internals you
381 should test your code carefully.
385 Documenting the use of '+name' with attributes that come from recently
386 composed roles. It makes sense, people are using it, and so why not
387 just officially support it.
389 The C<< Moose::Meta::Class->create >> method now supports roles.
391 It is now possible to make anonymous enum types by passing C<enum> an
392 array reference instead of the C<< enum $name => @values >>.
396 Added the C<make_immutable> keyword as a shortcut to calling
397 C<make_immutable> on the meta object. This eventually got removed!
399 Made C<< init_arg => undef >> work in Moose. This means "do not accept
400 a constructor parameter for this attribute".
402 Type errors now use the provided message. Prior to this release they
407 Moose is now a postmodern object system :)
409 The Role system was completely refactored. It is 100% backwards
410 compat, but the internals were totally changed. If you relied on the
411 internals then you are advised to test carefully.
413 Added method exclusion and aliasing for Roles in this release.
415 Added the L<Moose::Util::TypeConstraints::OptimizedConstraints>
418 Passing a list of values to an accessor (which is only expecting one
419 value) used to be silently ignored, now it throws an error.
423 Added parameterized types and did a pretty heavy refactoring of the
424 type constraint system.
426 Better framework extendability and better support for "making your own
429 =head1 Version 0.25 or before
431 Honestly, you shouldn't be using versions of Moose that are this old,
432 so many bug fixes and speed improvements have been made you would be
433 crazy to not upgrade.
435 Also, I am tired of going through the Changelog so I am stopping here,
436 if anyone would like to continue this please feel free.
440 Stevan Little E<lt>stevan@iinteractive.comE<gt>
442 =head1 COPYRIGHT AND LICENSE
444 Copyright 2009 by Infinity Interactive, Inc.
446 L<http://www.iinteractive.com>
448 This library is free software; you can redistribute it and/or modify
449 it under the same terms as Perl itself.