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 Calling $object->new() is no longer deprecated
25 We decided to undeprecate this. Now it just works.
27 =item C<get_attribute_map> is deprecated
29 The metaclass method C<get_attribute_map> was never meant to be public.
30 These were deprecated, and the work around if you still need the
31 functionality they provided is to iterate over the list of attribute
34 my %fields = map { $_ => $meta->get_attribute($_) } $meta->get_attribute_list;
42 =item Added Native delegation for Code refs
44 See L<Moose::Meta::Attribute::Native::Trait::Code> for details.
46 =item Calling $object->new() is deprecated
48 Moose has long supported this, but it's never really been documented, and we
49 don't think this is a good practice. If you want to construct an object from
50 an existing object, you should provide some sort of alternate constructor like
51 C<< $object->clone >>.
53 Calling C<< $object->new >> now issues a warning, and will be an error in a
56 =item Moose no longer warns if you call C<make_immutable> for a class with mutable ancestors
58 While in theory this is a good thing to warn about, we found so many
59 exceptions to this that doing this properly became quite problematic.
63 =head1 Version 0.89_02
67 =item New Native delegation methods from L<List::Util> and L<List::MoreUtils>
69 In particular, we now have C<reduce>, C<shuffle>, C<uniq>, and C<natatime>.
71 =item The Moose::Exporter with_caller feature is now deprecated
73 Use C<with_meta> instead. The C<with_caller> option will start warning in a
76 =item Moose now warns if you call C<make_immutable> for a class with mutable ancestors
78 This is dangerous because modifying a class after a subclass has been
79 immutabilized will lead to incorrect results in the subclass, due to inlining,
80 caching, etc. This occasionally happens accidentally, when a class loads one
81 of its subclasses in the middle of its class definition, so pointing out that
82 this may cause issues should be helpful. Metaclasses (classes that inherit
83 from L<Class::MOP::Object>) are currently exempt from this check, since at the
84 moment we aren't very consistent about which metaclasses we immutabilize.
86 =item C<enum> and C<duck_type> now take arrayrefs for all forms
88 Previously, calling these functions with a list would take the first element of
89 the list as the type constraint name, and use the remainder as the enum values
90 or method names. This makes the interface inconsistent with the anon-type forms
91 of these functions (which must take an arrayref), and a free-form list where
92 the first value is sometimes special is hard to validate (and harder to give
93 reasonable error messages for). These functions have been changed to take
94 arrayrefs in all their forms - so, C<< enum 'My::Type' => [qw(foo bar)] >> is
95 now the preferred way to create an enum type constraint. The old syntax still
96 works for now, but it will hopefully be deprecated and removed in a future
101 =head1 Version 0.89_01
103 L<Moose::Meta::Attribute::Native> has been moved into the Moose core from
104 L<MooseX::AttributeHelpers>. Major changes include:
108 =item C<traits>, not C<metaclass>
110 Method providers are only available via traits.
112 =item C<handles>, not C<provides> or C<curries>
114 The C<provides> syntax was like core Moose C<< handles => HASHREF >>
115 syntax, but with the keys and values reversed. This was confusing,
116 and AttributeHelpers now uses C<< handles => HASHREF >> in a way that
117 should be intuitive to anyone already familiar with how it is used for
120 The C<curries> functionality provided by AttributeHelpers has been
121 generalized to apply to all cases of C<< handles => HASHREF >>, though
122 not every piece of functionality has been ported (currying with a
123 CODEREF is not supported).
125 =item C<empty> is now C<is_empty>, and means empty, not non-empty
127 Previously, the C<empty> method provided by Arrays and Hashes returned true if
128 the attribute was B<not> empty (no elements). Now it returns true if the
129 attribute B<is> empty. It was also renamed to C<is_empty>, to reflect this.
131 =item C<find> was renamed to C<first>, and C<first> and C<last> were removed
133 L<List::Util> refers to the functionality that we used to provide under C<find>
134 as L<first|List::Util/first>, so that will likely be more familiar (and will
135 fit in better if we decide to add more List::Util functions). C<first> and
136 C<last> were removed, since their functionality is easily duplicated with
139 =item Helpers that take a coderef of one argument now use C<$_>
141 Subroutines passed as the first argument to C<first>, C<map>, and C<grep> now
142 receive their argument in C<$_> rather than as a parameter to the subroutine.
143 Helpers that take a coderef of two or more arguments remain using the argument
144 list (there are technical limitations to using C<$a> and C<$b> like C<sort>
147 See L<Moose::Meta::Attribute::Native> for the new documentation.
151 The C<alias> and C<excludes> role parameters have been renamed to C<-alias>
152 and C<-excludes>. The old names still work, but new code should use the new
153 names, and eventually the old ones will be deprecated and removed.
157 C<< use Moose -metaclass => 'Foo' >> now does alias resolution, just like
158 C<-traits> (and the C<metaclass> and C<traits> options to C<has>).
160 Added two functions C<meta_class_alias> and C<meta_attribute_alias> to
161 L<Moose::Util>, to simplify aliasing metaclasses and metatraits. This is
162 a wrapper around the old
164 package Moose::Meta::Class::Custom::Trait::FooTrait;
165 sub register_implementation { 'My::Meta::Trait' }
171 When an attribute generates I<no> accessors, we now warn. This is to help
172 users who forget the C<is> option. If you really do not want any accessors,
173 you can use C<< is => 'bare' >>. You can maintain back compat with older
174 versions of Moose by using something like:
176 ($Moose::VERSION >= 0.84 ? is => 'bare' : ())
178 When an accessor overwrites an existing method, we now warn. To work around
179 this warning (if you really must have this behavior), you can explicitly
180 remove the method before creating it as an accessor:
184 __PACKAGE__->meta->remove_method('foo');
190 When an unknown option is passed to C<has>, we now warn. You can silence
191 the warning by fixing your code. :)
193 The C<Role> type has been deprecated. On its own, it was useless,
194 since it just checked C<< $object->can('does') >>. If you were using
195 it as a parent type, just call C<role_type('Role::Name')> to create an
196 appropriate type instead.
200 C<use Moose::Exporter;> now imports C<strict> and C<warnings> into packages
205 C<DEMOLISHALL> and C<DEMOLISH> now receive an argument indicating whether or
206 not we are in global destruction.
210 Type constraints no longer run coercions for a value that already matches the
211 constraint. This may affect some (arguably buggy) edge case coercions that
212 rely on side effects in the C<via> clause.
216 L<Moose::Exporter> now accepts the C<-metaclass> option for easily
217 overriding the metaclass (without L<metaclass>). This works for classes
222 Added a C<duck_type> sugar function to L<Moose::Util::TypeConstraints>
223 to make integration with non-Moose classes easier. It simply checks if
224 C<< $obj->can() >> a list of methods.
226 A number of methods (mostly inherited from L<Class::MOP>) have been
227 renamed with a leading underscore to indicate their internal-ness. The
228 old method names will still work for a while, but will warn that the
229 method has been renamed. In a few cases, the method will be removed
230 entirely in the future. This may affect MooseX authors who were using
235 Calling C<subtype> with a name as the only argument now throws an
236 exception. If you want an anonymous subtype do:
238 my $subtype = subtype as 'Foo';
240 This is related to the changes in version 0.71_01.
242 The C<is_needed> method in L<Moose::Meta::Method::Destructor> is now
243 only usable as a class method. Previously, it worked as a class or
244 object method, with a different internal implementation for each
247 The internals of making a class immutable changed a lot in Class::MOP
248 0.78_02, and Moose's internals have changed along with it. The
249 external C<< $metaclass->make_immutable >> method still works the same
254 A mutable class accepted C<< Foo->new(undef) >> without complaint,
255 while an immutable class would blow up with an unhelpful error. Now,
256 in both cases we throw a helpful error instead.
258 This "feature" was originally added to allow for cases such as this:
266 return My::Class->new($args);
268 But we decided this is a bad idea and a little too magical, because it
269 can easily mask real errors.
271 =head1 Version 0.71_01
273 Calling C<type> or C<subtype> without the sugar helpers (C<as>,
274 C<where>, C<message>) is now deprecated.
276 As a side effect, this meant we ended up using Perl prototypes on
277 C<as>, and code like this will no longer work:
279 use Moose::Util::TypeConstraints;
280 use Declare::Constraints::Simple -All;
282 subtype 'ArrayOfInts'
284 => IsArrayRef(IsInt);
286 Instead it must be changed to this:
291 where => IsArrayRef(IsInt)
295 If you want to maintain backwards compat with older versions of Moose,
296 you must explicitly test Moose's C<VERSION>:
298 if ( Moose->VERSION < 0.71_01 ) {
299 subtype 'ArrayOfInts'
301 => IsArrayRef(IsInt);
307 where => IsArrayRef(IsInt)
314 We no longer pass the meta-attribute object as a final argument to
315 triggers. This actually changed for inlined code a while back, but the
316 non-inlined version and the docs were still out of date.
318 If by some chance you actually used this feature, the workaround is
319 simple. You fetch the attribute object from out of the C<$self>
320 that is passed as the first argument to trigger, like so:
326 my ( $self, $value ) = @_;
327 my $attr = $self->meta->find_attribute_by_name('foo');
335 If you created a subtype and passed a parent that Moose didn't know
336 about, it simply ignored the parent. Now it automatically creates the
337 parent as a class type. This may not be what you want, but is less
340 You could declare a name with subtype such as "Foo!Bar". Moose would
341 accept this allowed, but if you used it in a parameterized type such
342 as "ArrayRef[Foo!Bar]" it wouldn't work. We now do some vetting on
343 names created via the sugar functions, so that they can only contain
344 alphanumerics, ":", and ".".
348 Methods created via an attribute can now fulfill a C<requires>
349 declaration for a role. Honestly we don't know why Stevan didn't make
350 this work originally, he was just insane or something.
352 Stack traces from inlined code will now report the line and file as
353 being in your class, as opposed to in Moose guts.
355 =head1 Version 0.62_02
357 When a class does not provide all of a role's required methods, the
358 error thrown now mentions all of the missing methods, as opposed to
359 just the first missing method.
361 Moose will no longer inline a constructor for your class unless it
362 inherits its constructor from Moose::Object, and will warn when it
363 doesn't inline. If you want to force inlining anyway, pass
364 C<< replace_constructor => 1 >> to C<make_immutable>.
366 If you want to get rid of the warning, pass C<< inline_constructor =>
371 Removed the (deprecated) C<make_immutable> keyword.
373 Removing an attribute from a class now also removes delegation
374 (C<handles>) methods installed for that attribute. This is correct
375 behavior, but if you were wrongly relying on it you might get bit.
379 Roles now add methods by calling C<add_method>, not
380 C<alias_method>. They make sure to always provide a method object,
381 which will be cloned internally. This means that it is now possible to
382 track the source of a method provided by a role, and even follow its
383 history through intermediate roles. This means that methods added by
384 a role now show up when looking at a class's method list/map.
386 Parameter and Union args are now sorted, this makes Int|Str the same
387 constraint as Str|Int. Also, incoming type constraint strings are
388 normalized to remove all whitespace differences. This is mostly for
389 internals and should not affect outside code.
391 L<Moose::Exporter> will no longer remove a subroutine that the
392 exporting package re-exports. Moose re-exports the Carp::confess
393 function, among others. The reasoning is that we cannot know whether
394 you have also explicitly imported those functions for your own use, so
395 we err on the safe side and always keep them.
399 C<Moose::init_meta> should now be called as a method.
401 New modules for extension writers, L<Moose::Exporter> and
402 L<Moose::Util::MetaRole>.
404 =head1 Version 0.55_01
406 Implemented metaclass traits (and wrote a recipe for it):
408 use Moose -traits => 'Foo'
410 This should make writing small Moose extensions a little
415 Fixed C<coerce> to accept anon types just like C<subtype> can.
418 coerce $some_anon_type => from 'Str' => via { ... };
422 Added C<BUILDARGS>, a new step in C<< Moose::Object->new() >>.
426 Fixed how the C<< is => (ro|rw) >> works with custom defined
427 C<reader>, C<writer> and C<accessor> options. See the below table for
430 is => ro, writer => _foo # turns into (reader => foo, writer => _foo)
431 is => rw, writer => _foo # turns into (reader => foo, writer => _foo)
432 is => rw, accessor => _foo # turns into (accessor => _foo)
433 is => ro, accessor => _foo # error, accesor is rw
437 The C<before/around/after> method modifiers now support regexp
438 matching of method names. NOTE: this only works for classes, it is
439 currently not supported in roles, but, ... patches welcome.
441 The C<has> keyword for roles now accepts the same array ref form that
442 L<Moose>.pm does for classes.
444 A trigger on a read-only attribute is no longer an error, as it's
445 useful to trigger off of the constructor.
447 Subtypes of parameterizable types now are parameterizable types
452 Fixed issue where C<DEMOLISHALL> was eating the value in C<$@>, and so
453 not working correctly. It still kind of eats them, but so does vanilla
458 Inherited attributes may now be extended without restriction on the
459 type ('isa', 'does').
461 The entire set of Moose::Meta::TypeConstraint::* classes were
462 refactored in this release. If you were relying on their internals you
463 should test your code carefully.
467 Documenting the use of '+name' with attributes that come from recently
468 composed roles. It makes sense, people are using it, and so why not
469 just officially support it.
471 The C<< Moose::Meta::Class->create >> method now supports roles.
473 It is now possible to make anonymous enum types by passing C<enum> an
474 array reference instead of the C<< enum $name => @values >>.
478 Added the C<make_immutable> keyword as a shortcut to calling
479 C<make_immutable> on the meta object. This eventually got removed!
481 Made C<< init_arg => undef >> work in Moose. This means "do not accept
482 a constructor parameter for this attribute".
484 Type errors now use the provided message. Prior to this release they
489 Moose is now a postmodern object system :)
491 The Role system was completely refactored. It is 100% backwards
492 compat, but the internals were totally changed. If you relied on the
493 internals then you are advised to test carefully.
495 Added method exclusion and aliasing for Roles in this release.
497 Added the L<Moose::Util::TypeConstraints::OptimizedConstraints>
500 Passing a list of values to an accessor (which is only expecting one
501 value) used to be silently ignored, now it throws an error.
505 Added parameterized types and did a pretty heavy refactoring of the
506 type constraint system.
508 Better framework extendability and better support for "making your own
511 =head1 Version 0.25 or before
513 Honestly, you shouldn't be using versions of Moose that are this old,
514 so many bug fixes and speed improvements have been made you would be
515 crazy to not upgrade.
517 Also, I am tired of going through the Changelog so I am stopping here,
518 if anyone would like to continue this please feel free.
522 Stevan Little E<lt>stevan@iinteractive.comE<gt>
524 =head1 COPYRIGHT AND LICENSE
526 Copyright 2009 by Infinity Interactive, Inc.
528 L<http://www.iinteractive.com>
530 This library is free software; you can redistribute it and/or modify
531 it under the same terms as Perl itself.