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. All
30 C<get_*_methods> were deprecated, and the work around if you still need the
31 functionality they provided is to iterate over the list of names manually.
33 my %fields = map { $_ => $meta->get_attribute($_) } $meta->get_attribute_list;
41 =item Added Native delegation for Code refs
43 See L<Moose::Meta::Attribute::Native::Trait::Code> for details.
45 =item Calling $object->new() is deprecated
47 Moose has long supported this, but it's never really been documented, and we
48 don't think this is a good practice. If you want to construct an object from
49 an existing object, you should provide some sort of alternate constructor like
50 C<< $object->clone >>.
52 Calling C<< $object->new >> now issues a warning, and will be an error in a
55 =item Moose no longer warns if you call C<make_immutable> for a class with mutable ancestors
57 While in theory this is a good thing to warn about, we found so many
58 exceptions to this that doing this properly became quite problematic.
62 =head1 Version 0.89_02
66 =item New Native delegation methods from L<List::Util> and L<List::MoreUtils>
68 In particular, we now have C<reduce>, C<shuffle>, C<uniq>, and C<natatime>.
70 =item The Moose::Exporter with_caller feature is now deprecated
72 Use C<with_meta> instead. The C<with_caller> option will start warning in a
75 =item Moose now warns if you call C<make_immutable> for a class with mutable ancestors
77 This is dangerous because modifying a class after a subclass has been
78 immutabilized will lead to incorrect results in the subclass, due to inlining,
79 caching, etc. This occasionally happens accidentally, when a class loads one
80 of its subclasses in the middle of its class definition, so pointing out that
81 this may cause issues should be helpful. Metaclasses (classes that inherit
82 from L<Class::MOP::Object>) are currently exempt from this check, since at the
83 moment we aren't very consistent about which metaclasses we immutabilize.
85 =item C<enum> and C<duck_type> now take arrayrefs for all forms
87 Previously, calling these functions with a list would take the first element of
88 the list as the type constraint name, and use the remainder as the enum values
89 or method names. This makes the interface inconsistent with the anon-type forms
90 of these functions (which must take an arrayref), and a free-form list where
91 the first value is sometimes special is hard to validate (and harder to give
92 reasonable error messages for). These functions have been changed to take
93 arrayrefs in all their forms - so, C<< enum 'My::Type' => [qw(foo bar)] >> is
94 now the preferred way to create an enum type constraint. The old syntax still
95 works for now, but it will hopefully be deprecated and removed in a future
100 =head1 Version 0.89_01
102 L<Moose::Meta::Attribute::Native> has been moved into the Moose core from
103 L<MooseX::AttributeHelpers>. Major changes include:
107 =item C<traits>, not C<metaclass>
109 Method providers are only available via traits.
111 =item C<handles>, not C<provides> or C<curries>
113 The C<provides> syntax was like core Moose C<< handles => HASHREF >>
114 syntax, but with the keys and values reversed. This was confusing,
115 and AttributeHelpers now uses C<< handles => HASHREF >> in a way that
116 should be intuitive to anyone already familiar with how it is used for
119 The C<curries> functionality provided by AttributeHelpers has been
120 generalized to apply to all cases of C<< handles => HASHREF >>, though
121 not every piece of functionality has been ported (currying with a
122 CODEREF is not supported).
124 =item C<empty> is now C<is_empty>, and means empty, not non-empty
126 Previously, the C<empty> method provided by Arrays and Hashes returned true if
127 the attribute was B<not> empty (no elements). Now it returns true if the
128 attribute B<is> empty. It was also renamed to C<is_empty>, to reflect this.
130 =item C<find> was renamed to C<first>, and C<first> and C<last> were removed
132 L<List::Util> refers to the functionality that we used to provide under C<find>
133 as L<first|List::Util/first>, so that will likely be more familiar (and will
134 fit in better if we decide to add more List::Util functions). C<first> and
135 C<last> were removed, since their functionality is easily duplicated with
138 =item Helpers that take a coderef of one argument now use C<$_>
140 Subroutines passed as the first argument to C<first>, C<map>, and C<grep> now
141 receive their argument in C<$_> rather than as a parameter to the subroutine.
142 Helpers that take a coderef of two or more arguments remain using the argument
143 list (there are technical limitations to using C<$a> and C<$b> like C<sort>
146 See L<Moose::Meta::Attribute::Native> for the new documentation.
150 The C<alias> and C<excludes> role parameters have been renamed to C<-alias>
151 and C<-excludes>. The old names still work, but new code should use the new
152 names, and eventually the old ones will be deprecated and removed.
156 C<< use Moose -metaclass => 'Foo' >> now does alias resolution, just like
157 C<-traits> (and the C<metaclass> and C<traits> options to C<has>).
159 Added two functions C<meta_class_alias> and C<meta_attribute_alias> to
160 L<Moose::Util>, to simplify aliasing metaclasses and metatraits. This is
161 a wrapper around the old
163 package Moose::Meta::Class::Custom::Trait::FooTrait;
164 sub register_implementation { 'My::Meta::Trait' }
170 When an attribute generates I<no> accessors, we now warn. This is to help
171 users who forget the C<is> option. If you really do not want any accessors,
172 you can use C<< is => 'bare' >>. You can maintain back compat with older
173 versions of Moose by using something like:
175 ($Moose::VERSION >= 0.84 ? is => 'bare' : ())
177 When an accessor overwrites an existing method, we now warn. To work around
178 this warning (if you really must have this behavior), you can explicitly
179 remove the method before creating it as an accessor:
183 __PACKAGE__->meta->remove_method('foo');
189 When an unknown option is passed to C<has>, we now warn. You can silence
190 the warning by fixing your code. :)
192 The C<Role> type has been deprecated. On its own, it was useless,
193 since it just checked C<< $object->can('does') >>. If you were using
194 it as a parent type, just call C<role_type('Role::Name')> to create an
195 appropriate type instead.
199 C<use Moose::Exporter;> now imports C<strict> and C<warnings> into packages
204 C<DEMOLISHALL> and C<DEMOLISH> now receive an argument indicating whether or
205 not we are in global destruction.
209 Type constraints no longer run coercions for a value that already matches the
210 constraint. This may affect some (arguably buggy) edge case coercions that
211 rely on side effects in the C<via> clause.
215 L<Moose::Exporter> now accepts the C<-metaclass> option for easily
216 overriding the metaclass (without L<metaclass>). This works for classes
221 Added a C<duck_type> sugar function to L<Moose::Util::TypeConstraints>
222 to make integration with non-Moose classes easier. It simply checks if
223 C<< $obj->can() >> a list of methods.
225 A number of methods (mostly inherited from L<Class::MOP>) have been
226 renamed with a leading underscore to indicate their internal-ness. The
227 old method names will still work for a while, but will warn that the
228 method has been renamed. In a few cases, the method will be removed
229 entirely in the future. This may affect MooseX authors who were using
234 Calling C<subtype> with a name as the only argument now throws an
235 exception. If you want an anonymous subtype do:
237 my $subtype = subtype as 'Foo';
239 This is related to the changes in version 0.71_01.
241 The C<is_needed> method in L<Moose::Meta::Method::Destructor> is now
242 only usable as a class method. Previously, it worked as a class or
243 object method, with a different internal implementation for each
246 The internals of making a class immutable changed a lot in Class::MOP
247 0.78_02, and Moose's internals have changed along with it. The
248 external C<< $metaclass->make_immutable >> method still works the same
253 A mutable class accepted C<< Foo->new(undef) >> without complaint,
254 while an immutable class would blow up with an unhelpful error. Now,
255 in both cases we throw a helpful error instead.
257 This "feature" was originally added to allow for cases such as this:
265 return My::Class->new($args);
267 But we decided this is a bad idea and a little too magical, because it
268 can easily mask real errors.
270 =head1 Version 0.71_01
272 Calling C<type> or C<subtype> without the sugar helpers (C<as>,
273 C<where>, C<message>) is now deprecated.
275 As a side effect, this meant we ended up using Perl prototypes on
276 C<as>, and code like this will no longer work:
278 use Moose::Util::TypeConstraints;
279 use Declare::Constraints::Simple -All;
281 subtype 'ArrayOfInts'
283 => IsArrayRef(IsInt);
285 Instead it must be changed to this:
290 where => IsArrayRef(IsInt)
294 If you want to maintain backwards compat with older versions of Moose,
295 you must explicitly test Moose's C<VERSION>:
297 if ( Moose->VERSION < 0.71_01 ) {
298 subtype 'ArrayOfInts'
300 => IsArrayRef(IsInt);
306 where => IsArrayRef(IsInt)
313 We no longer pass the meta-attribute object as a final argument to
314 triggers. This actually changed for inlined code a while back, but the
315 non-inlined version and the docs were still out of date.
317 If by some chance you actually used this feature, the workaround is
318 simple. You fetch the attribute object from out of the C<$self>
319 that is passed as the first argument to trigger, like so:
325 my ( $self, $value ) = @_;
326 my $attr = $self->meta->find_attribute_by_name('foo');
334 If you created a subtype and passed a parent that Moose didn't know
335 about, it simply ignored the parent. Now it automatically creates the
336 parent as a class type. This may not be what you want, but is less
339 You could declare a name with subtype such as "Foo!Bar". Moose would
340 accept this allowed, but if you used it in a parameterized type such
341 as "ArrayRef[Foo!Bar]" it wouldn't work. We now do some vetting on
342 names created via the sugar functions, so that they can only contain
343 alphanumerics, ":", and ".".
347 Methods created via an attribute can now fulfill a C<requires>
348 declaration for a role. Honestly we don't know why Stevan didn't make
349 this work originally, he was just insane or something.
351 Stack traces from inlined code will now report the line and file as
352 being in your class, as opposed to in Moose guts.
354 =head1 Version 0.62_02
356 When a class does not provide all of a role's required methods, the
357 error thrown now mentions all of the missing methods, as opposed to
358 just the first missing method.
360 Moose will no longer inline a constructor for your class unless it
361 inherits its constructor from Moose::Object, and will warn when it
362 doesn't inline. If you want to force inlining anyway, pass
363 C<< replace_constructor => 1 >> to C<make_immutable>.
365 If you want to get rid of the warning, pass C<< inline_constructor =>
370 Removed the (deprecated) C<make_immutable> keyword.
372 Removing an attribute from a class now also removes delegation
373 (C<handles>) methods installed for that attribute. This is correct
374 behavior, but if you were wrongly relying on it you might get bit.
378 Roles now add methods by calling C<add_method>, not
379 C<alias_method>. They make sure to always provide a method object,
380 which will be cloned internally. This means that it is now possible to
381 track the source of a method provided by a role, and even follow its
382 history through intermediate roles. This means that methods added by
383 a role now show up when looking at a class's method list/map.
385 Parameter and Union args are now sorted, this makes Int|Str the same
386 constraint as Str|Int. Also, incoming type constraint strings are
387 normalized to remove all whitespace differences. This is mostly for
388 internals and should not affect outside code.
390 L<Moose::Exporter> will no longer remove a subroutine that the
391 exporting package re-exports. Moose re-exports the Carp::confess
392 function, among others. The reasoning is that we cannot know whether
393 you have also explicitly imported those functions for your own use, so
394 we err on the safe side and always keep them.
398 C<Moose::init_meta> should now be called as a method.
400 New modules for extension writers, L<Moose::Exporter> and
401 L<Moose::Util::MetaRole>.
403 =head1 Version 0.55_01
405 Implemented metaclass traits (and wrote a recipe for it):
407 use Moose -traits => 'Foo'
409 This should make writing small Moose extensions a little
414 Fixed C<coerce> to accept anon types just like C<subtype> can.
417 coerce $some_anon_type => from 'Str' => via { ... };
421 Added C<BUILDARGS>, a new step in C<< Moose::Object->new() >>.
425 Fixed how the C<< is => (ro|rw) >> works with custom defined
426 C<reader>, C<writer> and C<accessor> options. See the below table for
429 is => ro, writer => _foo # turns into (reader => foo, writer => _foo)
430 is => rw, writer => _foo # turns into (reader => foo, writer => _foo)
431 is => rw, accessor => _foo # turns into (accessor => _foo)
432 is => ro, accessor => _foo # error, accesor is rw
436 The C<before/around/after> method modifiers now support regexp
437 matching of method names. NOTE: this only works for classes, it is
438 currently not supported in roles, but, ... patches welcome.
440 The C<has> keyword for roles now accepts the same array ref form that
441 L<Moose>.pm does for classes.
443 A trigger on a read-only attribute is no longer an error, as it's
444 useful to trigger off of the constructor.
446 Subtypes of parameterizable types now are parameterizable types
451 Fixed issue where C<DEMOLISHALL> was eating the value in C<$@>, and so
452 not working correctly. It still kind of eats them, but so does vanilla
457 Inherited attributes may now be extended without restriction on the
458 type ('isa', 'does').
460 The entire set of Moose::Meta::TypeConstraint::* classes were
461 refactored in this release. If you were relying on their internals you
462 should test your code carefully.
466 Documenting the use of '+name' with attributes that come from recently
467 composed roles. It makes sense, people are using it, and so why not
468 just officially support it.
470 The C<< Moose::Meta::Class->create >> method now supports roles.
472 It is now possible to make anonymous enum types by passing C<enum> an
473 array reference instead of the C<< enum $name => @values >>.
477 Added the C<make_immutable> keyword as a shortcut to calling
478 C<make_immutable> on the meta object. This eventually got removed!
480 Made C<< init_arg => undef >> work in Moose. This means "do not accept
481 a constructor parameter for this attribute".
483 Type errors now use the provided message. Prior to this release they
488 Moose is now a postmodern object system :)
490 The Role system was completely refactored. It is 100% backwards
491 compat, but the internals were totally changed. If you relied on the
492 internals then you are advised to test carefully.
494 Added method exclusion and aliasing for Roles in this release.
496 Added the L<Moose::Util::TypeConstraints::OptimizedConstraints>
499 Passing a list of values to an accessor (which is only expecting one
500 value) used to be silently ignored, now it throws an error.
504 Added parameterized types and did a pretty heavy refactoring of the
505 type constraint system.
507 Better framework extendability and better support for "making your own
510 =head1 Version 0.25 or before
512 Honestly, you shouldn't be using versions of Moose that are this old,
513 so many bug fixes and speed improvements have been made you would be
514 crazy to not upgrade.
516 Also, I am tired of going through the Changelog so I am stopping here,
517 if anyone would like to continue this please feel free.
521 Stevan Little E<lt>stevan@iinteractive.comE<gt>
523 =head1 COPYRIGHT AND LICENSE
525 Copyright 2009 by Infinity Interactive, Inc.
527 L<http://www.iinteractive.com>
529 This library is free software; you can redistribute it and/or modify
530 it under the same terms as Perl itself.