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 Both C<get_method_map> and C<get_attribute_map> is deprecated
29 These metaclass methods were never meant to be public, and they are both now
30 deprecated. The work around if you still need the functionality they provided
31 is to iterate over the list of names manually.
33 my %fields = map { $_ => $meta->get_attribute($_) } $meta->get_attribute_list;
35 This was actually a change in L<Class::MOP>, but this version of Moose
36 requires a version of L<Class::MOP> that includes said change.
44 =item Added Native delegation for Code refs
46 See L<Moose::Meta::Attribute::Native::Trait::Code> for details.
48 =item Calling $object->new() is deprecated
50 Moose has long supported this, but it's never really been documented, and we
51 don't think this is a good practice. If you want to construct an object from
52 an existing object, you should provide some sort of alternate constructor like
53 C<< $object->clone >>.
55 Calling C<< $object->new >> now issues a warning, and will be an error in a
58 =item Moose no longer warns if you call C<make_immutable> for a class with mutable ancestors
60 While in theory this is a good thing to warn about, we found so many
61 exceptions to this that doing this properly became quite problematic.
65 =head1 Version 0.89_02
69 =item New Native delegation methods from L<List::Util> and L<List::MoreUtils>
71 In particular, we now have C<reduce>, C<shuffle>, C<uniq>, and C<natatime>.
73 =item The Moose::Exporter with_caller feature is now deprecated
75 Use C<with_meta> instead. The C<with_caller> option will start warning in a
78 =item Moose now warns if you call C<make_immutable> for a class with mutable ancestors
80 This is dangerous because modifying a class after a subclass has been
81 immutabilized will lead to incorrect results in the subclass, due to inlining,
82 caching, etc. This occasionally happens accidentally, when a class loads one
83 of its subclasses in the middle of its class definition, so pointing out that
84 this may cause issues should be helpful. Metaclasses (classes that inherit
85 from L<Class::MOP::Object>) are currently exempt from this check, since at the
86 moment we aren't very consistent about which metaclasses we immutabilize.
88 =item C<enum> and C<duck_type> now take arrayrefs for all forms
90 Previously, calling these functions with a list would take the first element of
91 the list as the type constraint name, and use the remainder as the enum values
92 or method names. This makes the interface inconsistent with the anon-type forms
93 of these functions (which must take an arrayref), and a free-form list where
94 the first value is sometimes special is hard to validate (and harder to give
95 reasonable error messages for). These functions have been changed to take
96 arrayrefs in all their forms - so, C<< enum 'My::Type' => [qw(foo bar)] >> is
97 now the preferred way to create an enum type constraint. The old syntax still
98 works for now, but it will hopefully be deprecated and removed in a future
103 =head1 Version 0.89_01
105 L<Moose::Meta::Attribute::Native> has been moved into the Moose core from
106 L<MooseX::AttributeHelpers>. Major changes include:
110 =item C<traits>, not C<metaclass>
112 Method providers are only available via traits.
114 =item C<handles>, not C<provides> or C<curries>
116 The C<provides> syntax was like core Moose C<< handles => HASHREF >>
117 syntax, but with the keys and values reversed. This was confusing,
118 and AttributeHelpers now uses C<< handles => HASHREF >> in a way that
119 should be intuitive to anyone already familiar with how it is used for
122 The C<curries> functionality provided by AttributeHelpers has been
123 generalized to apply to all cases of C<< handles => HASHREF >>, though
124 not every piece of functionality has been ported (currying with a
125 CODEREF is not supported).
127 =item C<empty> is now C<is_empty>, and means empty, not non-empty
129 Previously, the C<empty> method provided by Arrays and Hashes returned true if
130 the attribute was B<not> empty (no elements). Now it returns true if the
131 attribute B<is> empty. It was also renamed to C<is_empty>, to reflect this.
133 =item C<find> was renamed to C<first>, and C<first> and C<last> were removed
135 L<List::Util> refers to the functionality that we used to provide under C<find>
136 as L<first|List::Util/first>, so that will likely be more familiar (and will
137 fit in better if we decide to add more List::Util functions). C<first> and
138 C<last> were removed, since their functionality is easily duplicated with
141 =item Helpers that take a coderef of one argument now use C<$_>
143 Subroutines passed as the first argument to C<first>, C<map>, and C<grep> now
144 receive their argument in C<$_> rather than as a parameter to the subroutine.
145 Helpers that take a coderef of two or more arguments remain using the argument
146 list (there are technical limitations to using C<$a> and C<$b> like C<sort>
149 See L<Moose::Meta::Attribute::Native> for the new documentation.
153 The C<alias> and C<excludes> role parameters have been renamed to C<-alias>
154 and C<-excludes>. The old names still work, but new code should use the new
155 names, and eventually the old ones will be deprecated and removed.
159 C<< use Moose -metaclass => 'Foo' >> now does alias resolution, just like
160 C<-traits> (and the C<metaclass> and C<traits> options to C<has>).
162 Added two functions C<meta_class_alias> and C<meta_attribute_alias> to
163 L<Moose::Util>, to simplify aliasing metaclasses and metatraits. This is
164 a wrapper around the old
166 package Moose::Meta::Class::Custom::Trait::FooTrait;
167 sub register_implementation { 'My::Meta::Trait' }
173 When an attribute generates I<no> accessors, we now warn. This is to help
174 users who forget the C<is> option. If you really do not want any accessors,
175 you can use C<< is => 'bare' >>. You can maintain back compat with older
176 versions of Moose by using something like:
178 ($Moose::VERSION >= 0.84 ? is => 'bare' : ())
180 When an accessor overwrites an existing method, we now warn. To work around
181 this warning (if you really must have this behavior), you can explicitly
182 remove the method before creating it as an accessor:
186 __PACKAGE__->meta->remove_method('foo');
192 When an unknown option is passed to C<has>, we now warn. You can silence
193 the warning by fixing your code. :)
195 The C<Role> type has been deprecated. On its own, it was useless,
196 since it just checked C<< $object->can('does') >>. If you were using
197 it as a parent type, just call C<role_type('Role::Name')> to create an
198 appropriate type instead.
202 C<use Moose::Exporter;> now imports C<strict> and C<warnings> into packages
207 C<DEMOLISHALL> and C<DEMOLISH> now receive an argument indicating whether or
208 not we are in global destruction.
212 Type constraints no longer run coercions for a value that already matches the
213 constraint. This may affect some (arguably buggy) edge case coercions that
214 rely on side effects in the C<via> clause.
218 L<Moose::Exporter> now accepts the C<-metaclass> option for easily
219 overriding the metaclass (without L<metaclass>). This works for classes
224 Added a C<duck_type> sugar function to L<Moose::Util::TypeConstraints>
225 to make integration with non-Moose classes easier. It simply checks if
226 C<< $obj->can() >> a list of methods.
228 A number of methods (mostly inherited from L<Class::MOP>) have been
229 renamed with a leading underscore to indicate their internal-ness. The
230 old method names will still work for a while, but will warn that the
231 method has been renamed. In a few cases, the method will be removed
232 entirely in the future. This may affect MooseX authors who were using
237 Calling C<subtype> with a name as the only argument now throws an
238 exception. If you want an anonymous subtype do:
240 my $subtype = subtype as 'Foo';
242 This is related to the changes in version 0.71_01.
244 The C<is_needed> method in L<Moose::Meta::Method::Destructor> is now
245 only usable as a class method. Previously, it worked as a class or
246 object method, with a different internal implementation for each
249 The internals of making a class immutable changed a lot in Class::MOP
250 0.78_02, and Moose's internals have changed along with it. The
251 external C<< $metaclass->make_immutable >> method still works the same
256 A mutable class accepted C<< Foo->new(undef) >> without complaint,
257 while an immutable class would blow up with an unhelpful error. Now,
258 in both cases we throw a helpful error instead.
260 This "feature" was originally added to allow for cases such as this:
268 return My::Class->new($args);
270 But we decided this is a bad idea and a little too magical, because it
271 can easily mask real errors.
273 =head1 Version 0.71_01
275 Calling C<type> or C<subtype> without the sugar helpers (C<as>,
276 C<where>, C<message>) is now deprecated.
278 As a side effect, this meant we ended up using Perl prototypes on
279 C<as>, and code like this will no longer work:
281 use Moose::Util::TypeConstraints;
282 use Declare::Constraints::Simple -All;
284 subtype 'ArrayOfInts'
286 => IsArrayRef(IsInt);
288 Instead it must be changed to this:
293 where => IsArrayRef(IsInt)
297 If you want to maintain backwards compat with older versions of Moose,
298 you must explicitly test Moose's C<VERSION>:
300 if ( Moose->VERSION < 0.71_01 ) {
301 subtype 'ArrayOfInts'
303 => IsArrayRef(IsInt);
309 where => IsArrayRef(IsInt)
316 We no longer pass the meta-attribute object as a final argument to
317 triggers. This actually changed for inlined code a while back, but the
318 non-inlined version and the docs were still out of date.
320 If by some chance you actually used this feature, the workaround is
321 simple. You fetch the attribute object from out of the C<$self>
322 that is passed as the first argument to trigger, like so:
328 my ( $self, $value ) = @_;
329 my $attr = $self->meta->find_attribute_by_name('foo');
337 If you created a subtype and passed a parent that Moose didn't know
338 about, it simply ignored the parent. Now it automatically creates the
339 parent as a class type. This may not be what you want, but is less
342 You could declare a name with subtype such as "Foo!Bar". Moose would
343 accept this allowed, but if you used it in a parameterized type such
344 as "ArrayRef[Foo!Bar]" it wouldn't work. We now do some vetting on
345 names created via the sugar functions, so that they can only contain
346 alphanumerics, ":", and ".".
350 Methods created via an attribute can now fulfill a C<requires>
351 declaration for a role. Honestly we don't know why Stevan didn't make
352 this work originally, he was just insane or something.
354 Stack traces from inlined code will now report the line and file as
355 being in your class, as opposed to in Moose guts.
357 =head1 Version 0.62_02
359 When a class does not provide all of a role's required methods, the
360 error thrown now mentions all of the missing methods, as opposed to
361 just the first missing method.
363 Moose will no longer inline a constructor for your class unless it
364 inherits its constructor from Moose::Object, and will warn when it
365 doesn't inline. If you want to force inlining anyway, pass
366 C<< replace_constructor => 1 >> to C<make_immutable>.
368 If you want to get rid of the warning, pass C<< inline_constructor =>
373 Removed the (deprecated) C<make_immutable> keyword.
375 Removing an attribute from a class now also removes delegation
376 (C<handles>) methods installed for that attribute. This is correct
377 behavior, but if you were wrongly relying on it you might get bit.
381 Roles now add methods by calling C<add_method>, not
382 C<alias_method>. They make sure to always provide a method object,
383 which will be cloned internally. This means that it is now possible to
384 track the source of a method provided by a role, and even follow its
385 history through intermediate roles. This means that methods added by
386 a role now show up when looking at a class's method list/map.
388 Parameter and Union args are now sorted, this makes Int|Str the same
389 constraint as Str|Int. Also, incoming type constraint strings are
390 normalized to remove all whitespace differences. This is mostly for
391 internals and should not affect outside code.
393 L<Moose::Exporter> will no longer remove a subroutine that the
394 exporting package re-exports. Moose re-exports the Carp::confess
395 function, among others. The reasoning is that we cannot know whether
396 you have also explicitly imported those functions for your own use, so
397 we err on the safe side and always keep them.
401 C<Moose::init_meta> should now be called as a method.
403 New modules for extension writers, L<Moose::Exporter> and
404 L<Moose::Util::MetaRole>.
406 =head1 Version 0.55_01
408 Implemented metaclass traits (and wrote a recipe for it):
410 use Moose -traits => 'Foo'
412 This should make writing small Moose extensions a little
417 Fixed C<coerce> to accept anon types just like C<subtype> can.
420 coerce $some_anon_type => from 'Str' => via { ... };
424 Added C<BUILDARGS>, a new step in C<< Moose::Object->new() >>.
428 Fixed how the C<< is => (ro|rw) >> works with custom defined
429 C<reader>, C<writer> and C<accessor> options. See the below table for
432 is => ro, writer => _foo # turns into (reader => foo, writer => _foo)
433 is => rw, writer => _foo # turns into (reader => foo, writer => _foo)
434 is => rw, accessor => _foo # turns into (accessor => _foo)
435 is => ro, accessor => _foo # error, accesor is rw
439 The C<before/around/after> method modifiers now support regexp
440 matching of method names. NOTE: this only works for classes, it is
441 currently not supported in roles, but, ... patches welcome.
443 The C<has> keyword for roles now accepts the same array ref form that
444 L<Moose>.pm does for classes.
446 A trigger on a read-only attribute is no longer an error, as it's
447 useful to trigger off of the constructor.
449 Subtypes of parameterizable types now are parameterizable types
454 Fixed issue where C<DEMOLISHALL> was eating the value in C<$@>, and so
455 not working correctly. It still kind of eats them, but so does vanilla
460 Inherited attributes may now be extended without restriction on the
461 type ('isa', 'does').
463 The entire set of Moose::Meta::TypeConstraint::* classes were
464 refactored in this release. If you were relying on their internals you
465 should test your code carefully.
469 Documenting the use of '+name' with attributes that come from recently
470 composed roles. It makes sense, people are using it, and so why not
471 just officially support it.
473 The C<< Moose::Meta::Class->create >> method now supports roles.
475 It is now possible to make anonymous enum types by passing C<enum> an
476 array reference instead of the C<< enum $name => @values >>.
480 Added the C<make_immutable> keyword as a shortcut to calling
481 C<make_immutable> on the meta object. This eventually got removed!
483 Made C<< init_arg => undef >> work in Moose. This means "do not accept
484 a constructor parameter for this attribute".
486 Type errors now use the provided message. Prior to this release they
491 Moose is now a postmodern object system :)
493 The Role system was completely refactored. It is 100% backwards
494 compat, but the internals were totally changed. If you relied on the
495 internals then you are advised to test carefully.
497 Added method exclusion and aliasing for Roles in this release.
499 Added the L<Moose::Util::TypeConstraints::OptimizedConstraints>
502 Passing a list of values to an accessor (which is only expecting one
503 value) used to be silently ignored, now it throws an error.
507 Added parameterized types and did a pretty heavy refactoring of the
508 type constraint system.
510 Better framework extendability and better support for "making your own
513 =head1 Version 0.25 or before
515 Honestly, you shouldn't be using versions of Moose that are this old,
516 so many bug fixes and speed improvements have been made you would be
517 crazy to not upgrade.
519 Also, I am tired of going through the Changelog so I am stopping here,
520 if anyone would like to continue this please feel free.
524 Stevan Little E<lt>stevan@iinteractive.comE<gt>
526 =head1 COPYRIGHT AND LICENSE
528 Copyright 2009 by Infinity Interactive, Inc.
530 L<http://www.iinteractive.com>
532 This library is free software; you can redistribute it and/or modify
533 it under the same terms as Perl itself.