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 Added Native delegation for Code refs
25 See L<Moose::Meta::Attribute::Native::Trait::Code> for details.
27 =item Calling $object->new() is deprecated
29 Moose has long supported this, but it's never really been documented, and we
30 don't think this is a good practice. If you want to construct an object from
31 an existing object, you should provide some sort of alternate constructor like
32 C<< $object->clone >>.
34 Calling C<< $object->new >> now issues a warning, and will be an error in a
37 =item Moose no longer warns if you call C<make_immutable> for a class with mutable ancestors
39 While in theory this is a good thing to warn about, we found so many
40 exceptions to this that doing this properly became quite problematic.
44 =head1 Version 0.89_02
48 =item New Native delegation methods from L<List::Util> and L<List::MoreUtils>
50 In particular, we now have C<reduce>, C<shuffle>, C<uniq>, and C<natatime>.
52 =item The Moose::Exporter with_caller feature is now deprecated
54 Use C<with_meta> instead. The C<with_caller> option will start warning in a
57 =item Moose now warns if you call C<make_immutable> for a class with mutable ancestors
59 This is dangerous because modifying a class after a subclass has been
60 immutabilized will lead to incorrect results in the subclass, due to inlining,
61 caching, etc. This occasionally happens accidentally, when a class loads one
62 of its subclasses in the middle of its class definition, so pointing out that
63 this may cause issues should be helpful. Metaclasses (classes that inherit
64 from L<Class::MOP::Object>) are currently exempt from this check, since at the
65 moment we aren't very consistent about which metaclasses we immutabilize.
67 =item C<enum> and C<duck_type> now take arrayrefs for all forms
69 Previously, calling these functions with a list would take the first element of
70 the list as the type constraint name, and use the remainder as the enum values
71 or method names. This makes the interface inconsistent with the anon-type forms
72 of these functions (which must take an arrayref), and a free-form list where
73 the first value is sometimes special is hard to validate (and harder to give
74 reasonable error messages for). These functions have been changed to take
75 arrayrefs in all their forms - so, C<< enum 'My::Type' => [qw(foo bar)] >> is
76 now the preferred way to create an enum type constraint. The old syntax still
77 works for now, but it will hopefully be deprecated and removed in a future
82 =head1 Version 0.89_01
84 L<Moose::Meta::Attribute::Native> has been moved into the Moose core from
85 L<MooseX::AttributeHelpers>. Major changes include:
89 =item C<traits>, not C<metaclass>
91 Method providers are only available via traits.
93 =item C<handles>, not C<provides> or C<curries>
95 The C<provides> syntax was like core Moose C<< handles => HASHREF >>
96 syntax, but with the keys and values reversed. This was confusing,
97 and AttributeHelpers now uses C<< handles => HASHREF >> in a way that
98 should be intuitive to anyone already familiar with how it is used for
101 The C<curries> functionality provided by AttributeHelpers has been
102 generalized to apply to all cases of C<< handles => HASHREF >>, though
103 not every piece of functionality has been ported (currying with a
104 CODEREF is not supported).
106 =item C<empty> is now C<is_empty>, and means empty, not non-empty
108 Previously, the C<empty> method provided by Arrays and Hashes returned true if
109 the attribute was B<not> empty (no elements). Now it returns true if the
110 attribute B<is> empty. It was also renamed to C<is_empty>, to reflect this.
112 =item C<find> was renamed to C<first>, and C<first> and C<last> were removed
114 L<List::Util> refers to the functionality that we used to provide under C<find>
115 as L<first|List::Util/first>, so that will likely be more familiar (and will
116 fit in better if we decide to add more List::Util functions). C<first> and
117 C<last> were removed, since their functionality is easily duplicated with
120 =item Helpers that take a coderef of one argument now use C<$_>
122 Subroutines passed as the first argument to C<first>, C<map>, and C<grep> now
123 receive their argument in C<$_> rather than as a parameter to the subroutine.
124 Helpers that take a coderef of two or more arguments remain using the argument
125 list (there are technical limitations to using C<$a> and C<$b> like C<sort>
128 See L<Moose::Meta::Attribute::Native> for the new documentation.
132 The C<alias> and C<excludes> role parameters have been renamed to C<-alias>
133 and C<-excludes>. The old names still work, but new code should use the new
134 names, and eventually the old ones will be deprecated and removed.
138 C<< use Moose -metaclass => 'Foo' >> now does alias resolution, just like
139 C<-traits> (and the C<metaclass> and C<traits> options to C<has>).
141 Added two functions C<meta_class_alias> and C<meta_attribute_alias> to
142 L<Moose::Util>, to simplify aliasing metaclasses and metatraits. This is
143 a wrapper around the old
145 package Moose::Meta::Class::Custom::Trait::FooTrait;
146 sub register_implementation { 'My::Meta::Trait' }
152 When an attribute generates I<no> accessors, we now warn. This is to help
153 users who forget the C<is> option. If you really do not want any accessors,
154 you can use C<< is => 'bare' >>. You can maintain back compat with older
155 versions of Moose by using something like:
157 ($Moose::VERSION >= 0.84 ? is => 'bare' : ())
159 When an accessor overwrites an existing method, we now warn. To work around
160 this warning (if you really must have this behavior), you can explicitly
161 remove the method before creating it as an accessor:
165 __PACKAGE__->meta->remove_method('foo');
171 When an unknown option is passed to C<has>, we now warn. You can silence
172 the warning by fixing your code. :)
174 The C<Role> type has been deprecated. On its own, it was useless,
175 since it just checked C<< $object->can('does') >>. If you were using
176 it as a parent type, just call C<role_type('Role::Name')> to create an
177 appropriate type instead.
181 C<use Moose::Exporter;> now imports C<strict> and C<warnings> into packages
186 C<DEMOLISHALL> and C<DEMOLISH> now receive an argument indicating whether or
187 not we are in global destruction.
191 Type constraints no longer run coercions for a value that already matches the
192 constraint. This may affect some (arguably buggy) edge case coercions that
193 rely on side effects in the C<via> clause.
197 L<Moose::Exporter> now accepts the C<-metaclass> option for easily
198 overriding the metaclass (without L<metaclass>). This works for classes
203 Added a C<duck_type> sugar function to L<Moose::Util::TypeConstraints>
204 to make integration with non-Moose classes easier. It simply checks if
205 C<< $obj->can() >> a list of methods.
207 A number of methods (mostly inherited from L<Class::MOP>) have been
208 renamed with a leading underscore to indicate their internal-ness. The
209 old method names will still work for a while, but will warn that the
210 method has been renamed. In a few cases, the method will be removed
211 entirely in the future. This may affect MooseX authors who were using
216 Calling C<subtype> with a name as the only argument now throws an
217 exception. If you want an anonymous subtype do:
219 my $subtype = subtype as 'Foo';
221 This is related to the changes in version 0.71_01.
223 The C<is_needed> method in L<Moose::Meta::Method::Destructor> is now
224 only usable as a class method. Previously, it worked as a class or
225 object method, with a different internal implementation for each
228 The internals of making a class immutable changed a lot in Class::MOP
229 0.78_02, and Moose's internals have changed along with it. The
230 external C<< $metaclass->make_immutable >> method still works the same
235 A mutable class accepted C<< Foo->new(undef) >> without complaint,
236 while an immutable class would blow up with an unhelpful error. Now,
237 in both cases we throw a helpful error instead.
239 This "feature" was originally added to allow for cases such as this:
247 return My::Class->new($args);
249 But we decided this is a bad idea and a little too magical, because it
250 can easily mask real errors.
252 =head1 Version 0.71_01
254 Calling C<type> or C<subtype> without the sugar helpers (C<as>,
255 C<where>, C<message>) is now deprecated.
257 As a side effect, this meant we ended up using Perl prototypes on
258 C<as>, and code like this will no longer work:
260 use Moose::Util::TypeConstraints;
261 use Declare::Constraints::Simple -All;
263 subtype 'ArrayOfInts'
265 => IsArrayRef(IsInt);
267 Instead it must be changed to this:
272 where => IsArrayRef(IsInt)
276 If you want to maintain backwards compat with older versions of Moose,
277 you must explicitly test Moose's C<VERSION>:
279 if ( Moose->VERSION < 0.71_01 ) {
280 subtype 'ArrayOfInts'
282 => IsArrayRef(IsInt);
288 where => IsArrayRef(IsInt)
295 We no longer pass the meta-attribute object as a final argument to
296 triggers. This actually changed for inlined code a while back, but the
297 non-inlined version and the docs were still out of date.
299 If by some chance you actually used this feature, the workaround is
300 simple. You fetch the attribute object from out of the C<$self>
301 that is passed as the first argument to trigger, like so:
307 my ( $self, $value ) = @_;
308 my $attr = $self->meta->find_attribute_by_name('foo');
316 If you created a subtype and passed a parent that Moose didn't know
317 about, it simply ignored the parent. Now it automatically creates the
318 parent as a class type. This may not be what you want, but is less
321 You could declare a name with subtype such as "Foo!Bar". Moose would
322 accept this allowed, but if you used it in a parameterized type such
323 as "ArrayRef[Foo!Bar]" it wouldn't work. We now do some vetting on
324 names created via the sugar functions, so that they can only contain
325 alphanumerics, ":", and ".".
329 Methods created via an attribute can now fulfill a C<requires>
330 declaration for a role. Honestly we don't know why Stevan didn't make
331 this work originally, he was just insane or something.
333 Stack traces from inlined code will now report the line and file as
334 being in your class, as opposed to in Moose guts.
336 =head1 Version 0.62_02
338 When a class does not provide all of a role's required methods, the
339 error thrown now mentions all of the missing methods, as opposed to
340 just the first missing method.
342 Moose will no longer inline a constructor for your class unless it
343 inherits its constructor from Moose::Object, and will warn when it
344 doesn't inline. If you want to force inlining anyway, pass
345 C<< replace_constructor => 1 >> to C<make_immutable>.
347 If you want to get rid of the warning, pass C<< inline_constructor =>
352 Removed the (deprecated) C<make_immutable> keyword.
354 Removing an attribute from a class now also removes delegation
355 (C<handles>) methods installed for that attribute. This is correct
356 behavior, but if you were wrongly relying on it you might get bit.
360 Roles now add methods by calling C<add_method>, not
361 C<alias_method>. They make sure to always provide a method object,
362 which will be cloned internally. This means that it is now possible to
363 track the source of a method provided by a role, and even follow its
364 history through intermediate roles. This means that methods added by
365 a role now show up when looking at a class's method list/map.
367 Parameter and Union args are now sorted, this makes Int|Str the same
368 constraint as Str|Int. Also, incoming type constraint strings are
369 normalized to remove all whitespace differences. This is mostly for
370 internals and should not affect outside code.
372 L<Moose::Exporter> will no longer remove a subroutine that the
373 exporting package re-exports. Moose re-exports the Carp::confess
374 function, among others. The reasoning is that we cannot know whether
375 you have also explicitly imported those functions for your own use, so
376 we err on the safe side and always keep them.
380 C<Moose::init_meta> should now be called as a method.
382 New modules for extension writers, L<Moose::Exporter> and
383 L<Moose::Util::MetaRole>.
385 =head1 Version 0.55_01
387 Implemented metaclass traits (and wrote a recipe for it):
389 use Moose -traits => 'Foo'
391 This should make writing small Moose extensions a little
396 Fixed C<coerce> to accept anon types just like C<subtype> can.
399 coerce $some_anon_type => from 'Str' => via { ... };
403 Added C<BUILDARGS>, a new step in C<< Moose::Object->new() >>.
407 Fixed how the C<< is => (ro|rw) >> works with custom defined
408 C<reader>, C<writer> and C<accessor> options. See the below table for
411 is => ro, writer => _foo # turns into (reader => foo, writer => _foo)
412 is => rw, writer => _foo # turns into (reader => foo, writer => _foo)
413 is => rw, accessor => _foo # turns into (accessor => _foo)
414 is => ro, accessor => _foo # error, accesor is rw
418 The C<before/around/after> method modifiers now support regexp
419 matching of method names. NOTE: this only works for classes, it is
420 currently not supported in roles, but, ... patches welcome.
422 The C<has> keyword for roles now accepts the same array ref form that
423 L<Moose>.pm does for classes.
425 A trigger on a read-only attribute is no longer an error, as it's
426 useful to trigger off of the constructor.
428 Subtypes of parameterizable types now are parameterizable types
433 Fixed issue where C<DEMOLISHALL> was eating the value in C<$@>, and so
434 not working correctly. It still kind of eats them, but so does vanilla
439 Inherited attributes may now be extended without restriction on the
440 type ('isa', 'does').
442 The entire set of Moose::Meta::TypeConstraint::* classes were
443 refactored in this release. If you were relying on their internals you
444 should test your code carefully.
448 Documenting the use of '+name' with attributes that come from recently
449 composed roles. It makes sense, people are using it, and so why not
450 just officially support it.
452 The C<< Moose::Meta::Class->create >> method now supports roles.
454 It is now possible to make anonymous enum types by passing C<enum> an
455 array reference instead of the C<< enum $name => @values >>.
459 Added the C<make_immutable> keyword as a shortcut to calling
460 C<make_immutable> on the meta object. This eventually got removed!
462 Made C<< init_arg => undef >> work in Moose. This means "do not accept
463 a constructor parameter for this attribute".
465 Type errors now use the provided message. Prior to this release they
470 Moose is now a postmodern object system :)
472 The Role system was completely refactored. It is 100% backwards
473 compat, but the internals were totally changed. If you relied on the
474 internals then you are advised to test carefully.
476 Added method exclusion and aliasing for Roles in this release.
478 Added the L<Moose::Util::TypeConstraints::OptimizedConstraints>
481 Passing a list of values to an accessor (which is only expecting one
482 value) used to be silently ignored, now it throws an error.
486 Added parameterized types and did a pretty heavy refactoring of the
487 type constraint system.
489 Better framework extendability and better support for "making your own
492 =head1 Version 0.25 or before
494 Honestly, you shouldn't be using versions of Moose that are this old,
495 so many bug fixes and speed improvements have been made you would be
496 crazy to not upgrade.
498 Also, I am tired of going through the Changelog so I am stopping here,
499 if anyone would like to continue this please feel free.
503 Stevan Little E<lt>stevan@iinteractive.comE<gt>
505 =head1 COPYRIGHT AND LICENSE
507 Copyright 2009 by Infinity Interactive, Inc.
509 L<http://www.iinteractive.com>
511 This library is free software; you can redistribute it and/or modify
512 it under the same terms as Perl itself.