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
21 =item C<no Moose>, C<no Moose::Role>, and C<no Moose::Exporter> no longer unimport strict and warnings
23 This change was made in 1.05, and has now been reverted. We don't know if the
24 user has explicitly loaded strict or warnings outside on their own, and
25 unimporting them is just broken in that case.
31 =item L<Moose::Object/BUILD> methods are now called when calling C<new_object>
33 Previously, C<BUILD> methods would only be called from C<Moose::Object::new>,
34 but now they are also called when constructing an object via
35 C<Moose::Meta::Class::new_object>. C<BUILD> methods are an inherent part of the
36 object construction process, and this should make C<< $meta->new_object >>
37 actually usable without forcing people to use C<< $meta->name->new >>.
39 =item C<no Moose>, C<no Moose::Role>, and C<no Moose::Exporter> now unimport strict and warnings
41 In the interest of having C<no Moose> clean up everything that C<use Moose>
42 does in the calling scope, C<no Moose> (as well as all other
43 L<Moose::Exporter>-using modules) now unimports strict and warnings.
45 =item Metaclass compatibility checking and fixing should be much more robust
47 The L<metaclass compatibility|Moose/METACLASS COMPATIBILITY AND MOOSE> checking
48 and fixing algorithms have been completely rewritten, in both Class::MOP and
49 Moose. This should resolve many confusing errors when dealing with non-Moose
50 inheritance and with custom metaclasses for things like attributes,
51 constructors, etc. For correct code, the only thing that should require a
52 change is that custom error metaclasses must now inherit from
53 L<Moose::Error::Default>.
61 =item Moose::Meta::TypeConstraint::Class is_subtype_of behavior
63 Earlier versions of L<is_subtype_of|Moose::Meta::TypeConstraint::Class/is_subtype_of>
64 would incorrectly return true when called with itself, its own TC name or
65 its class name as an argument. (i.e. $foo_tc->is_subtype_of('Foo') == 1) This
66 behavior was a caused by C<isa> being checked before the class name. The old
67 behavior can be accessed with L<is_type_of|Moose::Meta::TypeConstraint::Class/is_type_of>
75 =item Moose::Meta::Attribute::Native::Trait::Code no longer creates reader methods by default
77 Earlier versions of L<Moose::Meta::Attribute::Native::Trait::Code> created
78 read-only accessors for the attributes it's been applied to, even if you didn't
79 ask for it with C<< is => 'ro' >>. This incorrect behaviour has now been fixed.
87 =item Moose::Util add_method_modifier behavior
89 add_method_modifier (and subsequently the sugar functions Moose::before,
90 Moose::after, and Moose::around) can now accept arrayrefs, with the same
91 behavior as lists. Types other than arrayref and regexp result in an error.
95 =head1 0.93_01 and 0.94
99 =item Moose::Util::MetaRole API has changed
101 The C<apply_metaclass_roles> function is now called C<apply_metaroles>. The
102 way arguments are supplied has been changed to force you to distinguish
103 between metaroles applied to L<Moose::Meta::Class> (and helpers) versus
104 L<Moose::Meta::Role>.
106 The old API still works, but will warn in a future release, and eventually be
109 =item Moose::Meta::Role has real attributes
111 The attributes returned by L<Moose::Meta::Role> are now instances of the
112 L<Moose::Meta::Role::Attribute> class, instead of bare hash references.
114 =item "no Moose" now removes C<blessed> and C<confess>
116 Moose is now smart enough to know exactly what it exported, even when it
117 re-exports functions from other packages. When you unimport Moose, it will
118 remove these functions from your namespace unless you I<also> imported them
119 directly from their respective packages.
121 If you have a C<no Moose> in your code I<before> you call C<blessed> or
122 C<confess>, your code will break. You can either move the C<no Moose> call
123 later in your code, or explicitly import the relevant functions from the
124 packages that provide them.
126 =item L<Moose::Exporter> is smarter about unimporting re-exports
128 The change above comes from a general improvement to L<Moose::Exporter>. It
129 will now unimport any function it exports, even if that function is a
130 re-export from another package.
132 =item Attributes in roles can no longer override class attributes with "+foo"
134 Previously, this worked more or less accidentally, because role attributes
135 weren't objects. This was never documented, but a few MooseX modules took
138 =item The composition_class_roles attribute in L<Moose::Meta::Role> is now a method
140 This was done to make it possible for roles to alter the the list of
141 composition class roles by applying a method modifiers. Previously, this was
142 an attribute and MooseX modules override it. Since that no longer works, this
145 This I<should> be an attribute, so this may switch back to being an attribute
146 in the future if we can figure out how to make this work.
154 =item Calling $object->new() is no longer deprecated
156 We decided to undeprecate this. Now it just works.
158 =item Both C<get_method_map> and C<get_attribute_map> is deprecated
160 These metaclass methods were never meant to be public, and they are both now
161 deprecated. The work around if you still need the functionality they provided
162 is to iterate over the list of names manually.
164 my %fields = map { $_ => $meta->get_attribute($_) } $meta->get_attribute_list;
166 This was actually a change in L<Class::MOP>, but this version of Moose
167 requires a version of L<Class::MOP> that includes said change.
175 =item Added Native delegation for Code refs
177 See L<Moose::Meta::Attribute::Native::Trait::Code> for details.
179 =item Calling $object->new() is deprecated
181 Moose has long supported this, but it's never really been documented, and we
182 don't think this is a good practice. If you want to construct an object from
183 an existing object, you should provide some sort of alternate constructor like
184 C<< $object->clone >>.
186 Calling C<< $object->new >> now issues a warning, and will be an error in a
189 =item Moose no longer warns if you call C<make_immutable> for a class with mutable ancestors
191 While in theory this is a good thing to warn about, we found so many
192 exceptions to this that doing this properly became quite problematic.
196 =head1 Version 0.89_02
200 =item New Native delegation methods from L<List::Util> and L<List::MoreUtils>
202 In particular, we now have C<reduce>, C<shuffle>, C<uniq>, and C<natatime>.
204 =item The Moose::Exporter with_caller feature is now deprecated
206 Use C<with_meta> instead. The C<with_caller> option will start warning in a
209 =item Moose now warns if you call C<make_immutable> for a class with mutable ancestors
211 This is dangerous because modifying a class after a subclass has been
212 immutabilized will lead to incorrect results in the subclass, due to inlining,
213 caching, etc. This occasionally happens accidentally, when a class loads one
214 of its subclasses in the middle of its class definition, so pointing out that
215 this may cause issues should be helpful. Metaclasses (classes that inherit
216 from L<Class::MOP::Object>) are currently exempt from this check, since at the
217 moment we aren't very consistent about which metaclasses we immutabilize.
219 =item C<enum> and C<duck_type> now take arrayrefs for all forms
221 Previously, calling these functions with a list would take the first element of
222 the list as the type constraint name, and use the remainder as the enum values
223 or method names. This makes the interface inconsistent with the anon-type forms
224 of these functions (which must take an arrayref), and a free-form list where
225 the first value is sometimes special is hard to validate (and harder to give
226 reasonable error messages for). These functions have been changed to take
227 arrayrefs in all their forms - so, C<< enum 'My::Type' => [qw(foo bar)] >> is
228 now the preferred way to create an enum type constraint. The old syntax still
229 works for now, but it will hopefully be deprecated and removed in a future
234 =head1 Version 0.89_01
236 L<Moose::Meta::Attribute::Native> has been moved into the Moose core from
237 L<MooseX::AttributeHelpers>. Major changes include:
241 =item C<traits>, not C<metaclass>
243 Method providers are only available via traits.
245 =item C<handles>, not C<provides> or C<curries>
247 The C<provides> syntax was like core Moose C<< handles => HASHREF >>
248 syntax, but with the keys and values reversed. This was confusing,
249 and AttributeHelpers now uses C<< handles => HASHREF >> in a way that
250 should be intuitive to anyone already familiar with how it is used for
253 The C<curries> functionality provided by AttributeHelpers has been
254 generalized to apply to all cases of C<< handles => HASHREF >>, though
255 not every piece of functionality has been ported (currying with a
256 CODEREF is not supported).
258 =item C<empty> is now C<is_empty>, and means empty, not non-empty
260 Previously, the C<empty> method provided by Arrays and Hashes returned true if
261 the attribute was B<not> empty (no elements). Now it returns true if the
262 attribute B<is> empty. It was also renamed to C<is_empty>, to reflect this.
264 =item C<find> was renamed to C<first>, and C<first> and C<last> were removed
266 L<List::Util> refers to the functionality that we used to provide under C<find>
267 as L<first|List::Util/first>, so that will likely be more familiar (and will
268 fit in better if we decide to add more List::Util functions). C<first> and
269 C<last> were removed, since their functionality is easily duplicated with
272 =item Helpers that take a coderef of one argument now use C<$_>
274 Subroutines passed as the first argument to C<first>, C<map>, and C<grep> now
275 receive their argument in C<$_> rather than as a parameter to the subroutine.
276 Helpers that take a coderef of two or more arguments remain using the argument
277 list (there are technical limitations to using C<$a> and C<$b> like C<sort>
280 See L<Moose::Meta::Attribute::Native> for the new documentation.
284 The C<alias> and C<excludes> role parameters have been renamed to C<-alias>
285 and C<-excludes>. The old names still work, but new code should use the new
286 names, and eventually the old ones will be deprecated and removed.
290 C<< use Moose -metaclass => 'Foo' >> now does alias resolution, just like
291 C<-traits> (and the C<metaclass> and C<traits> options to C<has>).
293 Added two functions C<meta_class_alias> and C<meta_attribute_alias> to
294 L<Moose::Util>, to simplify aliasing metaclasses and metatraits. This is
295 a wrapper around the old
297 package Moose::Meta::Class::Custom::Trait::FooTrait;
298 sub register_implementation { 'My::Meta::Trait' }
304 When an attribute generates I<no> accessors, we now warn. This is to help
305 users who forget the C<is> option. If you really do not want any accessors,
306 you can use C<< is => 'bare' >>. You can maintain back compat with older
307 versions of Moose by using something like:
309 ($Moose::VERSION >= 0.84 ? is => 'bare' : ())
311 When an accessor overwrites an existing method, we now warn. To work around
312 this warning (if you really must have this behavior), you can explicitly
313 remove the method before creating it as an accessor:
317 __PACKAGE__->meta->remove_method('foo');
323 When an unknown option is passed to C<has>, we now warn. You can silence
324 the warning by fixing your code. :)
326 The C<Role> type has been deprecated. On its own, it was useless,
327 since it just checked C<< $object->can('does') >>. If you were using
328 it as a parent type, just call C<role_type('Role::Name')> to create an
329 appropriate type instead.
333 C<use Moose::Exporter;> now imports C<strict> and C<warnings> into packages
338 C<DEMOLISHALL> and C<DEMOLISH> now receive an argument indicating whether or
339 not we are in global destruction.
343 Type constraints no longer run coercions for a value that already matches the
344 constraint. This may affect some (arguably buggy) edge case coercions that
345 rely on side effects in the C<via> clause.
349 L<Moose::Exporter> now accepts the C<-metaclass> option for easily
350 overriding the metaclass (without L<metaclass>). This works for classes
355 Added a C<duck_type> sugar function to L<Moose::Util::TypeConstraints>
356 to make integration with non-Moose classes easier. It simply checks if
357 C<< $obj->can() >> a list of methods.
359 A number of methods (mostly inherited from L<Class::MOP>) have been
360 renamed with a leading underscore to indicate their internal-ness. The
361 old method names will still work for a while, but will warn that the
362 method has been renamed. In a few cases, the method will be removed
363 entirely in the future. This may affect MooseX authors who were using
368 Calling C<subtype> with a name as the only argument now throws an
369 exception. If you want an anonymous subtype do:
371 my $subtype = subtype as 'Foo';
373 This is related to the changes in version 0.71_01.
375 The C<is_needed> method in L<Moose::Meta::Method::Destructor> is now
376 only usable as a class method. Previously, it worked as a class or
377 object method, with a different internal implementation for each
380 The internals of making a class immutable changed a lot in Class::MOP
381 0.78_02, and Moose's internals have changed along with it. The
382 external C<< $metaclass->make_immutable >> method still works the same
387 A mutable class accepted C<< Foo->new(undef) >> without complaint,
388 while an immutable class would blow up with an unhelpful error. Now,
389 in both cases we throw a helpful error instead.
391 This "feature" was originally added to allow for cases such as this:
399 return My::Class->new($args);
401 But we decided this is a bad idea and a little too magical, because it
402 can easily mask real errors.
404 =head1 Version 0.71_01
406 Calling C<type> or C<subtype> without the sugar helpers (C<as>,
407 C<where>, C<message>) is now deprecated.
409 As a side effect, this meant we ended up using Perl prototypes on
410 C<as>, and code like this will no longer work:
412 use Moose::Util::TypeConstraints;
413 use Declare::Constraints::Simple -All;
415 subtype 'ArrayOfInts'
417 => IsArrayRef(IsInt);
419 Instead it must be changed to this:
424 where => IsArrayRef(IsInt)
428 If you want to maintain backwards compat with older versions of Moose,
429 you must explicitly test Moose's C<VERSION>:
431 if ( Moose->VERSION < 0.71_01 ) {
432 subtype 'ArrayOfInts'
434 => IsArrayRef(IsInt);
440 where => IsArrayRef(IsInt)
447 We no longer pass the meta-attribute object as a final argument to
448 triggers. This actually changed for inlined code a while back, but the
449 non-inlined version and the docs were still out of date.
451 If by some chance you actually used this feature, the workaround is
452 simple. You fetch the attribute object from out of the C<$self>
453 that is passed as the first argument to trigger, like so:
459 my ( $self, $value ) = @_;
460 my $attr = $self->meta->find_attribute_by_name('foo');
468 If you created a subtype and passed a parent that Moose didn't know
469 about, it simply ignored the parent. Now it automatically creates the
470 parent as a class type. This may not be what you want, but is less
473 You could declare a name with subtype such as "Foo!Bar". Moose would
474 accept this allowed, but if you used it in a parameterized type such
475 as "ArrayRef[Foo!Bar]" it wouldn't work. We now do some vetting on
476 names created via the sugar functions, so that they can only contain
477 alphanumerics, ":", and ".".
481 Methods created via an attribute can now fulfill a C<requires>
482 declaration for a role. Honestly we don't know why Stevan didn't make
483 this work originally, he was just insane or something.
485 Stack traces from inlined code will now report the line and file as
486 being in your class, as opposed to in Moose guts.
488 =head1 Version 0.62_02
490 When a class does not provide all of a role's required methods, the
491 error thrown now mentions all of the missing methods, as opposed to
492 just the first missing method.
494 Moose will no longer inline a constructor for your class unless it
495 inherits its constructor from Moose::Object, and will warn when it
496 doesn't inline. If you want to force inlining anyway, pass
497 C<< replace_constructor => 1 >> to C<make_immutable>.
499 If you want to get rid of the warning, pass C<< inline_constructor =>
504 Removed the (deprecated) C<make_immutable> keyword.
506 Removing an attribute from a class now also removes delegation
507 (C<handles>) methods installed for that attribute. This is correct
508 behavior, but if you were wrongly relying on it you might get bit.
512 Roles now add methods by calling C<add_method>, not
513 C<alias_method>. They make sure to always provide a method object,
514 which will be cloned internally. This means that it is now possible to
515 track the source of a method provided by a role, and even follow its
516 history through intermediate roles. This means that methods added by
517 a role now show up when looking at a class's method list/map.
519 Parameter and Union args are now sorted, this makes Int|Str the same
520 constraint as Str|Int. Also, incoming type constraint strings are
521 normalized to remove all whitespace differences. This is mostly for
522 internals and should not affect outside code.
524 L<Moose::Exporter> will no longer remove a subroutine that the
525 exporting package re-exports. Moose re-exports the Carp::confess
526 function, among others. The reasoning is that we cannot know whether
527 you have also explicitly imported those functions for your own use, so
528 we err on the safe side and always keep them.
532 C<Moose::init_meta> should now be called as a method.
534 New modules for extension writers, L<Moose::Exporter> and
535 L<Moose::Util::MetaRole>.
537 =head1 Version 0.55_01
539 Implemented metaclass traits (and wrote a recipe for it):
541 use Moose -traits => 'Foo'
543 This should make writing small Moose extensions a little
548 Fixed C<coerce> to accept anon types just like C<subtype> can.
551 coerce $some_anon_type => from 'Str' => via { ... };
555 Added C<BUILDARGS>, a new step in C<< Moose::Object->new() >>.
559 Fixed how the C<< is => (ro|rw) >> works with custom defined
560 C<reader>, C<writer> and C<accessor> options. See the below table for
563 is => ro, writer => _foo # turns into (reader => foo, writer => _foo)
564 is => rw, writer => _foo # turns into (reader => foo, writer => _foo)
565 is => rw, accessor => _foo # turns into (accessor => _foo)
566 is => ro, accessor => _foo # error, accesor is rw
570 The C<before/around/after> method modifiers now support regexp
571 matching of method names. NOTE: this only works for classes, it is
572 currently not supported in roles, but, ... patches welcome.
574 The C<has> keyword for roles now accepts the same array ref form that
575 L<Moose>.pm does for classes.
577 A trigger on a read-only attribute is no longer an error, as it's
578 useful to trigger off of the constructor.
580 Subtypes of parameterizable types now are parameterizable types
585 Fixed issue where C<DEMOLISHALL> was eating the value in C<$@>, and so
586 not working correctly. It still kind of eats them, but so does vanilla
591 Inherited attributes may now be extended without restriction on the
592 type ('isa', 'does').
594 The entire set of Moose::Meta::TypeConstraint::* classes were
595 refactored in this release. If you were relying on their internals you
596 should test your code carefully.
600 Documenting the use of '+name' with attributes that come from recently
601 composed roles. It makes sense, people are using it, and so why not
602 just officially support it.
604 The C<< Moose::Meta::Class->create >> method now supports roles.
606 It is now possible to make anonymous enum types by passing C<enum> an
607 array reference instead of the C<< enum $name => @values >>.
611 Added the C<make_immutable> keyword as a shortcut to calling
612 C<make_immutable> on the meta object. This eventually got removed!
614 Made C<< init_arg => undef >> work in Moose. This means "do not accept
615 a constructor parameter for this attribute".
617 Type errors now use the provided message. Prior to this release they
622 Moose is now a postmodern object system :)
624 The Role system was completely refactored. It is 100% backwards
625 compat, but the internals were totally changed. If you relied on the
626 internals then you are advised to test carefully.
628 Added method exclusion and aliasing for Roles in this release.
630 Added the L<Moose::Util::TypeConstraints::OptimizedConstraints>
633 Passing a list of values to an accessor (which is only expecting one
634 value) used to be silently ignored, now it throws an error.
638 Added parameterized types and did a pretty heavy refactoring of the
639 type constraint system.
641 Better framework extendability and better support for "making your own
644 =head1 Version 0.25 or before
646 Honestly, you shouldn't be using versions of Moose that are this old,
647 so many bug fixes and speed improvements have been made you would be
648 crazy to not upgrade.
650 Also, I am tired of going through the Changelog so I am stopping here,
651 if anyone would like to continue this please feel free.
655 Stevan Little E<lt>stevan@iinteractive.comE<gt>
657 =head1 COPYRIGHT AND LICENSE
659 Copyright 2009 by Infinity Interactive, Inc.
661 L<http://www.iinteractive.com>
663 This library is free software; you can redistribute it and/or modify
664 it under the same terms as Perl itself.