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 L<Moose::Object/BUILD> methods are now called when calling C<new_object>
23 Previously, C<BUILD> methods would only be called from C<Moose::Object::new>,
24 but now they are also called when constructing an object via
25 C<Moose::Meta::Class::new_object>. C<BUILD> methods are an inherent part of the
26 object construction process, and this should make C<< $meta->new_object >>
27 actually usable without forcing people to use C<< $meta->name->new >>.
29 =item C<no Moose>, C<no Moose::Role>, and C<no Moose::Exporter> now unimport strict and warnings
31 In the interest of having C<no Moose> clean up everything that C<use Moose>
32 does in the calling scope, C<no Moose> (as well as all other
33 L<Moose::Exporter>-using modules) now unimports strict and warnings.
35 =item Metaclass compatibility checking and fixing should be much more robust
37 The L<metaclass compatibility|Moose/METACLASS COMPATIBILITY AND MOOSE> checking
38 and fixing algorithms have been completely rewritten, in both Class::MOP and
39 Moose. This should resolve many confusing errors when dealing with non-Moose
40 inheritance and with custom metaclasses for things like attributes,
49 =item Moose::Meta::TypeConstraint::Class is_subtype_of behavior
51 Earlier versions of L<is_subtype_of|Moose::Meta::TypeConstraint::Class/is_subtype_of>
52 would incorrectly return true when called with itself, its own TC name or
53 its class name as an argument. (i.e. $foo_tc->is_subtype_of('Foo') == 1) This
54 behavior was a caused by C<isa> being checked before the class name. The old
55 behavior can be accessed with L<is_type_of|Moose::Meta::TypeConstraint::Class/is_type_of>
63 =item Moose::Meta::Attribute::Native::Trait::Code no longer creates reader methods by default
65 Earlier versions of L<Moose::Meta::Attribute::Native::Trait::Code> created
66 read-only accessors for the attributes it's been applied to, even if you didn't
67 ask for it with C<< is => 'ro' >>. This incorrect behaviour has now been fixed.
75 =item Moose::Util add_method_modifier behavior
77 add_method_modifier (and subsequently the sugar functions Moose::before,
78 Moose::after, and Moose::around) can now accept arrayrefs, with the same
79 behavior as lists. Types other than arrayref and regexp result in an error.
83 =head1 0.93_01 and 0.94
87 =item Moose::Util::MetaRole API has changed
89 The C<apply_metaclass_roles> function is now called C<apply_metaroles>. The
90 way arguments are supplied has been changed to force you to distinguish
91 between metaroles applied to L<Moose::Meta::Class> (and helpers) versus
94 The old API still works, but will warn in a future release, and eventually be
97 =item Moose::Meta::Role has real attributes
99 The attributes returned by L<Moose::Meta::Role> are now instances of the
100 L<Moose::Meta::Role::Attribute> class, instead of bare hash references.
102 =item "no Moose" now removes C<blessed> and C<confess>
104 Moose is now smart enough to know exactly what it exported, even when it
105 re-exports functions from other packages. When you unimport Moose, it will
106 remove these functions from your namespace unless you I<also> imported them
107 directly from their respective packages.
109 If you have a C<no Moose> in your code I<before> you call C<blessed> or
110 C<confess>, your code will break. You can either move the C<no Moose> call
111 later in your code, or explicitly import the relevant functions from the
112 packages that provide them.
114 =item L<Moose::Exporter> is smarter about unimporting re-exports
116 The change above comes from a general improvement to L<Moose::Exporter>. It
117 will now unimport any function it exports, even if that function is a
118 re-export from another package.
120 =item Attributes in roles can no longer override class attributes with "+foo"
122 Previously, this worked more or less accidentally, because role attributes
123 weren't objects. This was never documented, but a few MooseX modules took
126 =item The composition_class_roles attribute in L<Moose::Meta::Role> is now a method
128 This was done to make it possible for roles to alter the the list of
129 composition class roles by applying a method modifiers. Previously, this was
130 an attribute and MooseX modules override it. Since that no longer works, this
133 This I<should> be an attribute, so this may switch back to being an attribute
134 in the future if we can figure out how to make this work.
142 =item Calling $object->new() is no longer deprecated
144 We decided to undeprecate this. Now it just works.
146 =item Both C<get_method_map> and C<get_attribute_map> is deprecated
148 These metaclass methods were never meant to be public, and they are both now
149 deprecated. The work around if you still need the functionality they provided
150 is to iterate over the list of names manually.
152 my %fields = map { $_ => $meta->get_attribute($_) } $meta->get_attribute_list;
154 This was actually a change in L<Class::MOP>, but this version of Moose
155 requires a version of L<Class::MOP> that includes said change.
163 =item Added Native delegation for Code refs
165 See L<Moose::Meta::Attribute::Native::Trait::Code> for details.
167 =item Calling $object->new() is deprecated
169 Moose has long supported this, but it's never really been documented, and we
170 don't think this is a good practice. If you want to construct an object from
171 an existing object, you should provide some sort of alternate constructor like
172 C<< $object->clone >>.
174 Calling C<< $object->new >> now issues a warning, and will be an error in a
177 =item Moose no longer warns if you call C<make_immutable> for a class with mutable ancestors
179 While in theory this is a good thing to warn about, we found so many
180 exceptions to this that doing this properly became quite problematic.
184 =head1 Version 0.89_02
188 =item New Native delegation methods from L<List::Util> and L<List::MoreUtils>
190 In particular, we now have C<reduce>, C<shuffle>, C<uniq>, and C<natatime>.
192 =item The Moose::Exporter with_caller feature is now deprecated
194 Use C<with_meta> instead. The C<with_caller> option will start warning in a
197 =item Moose now warns if you call C<make_immutable> for a class with mutable ancestors
199 This is dangerous because modifying a class after a subclass has been
200 immutabilized will lead to incorrect results in the subclass, due to inlining,
201 caching, etc. This occasionally happens accidentally, when a class loads one
202 of its subclasses in the middle of its class definition, so pointing out that
203 this may cause issues should be helpful. Metaclasses (classes that inherit
204 from L<Class::MOP::Object>) are currently exempt from this check, since at the
205 moment we aren't very consistent about which metaclasses we immutabilize.
207 =item C<enum> and C<duck_type> now take arrayrefs for all forms
209 Previously, calling these functions with a list would take the first element of
210 the list as the type constraint name, and use the remainder as the enum values
211 or method names. This makes the interface inconsistent with the anon-type forms
212 of these functions (which must take an arrayref), and a free-form list where
213 the first value is sometimes special is hard to validate (and harder to give
214 reasonable error messages for). These functions have been changed to take
215 arrayrefs in all their forms - so, C<< enum 'My::Type' => [qw(foo bar)] >> is
216 now the preferred way to create an enum type constraint. The old syntax still
217 works for now, but it will hopefully be deprecated and removed in a future
222 =head1 Version 0.89_01
224 L<Moose::Meta::Attribute::Native> has been moved into the Moose core from
225 L<MooseX::AttributeHelpers>. Major changes include:
229 =item C<traits>, not C<metaclass>
231 Method providers are only available via traits.
233 =item C<handles>, not C<provides> or C<curries>
235 The C<provides> syntax was like core Moose C<< handles => HASHREF >>
236 syntax, but with the keys and values reversed. This was confusing,
237 and AttributeHelpers now uses C<< handles => HASHREF >> in a way that
238 should be intuitive to anyone already familiar with how it is used for
241 The C<curries> functionality provided by AttributeHelpers has been
242 generalized to apply to all cases of C<< handles => HASHREF >>, though
243 not every piece of functionality has been ported (currying with a
244 CODEREF is not supported).
246 =item C<empty> is now C<is_empty>, and means empty, not non-empty
248 Previously, the C<empty> method provided by Arrays and Hashes returned true if
249 the attribute was B<not> empty (no elements). Now it returns true if the
250 attribute B<is> empty. It was also renamed to C<is_empty>, to reflect this.
252 =item C<find> was renamed to C<first>, and C<first> and C<last> were removed
254 L<List::Util> refers to the functionality that we used to provide under C<find>
255 as L<first|List::Util/first>, so that will likely be more familiar (and will
256 fit in better if we decide to add more List::Util functions). C<first> and
257 C<last> were removed, since their functionality is easily duplicated with
260 =item Helpers that take a coderef of one argument now use C<$_>
262 Subroutines passed as the first argument to C<first>, C<map>, and C<grep> now
263 receive their argument in C<$_> rather than as a parameter to the subroutine.
264 Helpers that take a coderef of two or more arguments remain using the argument
265 list (there are technical limitations to using C<$a> and C<$b> like C<sort>
268 See L<Moose::Meta::Attribute::Native> for the new documentation.
272 The C<alias> and C<excludes> role parameters have been renamed to C<-alias>
273 and C<-excludes>. The old names still work, but new code should use the new
274 names, and eventually the old ones will be deprecated and removed.
278 C<< use Moose -metaclass => 'Foo' >> now does alias resolution, just like
279 C<-traits> (and the C<metaclass> and C<traits> options to C<has>).
281 Added two functions C<meta_class_alias> and C<meta_attribute_alias> to
282 L<Moose::Util>, to simplify aliasing metaclasses and metatraits. This is
283 a wrapper around the old
285 package Moose::Meta::Class::Custom::Trait::FooTrait;
286 sub register_implementation { 'My::Meta::Trait' }
292 When an attribute generates I<no> accessors, we now warn. This is to help
293 users who forget the C<is> option. If you really do not want any accessors,
294 you can use C<< is => 'bare' >>. You can maintain back compat with older
295 versions of Moose by using something like:
297 ($Moose::VERSION >= 0.84 ? is => 'bare' : ())
299 When an accessor overwrites an existing method, we now warn. To work around
300 this warning (if you really must have this behavior), you can explicitly
301 remove the method before creating it as an accessor:
305 __PACKAGE__->meta->remove_method('foo');
311 When an unknown option is passed to C<has>, we now warn. You can silence
312 the warning by fixing your code. :)
314 The C<Role> type has been deprecated. On its own, it was useless,
315 since it just checked C<< $object->can('does') >>. If you were using
316 it as a parent type, just call C<role_type('Role::Name')> to create an
317 appropriate type instead.
321 C<use Moose::Exporter;> now imports C<strict> and C<warnings> into packages
326 C<DEMOLISHALL> and C<DEMOLISH> now receive an argument indicating whether or
327 not we are in global destruction.
331 Type constraints no longer run coercions for a value that already matches the
332 constraint. This may affect some (arguably buggy) edge case coercions that
333 rely on side effects in the C<via> clause.
337 L<Moose::Exporter> now accepts the C<-metaclass> option for easily
338 overriding the metaclass (without L<metaclass>). This works for classes
343 Added a C<duck_type> sugar function to L<Moose::Util::TypeConstraints>
344 to make integration with non-Moose classes easier. It simply checks if
345 C<< $obj->can() >> a list of methods.
347 A number of methods (mostly inherited from L<Class::MOP>) have been
348 renamed with a leading underscore to indicate their internal-ness. The
349 old method names will still work for a while, but will warn that the
350 method has been renamed. In a few cases, the method will be removed
351 entirely in the future. This may affect MooseX authors who were using
356 Calling C<subtype> with a name as the only argument now throws an
357 exception. If you want an anonymous subtype do:
359 my $subtype = subtype as 'Foo';
361 This is related to the changes in version 0.71_01.
363 The C<is_needed> method in L<Moose::Meta::Method::Destructor> is now
364 only usable as a class method. Previously, it worked as a class or
365 object method, with a different internal implementation for each
368 The internals of making a class immutable changed a lot in Class::MOP
369 0.78_02, and Moose's internals have changed along with it. The
370 external C<< $metaclass->make_immutable >> method still works the same
375 A mutable class accepted C<< Foo->new(undef) >> without complaint,
376 while an immutable class would blow up with an unhelpful error. Now,
377 in both cases we throw a helpful error instead.
379 This "feature" was originally added to allow for cases such as this:
387 return My::Class->new($args);
389 But we decided this is a bad idea and a little too magical, because it
390 can easily mask real errors.
392 =head1 Version 0.71_01
394 Calling C<type> or C<subtype> without the sugar helpers (C<as>,
395 C<where>, C<message>) is now deprecated.
397 As a side effect, this meant we ended up using Perl prototypes on
398 C<as>, and code like this will no longer work:
400 use Moose::Util::TypeConstraints;
401 use Declare::Constraints::Simple -All;
403 subtype 'ArrayOfInts'
405 => IsArrayRef(IsInt);
407 Instead it must be changed to this:
412 where => IsArrayRef(IsInt)
416 If you want to maintain backwards compat with older versions of Moose,
417 you must explicitly test Moose's C<VERSION>:
419 if ( Moose->VERSION < 0.71_01 ) {
420 subtype 'ArrayOfInts'
422 => IsArrayRef(IsInt);
428 where => IsArrayRef(IsInt)
435 We no longer pass the meta-attribute object as a final argument to
436 triggers. This actually changed for inlined code a while back, but the
437 non-inlined version and the docs were still out of date.
439 If by some chance you actually used this feature, the workaround is
440 simple. You fetch the attribute object from out of the C<$self>
441 that is passed as the first argument to trigger, like so:
447 my ( $self, $value ) = @_;
448 my $attr = $self->meta->find_attribute_by_name('foo');
456 If you created a subtype and passed a parent that Moose didn't know
457 about, it simply ignored the parent. Now it automatically creates the
458 parent as a class type. This may not be what you want, but is less
461 You could declare a name with subtype such as "Foo!Bar". Moose would
462 accept this allowed, but if you used it in a parameterized type such
463 as "ArrayRef[Foo!Bar]" it wouldn't work. We now do some vetting on
464 names created via the sugar functions, so that they can only contain
465 alphanumerics, ":", and ".".
469 Methods created via an attribute can now fulfill a C<requires>
470 declaration for a role. Honestly we don't know why Stevan didn't make
471 this work originally, he was just insane or something.
473 Stack traces from inlined code will now report the line and file as
474 being in your class, as opposed to in Moose guts.
476 =head1 Version 0.62_02
478 When a class does not provide all of a role's required methods, the
479 error thrown now mentions all of the missing methods, as opposed to
480 just the first missing method.
482 Moose will no longer inline a constructor for your class unless it
483 inherits its constructor from Moose::Object, and will warn when it
484 doesn't inline. If you want to force inlining anyway, pass
485 C<< replace_constructor => 1 >> to C<make_immutable>.
487 If you want to get rid of the warning, pass C<< inline_constructor =>
492 Removed the (deprecated) C<make_immutable> keyword.
494 Removing an attribute from a class now also removes delegation
495 (C<handles>) methods installed for that attribute. This is correct
496 behavior, but if you were wrongly relying on it you might get bit.
500 Roles now add methods by calling C<add_method>, not
501 C<alias_method>. They make sure to always provide a method object,
502 which will be cloned internally. This means that it is now possible to
503 track the source of a method provided by a role, and even follow its
504 history through intermediate roles. This means that methods added by
505 a role now show up when looking at a class's method list/map.
507 Parameter and Union args are now sorted, this makes Int|Str the same
508 constraint as Str|Int. Also, incoming type constraint strings are
509 normalized to remove all whitespace differences. This is mostly for
510 internals and should not affect outside code.
512 L<Moose::Exporter> will no longer remove a subroutine that the
513 exporting package re-exports. Moose re-exports the Carp::confess
514 function, among others. The reasoning is that we cannot know whether
515 you have also explicitly imported those functions for your own use, so
516 we err on the safe side and always keep them.
520 C<Moose::init_meta> should now be called as a method.
522 New modules for extension writers, L<Moose::Exporter> and
523 L<Moose::Util::MetaRole>.
525 =head1 Version 0.55_01
527 Implemented metaclass traits (and wrote a recipe for it):
529 use Moose -traits => 'Foo'
531 This should make writing small Moose extensions a little
536 Fixed C<coerce> to accept anon types just like C<subtype> can.
539 coerce $some_anon_type => from 'Str' => via { ... };
543 Added C<BUILDARGS>, a new step in C<< Moose::Object->new() >>.
547 Fixed how the C<< is => (ro|rw) >> works with custom defined
548 C<reader>, C<writer> and C<accessor> options. See the below table for
551 is => ro, writer => _foo # turns into (reader => foo, writer => _foo)
552 is => rw, writer => _foo # turns into (reader => foo, writer => _foo)
553 is => rw, accessor => _foo # turns into (accessor => _foo)
554 is => ro, accessor => _foo # error, accesor is rw
558 The C<before/around/after> method modifiers now support regexp
559 matching of method names. NOTE: this only works for classes, it is
560 currently not supported in roles, but, ... patches welcome.
562 The C<has> keyword for roles now accepts the same array ref form that
563 L<Moose>.pm does for classes.
565 A trigger on a read-only attribute is no longer an error, as it's
566 useful to trigger off of the constructor.
568 Subtypes of parameterizable types now are parameterizable types
573 Fixed issue where C<DEMOLISHALL> was eating the value in C<$@>, and so
574 not working correctly. It still kind of eats them, but so does vanilla
579 Inherited attributes may now be extended without restriction on the
580 type ('isa', 'does').
582 The entire set of Moose::Meta::TypeConstraint::* classes were
583 refactored in this release. If you were relying on their internals you
584 should test your code carefully.
588 Documenting the use of '+name' with attributes that come from recently
589 composed roles. It makes sense, people are using it, and so why not
590 just officially support it.
592 The C<< Moose::Meta::Class->create >> method now supports roles.
594 It is now possible to make anonymous enum types by passing C<enum> an
595 array reference instead of the C<< enum $name => @values >>.
599 Added the C<make_immutable> keyword as a shortcut to calling
600 C<make_immutable> on the meta object. This eventually got removed!
602 Made C<< init_arg => undef >> work in Moose. This means "do not accept
603 a constructor parameter for this attribute".
605 Type errors now use the provided message. Prior to this release they
610 Moose is now a postmodern object system :)
612 The Role system was completely refactored. It is 100% backwards
613 compat, but the internals were totally changed. If you relied on the
614 internals then you are advised to test carefully.
616 Added method exclusion and aliasing for Roles in this release.
618 Added the L<Moose::Util::TypeConstraints::OptimizedConstraints>
621 Passing a list of values to an accessor (which is only expecting one
622 value) used to be silently ignored, now it throws an error.
626 Added parameterized types and did a pretty heavy refactoring of the
627 type constraint system.
629 Better framework extendability and better support for "making your own
632 =head1 Version 0.25 or before
634 Honestly, you shouldn't be using versions of Moose that are this old,
635 so many bug fixes and speed improvements have been made you would be
636 crazy to not upgrade.
638 Also, I am tired of going through the Changelog so I am stopping here,
639 if anyone would like to continue this please feel free.
643 Stevan Little E<lt>stevan@iinteractive.comE<gt>
645 =head1 COPYRIGHT AND LICENSE
647 Copyright 2009 by Infinity Interactive, Inc.
649 L<http://www.iinteractive.com>
651 This library is free software; you can redistribute it and/or modify
652 it under the same terms as Perl itself.