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
19 =head1 0.93_01 and 0.94
23 =item Moose::Util::MetaRole API has changed
25 The C<apply_metaclass_roles> function is now called C<apply_metaroles>. The
26 way arguments are supplied has been changed to force you to distinguish
27 between metaroles applied to L<Moose::Meta::Class> (and helpers) versus
30 The old API still works, but will warn in a future release, and eventually be
33 =item Moose::Meta::Role has real attributes
35 The attributes returned by L<Moose::Meta::Role> are now instances of the
36 L<Moose::Meta::Role::Attribute> class, instead of bare hash references.
38 <<<<<<< HEAD:lib/Moose/Manual/Delta.pod
39 =item "no Moose" now removes C<blessed> and C<confess>
41 Moose is now smart enough to know exactly what it exported, even when it
42 re-exports functions from other packages. When you unimport Moose, it will
43 remove these functions from your namespace unless you I<also> imported them
44 directly from their respective packages.
46 If you have a C<no Moose> in your code I<before> you call C<blessed> or
47 C<confess>, your code will break. You can either move the C<no Moose> call
48 later in your code, or explicitly import the relevant functions from the
49 packages that provide them.
51 =item L<Moose::Exporter> is smarter about unimporting re-exports
53 The change above comes from a general improvement to L<Moose::Exporter>. It
54 will now unimport any function it exports, even if that function is a
55 re-export from another package.
57 =item Attributes in roles can no longer override class attributes with "+foo"
59 Previously, this worked more or less accidentally, because role attributes
60 weren't objects. This was never documented, but a few MooseX modules took
63 =item The composition_class_roles attribute in L<Moose::Meta::Role> is now a method
65 This was done to make it possible for roles to alter the the list of
66 composition class roles by applying a method modifiers. Previously, this was
67 an attribute and MooseX modules override it. Since that no longer works, this
70 This I<should> be an attribute, so this may switch back to being an attribute
71 in the future if we can figure out how to make this work.
79 =item Calling $object->new() is no longer deprecated
81 We decided to undeprecate this. Now it just works.
83 =item Both C<get_method_map> and C<get_attribute_map> is deprecated
85 These metaclass methods were never meant to be public, and they are both now
86 deprecated. The work around if you still need the functionality they provided
87 is to iterate over the list of names manually.
89 my %fields = map { $_ => $meta->get_attribute($_) } $meta->get_attribute_list;
91 This was actually a change in L<Class::MOP>, but this version of Moose
92 requires a version of L<Class::MOP> that includes said change.
100 =item Added Native delegation for Code refs
102 See L<Moose::Meta::Attribute::Native::Trait::Code> for details.
104 =item Calling $object->new() is deprecated
106 Moose has long supported this, but it's never really been documented, and we
107 don't think this is a good practice. If you want to construct an object from
108 an existing object, you should provide some sort of alternate constructor like
109 C<< $object->clone >>.
111 Calling C<< $object->new >> now issues a warning, and will be an error in a
114 =item Moose no longer warns if you call C<make_immutable> for a class with mutable ancestors
116 While in theory this is a good thing to warn about, we found so many
117 exceptions to this that doing this properly became quite problematic.
121 =head1 Version 0.89_02
125 =item New Native delegation methods from L<List::Util> and L<List::MoreUtils>
127 In particular, we now have C<reduce>, C<shuffle>, C<uniq>, and C<natatime>.
129 =item The Moose::Exporter with_caller feature is now deprecated
131 Use C<with_meta> instead. The C<with_caller> option will start warning in a
134 =item Moose now warns if you call C<make_immutable> for a class with mutable ancestors
136 This is dangerous because modifying a class after a subclass has been
137 immutabilized will lead to incorrect results in the subclass, due to inlining,
138 caching, etc. This occasionally happens accidentally, when a class loads one
139 of its subclasses in the middle of its class definition, so pointing out that
140 this may cause issues should be helpful. Metaclasses (classes that inherit
141 from L<Class::MOP::Object>) are currently exempt from this check, since at the
142 moment we aren't very consistent about which metaclasses we immutabilize.
144 =item C<enum> and C<duck_type> now take arrayrefs for all forms
146 Previously, calling these functions with a list would take the first element of
147 the list as the type constraint name, and use the remainder as the enum values
148 or method names. This makes the interface inconsistent with the anon-type forms
149 of these functions (which must take an arrayref), and a free-form list where
150 the first value is sometimes special is hard to validate (and harder to give
151 reasonable error messages for). These functions have been changed to take
152 arrayrefs in all their forms - so, C<< enum 'My::Type' => [qw(foo bar)] >> is
153 now the preferred way to create an enum type constraint. The old syntax still
154 works for now, but it will hopefully be deprecated and removed in a future
159 =head1 Version 0.89_01
161 L<Moose::Meta::Attribute::Native> has been moved into the Moose core from
162 L<MooseX::AttributeHelpers>. Major changes include:
166 =item C<traits>, not C<metaclass>
168 Method providers are only available via traits.
170 =item C<handles>, not C<provides> or C<curries>
172 The C<provides> syntax was like core Moose C<< handles => HASHREF >>
173 syntax, but with the keys and values reversed. This was confusing,
174 and AttributeHelpers now uses C<< handles => HASHREF >> in a way that
175 should be intuitive to anyone already familiar with how it is used for
178 The C<curries> functionality provided by AttributeHelpers has been
179 generalized to apply to all cases of C<< handles => HASHREF >>, though
180 not every piece of functionality has been ported (currying with a
181 CODEREF is not supported).
183 =item C<empty> is now C<is_empty>, and means empty, not non-empty
185 Previously, the C<empty> method provided by Arrays and Hashes returned true if
186 the attribute was B<not> empty (no elements). Now it returns true if the
187 attribute B<is> empty. It was also renamed to C<is_empty>, to reflect this.
189 =item C<find> was renamed to C<first>, and C<first> and C<last> were removed
191 L<List::Util> refers to the functionality that we used to provide under C<find>
192 as L<first|List::Util/first>, so that will likely be more familiar (and will
193 fit in better if we decide to add more List::Util functions). C<first> and
194 C<last> were removed, since their functionality is easily duplicated with
197 =item Helpers that take a coderef of one argument now use C<$_>
199 Subroutines passed as the first argument to C<first>, C<map>, and C<grep> now
200 receive their argument in C<$_> rather than as a parameter to the subroutine.
201 Helpers that take a coderef of two or more arguments remain using the argument
202 list (there are technical limitations to using C<$a> and C<$b> like C<sort>
205 See L<Moose::Meta::Attribute::Native> for the new documentation.
209 The C<alias> and C<excludes> role parameters have been renamed to C<-alias>
210 and C<-excludes>. The old names still work, but new code should use the new
211 names, and eventually the old ones will be deprecated and removed.
215 C<< use Moose -metaclass => 'Foo' >> now does alias resolution, just like
216 C<-traits> (and the C<metaclass> and C<traits> options to C<has>).
218 Added two functions C<meta_class_alias> and C<meta_attribute_alias> to
219 L<Moose::Util>, to simplify aliasing metaclasses and metatraits. This is
220 a wrapper around the old
222 package Moose::Meta::Class::Custom::Trait::FooTrait;
223 sub register_implementation { 'My::Meta::Trait' }
229 When an attribute generates I<no> accessors, we now warn. This is to help
230 users who forget the C<is> option. If you really do not want any accessors,
231 you can use C<< is => 'bare' >>. You can maintain back compat with older
232 versions of Moose by using something like:
234 ($Moose::VERSION >= 0.84 ? is => 'bare' : ())
236 When an accessor overwrites an existing method, we now warn. To work around
237 this warning (if you really must have this behavior), you can explicitly
238 remove the method before creating it as an accessor:
242 __PACKAGE__->meta->remove_method('foo');
248 When an unknown option is passed to C<has>, we now warn. You can silence
249 the warning by fixing your code. :)
251 The C<Role> type has been deprecated. On its own, it was useless,
252 since it just checked C<< $object->can('does') >>. If you were using
253 it as a parent type, just call C<role_type('Role::Name')> to create an
254 appropriate type instead.
258 C<use Moose::Exporter;> now imports C<strict> and C<warnings> into packages
263 C<DEMOLISHALL> and C<DEMOLISH> now receive an argument indicating whether or
264 not we are in global destruction.
268 Type constraints no longer run coercions for a value that already matches the
269 constraint. This may affect some (arguably buggy) edge case coercions that
270 rely on side effects in the C<via> clause.
274 L<Moose::Exporter> now accepts the C<-metaclass> option for easily
275 overriding the metaclass (without L<metaclass>). This works for classes
280 Added a C<duck_type> sugar function to L<Moose::Util::TypeConstraints>
281 to make integration with non-Moose classes easier. It simply checks if
282 C<< $obj->can() >> a list of methods.
284 A number of methods (mostly inherited from L<Class::MOP>) have been
285 renamed with a leading underscore to indicate their internal-ness. The
286 old method names will still work for a while, but will warn that the
287 method has been renamed. In a few cases, the method will be removed
288 entirely in the future. This may affect MooseX authors who were using
293 Calling C<subtype> with a name as the only argument now throws an
294 exception. If you want an anonymous subtype do:
296 my $subtype = subtype as 'Foo';
298 This is related to the changes in version 0.71_01.
300 The C<is_needed> method in L<Moose::Meta::Method::Destructor> is now
301 only usable as a class method. Previously, it worked as a class or
302 object method, with a different internal implementation for each
305 The internals of making a class immutable changed a lot in Class::MOP
306 0.78_02, and Moose's internals have changed along with it. The
307 external C<< $metaclass->make_immutable >> method still works the same
312 A mutable class accepted C<< Foo->new(undef) >> without complaint,
313 while an immutable class would blow up with an unhelpful error. Now,
314 in both cases we throw a helpful error instead.
316 This "feature" was originally added to allow for cases such as this:
324 return My::Class->new($args);
326 But we decided this is a bad idea and a little too magical, because it
327 can easily mask real errors.
329 =head1 Version 0.71_01
331 Calling C<type> or C<subtype> without the sugar helpers (C<as>,
332 C<where>, C<message>) is now deprecated.
334 As a side effect, this meant we ended up using Perl prototypes on
335 C<as>, and code like this will no longer work:
337 use Moose::Util::TypeConstraints;
338 use Declare::Constraints::Simple -All;
340 subtype 'ArrayOfInts'
342 => IsArrayRef(IsInt);
344 Instead it must be changed to this:
349 where => IsArrayRef(IsInt)
353 If you want to maintain backwards compat with older versions of Moose,
354 you must explicitly test Moose's C<VERSION>:
356 if ( Moose->VERSION < 0.71_01 ) {
357 subtype 'ArrayOfInts'
359 => IsArrayRef(IsInt);
365 where => IsArrayRef(IsInt)
372 We no longer pass the meta-attribute object as a final argument to
373 triggers. This actually changed for inlined code a while back, but the
374 non-inlined version and the docs were still out of date.
376 If by some chance you actually used this feature, the workaround is
377 simple. You fetch the attribute object from out of the C<$self>
378 that is passed as the first argument to trigger, like so:
384 my ( $self, $value ) = @_;
385 my $attr = $self->meta->find_attribute_by_name('foo');
393 If you created a subtype and passed a parent that Moose didn't know
394 about, it simply ignored the parent. Now it automatically creates the
395 parent as a class type. This may not be what you want, but is less
398 You could declare a name with subtype such as "Foo!Bar". Moose would
399 accept this allowed, but if you used it in a parameterized type such
400 as "ArrayRef[Foo!Bar]" it wouldn't work. We now do some vetting on
401 names created via the sugar functions, so that they can only contain
402 alphanumerics, ":", and ".".
406 Methods created via an attribute can now fulfill a C<requires>
407 declaration for a role. Honestly we don't know why Stevan didn't make
408 this work originally, he was just insane or something.
410 Stack traces from inlined code will now report the line and file as
411 being in your class, as opposed to in Moose guts.
413 =head1 Version 0.62_02
415 When a class does not provide all of a role's required methods, the
416 error thrown now mentions all of the missing methods, as opposed to
417 just the first missing method.
419 Moose will no longer inline a constructor for your class unless it
420 inherits its constructor from Moose::Object, and will warn when it
421 doesn't inline. If you want to force inlining anyway, pass
422 C<< replace_constructor => 1 >> to C<make_immutable>.
424 If you want to get rid of the warning, pass C<< inline_constructor =>
429 Removed the (deprecated) C<make_immutable> keyword.
431 Removing an attribute from a class now also removes delegation
432 (C<handles>) methods installed for that attribute. This is correct
433 behavior, but if you were wrongly relying on it you might get bit.
437 Roles now add methods by calling C<add_method>, not
438 C<alias_method>. They make sure to always provide a method object,
439 which will be cloned internally. This means that it is now possible to
440 track the source of a method provided by a role, and even follow its
441 history through intermediate roles. This means that methods added by
442 a role now show up when looking at a class's method list/map.
444 Parameter and Union args are now sorted, this makes Int|Str the same
445 constraint as Str|Int. Also, incoming type constraint strings are
446 normalized to remove all whitespace differences. This is mostly for
447 internals and should not affect outside code.
449 L<Moose::Exporter> will no longer remove a subroutine that the
450 exporting package re-exports. Moose re-exports the Carp::confess
451 function, among others. The reasoning is that we cannot know whether
452 you have also explicitly imported those functions for your own use, so
453 we err on the safe side and always keep them.
457 C<Moose::init_meta> should now be called as a method.
459 New modules for extension writers, L<Moose::Exporter> and
460 L<Moose::Util::MetaRole>.
462 =head1 Version 0.55_01
464 Implemented metaclass traits (and wrote a recipe for it):
466 use Moose -traits => 'Foo'
468 This should make writing small Moose extensions a little
473 Fixed C<coerce> to accept anon types just like C<subtype> can.
476 coerce $some_anon_type => from 'Str' => via { ... };
480 Added C<BUILDARGS>, a new step in C<< Moose::Object->new() >>.
484 Fixed how the C<< is => (ro|rw) >> works with custom defined
485 C<reader>, C<writer> and C<accessor> options. See the below table for
488 is => ro, writer => _foo # turns into (reader => foo, writer => _foo)
489 is => rw, writer => _foo # turns into (reader => foo, writer => _foo)
490 is => rw, accessor => _foo # turns into (accessor => _foo)
491 is => ro, accessor => _foo # error, accesor is rw
495 The C<before/around/after> method modifiers now support regexp
496 matching of method names. NOTE: this only works for classes, it is
497 currently not supported in roles, but, ... patches welcome.
499 The C<has> keyword for roles now accepts the same array ref form that
500 L<Moose>.pm does for classes.
502 A trigger on a read-only attribute is no longer an error, as it's
503 useful to trigger off of the constructor.
505 Subtypes of parameterizable types now are parameterizable types
510 Fixed issue where C<DEMOLISHALL> was eating the value in C<$@>, and so
511 not working correctly. It still kind of eats them, but so does vanilla
516 Inherited attributes may now be extended without restriction on the
517 type ('isa', 'does').
519 The entire set of Moose::Meta::TypeConstraint::* classes were
520 refactored in this release. If you were relying on their internals you
521 should test your code carefully.
525 Documenting the use of '+name' with attributes that come from recently
526 composed roles. It makes sense, people are using it, and so why not
527 just officially support it.
529 The C<< Moose::Meta::Class->create >> method now supports roles.
531 It is now possible to make anonymous enum types by passing C<enum> an
532 array reference instead of the C<< enum $name => @values >>.
536 Added the C<make_immutable> keyword as a shortcut to calling
537 C<make_immutable> on the meta object. This eventually got removed!
539 Made C<< init_arg => undef >> work in Moose. This means "do not accept
540 a constructor parameter for this attribute".
542 Type errors now use the provided message. Prior to this release they
547 Moose is now a postmodern object system :)
549 The Role system was completely refactored. It is 100% backwards
550 compat, but the internals were totally changed. If you relied on the
551 internals then you are advised to test carefully.
553 Added method exclusion and aliasing for Roles in this release.
555 Added the L<Moose::Util::TypeConstraints::OptimizedConstraints>
558 Passing a list of values to an accessor (which is only expecting one
559 value) used to be silently ignored, now it throws an error.
563 Added parameterized types and did a pretty heavy refactoring of the
564 type constraint system.
566 Better framework extendability and better support for "making your own
569 =head1 Version 0.25 or before
571 Honestly, you shouldn't be using versions of Moose that are this old,
572 so many bug fixes and speed improvements have been made you would be
573 crazy to not upgrade.
575 Also, I am tired of going through the Changelog so I am stopping here,
576 if anyone would like to continue this please feel free.
580 Stevan Little E<lt>stevan@iinteractive.comE<gt>
582 =head1 COPYRIGHT AND LICENSE
584 Copyright 2009 by Infinity Interactive, Inc.
586 L<http://www.iinteractive.com>
588 This library is free software; you can redistribute it and/or modify
589 it under the same terms as Perl itself.