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 "no Moose" now removes C<blessed> and C<confess>
25 Moose is now smart enough to know exactly what it exported, even when it
26 re-exports functions from other packages. When you unimport Moose, it will
27 remove these functions from your namespace unless you I<also> imported them
28 directly from their respective packages.
30 If you have a C<no Moose> in your code I<before> you call C<blessed> or
31 C<confess>, your code will break. You can either move the C<no Moose> call
32 later in your code, or explicitly import the relevant functions from the
33 packages that provide them.
35 =item L<Moose::Exporter> is smarter about unimporting re-exports
37 The change above comes from a general improvement to L<Moose::Exporter>. It
38 will now unimport any function it exports, even if that function is a
39 re-export from another package.
41 =item Attributes in roles can no longer override class attributes with "+foo"
43 Previously, this worked more or less accidentally, because role attributes
44 weren't objects. This was never documented, but a few MooseX modules took
47 =item The composition_class_roles attribute in L<Moose::Meta::Role> is now a method
49 This was done to make it possible for roles to alter the the list of
50 composition class roles by applying a method modifiers. Previously, this was
51 an attribute and MooseX modules override it. Since that no longer works, this
54 This I<should> be an attribute, so this may switch back to being an attribute
55 in the future if we can figure out how to make this work.
63 =item Calling $object->new() is no longer deprecated
65 We decided to undeprecate this. Now it just works.
67 =item Both C<get_method_map> and C<get_attribute_map> is deprecated
69 These metaclass methods were never meant to be public, and they are both now
70 deprecated. The work around if you still need the functionality they provided
71 is to iterate over the list of names manually.
73 my %fields = map { $_ => $meta->get_attribute($_) } $meta->get_attribute_list;
75 This was actually a change in L<Class::MOP>, but this version of Moose
76 requires a version of L<Class::MOP> that includes said change.
84 =item Added Native delegation for Code refs
86 See L<Moose::Meta::Attribute::Native::Trait::Code> for details.
88 =item Calling $object->new() is deprecated
90 Moose has long supported this, but it's never really been documented, and we
91 don't think this is a good practice. If you want to construct an object from
92 an existing object, you should provide some sort of alternate constructor like
93 C<< $object->clone >>.
95 Calling C<< $object->new >> now issues a warning, and will be an error in a
98 =item Moose no longer warns if you call C<make_immutable> for a class with mutable ancestors
100 While in theory this is a good thing to warn about, we found so many
101 exceptions to this that doing this properly became quite problematic.
105 =head1 Version 0.89_02
109 =item New Native delegation methods from L<List::Util> and L<List::MoreUtils>
111 In particular, we now have C<reduce>, C<shuffle>, C<uniq>, and C<natatime>.
113 =item The Moose::Exporter with_caller feature is now deprecated
115 Use C<with_meta> instead. The C<with_caller> option will start warning in a
118 =item Moose now warns if you call C<make_immutable> for a class with mutable ancestors
120 This is dangerous because modifying a class after a subclass has been
121 immutabilized will lead to incorrect results in the subclass, due to inlining,
122 caching, etc. This occasionally happens accidentally, when a class loads one
123 of its subclasses in the middle of its class definition, so pointing out that
124 this may cause issues should be helpful. Metaclasses (classes that inherit
125 from L<Class::MOP::Object>) are currently exempt from this check, since at the
126 moment we aren't very consistent about which metaclasses we immutabilize.
128 =item C<enum> and C<duck_type> now take arrayrefs for all forms
130 Previously, calling these functions with a list would take the first element of
131 the list as the type constraint name, and use the remainder as the enum values
132 or method names. This makes the interface inconsistent with the anon-type forms
133 of these functions (which must take an arrayref), and a free-form list where
134 the first value is sometimes special is hard to validate (and harder to give
135 reasonable error messages for). These functions have been changed to take
136 arrayrefs in all their forms - so, C<< enum 'My::Type' => [qw(foo bar)] >> is
137 now the preferred way to create an enum type constraint. The old syntax still
138 works for now, but it will hopefully be deprecated and removed in a future
143 =head1 Version 0.89_01
145 L<Moose::Meta::Attribute::Native> has been moved into the Moose core from
146 L<MooseX::AttributeHelpers>. Major changes include:
150 =item C<traits>, not C<metaclass>
152 Method providers are only available via traits.
154 =item C<handles>, not C<provides> or C<curries>
156 The C<provides> syntax was like core Moose C<< handles => HASHREF >>
157 syntax, but with the keys and values reversed. This was confusing,
158 and AttributeHelpers now uses C<< handles => HASHREF >> in a way that
159 should be intuitive to anyone already familiar with how it is used for
162 The C<curries> functionality provided by AttributeHelpers has been
163 generalized to apply to all cases of C<< handles => HASHREF >>, though
164 not every piece of functionality has been ported (currying with a
165 CODEREF is not supported).
167 =item C<empty> is now C<is_empty>, and means empty, not non-empty
169 Previously, the C<empty> method provided by Arrays and Hashes returned true if
170 the attribute was B<not> empty (no elements). Now it returns true if the
171 attribute B<is> empty. It was also renamed to C<is_empty>, to reflect this.
173 =item C<find> was renamed to C<first>, and C<first> and C<last> were removed
175 L<List::Util> refers to the functionality that we used to provide under C<find>
176 as L<first|List::Util/first>, so that will likely be more familiar (and will
177 fit in better if we decide to add more List::Util functions). C<first> and
178 C<last> were removed, since their functionality is easily duplicated with
181 =item Helpers that take a coderef of one argument now use C<$_>
183 Subroutines passed as the first argument to C<first>, C<map>, and C<grep> now
184 receive their argument in C<$_> rather than as a parameter to the subroutine.
185 Helpers that take a coderef of two or more arguments remain using the argument
186 list (there are technical limitations to using C<$a> and C<$b> like C<sort>
189 See L<Moose::Meta::Attribute::Native> for the new documentation.
193 The C<alias> and C<excludes> role parameters have been renamed to C<-alias>
194 and C<-excludes>. The old names still work, but new code should use the new
195 names, and eventually the old ones will be deprecated and removed.
199 C<< use Moose -metaclass => 'Foo' >> now does alias resolution, just like
200 C<-traits> (and the C<metaclass> and C<traits> options to C<has>).
202 Added two functions C<meta_class_alias> and C<meta_attribute_alias> to
203 L<Moose::Util>, to simplify aliasing metaclasses and metatraits. This is
204 a wrapper around the old
206 package Moose::Meta::Class::Custom::Trait::FooTrait;
207 sub register_implementation { 'My::Meta::Trait' }
213 When an attribute generates I<no> accessors, we now warn. This is to help
214 users who forget the C<is> option. If you really do not want any accessors,
215 you can use C<< is => 'bare' >>. You can maintain back compat with older
216 versions of Moose by using something like:
218 ($Moose::VERSION >= 0.84 ? is => 'bare' : ())
220 When an accessor overwrites an existing method, we now warn. To work around
221 this warning (if you really must have this behavior), you can explicitly
222 remove the method before creating it as an accessor:
226 __PACKAGE__->meta->remove_method('foo');
232 When an unknown option is passed to C<has>, we now warn. You can silence
233 the warning by fixing your code. :)
235 The C<Role> type has been deprecated. On its own, it was useless,
236 since it just checked C<< $object->can('does') >>. If you were using
237 it as a parent type, just call C<role_type('Role::Name')> to create an
238 appropriate type instead.
242 C<use Moose::Exporter;> now imports C<strict> and C<warnings> into packages
247 C<DEMOLISHALL> and C<DEMOLISH> now receive an argument indicating whether or
248 not we are in global destruction.
252 Type constraints no longer run coercions for a value that already matches the
253 constraint. This may affect some (arguably buggy) edge case coercions that
254 rely on side effects in the C<via> clause.
258 L<Moose::Exporter> now accepts the C<-metaclass> option for easily
259 overriding the metaclass (without L<metaclass>). This works for classes
264 Added a C<duck_type> sugar function to L<Moose::Util::TypeConstraints>
265 to make integration with non-Moose classes easier. It simply checks if
266 C<< $obj->can() >> a list of methods.
268 A number of methods (mostly inherited from L<Class::MOP>) have been
269 renamed with a leading underscore to indicate their internal-ness. The
270 old method names will still work for a while, but will warn that the
271 method has been renamed. In a few cases, the method will be removed
272 entirely in the future. This may affect MooseX authors who were using
277 Calling C<subtype> with a name as the only argument now throws an
278 exception. If you want an anonymous subtype do:
280 my $subtype = subtype as 'Foo';
282 This is related to the changes in version 0.71_01.
284 The C<is_needed> method in L<Moose::Meta::Method::Destructor> is now
285 only usable as a class method. Previously, it worked as a class or
286 object method, with a different internal implementation for each
289 The internals of making a class immutable changed a lot in Class::MOP
290 0.78_02, and Moose's internals have changed along with it. The
291 external C<< $metaclass->make_immutable >> method still works the same
296 A mutable class accepted C<< Foo->new(undef) >> without complaint,
297 while an immutable class would blow up with an unhelpful error. Now,
298 in both cases we throw a helpful error instead.
300 This "feature" was originally added to allow for cases such as this:
308 return My::Class->new($args);
310 But we decided this is a bad idea and a little too magical, because it
311 can easily mask real errors.
313 =head1 Version 0.71_01
315 Calling C<type> or C<subtype> without the sugar helpers (C<as>,
316 C<where>, C<message>) is now deprecated.
318 As a side effect, this meant we ended up using Perl prototypes on
319 C<as>, and code like this will no longer work:
321 use Moose::Util::TypeConstraints;
322 use Declare::Constraints::Simple -All;
324 subtype 'ArrayOfInts'
326 => IsArrayRef(IsInt);
328 Instead it must be changed to this:
333 where => IsArrayRef(IsInt)
337 If you want to maintain backwards compat with older versions of Moose,
338 you must explicitly test Moose's C<VERSION>:
340 if ( Moose->VERSION < 0.71_01 ) {
341 subtype 'ArrayOfInts'
343 => IsArrayRef(IsInt);
349 where => IsArrayRef(IsInt)
356 We no longer pass the meta-attribute object as a final argument to
357 triggers. This actually changed for inlined code a while back, but the
358 non-inlined version and the docs were still out of date.
360 If by some chance you actually used this feature, the workaround is
361 simple. You fetch the attribute object from out of the C<$self>
362 that is passed as the first argument to trigger, like so:
368 my ( $self, $value ) = @_;
369 my $attr = $self->meta->find_attribute_by_name('foo');
377 If you created a subtype and passed a parent that Moose didn't know
378 about, it simply ignored the parent. Now it automatically creates the
379 parent as a class type. This may not be what you want, but is less
382 You could declare a name with subtype such as "Foo!Bar". Moose would
383 accept this allowed, but if you used it in a parameterized type such
384 as "ArrayRef[Foo!Bar]" it wouldn't work. We now do some vetting on
385 names created via the sugar functions, so that they can only contain
386 alphanumerics, ":", and ".".
390 Methods created via an attribute can now fulfill a C<requires>
391 declaration for a role. Honestly we don't know why Stevan didn't make
392 this work originally, he was just insane or something.
394 Stack traces from inlined code will now report the line and file as
395 being in your class, as opposed to in Moose guts.
397 =head1 Version 0.62_02
399 When a class does not provide all of a role's required methods, the
400 error thrown now mentions all of the missing methods, as opposed to
401 just the first missing method.
403 Moose will no longer inline a constructor for your class unless it
404 inherits its constructor from Moose::Object, and will warn when it
405 doesn't inline. If you want to force inlining anyway, pass
406 C<< replace_constructor => 1 >> to C<make_immutable>.
408 If you want to get rid of the warning, pass C<< inline_constructor =>
413 Removed the (deprecated) C<make_immutable> keyword.
415 Removing an attribute from a class now also removes delegation
416 (C<handles>) methods installed for that attribute. This is correct
417 behavior, but if you were wrongly relying on it you might get bit.
421 Roles now add methods by calling C<add_method>, not
422 C<alias_method>. They make sure to always provide a method object,
423 which will be cloned internally. This means that it is now possible to
424 track the source of a method provided by a role, and even follow its
425 history through intermediate roles. This means that methods added by
426 a role now show up when looking at a class's method list/map.
428 Parameter and Union args are now sorted, this makes Int|Str the same
429 constraint as Str|Int. Also, incoming type constraint strings are
430 normalized to remove all whitespace differences. This is mostly for
431 internals and should not affect outside code.
433 L<Moose::Exporter> will no longer remove a subroutine that the
434 exporting package re-exports. Moose re-exports the Carp::confess
435 function, among others. The reasoning is that we cannot know whether
436 you have also explicitly imported those functions for your own use, so
437 we err on the safe side and always keep them.
441 C<Moose::init_meta> should now be called as a method.
443 New modules for extension writers, L<Moose::Exporter> and
444 L<Moose::Util::MetaRole>.
446 =head1 Version 0.55_01
448 Implemented metaclass traits (and wrote a recipe for it):
450 use Moose -traits => 'Foo'
452 This should make writing small Moose extensions a little
457 Fixed C<coerce> to accept anon types just like C<subtype> can.
460 coerce $some_anon_type => from 'Str' => via { ... };
464 Added C<BUILDARGS>, a new step in C<< Moose::Object->new() >>.
468 Fixed how the C<< is => (ro|rw) >> works with custom defined
469 C<reader>, C<writer> and C<accessor> options. See the below table for
472 is => ro, writer => _foo # turns into (reader => foo, writer => _foo)
473 is => rw, writer => _foo # turns into (reader => foo, writer => _foo)
474 is => rw, accessor => _foo # turns into (accessor => _foo)
475 is => ro, accessor => _foo # error, accesor is rw
479 The C<before/around/after> method modifiers now support regexp
480 matching of method names. NOTE: this only works for classes, it is
481 currently not supported in roles, but, ... patches welcome.
483 The C<has> keyword for roles now accepts the same array ref form that
484 L<Moose>.pm does for classes.
486 A trigger on a read-only attribute is no longer an error, as it's
487 useful to trigger off of the constructor.
489 Subtypes of parameterizable types now are parameterizable types
494 Fixed issue where C<DEMOLISHALL> was eating the value in C<$@>, and so
495 not working correctly. It still kind of eats them, but so does vanilla
500 Inherited attributes may now be extended without restriction on the
501 type ('isa', 'does').
503 The entire set of Moose::Meta::TypeConstraint::* classes were
504 refactored in this release. If you were relying on their internals you
505 should test your code carefully.
509 Documenting the use of '+name' with attributes that come from recently
510 composed roles. It makes sense, people are using it, and so why not
511 just officially support it.
513 The C<< Moose::Meta::Class->create >> method now supports roles.
515 It is now possible to make anonymous enum types by passing C<enum> an
516 array reference instead of the C<< enum $name => @values >>.
520 Added the C<make_immutable> keyword as a shortcut to calling
521 C<make_immutable> on the meta object. This eventually got removed!
523 Made C<< init_arg => undef >> work in Moose. This means "do not accept
524 a constructor parameter for this attribute".
526 Type errors now use the provided message. Prior to this release they
531 Moose is now a postmodern object system :)
533 The Role system was completely refactored. It is 100% backwards
534 compat, but the internals were totally changed. If you relied on the
535 internals then you are advised to test carefully.
537 Added method exclusion and aliasing for Roles in this release.
539 Added the L<Moose::Util::TypeConstraints::OptimizedConstraints>
542 Passing a list of values to an accessor (which is only expecting one
543 value) used to be silently ignored, now it throws an error.
547 Added parameterized types and did a pretty heavy refactoring of the
548 type constraint system.
550 Better framework extendability and better support for "making your own
553 =head1 Version 0.25 or before
555 Honestly, you shouldn't be using versions of Moose that are this old,
556 so many bug fixes and speed improvements have been made you would be
557 crazy to not upgrade.
559 Also, I am tired of going through the Changelog so I am stopping here,
560 if anyone would like to continue this please feel free.
564 Stevan Little E<lt>stevan@iinteractive.comE<gt>
566 =head1 COPYRIGHT AND LICENSE
568 Copyright 2009 by Infinity Interactive, Inc.
570 L<http://www.iinteractive.com>
572 This library is free software; you can redistribute it and/or modify
573 it under the same terms as Perl itself.