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 Moose::Meta::TypeConstraint::Class is_subtype_of behavior
25 Earlier versions of L<is_subtype_of|Moose::Meta::TypeConstraint::Class/is_subtype_of>
26 would incorrectly return true when called with itself, its own TC name or
27 its class name as an argument. (i.e. $foo_tc->is_subtype_of('Foo') == 1) This
28 behavior was a caused by C<isa> being checked before the class name. The old
29 behavior can be accessed with L<is_type_of|Moose::Meta::TypeConstraint::Class/is_type_of>
37 =item Moose::Meta::Attribute::Native::Trait::Code no longer creates reader methods by default
39 Earlier versions of L<Moose::Meta::Attribute::Native::Trait::Code> created
40 read-only accessors for the attributes it's been applied to, even if you didn't
41 ask for it with C<< is => 'ro' >>. This incorrect behaviour has now been fixed.
49 =item Moose::Util add_method_modifier behavior
51 add_method_modifier (and subsequently the sugar functions Moose::before,
52 Moose::after, and Moose::around) can now accept arrayrefs, with the same
53 behavior as lists. Types other than arrayref and regexp result in an error.
57 =head1 0.93_01 and 0.94
61 =item Moose::Util::MetaRole API has changed
63 The C<apply_metaclass_roles> function is now called C<apply_metaroles>. The
64 way arguments are supplied has been changed to force you to distinguish
65 between metaroles applied to L<Moose::Meta::Class> (and helpers) versus
68 The old API still works, but will warn in a future release, and eventually be
71 =item Moose::Meta::Role has real attributes
73 The attributes returned by L<Moose::Meta::Role> are now instances of the
74 L<Moose::Meta::Role::Attribute> class, instead of bare hash references.
76 =item "no Moose" now removes C<blessed> and C<confess>
78 Moose is now smart enough to know exactly what it exported, even when it
79 re-exports functions from other packages. When you unimport Moose, it will
80 remove these functions from your namespace unless you I<also> imported them
81 directly from their respective packages.
83 If you have a C<no Moose> in your code I<before> you call C<blessed> or
84 C<confess>, your code will break. You can either move the C<no Moose> call
85 later in your code, or explicitly import the relevant functions from the
86 packages that provide them.
88 =item L<Moose::Exporter> is smarter about unimporting re-exports
90 The change above comes from a general improvement to L<Moose::Exporter>. It
91 will now unimport any function it exports, even if that function is a
92 re-export from another package.
94 =item Attributes in roles can no longer override class attributes with "+foo"
96 Previously, this worked more or less accidentally, because role attributes
97 weren't objects. This was never documented, but a few MooseX modules took
100 =item The composition_class_roles attribute in L<Moose::Meta::Role> is now a method
102 This was done to make it possible for roles to alter the the list of
103 composition class roles by applying a method modifiers. Previously, this was
104 an attribute and MooseX modules override it. Since that no longer works, this
107 This I<should> be an attribute, so this may switch back to being an attribute
108 in the future if we can figure out how to make this work.
116 =item Calling $object->new() is no longer deprecated
118 We decided to undeprecate this. Now it just works.
120 =item Both C<get_method_map> and C<get_attribute_map> is deprecated
122 These metaclass methods were never meant to be public, and they are both now
123 deprecated. The work around if you still need the functionality they provided
124 is to iterate over the list of names manually.
126 my %fields = map { $_ => $meta->get_attribute($_) } $meta->get_attribute_list;
128 This was actually a change in L<Class::MOP>, but this version of Moose
129 requires a version of L<Class::MOP> that includes said change.
137 =item Added Native delegation for Code refs
139 See L<Moose::Meta::Attribute::Native::Trait::Code> for details.
141 =item Calling $object->new() is deprecated
143 Moose has long supported this, but it's never really been documented, and we
144 don't think this is a good practice. If you want to construct an object from
145 an existing object, you should provide some sort of alternate constructor like
146 C<< $object->clone >>.
148 Calling C<< $object->new >> now issues a warning, and will be an error in a
151 =item Moose no longer warns if you call C<make_immutable> for a class with mutable ancestors
153 While in theory this is a good thing to warn about, we found so many
154 exceptions to this that doing this properly became quite problematic.
158 =head1 Version 0.89_02
162 =item New Native delegation methods from L<List::Util> and L<List::MoreUtils>
164 In particular, we now have C<reduce>, C<shuffle>, C<uniq>, and C<natatime>.
166 =item The Moose::Exporter with_caller feature is now deprecated
168 Use C<with_meta> instead. The C<with_caller> option will start warning in a
171 =item Moose now warns if you call C<make_immutable> for a class with mutable ancestors
173 This is dangerous because modifying a class after a subclass has been
174 immutabilized will lead to incorrect results in the subclass, due to inlining,
175 caching, etc. This occasionally happens accidentally, when a class loads one
176 of its subclasses in the middle of its class definition, so pointing out that
177 this may cause issues should be helpful. Metaclasses (classes that inherit
178 from L<Class::MOP::Object>) are currently exempt from this check, since at the
179 moment we aren't very consistent about which metaclasses we immutabilize.
181 =item C<enum> and C<duck_type> now take arrayrefs for all forms
183 Previously, calling these functions with a list would take the first element of
184 the list as the type constraint name, and use the remainder as the enum values
185 or method names. This makes the interface inconsistent with the anon-type forms
186 of these functions (which must take an arrayref), and a free-form list where
187 the first value is sometimes special is hard to validate (and harder to give
188 reasonable error messages for). These functions have been changed to take
189 arrayrefs in all their forms - so, C<< enum 'My::Type' => [qw(foo bar)] >> is
190 now the preferred way to create an enum type constraint. The old syntax still
191 works for now, but it will hopefully be deprecated and removed in a future
196 =head1 Version 0.89_01
198 L<Moose::Meta::Attribute::Native> has been moved into the Moose core from
199 L<MooseX::AttributeHelpers>. Major changes include:
203 =item C<traits>, not C<metaclass>
205 Method providers are only available via traits.
207 =item C<handles>, not C<provides> or C<curries>
209 The C<provides> syntax was like core Moose C<< handles => HASHREF >>
210 syntax, but with the keys and values reversed. This was confusing,
211 and AttributeHelpers now uses C<< handles => HASHREF >> in a way that
212 should be intuitive to anyone already familiar with how it is used for
215 The C<curries> functionality provided by AttributeHelpers has been
216 generalized to apply to all cases of C<< handles => HASHREF >>, though
217 not every piece of functionality has been ported (currying with a
218 CODEREF is not supported).
220 =item C<empty> is now C<is_empty>, and means empty, not non-empty
222 Previously, the C<empty> method provided by Arrays and Hashes returned true if
223 the attribute was B<not> empty (no elements). Now it returns true if the
224 attribute B<is> empty. It was also renamed to C<is_empty>, to reflect this.
226 =item C<find> was renamed to C<first>, and C<first> and C<last> were removed
228 L<List::Util> refers to the functionality that we used to provide under C<find>
229 as L<first|List::Util/first>, so that will likely be more familiar (and will
230 fit in better if we decide to add more List::Util functions). C<first> and
231 C<last> were removed, since their functionality is easily duplicated with
234 =item Helpers that take a coderef of one argument now use C<$_>
236 Subroutines passed as the first argument to C<first>, C<map>, and C<grep> now
237 receive their argument in C<$_> rather than as a parameter to the subroutine.
238 Helpers that take a coderef of two or more arguments remain using the argument
239 list (there are technical limitations to using C<$a> and C<$b> like C<sort>
242 See L<Moose::Meta::Attribute::Native> for the new documentation.
246 The C<alias> and C<excludes> role parameters have been renamed to C<-alias>
247 and C<-excludes>. The old names still work, but new code should use the new
248 names, and eventually the old ones will be deprecated and removed.
252 C<< use Moose -metaclass => 'Foo' >> now does alias resolution, just like
253 C<-traits> (and the C<metaclass> and C<traits> options to C<has>).
255 Added two functions C<meta_class_alias> and C<meta_attribute_alias> to
256 L<Moose::Util>, to simplify aliasing metaclasses and metatraits. This is
257 a wrapper around the old
259 package Moose::Meta::Class::Custom::Trait::FooTrait;
260 sub register_implementation { 'My::Meta::Trait' }
266 When an attribute generates I<no> accessors, we now warn. This is to help
267 users who forget the C<is> option. If you really do not want any accessors,
268 you can use C<< is => 'bare' >>. You can maintain back compat with older
269 versions of Moose by using something like:
271 ($Moose::VERSION >= 0.84 ? is => 'bare' : ())
273 When an accessor overwrites an existing method, we now warn. To work around
274 this warning (if you really must have this behavior), you can explicitly
275 remove the method before creating it as an accessor:
279 __PACKAGE__->meta->remove_method('foo');
285 When an unknown option is passed to C<has>, we now warn. You can silence
286 the warning by fixing your code. :)
288 The C<Role> type has been deprecated. On its own, it was useless,
289 since it just checked C<< $object->can('does') >>. If you were using
290 it as a parent type, just call C<role_type('Role::Name')> to create an
291 appropriate type instead.
295 C<use Moose::Exporter;> now imports C<strict> and C<warnings> into packages
300 C<DEMOLISHALL> and C<DEMOLISH> now receive an argument indicating whether or
301 not we are in global destruction.
305 Type constraints no longer run coercions for a value that already matches the
306 constraint. This may affect some (arguably buggy) edge case coercions that
307 rely on side effects in the C<via> clause.
311 L<Moose::Exporter> now accepts the C<-metaclass> option for easily
312 overriding the metaclass (without L<metaclass>). This works for classes
317 Added a C<duck_type> sugar function to L<Moose::Util::TypeConstraints>
318 to make integration with non-Moose classes easier. It simply checks if
319 C<< $obj->can() >> a list of methods.
321 A number of methods (mostly inherited from L<Class::MOP>) have been
322 renamed with a leading underscore to indicate their internal-ness. The
323 old method names will still work for a while, but will warn that the
324 method has been renamed. In a few cases, the method will be removed
325 entirely in the future. This may affect MooseX authors who were using
330 Calling C<subtype> with a name as the only argument now throws an
331 exception. If you want an anonymous subtype do:
333 my $subtype = subtype as 'Foo';
335 This is related to the changes in version 0.71_01.
337 The C<is_needed> method in L<Moose::Meta::Method::Destructor> is now
338 only usable as a class method. Previously, it worked as a class or
339 object method, with a different internal implementation for each
342 The internals of making a class immutable changed a lot in Class::MOP
343 0.78_02, and Moose's internals have changed along with it. The
344 external C<< $metaclass->make_immutable >> method still works the same
349 A mutable class accepted C<< Foo->new(undef) >> without complaint,
350 while an immutable class would blow up with an unhelpful error. Now,
351 in both cases we throw a helpful error instead.
353 This "feature" was originally added to allow for cases such as this:
361 return My::Class->new($args);
363 But we decided this is a bad idea and a little too magical, because it
364 can easily mask real errors.
366 =head1 Version 0.71_01
368 Calling C<type> or C<subtype> without the sugar helpers (C<as>,
369 C<where>, C<message>) is now deprecated.
371 As a side effect, this meant we ended up using Perl prototypes on
372 C<as>, and code like this will no longer work:
374 use Moose::Util::TypeConstraints;
375 use Declare::Constraints::Simple -All;
377 subtype 'ArrayOfInts'
379 => IsArrayRef(IsInt);
381 Instead it must be changed to this:
386 where => IsArrayRef(IsInt)
390 If you want to maintain backwards compat with older versions of Moose,
391 you must explicitly test Moose's C<VERSION>:
393 if ( Moose->VERSION < 0.71_01 ) {
394 subtype 'ArrayOfInts'
396 => IsArrayRef(IsInt);
402 where => IsArrayRef(IsInt)
409 We no longer pass the meta-attribute object as a final argument to
410 triggers. This actually changed for inlined code a while back, but the
411 non-inlined version and the docs were still out of date.
413 If by some chance you actually used this feature, the workaround is
414 simple. You fetch the attribute object from out of the C<$self>
415 that is passed as the first argument to trigger, like so:
421 my ( $self, $value ) = @_;
422 my $attr = $self->meta->find_attribute_by_name('foo');
430 If you created a subtype and passed a parent that Moose didn't know
431 about, it simply ignored the parent. Now it automatically creates the
432 parent as a class type. This may not be what you want, but is less
435 You could declare a name with subtype such as "Foo!Bar". Moose would
436 accept this allowed, but if you used it in a parameterized type such
437 as "ArrayRef[Foo!Bar]" it wouldn't work. We now do some vetting on
438 names created via the sugar functions, so that they can only contain
439 alphanumerics, ":", and ".".
443 Methods created via an attribute can now fulfill a C<requires>
444 declaration for a role. Honestly we don't know why Stevan didn't make
445 this work originally, he was just insane or something.
447 Stack traces from inlined code will now report the line and file as
448 being in your class, as opposed to in Moose guts.
450 =head1 Version 0.62_02
452 When a class does not provide all of a role's required methods, the
453 error thrown now mentions all of the missing methods, as opposed to
454 just the first missing method.
456 Moose will no longer inline a constructor for your class unless it
457 inherits its constructor from Moose::Object, and will warn when it
458 doesn't inline. If you want to force inlining anyway, pass
459 C<< replace_constructor => 1 >> to C<make_immutable>.
461 If you want to get rid of the warning, pass C<< inline_constructor =>
466 Removed the (deprecated) C<make_immutable> keyword.
468 Removing an attribute from a class now also removes delegation
469 (C<handles>) methods installed for that attribute. This is correct
470 behavior, but if you were wrongly relying on it you might get bit.
474 Roles now add methods by calling C<add_method>, not
475 C<alias_method>. They make sure to always provide a method object,
476 which will be cloned internally. This means that it is now possible to
477 track the source of a method provided by a role, and even follow its
478 history through intermediate roles. This means that methods added by
479 a role now show up when looking at a class's method list/map.
481 Parameter and Union args are now sorted, this makes Int|Str the same
482 constraint as Str|Int. Also, incoming type constraint strings are
483 normalized to remove all whitespace differences. This is mostly for
484 internals and should not affect outside code.
486 L<Moose::Exporter> will no longer remove a subroutine that the
487 exporting package re-exports. Moose re-exports the Carp::confess
488 function, among others. The reasoning is that we cannot know whether
489 you have also explicitly imported those functions for your own use, so
490 we err on the safe side and always keep them.
494 C<Moose::init_meta> should now be called as a method.
496 New modules for extension writers, L<Moose::Exporter> and
497 L<Moose::Util::MetaRole>.
499 =head1 Version 0.55_01
501 Implemented metaclass traits (and wrote a recipe for it):
503 use Moose -traits => 'Foo'
505 This should make writing small Moose extensions a little
510 Fixed C<coerce> to accept anon types just like C<subtype> can.
513 coerce $some_anon_type => from 'Str' => via { ... };
517 Added C<BUILDARGS>, a new step in C<< Moose::Object->new() >>.
521 Fixed how the C<< is => (ro|rw) >> works with custom defined
522 C<reader>, C<writer> and C<accessor> options. See the below table for
525 is => ro, writer => _foo # turns into (reader => foo, writer => _foo)
526 is => rw, writer => _foo # turns into (reader => foo, writer => _foo)
527 is => rw, accessor => _foo # turns into (accessor => _foo)
528 is => ro, accessor => _foo # error, accesor is rw
532 The C<before/around/after> method modifiers now support regexp
533 matching of method names. NOTE: this only works for classes, it is
534 currently not supported in roles, but, ... patches welcome.
536 The C<has> keyword for roles now accepts the same array ref form that
537 L<Moose>.pm does for classes.
539 A trigger on a read-only attribute is no longer an error, as it's
540 useful to trigger off of the constructor.
542 Subtypes of parameterizable types now are parameterizable types
547 Fixed issue where C<DEMOLISHALL> was eating the value in C<$@>, and so
548 not working correctly. It still kind of eats them, but so does vanilla
553 Inherited attributes may now be extended without restriction on the
554 type ('isa', 'does').
556 The entire set of Moose::Meta::TypeConstraint::* classes were
557 refactored in this release. If you were relying on their internals you
558 should test your code carefully.
562 Documenting the use of '+name' with attributes that come from recently
563 composed roles. It makes sense, people are using it, and so why not
564 just officially support it.
566 The C<< Moose::Meta::Class->create >> method now supports roles.
568 It is now possible to make anonymous enum types by passing C<enum> an
569 array reference instead of the C<< enum $name => @values >>.
573 Added the C<make_immutable> keyword as a shortcut to calling
574 C<make_immutable> on the meta object. This eventually got removed!
576 Made C<< init_arg => undef >> work in Moose. This means "do not accept
577 a constructor parameter for this attribute".
579 Type errors now use the provided message. Prior to this release they
584 Moose is now a postmodern object system :)
586 The Role system was completely refactored. It is 100% backwards
587 compat, but the internals were totally changed. If you relied on the
588 internals then you are advised to test carefully.
590 Added method exclusion and aliasing for Roles in this release.
592 Added the L<Moose::Util::TypeConstraints::OptimizedConstraints>
595 Passing a list of values to an accessor (which is only expecting one
596 value) used to be silently ignored, now it throws an error.
600 Added parameterized types and did a pretty heavy refactoring of the
601 type constraint system.
603 Better framework extendability and better support for "making your own
606 =head1 Version 0.25 or before
608 Honestly, you shouldn't be using versions of Moose that are this old,
609 so many bug fixes and speed improvements have been made you would be
610 crazy to not upgrade.
612 Also, I am tired of going through the Changelog so I am stopping here,
613 if anyone would like to continue this please feel free.
617 Stevan Little E<lt>stevan@iinteractive.comE<gt>
619 =head1 COPYRIGHT AND LICENSE
621 Copyright 2009 by Infinity Interactive, Inc.
623 L<http://www.iinteractive.com>
625 This library is free software; you can redistribute it and/or modify
626 it under the same terms as Perl itself.