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 Version 0.89_02
23 =item New Native delegation methods from L<List::Util> and L<List::MoreUtils>
25 In particular, we now have C<reduce>, C<shuffle>, C<uniq>, and C<natatime>.
27 =item The Moose::Exporter with_caller feature is now deprecated
29 Use C<with_meta> instead. The C<with_caller> option will start warning in a
32 =item Moose now warns if you call C<make_immutable> for a class with mutable ancestors
34 This is dangerous because modifying a class after a subclass has been
35 immutabilized will lead to incorrect results in the subclass, due to inlining,
36 caching, etc. This occasionally happens accidentally, when a class loads one
37 of its subclasses in the middle of its class definition, so pointing out that
38 this may cause issues should be helpful. Metaclasses (classes that inherit
39 from L<Class::MOP::Object>) are currently exempt from this check, since at the
40 moment we aren't very consistent about which metaclasses we immutabilize.
41 Anonymous classes are also exempt, since they are often created automatically,
42 and the user is never given a choice about whether or not to make them
43 immutable. If you're sure you know what you're doing, you also can pass the
44 C<allow_mutable_ancestors> option to make_immutable to silence the warning
45 (but be aware that modifying those mutable ancestors can still lead to
46 incorrect behavior in your subclass).
51 =head1 Version 0.89_01
53 L<Moose::Meta::Attribute::Native> has been moved into the Moose core from
54 L<MooseX::AttributeHelpers>. Major changes include:
58 =item C<traits>, not C<metaclass>
60 Method providers are only available via traits.
62 =item C<handles>, not C<provides> or C<curries>
64 The C<provides> syntax was like core Moose C<< handles => HASHREF >>
65 syntax, but with the keys and values reversed. This was confusing,
66 and AttributeHelpers now uses C<< handles => HASHREF >> in a way that
67 should be intuitive to anyone already familiar with how it is used for
70 The C<curries> functionality provided by AttributeHelpers has been
71 generalized to apply to all cases of C<< handles => HASHREF >>, though
72 not every piece of functionality has been ported (currying with a
73 CODEREF is not supported).
75 =item C<empty> is now C<is_empty>, and means empty, not non-empty
77 Previously, the C<empty> method provided by Arrays and Hashes returned true if
78 the attribute was B<not> empty (no elements). Now it returns true if the
79 attribute B<is> empty. It was also renamed to C<is_empty>, to reflect this.
81 =item C<find> was renamed to C<first>, and C<first> and C<last> were removed
83 L<List::Util> refers to the functionality that we used to provide under C<find>
84 as L<first|List::Util/first>, so that will likely be more familiar (and will
85 fit in better if we decide to add more List::Util functions). C<first> and
86 C<last> were removed, since their functionality is easily duplicated with
89 =item Helpers that take a coderef of one argument now use C<$_>
91 Subroutines passed as the first argument to C<first>, C<map>, and C<grep> now
92 receive their argument in C<$_> rather than as a parameter to the subroutine.
93 Helpers that take a coderef of two or more arguments remain using the argument
94 list (there are technical limitations to using C<$a> and C<$b> like C<sort>
97 See L<Moose::Meta::Attribute::Native> for the new documentation.
101 The C<alias> and C<excludes> role parameters have been renamed to C<-alias>
102 and C<-excludes>. The old names still work, but new code should use the new
103 names, and eventually the old ones will be deprecated and removed.
107 C<< use Moose -metaclass => 'Foo' >> now does alias resolution, just like
108 C<-traits> (and the C<metaclass> and C<traits> options to C<has>).
110 Added two functions C<meta_class_alias> and C<meta_attribute_alias> to
111 L<Moose::Util>, to simplify aliasing metaclasses and metatraits. This is
112 a wrapper around the old
114 package Moose::Meta::Class::Custom::Trait::FooTrait;
115 sub register_implementation { 'My::Meta::Trait' }
121 When an attribute generates I<no> accessors, we now warn. This is to help
122 users who forget the C<is> option. If you really do not want any accessors,
123 you can use C<< is => 'bare' >>. You can maintain back compat with older
124 versions of Moose by using something like:
126 ($Moose::VERSION >= 0.84 ? is => 'bare' : ())
128 When an accessor overwrites an existing method, we now warn. To work around
129 this warning (if you really must have this behavior), you can explicitly
130 remove the method before creating it as an accessor:
134 __PACKAGE__->meta->remove_method('foo');
140 When an unknown option is passed to C<has>, we now warn. You can silence
141 the warning by fixing your code. :)
143 The C<Role> type has been deprecated. On its own, it was useless,
144 since it just checked C<< $object->can('does') >>. If you were using
145 it as a parent type, just call C<role_type('Role::Name')> to create an
146 appropriate type instead.
150 C<use Moose::Exporter;> now imports C<strict> and C<warnings> into packages
155 C<DEMOLISHALL> and C<DEMOLISH> now receive an argument indicating whether or
156 not we are in global destruction.
160 Type constraints no longer run coercions for a value that already matches the
161 constraint. This may affect some (arguably buggy) edge case coercions that
162 rely on side effects in the C<via> clause.
166 L<Moose::Exporter> now accepts the C<-metaclass> option for easily
167 overriding the metaclass (without L<metaclass>). This works for classes
172 Added a C<duck_type> sugar function to L<Moose::Util::TypeConstraints>
173 to make integration with non-Moose classes easier. It simply checks if
174 C<< $obj->can() >> a list of methods.
176 A number of methods (mostly inherited from L<Class::MOP>) have been
177 renamed with a leading underscore to indicate their internal-ness. The
178 old method names will still work for a while, but will warn that the
179 method has been renamed. In a few cases, the method will be removed
180 entirely in the future. This may affect MooseX authors who were using
185 Calling C<subtype> with a name as the only argument now throws an
186 exception. If you want an anonymous subtype do:
188 my $subtype = subtype as 'Foo';
190 This is related to the changes in version 0.71_01.
192 The C<is_needed> method in L<Moose::Meta::Method::Destructor> is now
193 only usable as a class method. Previously, it worked as a class or
194 object method, with a different internal implementation for each
197 The internals of making a class immutable changed a lot in Class::MOP
198 0.78_02, and Moose's internals have changed along with it. The
199 external C<< $metaclass->make_immutable >> method still works the same
204 A mutable class accepted C<< Foo->new(undef) >> without complaint,
205 while an immutable class would blow up with an unhelpful error. Now,
206 in both cases we throw a helpful error instead.
208 This "feature" was originally added to allow for cases such as this:
216 return My::Class->new($args);
218 But we decided this is a bad idea and a little too magical, because it
219 can easily mask real errors.
221 =head1 Version 0.71_01
223 Calling C<type> or C<subtype> without the sugar helpers (C<as>,
224 C<where>, C<message>) is now deprecated.
226 As a side effect, this meant we ended up using Perl prototypes on
227 C<as>, and code like this will no longer work:
229 use Moose::Util::TypeConstraints;
230 use Declare::Constraints::Simple -All;
232 subtype 'ArrayOfInts'
234 => IsArrayRef(IsInt);
236 Instead it must be changed to this:
241 where => IsArrayRef(IsInt)
245 If you want to maintain backwards compat with older versions of Moose,
246 you must explicitly test Moose's C<VERSION>:
248 if ( Moose->VERSION < 0.71_01 ) {
249 subtype 'ArrayOfInts'
251 => IsArrayRef(IsInt);
257 where => IsArrayRef(IsInt)
264 We no longer pass the meta-attribute object as a final argument to
265 triggers. This actually changed for inlined code a while back, but the
266 non-inlined version and the docs were still out of date.
268 If by some chance you actually used this feature, the workaround is
269 simple. You fetch the attribute object from out of the C<$self>
270 that is passed as the first argument to trigger, like so:
276 my ( $self, $value ) = @_;
277 my $attr = $self->meta->find_attribute_by_name('foo');
285 If you created a subtype and passed a parent that Moose didn't know
286 about, it simply ignored the parent. Now it automatically creates the
287 parent as a class type. This may not be what you want, but is less
290 You could declare a name with subtype such as "Foo!Bar". Moose would
291 accept this allowed, but if you used it in a parameterized type such
292 as "ArrayRef[Foo!Bar]" it wouldn't work. We now do some vetting on
293 names created via the sugar functions, so that they can only contain
294 alphanumerics, ":", and ".".
298 Methods created via an attribute can now fulfill a C<requires>
299 declaration for a role. Honestly we don't know why Stevan didn't make
300 this work originally, he was just insane or something.
302 Stack traces from inlined code will now report the line and file as
303 being in your class, as opposed to in Moose guts.
305 =head1 Version 0.62_02
307 When a class does not provide all of a role's required methods, the
308 error thrown now mentions all of the missing methods, as opposed to
309 just the first missing method.
311 Moose will no longer inline a constructor for your class unless it
312 inherits its constructor from Moose::Object, and will warn when it
313 doesn't inline. If you want to force inlining anyway, pass
314 C<< replace_constructor => 1 >> to C<make_immutable>.
316 If you want to get rid of the warning, pass C<< inline_constructor =>
321 Removed the (deprecated) C<make_immutable> keyword.
323 Removing an attribute from a class now also removes delegation
324 (C<handles>) methods installed for that attribute. This is correct
325 behavior, but if you were wrongly relying on it you might get bit.
329 Roles now add methods by calling C<add_method>, not
330 C<alias_method>. They make sure to always provide a method object,
331 which will be cloned internally. This means that it is now possible to
332 track the source of a method provided by a role, and even follow its
333 history through intermediate roles. This means that methods added by
334 a role now show up when looking at a class's method list/map.
336 Parameter and Union args are now sorted, this makes Int|Str the same
337 constraint as Str|Int. Also, incoming type constraint strings are
338 normalized to remove all whitespace differences. This is mostly for
339 internals and should not affect outside code.
341 L<Moose::Exporter> will no longer remove a subroutine that the
342 exporting package re-exports. Moose re-exports the Carp::confess
343 function, among others. The reasoning is that we cannot know whether
344 you have also explicitly imported those functions for your own use, so
345 we err on the safe side and always keep them.
349 C<Moose::init_meta> should now be called as a method.
351 New modules for extension writers, L<Moose::Exporter> and
352 L<Moose::Util::MetaRole>.
354 =head1 Version 0.55_01
356 Implemented metaclass traits (and wrote a recipe for it):
358 use Moose -traits => 'Foo'
360 This should make writing small Moose extensions a little
365 Fixed C<coerce> to accept anon types just like C<subtype> can.
368 coerce $some_anon_type => from 'Str' => via { ... };
372 Added C<BUILDARGS>, a new step in C<< Moose::Object->new() >>.
376 Fixed how the C<< is => (ro|rw) >> works with custom defined
377 C<reader>, C<writer> and C<accessor> options. See the below table for
380 is => ro, writer => _foo # turns into (reader => foo, writer => _foo)
381 is => rw, writer => _foo # turns into (reader => foo, writer => _foo)
382 is => rw, accessor => _foo # turns into (accessor => _foo)
383 is => ro, accessor => _foo # error, accesor is rw
387 The C<before/around/after> method modifiers now support regexp
388 matching of method names. NOTE: this only works for classes, it is
389 currently not supported in roles, but, ... patches welcome.
391 The C<has> keyword for roles now accepts the same array ref form that
392 L<Moose>.pm does for classes.
394 A trigger on a read-only attribute is no longer an error, as it's
395 useful to trigger off of the constructor.
397 Subtypes of parameterizable types now are parameterizable types
402 Fixed issue where C<DEMOLISHALL> was eating the value in C<$@>, and so
403 not working correctly. It still kind of eats them, but so does vanilla
408 Inherited attributes may now be extended without restriction on the
409 type ('isa', 'does').
411 The entire set of Moose::Meta::TypeConstraint::* classes were
412 refactored in this release. If you were relying on their internals you
413 should test your code carefully.
417 Documenting the use of '+name' with attributes that come from recently
418 composed roles. It makes sense, people are using it, and so why not
419 just officially support it.
421 The C<< Moose::Meta::Class->create >> method now supports roles.
423 It is now possible to make anonymous enum types by passing C<enum> an
424 array reference instead of the C<< enum $name => @values >>.
428 Added the C<make_immutable> keyword as a shortcut to calling
429 C<make_immutable> on the meta object. This eventually got removed!
431 Made C<< init_arg => undef >> work in Moose. This means "do not accept
432 a constructor parameter for this attribute".
434 Type errors now use the provided message. Prior to this release they
439 Moose is now a postmodern object system :)
441 The Role system was completely refactored. It is 100% backwards
442 compat, but the internals were totally changed. If you relied on the
443 internals then you are advised to test carefully.
445 Added method exclusion and aliasing for Roles in this release.
447 Added the L<Moose::Util::TypeConstraints::OptimizedConstraints>
450 Passing a list of values to an accessor (which is only expecting one
451 value) used to be silently ignored, now it throws an error.
455 Added parameterized types and did a pretty heavy refactoring of the
456 type constraint system.
458 Better framework extendability and better support for "making your own
461 =head1 Version 0.25 or before
463 Honestly, you shouldn't be using versions of Moose that are this old,
464 so many bug fixes and speed improvements have been made you would be
465 crazy to not upgrade.
467 Also, I am tired of going through the Changelog so I am stopping here,
468 if anyone would like to continue this please feel free.
472 Stevan Little E<lt>stevan@iinteractive.comE<gt>
474 =head1 COPYRIGHT AND LICENSE
476 Copyright 2009 by Infinity Interactive, Inc.
478 L<http://www.iinteractive.com>
480 This library is free software; you can redistribute it and/or modify
481 it under the same terms as Perl itself.