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
34 Moose now warns if you call C<make_immutable> for a class with mutable
35 ancestors. This is dangerous because modifying a class after a subclass has
36 been immutablized will lead to incorrect results in the subclass, due to
37 inlining, caching, etc. This occasionally happens accidentally, when a class
38 loads one of its subclasses in the middle of its class definition, so pointing
39 out that this may cause issues should be helpful. Metaclasses (classes that
40 inherit from L<Class::MOP::Object>) are currently exempt from this check, since
41 at the moment we aren't very consistent about which metaclasses we immutablize.
43 =head1 Version 0.89_01
45 L<Moose::Meta::Attribute::Native> has been moved into the Moose core from
46 L<MooseX::AttributeHelpers>. Major changes include:
50 =item C<traits>, not C<metaclass>
52 Method providers are only available via traits.
54 =item C<handles>, not C<provides> or C<curries>
56 The C<provides> syntax was like core Moose C<< handles => HASHREF >>
57 syntax, but with the keys and values reversed. This was confusing,
58 and AttributeHelpers now uses C<< handles => HASHREF >> in a way that
59 should be intuitive to anyone already familiar with how it is used for
62 The C<curries> functionality provided by AttributeHelpers has been
63 generalized to apply to all cases of C<< handles => HASHREF >>, though
64 not every piece of functionality has been ported (currying with a
65 CODEREF is not supported).
67 =item C<empty> is now C<is_empty>, and means empty, not non-empty
69 Previously, the C<empty> method provided by Arrays and Hashes returned true if
70 the attribute was B<not> empty (no elements). Now it returns true if the
71 attribute B<is> empty. It was also renamed to C<is_empty>, to reflect this.
73 =item C<find> was renamed to C<first>, and C<first> and C<last> were removed
75 L<List::Util> refers to the functionality that we used to provide under C<find>
76 as L<first|List::Util/first>, so that will likely be more familiar (and will
77 fit in better if we decide to add more List::Util functions). C<first> and
78 C<last> were removed, since their functionality is easily duplicated with
81 =item Helpers that take a coderef of one argument now use C<$_>
83 Subroutines passed as the first argument to C<first>, C<map>, and C<grep> now
84 receive their argument in C<$_> rather than as a parameter to the subroutine.
85 Helpers that take a coderef of two or more arguments remain using the argument
86 list (there are technical limitations to using C<$a> and C<$b> like C<sort>
89 See L<Moose::Meta::Attribute::Native> for the new documentation.
95 C<< use Moose -metaclass => 'Foo' >> now does alias resolution, just like
96 C<-traits> (and the C<metaclass> and C<traits> options to C<has>).
98 Added two functions C<meta_class_alias> and C<meta_attribute_alias> to
99 L<Moose::Util>, to simplify aliasing metaclasses and metatraits. This is
100 a wrapper around the old
102 package Moose::Meta::Class::Custom::Trait::FooTrait;
103 sub register_implementation { 'My::Meta::Trait' }
107 The C<alias> and C<excludes> role parameters have been renamed to C<-alias>
108 and C<-excludes>. The old names still work, but new code should use the new
109 names, and eventually the old ones will be deprecated and removed.
113 When an attribute generates I<no> accessors, we now warn. This is to help
114 users who forget the C<is> option. If you really do not want any accessors,
115 you can use C<< is => 'bare' >>. You can maintain back compat with older
116 versions of Moose by using something like:
118 ($Moose::VERSION >= 0.84 ? is => 'bare' : ())
120 When an accessor overwrites an existing method, we now warn. To work around
121 this warning (if you really must have this behavior), you can explicitly
122 remove the method before creating it as an accessor:
126 __PACKAGE__->meta->remove_method('foo');
132 When an unknown option is passed to C<has>, we now warn. You can silence
133 the warning by fixing your code. :)
135 The C<Role> type has been deprecated. On its own, it was useless,
136 since it just checked C<< $object->can('does') >>. If you were using
137 it as a parent type, just call C<role_type('Role::Name')> to create an
138 appropriate type instead.
142 C<use Moose::Exporter;> now imports C<strict> and C<warnings> into packages
147 C<DEMOLISHALL> and C<DEMOLISH> now receive an argument indicating whether or
148 not we are in global destruction.
152 Type constraints no longer run coercions for a value that already matches the
153 constraint. This may affect some (arguably buggy) edge case coercions that
154 rely on side effects in the C<via> clause.
158 L<Moose::Exporter> now accepts the C<-metaclass> option for easily
159 overriding the metaclass (without L<metaclass>). This works for classes
164 Added a C<duck_type> sugar function to L<Moose::Util::TypeConstraints>
165 to make integration with non-Moose classes easier. It simply checks if
166 C<< $obj->can() >> a list of methods.
168 A number of methods (mostly inherited from L<Class::MOP>) have been
169 renamed with a leading underscore to indicate their internal-ness. The
170 old method names will still work for a while, but will warn that the
171 method has been renamed. In a few cases, the method will be removed
172 entirely in the future. This may affect MooseX authors who were using
177 Calling C<subtype> with a name as the only argument now throws an
178 exception. If you want an anonymous subtype do:
180 my $subtype = subtype as 'Foo';
182 This is related to the changes in version 0.71_01.
184 The C<is_needed> method in L<Moose::Meta::Method::Destructor> is now
185 only usable as a class method. Previously, it worked as a class or
186 object method, with a different internal implementation for each
189 The internals of making a class immutable changed a lot in Class::MOP
190 0.78_02, and Moose's internals have changed along with it. The
191 external C<< $metaclass->make_immutable >> method still works the same
196 A mutable class accepted C<< Foo->new(undef) >> without complaint,
197 while an immutable class would blow up with an unhelpful error. Now,
198 in both cases we throw a helpful error instead.
200 This "feature" was originally added to allow for cases such as this:
208 return My::Class->new($args);
210 But we decided this is a bad idea and a little too magical, because it
211 can easily mask real errors.
213 =head1 Version 0.71_01
215 Calling C<type> or C<subtype> without the sugar helpers (C<as>,
216 C<where>, C<message>) is now deprecated.
218 As a side effect, this meant we ended up using Perl prototypes on
219 C<as>, and code like this will no longer work:
221 use Moose::Util::TypeConstraints;
222 use Declare::Constraints::Simple -All;
224 subtype 'ArrayOfInts'
226 => IsArrayRef(IsInt);
228 Instead it must be changed to this:
233 where => IsArrayRef(IsInt)
237 If you want to maintain backwards compat with older versions of Moose,
238 you must explicitly test Moose's C<VERSION>:
240 if ( Moose->VERSION < 0.71_01 ) {
241 subtype 'ArrayOfInts'
243 => IsArrayRef(IsInt);
249 where => IsArrayRef(IsInt)
256 We no longer pass the meta-attribute object as a final argument to
257 triggers. This actually changed for inlined code a while back, but the
258 non-inlined version and the docs were still out of date.
260 If by some chance you actually used this feature, the workaround is
261 simple. You fetch the attribute object from out of the C<$self>
262 that is passed as the first argument to trigger, like so:
268 my ( $self, $value ) = @_;
269 my $attr = $self->meta->find_attribute_by_name('foo');
277 If you created a subtype and passed a parent that Moose didn't know
278 about, it simply ignored the parent. Now it automatically creates the
279 parent as a class type. This may not be what you want, but is less
282 You could declare a name with subtype such as "Foo!Bar". Moose would
283 accept this allowed, but if you used it in a parameterized type such
284 as "ArrayRef[Foo!Bar]" it wouldn't work. We now do some vetting on
285 names created via the sugar functions, so that they can only contain
286 alphanumerics, ":", and ".".
290 Methods created via an attribute can now fulfill a C<requires>
291 declaration for a role. Honestly we don't know why Stevan didn't make
292 this work originally, he was just insane or something.
294 Stack traces from inlined code will now report the line and file as
295 being in your class, as opposed to in Moose guts.
297 =head1 Version 0.62_02
299 When a class does not provide all of a role's required methods, the
300 error thrown now mentions all of the missing methods, as opposed to
301 just the first missing method.
303 Moose will no longer inline a constructor for your class unless it
304 inherits its constructor from Moose::Object, and will warn when it
305 doesn't inline. If you want to force inlining anyway, pass
306 C<< replace_constructor => 1 >> to C<make_immutable>.
308 If you want to get rid of the warning, pass C<< inline_constructor =>
313 Removed the (deprecated) C<make_immutable> keyword.
315 Removing an attribute from a class now also removes delegation
316 (C<handles>) methods installed for that attribute. This is correct
317 behavior, but if you were wrongly relying on it you might get bit.
321 Roles now add methods by calling C<add_method>, not
322 C<alias_method>. They make sure to always provide a method object,
323 which will be cloned internally. This means that it is now possible to
324 track the source of a method provided by a role, and even follow its
325 history through intermediate roles. This means that methods added by
326 a role now show up when looking at a class's method list/map.
328 Parameter and Union args are now sorted, this makes Int|Str the same
329 constraint as Str|Int. Also, incoming type constraint strings are
330 normalized to remove all whitespace differences. This is mostly for
331 internals and should not affect outside code.
333 L<Moose::Exporter> will no longer remove a subroutine that the
334 exporting package re-exports. Moose re-exports the Carp::confess
335 function, among others. The reasoning is that we cannot know whether
336 you have also explicitly imported those functions for your own use, so
337 we err on the safe side and always keep them.
341 C<Moose::init_meta> should now be called as a method.
343 New modules for extension writers, L<Moose::Exporter> and
344 L<Moose::Util::MetaRole>.
346 =head1 Version 0.55_01
348 Implemented metaclass traits (and wrote a recipe for it):
350 use Moose -traits => 'Foo'
352 This should make writing small Moose extensions a little
357 Fixed C<coerce> to accept anon types just like C<subtype> can.
360 coerce $some_anon_type => from 'Str' => via { ... };
364 Added C<BUILDARGS>, a new step in C<< Moose::Object->new() >>.
368 Fixed how the C<< is => (ro|rw) >> works with custom defined
369 C<reader>, C<writer> and C<accessor> options. See the below table for
372 is => ro, writer => _foo # turns into (reader => foo, writer => _foo)
373 is => rw, writer => _foo # turns into (reader => foo, writer => _foo)
374 is => rw, accessor => _foo # turns into (accessor => _foo)
375 is => ro, accessor => _foo # error, accesor is rw
379 The C<before/around/after> method modifiers now support regexp
380 matching of method names. NOTE: this only works for classes, it is
381 currently not supported in roles, but, ... patches welcome.
383 The C<has> keyword for roles now accepts the same array ref form that
384 L<Moose>.pm does for classes.
386 A trigger on a read-only attribute is no longer an error, as it's
387 useful to trigger off of the constructor.
389 Subtypes of parameterizable types now are parameterizable types
394 Fixed issue where C<DEMOLISHALL> was eating the value in C<$@>, and so
395 not working correctly. It still kind of eats them, but so does vanilla
400 Inherited attributes may now be extended without restriction on the
401 type ('isa', 'does').
403 The entire set of Moose::Meta::TypeConstraint::* classes were
404 refactored in this release. If you were relying on their internals you
405 should test your code carefully.
409 Documenting the use of '+name' with attributes that come from recently
410 composed roles. It makes sense, people are using it, and so why not
411 just officially support it.
413 The C<< Moose::Meta::Class->create >> method now supports roles.
415 It is now possible to make anonymous enum types by passing C<enum> an
416 array reference instead of the C<< enum $name => @values >>.
420 Added the C<make_immutable> keyword as a shortcut to calling
421 C<make_immutable> on the meta object. This eventually got removed!
423 Made C<< init_arg => undef >> work in Moose. This means "do not accept
424 a constructor parameter for this attribute".
426 Type errors now use the provided message. Prior to this release they
431 Moose is now a postmodern object system :)
433 The Role system was completely refactored. It is 100% backwards
434 compat, but the internals were totally changed. If you relied on the
435 internals then you are advised to test carefully.
437 Added method exclusion and aliasing for Roles in this release.
439 Added the L<Moose::Util::TypeConstraints::OptimizedConstraints>
442 Passing a list of values to an accessor (which is only expecting one
443 value) used to be silently ignored, now it throws an error.
447 Added parameterized types and did a pretty heavy refactoring of the
448 type constraint system.
450 Better framework extendability and better support for "making your own
453 =head1 Version 0.25 or before
455 Honestly, you shouldn't be using versions of Moose that are this old,
456 so many bug fixes and speed improvements have been made you would be
457 crazy to not upgrade.
459 Also, I am tired of going through the Changelog so I am stopping here,
460 if anyone would like to continue this please feel free.
464 Stevan Little E<lt>stevan@iinteractive.comE<gt>
466 =head1 COPYRIGHT AND LICENSE
468 Copyright 2009 by Infinity Interactive, Inc.
470 L<http://www.iinteractive.com>
472 This library is free software; you can redistribute it and/or modify
473 it under the same terms as Perl itself.