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.
45 =head1 Version 0.89_01
47 L<Moose::Meta::Attribute::Native> has been moved into the Moose core from
48 L<MooseX::AttributeHelpers>. Major changes include:
52 =item C<traits>, not C<metaclass>
54 Method providers are only available via traits.
56 =item C<handles>, not C<provides> or C<curries>
58 The C<provides> syntax was like core Moose C<< handles => HASHREF >>
59 syntax, but with the keys and values reversed. This was confusing,
60 and AttributeHelpers now uses C<< handles => HASHREF >> in a way that
61 should be intuitive to anyone already familiar with how it is used for
64 The C<curries> functionality provided by AttributeHelpers has been
65 generalized to apply to all cases of C<< handles => HASHREF >>, though
66 not every piece of functionality has been ported (currying with a
67 CODEREF is not supported).
69 =item C<empty> is now C<is_empty>, and means empty, not non-empty
71 Previously, the C<empty> method provided by Arrays and Hashes returned true if
72 the attribute was B<not> empty (no elements). Now it returns true if the
73 attribute B<is> empty. It was also renamed to C<is_empty>, to reflect this.
75 =item C<find> was renamed to C<first>, and C<first> and C<last> were removed
77 L<List::Util> refers to the functionality that we used to provide under C<find>
78 as L<first|List::Util/first>, so that will likely be more familiar (and will
79 fit in better if we decide to add more List::Util functions). C<first> and
80 C<last> were removed, since their functionality is easily duplicated with
83 =item Helpers that take a coderef of one argument now use C<$_>
85 Subroutines passed as the first argument to C<first>, C<map>, and C<grep> now
86 receive their argument in C<$_> rather than as a parameter to the subroutine.
87 Helpers that take a coderef of two or more arguments remain using the argument
88 list (there are technical limitations to using C<$a> and C<$b> like C<sort>
91 See L<Moose::Meta::Attribute::Native> for the new documentation.
97 C<< use Moose -metaclass => 'Foo' >> now does alias resolution, just like
98 C<-traits> (and the C<metaclass> and C<traits> options to C<has>).
100 Added two functions C<meta_class_alias> and C<meta_attribute_alias> to
101 L<Moose::Util>, to simplify aliasing metaclasses and metatraits. This is
102 a wrapper around the old
104 package Moose::Meta::Class::Custom::Trait::FooTrait;
105 sub register_implementation { 'My::Meta::Trait' }
109 The C<alias> and C<excludes> role parameters have been renamed to C<-alias>
110 and C<-excludes>. The old names still work, but new code should use the new
111 names, and eventually the old ones will be deprecated and removed.
115 When an attribute generates I<no> accessors, we now warn. This is to help
116 users who forget the C<is> option. If you really do not want any accessors,
117 you can use C<< is => 'bare' >>. You can maintain back compat with older
118 versions of Moose by using something like:
120 ($Moose::VERSION >= 0.84 ? is => 'bare' : ())
122 When an accessor overwrites an existing method, we now warn. To work around
123 this warning (if you really must have this behavior), you can explicitly
124 remove the method before creating it as an accessor:
128 __PACKAGE__->meta->remove_method('foo');
134 When an unknown option is passed to C<has>, we now warn. You can silence
135 the warning by fixing your code. :)
137 The C<Role> type has been deprecated. On its own, it was useless,
138 since it just checked C<< $object->can('does') >>. If you were using
139 it as a parent type, just call C<role_type('Role::Name')> to create an
140 appropriate type instead.
144 C<use Moose::Exporter;> now imports C<strict> and C<warnings> into packages
149 C<DEMOLISHALL> and C<DEMOLISH> now receive an argument indicating whether or
150 not we are in global destruction.
154 Type constraints no longer run coercions for a value that already matches the
155 constraint. This may affect some (arguably buggy) edge case coercions that
156 rely on side effects in the C<via> clause.
160 L<Moose::Exporter> now accepts the C<-metaclass> option for easily
161 overriding the metaclass (without L<metaclass>). This works for classes
166 Added a C<duck_type> sugar function to L<Moose::Util::TypeConstraints>
167 to make integration with non-Moose classes easier. It simply checks if
168 C<< $obj->can() >> a list of methods.
170 A number of methods (mostly inherited from L<Class::MOP>) have been
171 renamed with a leading underscore to indicate their internal-ness. The
172 old method names will still work for a while, but will warn that the
173 method has been renamed. In a few cases, the method will be removed
174 entirely in the future. This may affect MooseX authors who were using
179 Calling C<subtype> with a name as the only argument now throws an
180 exception. If you want an anonymous subtype do:
182 my $subtype = subtype as 'Foo';
184 This is related to the changes in version 0.71_01.
186 The C<is_needed> method in L<Moose::Meta::Method::Destructor> is now
187 only usable as a class method. Previously, it worked as a class or
188 object method, with a different internal implementation for each
191 The internals of making a class immutable changed a lot in Class::MOP
192 0.78_02, and Moose's internals have changed along with it. The
193 external C<< $metaclass->make_immutable >> method still works the same
198 A mutable class accepted C<< Foo->new(undef) >> without complaint,
199 while an immutable class would blow up with an unhelpful error. Now,
200 in both cases we throw a helpful error instead.
202 This "feature" was originally added to allow for cases such as this:
210 return My::Class->new($args);
212 But we decided this is a bad idea and a little too magical, because it
213 can easily mask real errors.
215 =head1 Version 0.71_01
217 Calling C<type> or C<subtype> without the sugar helpers (C<as>,
218 C<where>, C<message>) is now deprecated.
220 As a side effect, this meant we ended up using Perl prototypes on
221 C<as>, and code like this will no longer work:
223 use Moose::Util::TypeConstraints;
224 use Declare::Constraints::Simple -All;
226 subtype 'ArrayOfInts'
228 => IsArrayRef(IsInt);
230 Instead it must be changed to this:
235 where => IsArrayRef(IsInt)
239 If you want to maintain backwards compat with older versions of Moose,
240 you must explicitly test Moose's C<VERSION>:
242 if ( Moose->VERSION < 0.71_01 ) {
243 subtype 'ArrayOfInts'
245 => IsArrayRef(IsInt);
251 where => IsArrayRef(IsInt)
258 We no longer pass the meta-attribute object as a final argument to
259 triggers. This actually changed for inlined code a while back, but the
260 non-inlined version and the docs were still out of date.
262 If by some chance you actually used this feature, the workaround is
263 simple. You fetch the attribute object from out of the C<$self>
264 that is passed as the first argument to trigger, like so:
270 my ( $self, $value ) = @_;
271 my $attr = $self->meta->find_attribute_by_name('foo');
279 If you created a subtype and passed a parent that Moose didn't know
280 about, it simply ignored the parent. Now it automatically creates the
281 parent as a class type. This may not be what you want, but is less
284 You could declare a name with subtype such as "Foo!Bar". Moose would
285 accept this allowed, but if you used it in a parameterized type such
286 as "ArrayRef[Foo!Bar]" it wouldn't work. We now do some vetting on
287 names created via the sugar functions, so that they can only contain
288 alphanumerics, ":", and ".".
292 Methods created via an attribute can now fulfill a C<requires>
293 declaration for a role. Honestly we don't know why Stevan didn't make
294 this work originally, he was just insane or something.
296 Stack traces from inlined code will now report the line and file as
297 being in your class, as opposed to in Moose guts.
299 =head1 Version 0.62_02
301 When a class does not provide all of a role's required methods, the
302 error thrown now mentions all of the missing methods, as opposed to
303 just the first missing method.
305 Moose will no longer inline a constructor for your class unless it
306 inherits its constructor from Moose::Object, and will warn when it
307 doesn't inline. If you want to force inlining anyway, pass
308 C<< replace_constructor => 1 >> to C<make_immutable>.
310 If you want to get rid of the warning, pass C<< inline_constructor =>
315 Removed the (deprecated) C<make_immutable> keyword.
317 Removing an attribute from a class now also removes delegation
318 (C<handles>) methods installed for that attribute. This is correct
319 behavior, but if you were wrongly relying on it you might get bit.
323 Roles now add methods by calling C<add_method>, not
324 C<alias_method>. They make sure to always provide a method object,
325 which will be cloned internally. This means that it is now possible to
326 track the source of a method provided by a role, and even follow its
327 history through intermediate roles. This means that methods added by
328 a role now show up when looking at a class's method list/map.
330 Parameter and Union args are now sorted, this makes Int|Str the same
331 constraint as Str|Int. Also, incoming type constraint strings are
332 normalized to remove all whitespace differences. This is mostly for
333 internals and should not affect outside code.
335 L<Moose::Exporter> will no longer remove a subroutine that the
336 exporting package re-exports. Moose re-exports the Carp::confess
337 function, among others. The reasoning is that we cannot know whether
338 you have also explicitly imported those functions for your own use, so
339 we err on the safe side and always keep them.
343 C<Moose::init_meta> should now be called as a method.
345 New modules for extension writers, L<Moose::Exporter> and
346 L<Moose::Util::MetaRole>.
348 =head1 Version 0.55_01
350 Implemented metaclass traits (and wrote a recipe for it):
352 use Moose -traits => 'Foo'
354 This should make writing small Moose extensions a little
359 Fixed C<coerce> to accept anon types just like C<subtype> can.
362 coerce $some_anon_type => from 'Str' => via { ... };
366 Added C<BUILDARGS>, a new step in C<< Moose::Object->new() >>.
370 Fixed how the C<< is => (ro|rw) >> works with custom defined
371 C<reader>, C<writer> and C<accessor> options. See the below table for
374 is => ro, writer => _foo # turns into (reader => foo, writer => _foo)
375 is => rw, writer => _foo # turns into (reader => foo, writer => _foo)
376 is => rw, accessor => _foo # turns into (accessor => _foo)
377 is => ro, accessor => _foo # error, accesor is rw
381 The C<before/around/after> method modifiers now support regexp
382 matching of method names. NOTE: this only works for classes, it is
383 currently not supported in roles, but, ... patches welcome.
385 The C<has> keyword for roles now accepts the same array ref form that
386 L<Moose>.pm does for classes.
388 A trigger on a read-only attribute is no longer an error, as it's
389 useful to trigger off of the constructor.
391 Subtypes of parameterizable types now are parameterizable types
396 Fixed issue where C<DEMOLISHALL> was eating the value in C<$@>, and so
397 not working correctly. It still kind of eats them, but so does vanilla
402 Inherited attributes may now be extended without restriction on the
403 type ('isa', 'does').
405 The entire set of Moose::Meta::TypeConstraint::* classes were
406 refactored in this release. If you were relying on their internals you
407 should test your code carefully.
411 Documenting the use of '+name' with attributes that come from recently
412 composed roles. It makes sense, people are using it, and so why not
413 just officially support it.
415 The C<< Moose::Meta::Class->create >> method now supports roles.
417 It is now possible to make anonymous enum types by passing C<enum> an
418 array reference instead of the C<< enum $name => @values >>.
422 Added the C<make_immutable> keyword as a shortcut to calling
423 C<make_immutable> on the meta object. This eventually got removed!
425 Made C<< init_arg => undef >> work in Moose. This means "do not accept
426 a constructor parameter for this attribute".
428 Type errors now use the provided message. Prior to this release they
433 Moose is now a postmodern object system :)
435 The Role system was completely refactored. It is 100% backwards
436 compat, but the internals were totally changed. If you relied on the
437 internals then you are advised to test carefully.
439 Added method exclusion and aliasing for Roles in this release.
441 Added the L<Moose::Util::TypeConstraints::OptimizedConstraints>
444 Passing a list of values to an accessor (which is only expecting one
445 value) used to be silently ignored, now it throws an error.
449 Added parameterized types and did a pretty heavy refactoring of the
450 type constraint system.
452 Better framework extendability and better support for "making your own
455 =head1 Version 0.25 or before
457 Honestly, you shouldn't be using versions of Moose that are this old,
458 so many bug fixes and speed improvements have been made you would be
459 crazy to not upgrade.
461 Also, I am tired of going through the Changelog so I am stopping here,
462 if anyone would like to continue this please feel free.
466 Stevan Little E<lt>stevan@iinteractive.comE<gt>
468 =head1 COPYRIGHT AND LICENSE
470 Copyright 2009 by Infinity Interactive, Inc.
472 L<http://www.iinteractive.com>
474 This library is free software; you can redistribute it and/or modify
475 it under the same terms as Perl itself.