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
21 L<Moose> now warns about a class overriding methods from roles it
22 consumes. This warning is useful for discovering I<accidental> name
23 collisions, which is part of why using roles is much less painful than
24 multiple inheritance. You can silence this warning by explicitly
25 excluding methods you override from roles. For example,
28 sub foo { "Default role implementation" }
31 with 'Role' => { excludes => 'foo' };
32 sub foo { "Overriding class implementation" }
34 Since this warning has been decried by some (such as chromatic in
35 L<http://www.modernperlbooks.com/mt/2009/04/the-value-of-a-warning.html>),
36 we ask that you provide feedback about whether this warning has helped or
37 hindered you. If it turns out to have been a bad idea, we will not
38 hesitate to remove it from future versions.
42 L<Moose::Exporter> now accepts the C<-metaclass> option for easily
43 overriding the metaclass (without L<metaclass>). This works for classes
48 Added a C<duck_type> sugar function to L<Moose::Util::TypeConstraints>
49 to make integration with non-Moose classes easier. It simply checks if
50 C<< $obj->can() >> a list of methods.
52 A number of methods (mostly inherited from L<Class::MOP>) have been
53 renamed with a leading underscore to indicate their internal-ness. The
54 old method names will still work for a while, but will warn that the
55 method has been renamed. In a few cases, the method will be removed
56 entirely in the future. This may affect MooseX authors who were using
61 Calling C<subtype> with a name as the only argument now throws an
62 exception. If you want an anonymous subtype do:
64 my $subtype = subtype as 'Foo';
66 This is related to the changes in version 0.71_01.
68 The C<is_needed> method in L<Moose::Meta::Method::Destructor> is now
69 only usable as a class method. Previously, it worked as a class or
70 object method, with a different internal implementation for each
73 The internals of making a class immutable changed a lot in Class::MOP
74 0.78_02, and Moose's internals have changed along with it. The
75 external C<< $metaclass->make_immutable >> method still works the same
80 A mutable class accepted C<< Foo->new(undef) >> without complaint,
81 while an immutable class would blow up with an unhelpful error. Now,
82 in both cases we throw a helpful error instead.
84 This "feature" was originally added to allow for cases such as this:
92 return My::Class->new($args);
94 But we decided this is a bad idea and a little too magical, because it
95 can easily mask real errors.
97 =head1 Version 0.71_01
99 Calling C<type> or C<subtype> without the sugar helpers (C<as>,
100 C<where>, C<message>) is now deprecated.
102 As a side effect, this meant we ended up using Perl prototypes on
103 C<as>, and code like this will no longer work:
105 use Moose::Util::TypeConstraints;
106 use Declare::Constraints::Simple -All;
108 subtype 'ArrayOfInts'
110 => IsArrayRef(IsInt);
112 Instead it must be changed to this:
117 where => IsArrayRef(IsInt)
121 If you want to maintain backwards compat with older versions of Moose,
122 you must explicitly test Moose's C<VERSION>:
124 if ( Moose->VERSION < 0.71_01 ) {
125 subtype 'ArrayOfInts'
127 => IsArrayRef(IsInt);
133 where => IsArrayRef(IsInt)
140 We no longer pass the meta-attribute object as a final argument to
141 triggers. This actually changed for inlined code a while back, but the
142 non-inlined version and the docs were still out of date.
144 If by some chance you actually used this feature, the workaround is
145 simple. You fetch the attribute object from out of the C<$self>
146 that is passed as the first argument to trigger, like so:
152 my ( $self, $value ) = @_;
153 my $attr = $self->meta->find_attribute_by_name('foo');
161 If you created a subtype and passed a parent that Moose didn't know
162 about, it simply ignored the parent. Now it automatically creates the
163 parent as a class type. This may not be what you want, but is less
166 You could declare a name with subtype such as "Foo!Bar". Moose would
167 accept this allowed, but if you used it in a parameterized type such
168 as "ArrayRef[Foo!Bar]" it wouldn't work. We now do some vetting on
169 names created via the sugar functions, so that they can only contain
170 alphanumerics, ":", and ".".
174 Methods created via an attribute can now fulfill a C<requires>
175 declaration for a role. Honestly we don't know why Stevan didn't make
176 this work originally, he was just insane or something.
178 Stack traces from inlined code will now report the line and file as
179 being in your class, as opposed to in Moose guts.
181 =head1 Version 0.62_02
183 When a class does not provide all of a role's required methods, the
184 error thrown now mentions all of the missing methods, as opposed to
185 just the first missing method.
187 Moose will no longer inline a constructor for your class unless it
188 inherits its constructor from Moose::Object, and will warn when it
189 doesn't inline. If you want to force inlining anyway, pass
190 C<< "replace_constructor => 1 >> to C<make_immutable>.
192 If you want to get rid of the warning, pass C<< inline_constructor =>
197 Removed the (deprecated) C<make_immutable> keyword.
199 Removing an attribute from a class now also removes delegation
200 (C<handles>) methods installed for that attribute. This is correct
201 behavior, but if you were wrongly relying on it you might get bit.
205 Roles now add methods by calling C<add_method>, not
206 C<alias_method>. They make sure to always provide a method object,
207 which will be cloned internally. This means that it is now possible to
208 track the source of a method provided by a role, and even follow its
209 history through intermediate roles. This means that methods added by
210 a role now show up when looking at a class's method list/map.
212 Parameter and Union args are now sorted, this makes Int|Str the same
213 constraint as Str|Int. Also, incoming type constraint strings are
214 normalized to remove all whitespace differences. This is mostly for
215 internals and should not affect outside code.
217 L<Moose::Exporter> will no longer remove a subroutine that the
218 exporting package re-exports. Moose re-exports the Carp::confess
219 function, among others. The reasoning is that we cannot know whether
220 you have also explicitly imported those functions for your own use, so
221 we err on the safe side and always keep them.
225 C<Moose::init_meta> should now be called as a method.
227 New modules for extension writers, L<Moose::Exporter> and
228 L<Moose::Util::MetaRole>.
230 =head1 Version 0.55_01
232 Implemented metaclass traits (and wrote a recipe for it):
234 use Moose -traits => 'Foo'
236 This should make writing small Moose extensions a little
241 Fixed C<coerce> to accept anon types just like C<subtype> can.
244 coerce $some_anon_type => from 'Str' => via { ... };
248 Added C<BUILDARGS>, a new step in C<< Moose::Object->new() >>.
252 Fixed how the C<< is => (ro|rw) >> works with custom defined
253 C<reader>, C<writer> and C<accessor> options. See the below table for
256 is => ro, writer => _foo # turns into (reader => foo, writer => _foo)
257 is => rw, writer => _foo # turns into (reader => foo, writer => _foo)
258 is => rw, accessor => _foo # turns into (accessor => _foo)
259 is => ro, accessor => _foo # error, accesor is rw
263 The C<before/around/after> method modifiers now support regexp
264 matching of method names. NOTE: this only works for classes, it is
265 currently not supported in roles, but, ... patches welcome.
267 The C<has> keyword for roles now accepts the same array ref form that
268 L<Moose>.pm does for classes.
270 A trigger on a read-only attribute is no longer an error, as it's
271 useful to trigger off of the constructor.
273 Subtypes of parameterizable types now are parameterizable types
278 Fixed issue where C<DEMOLISHALL> was eating the value in C<$@>, and so
279 not working correctly. It still kind of eats them, but so does vanilla
284 Inherited attributes may now be extended without restriction on the
285 type ('isa', 'does').
287 The entire set of Moose::Meta::TypeConstraint::* classes were
288 refactored in this release. If you were relying on their internals you
289 should test your code carefully.
293 Documenting the use of '+name' with attributes that come from recently
294 composed roles. It makes sense, people are using it, and so why not
295 just officially support it.
297 The C<< Moose::Meta::Class->create >> method now supports roles.
299 It is now possible to make anonymous enum types by passing C<enum> an
300 array reference instead of the C<< enum $name => @values >>.
304 Added the C<make_immutable> keyword as a shortcut to calling
305 C<make_immutable> on the meta object. This eventually got removed!
307 Made C<< init_arg => undef >> work in Moose. This means "do not accept
308 a constructor parameter for this attribute".
310 Type errors now use the provided message. Prior to this release they
315 Moose is now a postmodern object system :)
317 The Role system was completely refactored. It is 100% backwards
318 compat, but the internals were totally changed. If you relied on the
319 internals then you are advised to test carefully.
321 Added method exclusion and aliasing for Roles in this release.
323 Added the L<Moose::Util::TypeConstraints::OptimizedConstraints>
326 Passing a list of values to an accessor (which is only expecting one
327 value) used to be silently ignored, now it throws an error.
331 Added parameterized types and did a pretty heavy refactoring of the
332 type constraint system.
334 Better framework extendability and better support for "making your own
337 =head1 Version 0.25 or before
339 Honestly, you shouldn't be using versions of Moose that are this old,
340 so many bug fixes and speed improvements have been made you would be
341 crazy to not upgrade.
343 Also, I am tired of going through the Changelog so I am stopping here,
344 if anyone would like to continue this please feel free.
348 Stevan Little E<lt>stevan@iinteractive.comE<gt>
350 =head1 COPYRIGHT AND LICENSE
352 Copyright 2009 by Infinity Interactive, Inc.
354 L<http://www.iinteractive.com>
356 This library is free software; you can redistribute it and/or modify
357 it under the same terms as Perl itself.