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.
40 Type constraints no longer run coercions for a value that already matches the
41 constraint. This may affect some (arguably buggy) edge case coercions that
42 rely on side effects in the C<via> clause.
46 L<Moose::Exporter> now accepts the C<-metaclass> option for easily
47 overriding the metaclass (without L<metaclass>). This works for classes
52 Added a C<duck_type> sugar function to L<Moose::Util::TypeConstraints>
53 to make integration with non-Moose classes easier. It simply checks if
54 C<< $obj->can() >> a list of methods.
56 A number of methods (mostly inherited from L<Class::MOP>) have been
57 renamed with a leading underscore to indicate their internal-ness. The
58 old method names will still work for a while, but will warn that the
59 method has been renamed. In a few cases, the method will be removed
60 entirely in the future. This may affect MooseX authors who were using
65 Calling C<subtype> with a name as the only argument now throws an
66 exception. If you want an anonymous subtype do:
68 my $subtype = subtype as 'Foo';
70 This is related to the changes in version 0.71_01.
72 The C<is_needed> method in L<Moose::Meta::Method::Destructor> is now
73 only usable as a class method. Previously, it worked as a class or
74 object method, with a different internal implementation for each
77 The internals of making a class immutable changed a lot in Class::MOP
78 0.78_02, and Moose's internals have changed along with it. The
79 external C<< $metaclass->make_immutable >> method still works the same
84 A mutable class accepted C<< Foo->new(undef) >> without complaint,
85 while an immutable class would blow up with an unhelpful error. Now,
86 in both cases we throw a helpful error instead.
88 This "feature" was originally added to allow for cases such as this:
96 return My::Class->new($args);
98 But we decided this is a bad idea and a little too magical, because it
99 can easily mask real errors.
101 =head1 Version 0.71_01
103 Calling C<type> or C<subtype> without the sugar helpers (C<as>,
104 C<where>, C<message>) is now deprecated.
106 As a side effect, this meant we ended up using Perl prototypes on
107 C<as>, and code like this will no longer work:
109 use Moose::Util::TypeConstraints;
110 use Declare::Constraints::Simple -All;
112 subtype 'ArrayOfInts'
114 => IsArrayRef(IsInt);
116 Instead it must be changed to this:
121 where => IsArrayRef(IsInt)
125 If you want to maintain backwards compat with older versions of Moose,
126 you must explicitly test Moose's C<VERSION>:
128 if ( Moose->VERSION < 0.71_01 ) {
129 subtype 'ArrayOfInts'
131 => IsArrayRef(IsInt);
137 where => IsArrayRef(IsInt)
144 We no longer pass the meta-attribute object as a final argument to
145 triggers. This actually changed for inlined code a while back, but the
146 non-inlined version and the docs were still out of date.
148 If by some chance you actually used this feature, the workaround is
149 simple. You fetch the attribute object from out of the C<$self>
150 that is passed as the first argument to trigger, like so:
156 my ( $self, $value ) = @_;
157 my $attr = $self->meta->find_attribute_by_name('foo');
165 If you created a subtype and passed a parent that Moose didn't know
166 about, it simply ignored the parent. Now it automatically creates the
167 parent as a class type. This may not be what you want, but is less
170 You could declare a name with subtype such as "Foo!Bar". Moose would
171 accept this allowed, but if you used it in a parameterized type such
172 as "ArrayRef[Foo!Bar]" it wouldn't work. We now do some vetting on
173 names created via the sugar functions, so that they can only contain
174 alphanumerics, ":", and ".".
178 Methods created via an attribute can now fulfill a C<requires>
179 declaration for a role. Honestly we don't know why Stevan didn't make
180 this work originally, he was just insane or something.
182 Stack traces from inlined code will now report the line and file as
183 being in your class, as opposed to in Moose guts.
185 =head1 Version 0.62_02
187 When a class does not provide all of a role's required methods, the
188 error thrown now mentions all of the missing methods, as opposed to
189 just the first missing method.
191 Moose will no longer inline a constructor for your class unless it
192 inherits its constructor from Moose::Object, and will warn when it
193 doesn't inline. If you want to force inlining anyway, pass
194 C<< "replace_constructor => 1 >> to C<make_immutable>.
196 If you want to get rid of the warning, pass C<< inline_constructor =>
201 Removed the (deprecated) C<make_immutable> keyword.
203 Removing an attribute from a class now also removes delegation
204 (C<handles>) methods installed for that attribute. This is correct
205 behavior, but if you were wrongly relying on it you might get bit.
209 Roles now add methods by calling C<add_method>, not
210 C<alias_method>. They make sure to always provide a method object,
211 which will be cloned internally. This means that it is now possible to
212 track the source of a method provided by a role, and even follow its
213 history through intermediate roles. This means that methods added by
214 a role now show up when looking at a class's method list/map.
216 Parameter and Union args are now sorted, this makes Int|Str the same
217 constraint as Str|Int. Also, incoming type constraint strings are
218 normalized to remove all whitespace differences. This is mostly for
219 internals and should not affect outside code.
221 L<Moose::Exporter> will no longer remove a subroutine that the
222 exporting package re-exports. Moose re-exports the Carp::confess
223 function, among others. The reasoning is that we cannot know whether
224 you have also explicitly imported those functions for your own use, so
225 we err on the safe side and always keep them.
229 C<Moose::init_meta> should now be called as a method.
231 New modules for extension writers, L<Moose::Exporter> and
232 L<Moose::Util::MetaRole>.
234 =head1 Version 0.55_01
236 Implemented metaclass traits (and wrote a recipe for it):
238 use Moose -traits => 'Foo'
240 This should make writing small Moose extensions a little
245 Fixed C<coerce> to accept anon types just like C<subtype> can.
248 coerce $some_anon_type => from 'Str' => via { ... };
252 Added C<BUILDARGS>, a new step in C<< Moose::Object->new() >>.
256 Fixed how the C<< is => (ro|rw) >> works with custom defined
257 C<reader>, C<writer> and C<accessor> options. See the below table for
260 is => ro, writer => _foo # turns into (reader => foo, writer => _foo)
261 is => rw, writer => _foo # turns into (reader => foo, writer => _foo)
262 is => rw, accessor => _foo # turns into (accessor => _foo)
263 is => ro, accessor => _foo # error, accesor is rw
267 The C<before/around/after> method modifiers now support regexp
268 matching of method names. NOTE: this only works for classes, it is
269 currently not supported in roles, but, ... patches welcome.
271 The C<has> keyword for roles now accepts the same array ref form that
272 L<Moose>.pm does for classes.
274 A trigger on a read-only attribute is no longer an error, as it's
275 useful to trigger off of the constructor.
277 Subtypes of parameterizable types now are parameterizable types
282 Fixed issue where C<DEMOLISHALL> was eating the value in C<$@>, and so
283 not working correctly. It still kind of eats them, but so does vanilla
288 Inherited attributes may now be extended without restriction on the
289 type ('isa', 'does').
291 The entire set of Moose::Meta::TypeConstraint::* classes were
292 refactored in this release. If you were relying on their internals you
293 should test your code carefully.
297 Documenting the use of '+name' with attributes that come from recently
298 composed roles. It makes sense, people are using it, and so why not
299 just officially support it.
301 The C<< Moose::Meta::Class->create >> method now supports roles.
303 It is now possible to make anonymous enum types by passing C<enum> an
304 array reference instead of the C<< enum $name => @values >>.
308 Added the C<make_immutable> keyword as a shortcut to calling
309 C<make_immutable> on the meta object. This eventually got removed!
311 Made C<< init_arg => undef >> work in Moose. This means "do not accept
312 a constructor parameter for this attribute".
314 Type errors now use the provided message. Prior to this release they
319 Moose is now a postmodern object system :)
321 The Role system was completely refactored. It is 100% backwards
322 compat, but the internals were totally changed. If you relied on the
323 internals then you are advised to test carefully.
325 Added method exclusion and aliasing for Roles in this release.
327 Added the L<Moose::Util::TypeConstraints::OptimizedConstraints>
330 Passing a list of values to an accessor (which is only expecting one
331 value) used to be silently ignored, now it throws an error.
335 Added parameterized types and did a pretty heavy refactoring of the
336 type constraint system.
338 Better framework extendability and better support for "making your own
341 =head1 Version 0.25 or before
343 Honestly, you shouldn't be using versions of Moose that are this old,
344 so many bug fixes and speed improvements have been made you would be
345 crazy to not upgrade.
347 Also, I am tired of going through the Changelog so I am stopping here,
348 if anyone would like to continue this please feel free.
352 Stevan Little E<lt>stevan@iinteractive.comE<gt>
354 =head1 COPYRIGHT AND LICENSE
356 Copyright 2009 by Infinity Interactive, Inc.
358 L<http://www.iinteractive.com>
360 This library is free software; you can redistribute it and/or modify
361 it under the same terms as Perl itself.