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 0.93_01 and 0.94
23 =item "no Moose" now removes C<blessed> and C<confess>
25 Moose is now smart enough to know exactly what it exported, even when it
26 re-exports functions from other packages. When you unimport Moose, it will
27 remove these functions from your namespace unless you I<also> imported them
28 directly from their respective packages.
30 If you have a C<no Moose> in your code I<before> you call C<blessed> or
31 C<confess>, your code will break. You can either move the C<no Moose> call
32 later in your code, or explicitly import the relevant functions from the
33 packages that provide them.
35 =item L<Moose::Exporter> is smarter about unimporting re-exports
37 The change above comes from a general improvement to L<Moose::Exporter>. It
38 will now unimport any function it exports, even if that function is a
39 re-export from another package.
47 =item Calling $object->new() is no longer deprecated
49 We decided to undeprecate this. Now it just works.
51 =item Both C<get_method_map> and C<get_attribute_map> is deprecated
53 These metaclass methods were never meant to be public, and they are both now
54 deprecated. The work around if you still need the functionality they provided
55 is to iterate over the list of names manually.
57 my %fields = map { $_ => $meta->get_attribute($_) } $meta->get_attribute_list;
59 This was actually a change in L<Class::MOP>, but this version of Moose
60 requires a version of L<Class::MOP> that includes said change.
68 =item Added Native delegation for Code refs
70 See L<Moose::Meta::Attribute::Native::Trait::Code> for details.
72 =item Calling $object->new() is deprecated
74 Moose has long supported this, but it's never really been documented, and we
75 don't think this is a good practice. If you want to construct an object from
76 an existing object, you should provide some sort of alternate constructor like
77 C<< $object->clone >>.
79 Calling C<< $object->new >> now issues a warning, and will be an error in a
82 =item Moose no longer warns if you call C<make_immutable> for a class with mutable ancestors
84 While in theory this is a good thing to warn about, we found so many
85 exceptions to this that doing this properly became quite problematic.
89 =head1 Version 0.89_02
93 =item New Native delegation methods from L<List::Util> and L<List::MoreUtils>
95 In particular, we now have C<reduce>, C<shuffle>, C<uniq>, and C<natatime>.
97 =item The Moose::Exporter with_caller feature is now deprecated
99 Use C<with_meta> instead. The C<with_caller> option will start warning in a
102 =item Moose now warns if you call C<make_immutable> for a class with mutable ancestors
104 This is dangerous because modifying a class after a subclass has been
105 immutabilized will lead to incorrect results in the subclass, due to inlining,
106 caching, etc. This occasionally happens accidentally, when a class loads one
107 of its subclasses in the middle of its class definition, so pointing out that
108 this may cause issues should be helpful. Metaclasses (classes that inherit
109 from L<Class::MOP::Object>) are currently exempt from this check, since at the
110 moment we aren't very consistent about which metaclasses we immutabilize.
112 =item C<enum> and C<duck_type> now take arrayrefs for all forms
114 Previously, calling these functions with a list would take the first element of
115 the list as the type constraint name, and use the remainder as the enum values
116 or method names. This makes the interface inconsistent with the anon-type forms
117 of these functions (which must take an arrayref), and a free-form list where
118 the first value is sometimes special is hard to validate (and harder to give
119 reasonable error messages for). These functions have been changed to take
120 arrayrefs in all their forms - so, C<< enum 'My::Type' => [qw(foo bar)] >> is
121 now the preferred way to create an enum type constraint. The old syntax still
122 works for now, but it will hopefully be deprecated and removed in a future
127 =head1 Version 0.89_01
129 L<Moose::Meta::Attribute::Native> has been moved into the Moose core from
130 L<MooseX::AttributeHelpers>. Major changes include:
134 =item C<traits>, not C<metaclass>
136 Method providers are only available via traits.
138 =item C<handles>, not C<provides> or C<curries>
140 The C<provides> syntax was like core Moose C<< handles => HASHREF >>
141 syntax, but with the keys and values reversed. This was confusing,
142 and AttributeHelpers now uses C<< handles => HASHREF >> in a way that
143 should be intuitive to anyone already familiar with how it is used for
146 The C<curries> functionality provided by AttributeHelpers has been
147 generalized to apply to all cases of C<< handles => HASHREF >>, though
148 not every piece of functionality has been ported (currying with a
149 CODEREF is not supported).
151 =item C<empty> is now C<is_empty>, and means empty, not non-empty
153 Previously, the C<empty> method provided by Arrays and Hashes returned true if
154 the attribute was B<not> empty (no elements). Now it returns true if the
155 attribute B<is> empty. It was also renamed to C<is_empty>, to reflect this.
157 =item C<find> was renamed to C<first>, and C<first> and C<last> were removed
159 L<List::Util> refers to the functionality that we used to provide under C<find>
160 as L<first|List::Util/first>, so that will likely be more familiar (and will
161 fit in better if we decide to add more List::Util functions). C<first> and
162 C<last> were removed, since their functionality is easily duplicated with
165 =item Helpers that take a coderef of one argument now use C<$_>
167 Subroutines passed as the first argument to C<first>, C<map>, and C<grep> now
168 receive their argument in C<$_> rather than as a parameter to the subroutine.
169 Helpers that take a coderef of two or more arguments remain using the argument
170 list (there are technical limitations to using C<$a> and C<$b> like C<sort>
173 See L<Moose::Meta::Attribute::Native> for the new documentation.
177 The C<alias> and C<excludes> role parameters have been renamed to C<-alias>
178 and C<-excludes>. The old names still work, but new code should use the new
179 names, and eventually the old ones will be deprecated and removed.
183 C<< use Moose -metaclass => 'Foo' >> now does alias resolution, just like
184 C<-traits> (and the C<metaclass> and C<traits> options to C<has>).
186 Added two functions C<meta_class_alias> and C<meta_attribute_alias> to
187 L<Moose::Util>, to simplify aliasing metaclasses and metatraits. This is
188 a wrapper around the old
190 package Moose::Meta::Class::Custom::Trait::FooTrait;
191 sub register_implementation { 'My::Meta::Trait' }
197 When an attribute generates I<no> accessors, we now warn. This is to help
198 users who forget the C<is> option. If you really do not want any accessors,
199 you can use C<< is => 'bare' >>. You can maintain back compat with older
200 versions of Moose by using something like:
202 ($Moose::VERSION >= 0.84 ? is => 'bare' : ())
204 When an accessor overwrites an existing method, we now warn. To work around
205 this warning (if you really must have this behavior), you can explicitly
206 remove the method before creating it as an accessor:
210 __PACKAGE__->meta->remove_method('foo');
216 When an unknown option is passed to C<has>, we now warn. You can silence
217 the warning by fixing your code. :)
219 The C<Role> type has been deprecated. On its own, it was useless,
220 since it just checked C<< $object->can('does') >>. If you were using
221 it as a parent type, just call C<role_type('Role::Name')> to create an
222 appropriate type instead.
226 C<use Moose::Exporter;> now imports C<strict> and C<warnings> into packages
231 C<DEMOLISHALL> and C<DEMOLISH> now receive an argument indicating whether or
232 not we are in global destruction.
236 Type constraints no longer run coercions for a value that already matches the
237 constraint. This may affect some (arguably buggy) edge case coercions that
238 rely on side effects in the C<via> clause.
242 L<Moose::Exporter> now accepts the C<-metaclass> option for easily
243 overriding the metaclass (without L<metaclass>). This works for classes
248 Added a C<duck_type> sugar function to L<Moose::Util::TypeConstraints>
249 to make integration with non-Moose classes easier. It simply checks if
250 C<< $obj->can() >> a list of methods.
252 A number of methods (mostly inherited from L<Class::MOP>) have been
253 renamed with a leading underscore to indicate their internal-ness. The
254 old method names will still work for a while, but will warn that the
255 method has been renamed. In a few cases, the method will be removed
256 entirely in the future. This may affect MooseX authors who were using
261 Calling C<subtype> with a name as the only argument now throws an
262 exception. If you want an anonymous subtype do:
264 my $subtype = subtype as 'Foo';
266 This is related to the changes in version 0.71_01.
268 The C<is_needed> method in L<Moose::Meta::Method::Destructor> is now
269 only usable as a class method. Previously, it worked as a class or
270 object method, with a different internal implementation for each
273 The internals of making a class immutable changed a lot in Class::MOP
274 0.78_02, and Moose's internals have changed along with it. The
275 external C<< $metaclass->make_immutable >> method still works the same
280 A mutable class accepted C<< Foo->new(undef) >> without complaint,
281 while an immutable class would blow up with an unhelpful error. Now,
282 in both cases we throw a helpful error instead.
284 This "feature" was originally added to allow for cases such as this:
292 return My::Class->new($args);
294 But we decided this is a bad idea and a little too magical, because it
295 can easily mask real errors.
297 =head1 Version 0.71_01
299 Calling C<type> or C<subtype> without the sugar helpers (C<as>,
300 C<where>, C<message>) is now deprecated.
302 As a side effect, this meant we ended up using Perl prototypes on
303 C<as>, and code like this will no longer work:
305 use Moose::Util::TypeConstraints;
306 use Declare::Constraints::Simple -All;
308 subtype 'ArrayOfInts'
310 => IsArrayRef(IsInt);
312 Instead it must be changed to this:
317 where => IsArrayRef(IsInt)
321 If you want to maintain backwards compat with older versions of Moose,
322 you must explicitly test Moose's C<VERSION>:
324 if ( Moose->VERSION < 0.71_01 ) {
325 subtype 'ArrayOfInts'
327 => IsArrayRef(IsInt);
333 where => IsArrayRef(IsInt)
340 We no longer pass the meta-attribute object as a final argument to
341 triggers. This actually changed for inlined code a while back, but the
342 non-inlined version and the docs were still out of date.
344 If by some chance you actually used this feature, the workaround is
345 simple. You fetch the attribute object from out of the C<$self>
346 that is passed as the first argument to trigger, like so:
352 my ( $self, $value ) = @_;
353 my $attr = $self->meta->find_attribute_by_name('foo');
361 If you created a subtype and passed a parent that Moose didn't know
362 about, it simply ignored the parent. Now it automatically creates the
363 parent as a class type. This may not be what you want, but is less
366 You could declare a name with subtype such as "Foo!Bar". Moose would
367 accept this allowed, but if you used it in a parameterized type such
368 as "ArrayRef[Foo!Bar]" it wouldn't work. We now do some vetting on
369 names created via the sugar functions, so that they can only contain
370 alphanumerics, ":", and ".".
374 Methods created via an attribute can now fulfill a C<requires>
375 declaration for a role. Honestly we don't know why Stevan didn't make
376 this work originally, he was just insane or something.
378 Stack traces from inlined code will now report the line and file as
379 being in your class, as opposed to in Moose guts.
381 =head1 Version 0.62_02
383 When a class does not provide all of a role's required methods, the
384 error thrown now mentions all of the missing methods, as opposed to
385 just the first missing method.
387 Moose will no longer inline a constructor for your class unless it
388 inherits its constructor from Moose::Object, and will warn when it
389 doesn't inline. If you want to force inlining anyway, pass
390 C<< replace_constructor => 1 >> to C<make_immutable>.
392 If you want to get rid of the warning, pass C<< inline_constructor =>
397 Removed the (deprecated) C<make_immutable> keyword.
399 Removing an attribute from a class now also removes delegation
400 (C<handles>) methods installed for that attribute. This is correct
401 behavior, but if you were wrongly relying on it you might get bit.
405 Roles now add methods by calling C<add_method>, not
406 C<alias_method>. They make sure to always provide a method object,
407 which will be cloned internally. This means that it is now possible to
408 track the source of a method provided by a role, and even follow its
409 history through intermediate roles. This means that methods added by
410 a role now show up when looking at a class's method list/map.
412 Parameter and Union args are now sorted, this makes Int|Str the same
413 constraint as Str|Int. Also, incoming type constraint strings are
414 normalized to remove all whitespace differences. This is mostly for
415 internals and should not affect outside code.
417 L<Moose::Exporter> will no longer remove a subroutine that the
418 exporting package re-exports. Moose re-exports the Carp::confess
419 function, among others. The reasoning is that we cannot know whether
420 you have also explicitly imported those functions for your own use, so
421 we err on the safe side and always keep them.
425 C<Moose::init_meta> should now be called as a method.
427 New modules for extension writers, L<Moose::Exporter> and
428 L<Moose::Util::MetaRole>.
430 =head1 Version 0.55_01
432 Implemented metaclass traits (and wrote a recipe for it):
434 use Moose -traits => 'Foo'
436 This should make writing small Moose extensions a little
441 Fixed C<coerce> to accept anon types just like C<subtype> can.
444 coerce $some_anon_type => from 'Str' => via { ... };
448 Added C<BUILDARGS>, a new step in C<< Moose::Object->new() >>.
452 Fixed how the C<< is => (ro|rw) >> works with custom defined
453 C<reader>, C<writer> and C<accessor> options. See the below table for
456 is => ro, writer => _foo # turns into (reader => foo, writer => _foo)
457 is => rw, writer => _foo # turns into (reader => foo, writer => _foo)
458 is => rw, accessor => _foo # turns into (accessor => _foo)
459 is => ro, accessor => _foo # error, accesor is rw
463 The C<before/around/after> method modifiers now support regexp
464 matching of method names. NOTE: this only works for classes, it is
465 currently not supported in roles, but, ... patches welcome.
467 The C<has> keyword for roles now accepts the same array ref form that
468 L<Moose>.pm does for classes.
470 A trigger on a read-only attribute is no longer an error, as it's
471 useful to trigger off of the constructor.
473 Subtypes of parameterizable types now are parameterizable types
478 Fixed issue where C<DEMOLISHALL> was eating the value in C<$@>, and so
479 not working correctly. It still kind of eats them, but so does vanilla
484 Inherited attributes may now be extended without restriction on the
485 type ('isa', 'does').
487 The entire set of Moose::Meta::TypeConstraint::* classes were
488 refactored in this release. If you were relying on their internals you
489 should test your code carefully.
493 Documenting the use of '+name' with attributes that come from recently
494 composed roles. It makes sense, people are using it, and so why not
495 just officially support it.
497 The C<< Moose::Meta::Class->create >> method now supports roles.
499 It is now possible to make anonymous enum types by passing C<enum> an
500 array reference instead of the C<< enum $name => @values >>.
504 Added the C<make_immutable> keyword as a shortcut to calling
505 C<make_immutable> on the meta object. This eventually got removed!
507 Made C<< init_arg => undef >> work in Moose. This means "do not accept
508 a constructor parameter for this attribute".
510 Type errors now use the provided message. Prior to this release they
515 Moose is now a postmodern object system :)
517 The Role system was completely refactored. It is 100% backwards
518 compat, but the internals were totally changed. If you relied on the
519 internals then you are advised to test carefully.
521 Added method exclusion and aliasing for Roles in this release.
523 Added the L<Moose::Util::TypeConstraints::OptimizedConstraints>
526 Passing a list of values to an accessor (which is only expecting one
527 value) used to be silently ignored, now it throws an error.
531 Added parameterized types and did a pretty heavy refactoring of the
532 type constraint system.
534 Better framework extendability and better support for "making your own
537 =head1 Version 0.25 or before
539 Honestly, you shouldn't be using versions of Moose that are this old,
540 so many bug fixes and speed improvements have been made you would be
541 crazy to not upgrade.
543 Also, I am tired of going through the Changelog so I am stopping here,
544 if anyone would like to continue this please feel free.
548 Stevan Little E<lt>stevan@iinteractive.comE<gt>
550 =head1 COPYRIGHT AND LICENSE
552 Copyright 2009 by Infinity Interactive, Inc.
554 L<http://www.iinteractive.com>
556 This library is free software; you can redistribute it and/or modify
557 it under the same terms as Perl itself.