1Moose::Manual::Delta(3)User Contributed Perl DocumentatioMnoose::Manual::Delta(3)
2
6 Moose::Manual::Delta - Important Changes in Moose
7
9 This documents any important or noteworthy changes in Moose, with a
10 focus on backwards. This does duplicate data from the Changes file, but
11 aims to provide more details and when possible workarounds.
12 Besides helping keep up with changes, you can also use this document
14 for finding the lowest version of Moose that supported a given feature.
15 If you encounter a problem and have a solution but don't see it
16 documented here, or think we missed an important feature, please send
17 us a patch.
18
20 All deprecated features now warn
21 Previously, deprecation mostly consisted of simply saying "X is
22 deprecated" in the Changes file. We were not very consistent about
23 actually warning. Now, all deprecated features still present in
24 Moose actually give a warning. The warning is issued once per
25 calling package. See Moose::Deprecated for more details.
26 You cannot pass "coerce => 1" unless the attribute's type constraint
28 has a coercion
29 Previously, this was accepted, and it sort of worked, except that
30 if you attempted to set the attribute after the object was created,
31 you would get a runtime error.
32 Now you will get a warning when you attempt to define the
34 attribute.
35 "no Moose", "no Moose::Role", and "no Moose::Exporter" no longer
37 unimport strict and warnings
38 This change was made in 1.05, and has now been reverted. We don't
39 know if the user has explicitly loaded strict or warnings on their
40 own, and unimporting them is just broken in that case.
41 Reversed logic when defining which options can be changed
43 Moose::Meta::Attribute now allows all options to be changed in an
44 overridden attribute. The previous behaviour required each option
45 to be whitelisted using the "legal_options_for_inheritance" method.
46 This method has been removed, and there is a new method,
47 "illegal_options_for_inheritance", which can now be used to prevent
48 certain options from being changeable.
49 In addition, we only throw an error if the illegal option is
51 actually changed. If the superclass didn't specify this option at
52 all when defining the attribute, the subclass version can still add
53 it as an option.
54 Example of overriding this in an attribute trait:
56 package Bar::Meta::Attribute;
58 use Moose::Role;
59 has 'my_illegal_option' => (
61 isa => 'CodeRef',
62 is => 'rw',
63 );
64 around illegal_options_for_inheritance => sub {
66 return ( shift->(@_), qw/my_illegal_option/ );
67 };
68
70 "BUILD" in Moose::Object methods are now called when calling
71 "new_object"
72 Previously, "BUILD" methods would only be called from
73 "Moose::Object::new", but now they are also called when
74 constructing an object via "Moose::Meta::Class::new_object".
75 "BUILD" methods are an inherent part of the object construction
76 process, and this should make "$meta->new_object" actually usable
77 without forcing people to use "$meta->name->new".
78 "no Moose", "no Moose::Role", and "no Moose::Exporter" now unimport
80 strict and warnings
81 In the interest of having "no Moose" clean up everything that "use
82 Moose" does in the calling scope, "no Moose" (as well as all other
83 Moose::Exporter-using modules) now unimports strict and warnings.
84 Metaclass compatibility checking and fixing should be much more robust
86 The metaclass compatibility checking and fixing algorithms have
87 been completely rewritten, in both Class::MOP and Moose. This
88 should resolve many confusing errors when dealing with non-Moose
89 inheritance and with custom metaclasses for things like attributes,
90 constructors, etc. For correct code, the only thing that should
91 require a change is that custom error metaclasses must now inherit
92 from Moose::Error::Default.
93
95 Moose::Meta::TypeConstraint::Class is_subtype_of behavior
96 Earlier versions of is_subtype_of would incorrectly return true
97 when called with itself, its own TC name or its class name as an
98 argument. (i.e. $foo_tc->is_subtype_of('Foo') == 1) This behavior
99 was a caused by "isa" being checked before the class name. The old
100 behavior can be accessed with is_type_of
101
103 Moose::Meta::Attribute::Native::Trait::Code no longer creates reader
104 methods by default
105 Earlier versions of Moose::Meta::Attribute::Native::Trait::Code
106 created read-only accessors for the attributes it's been applied
107 to, even if you didn't ask for it with "is => 'ro'". This incorrect
108 behaviour has now been fixed.
109
111 Moose::Util add_method_modifier behavior
112 add_method_modifier (and subsequently the sugar functions
113 Moose::before, Moose::after, and Moose::around) can now accept
114 arrayrefs, with the same behavior as lists. Types other than
115 arrayref and regexp result in an error.
116
118 Moose::Util::MetaRole API has changed
119 The "apply_metaclass_roles" function is now called
120 "apply_metaroles". The way arguments are supplied has been changed
121 to force you to distinguish between metaroles applied to
122 Moose::Meta::Class (and helpers) versus Moose::Meta::Role.
123 The old API still works, but will warn in a future release, and
125 eventually be removed.
126 Moose::Meta::Role has real attributes
128 The attributes returned by Moose::Meta::Role are now instances of
129 the Moose::Meta::Role::Attribute class, instead of bare hash
130 references.
131 "no Moose" now removes "blessed" and "confess"
133 Moose is now smart enough to know exactly what it exported, even
134 when it re-exports functions from other packages. When you unimport
135 Moose, it will remove these functions from your namespace unless
136 you also imported them directly from their respective packages.
137 If you have a "no Moose" in your code before you call "blessed" or
139 "confess", your code will break. You can either move the "no Moose"
140 call later in your code, or explicitly import the relevant
141 functions from the packages that provide them.
142 Moose::Exporter is smarter about unimporting re-exports
144 The change above comes from a general improvement to
145 Moose::Exporter. It will now unimport any function it exports, even
146 if that function is a re-export from another package.
147 Attributes in roles can no longer override class attributes with "+foo"
149 Previously, this worked more or less accidentally, because role
150 attributes weren't objects. This was never documented, but a few
151 MooseX modules took advantage of this.
152 The composition_class_roles attribute in Moose::Meta::Role is now a
154 method
155 This was done to make it possible for roles to alter the the list
156 of composition class roles by applying a method modifiers.
157 Previously, this was an attribute and MooseX modules override it.
158 Since that no longer works, this was made a method.
159 This should be an attribute, so this may switch back to being an
161 attribute in the future if we can figure out how to make this work.
162
164 Calling $object->new() is no longer deprecated
165 We decided to undeprecate this. Now it just works.
166 Both "get_method_map" and "get_attribute_map" is deprecated
168 These metaclass methods were never meant to be public, and they are
169 both now deprecated. The work around if you still need the
170 functionality they provided is to iterate over the list of names
171 manually.
172 my %fields = map { $_ => $meta->get_attribute($_) } $meta->get_attribute_list;
174 This was actually a change in Class::MOP, but this version of Moose
176 requires a version of Class::MOP that includes said change.
177
179 Added Native delegation for Code refs
180 See Moose::Meta::Attribute::Native::Trait::Code for details.
181 Calling $object->new() is deprecated
183 Moose has long supported this, but it's never really been
184 documented, and we don't think this is a good practice. If you want
185 to construct an object from an existing object, you should provide
186 some sort of alternate constructor like "$object->clone".
187 Calling "$object->new" now issues a warning, and will be an error
189 in a future release.
190 Moose no longer warns if you call "make_immutable" for a class with
192 mutable ancestors
193 While in theory this is a good thing to warn about, we found so
194 many exceptions to this that doing this properly became quite
195 problematic.
196
198 New Native delegation methods from List::Util and List::MoreUtils
199 In particular, we now have "reduce", "shuffle", "uniq", and
200 "natatime".
201 The Moose::Exporter with_caller feature is now deprecated
203 Use "with_meta" instead. The "with_caller" option will start
204 warning in a future release.
205 Moose now warns if you call "make_immutable" for a class with mutable
207 ancestors
208 This is dangerous because modifying a class after a subclass has
209 been immutabilized will lead to incorrect results in the subclass,
210 due to inlining, caching, etc. This occasionally happens
211 accidentally, when a class loads one of its subclasses in the
212 middle of its class definition, so pointing out that this may cause
213 issues should be helpful. Metaclasses (classes that inherit from
214 Class::MOP::Object) are currently exempt from this check, since at
215 the moment we aren't very consistent about which metaclasses we
216 immutabilize.
217 "enum" and "duck_type" now take arrayrefs for all forms
219 Previously, calling these functions with a list would take the
220 first element of the list as the type constraint name, and use the
221 remainder as the enum values or method names. This makes the
222 interface inconsistent with the anon-type forms of these functions
223 (which must take an arrayref), and a free-form list where the first
224 value is sometimes special is hard to validate (and harder to give
225 reasonable error messages for). These functions have been changed
226 to take arrayrefs in all their forms - so, "enum 'My::Type' =>
227 [qw(foo bar)]" is now the preferred way to create an enum type
228 constraint. The old syntax still works for now, but it will
229 hopefully be deprecated and removed in a future release.
230
232 Moose::Meta::Attribute::Native has been moved into the Moose core from
233 MooseX::AttributeHelpers. Major changes include:
234 "traits", not "metaclass"
236 Method providers are only available via traits.
237 "handles", not "provides" or "curries"
239 The "provides" syntax was like core Moose "handles => HASHREF"
240 syntax, but with the keys and values reversed. This was confusing,
241 and AttributeHelpers now uses "handles => HASHREF" in a way that
242 should be intuitive to anyone already familiar with how it is used
243 for other attributes.
244 The "curries" functionality provided by AttributeHelpers has been
246 generalized to apply to all cases of "handles => HASHREF", though
247 not every piece of functionality has been ported (currying with a
248 CODEREF is not supported).
249 "empty" is now "is_empty", and means empty, not non-empty
251 Previously, the "empty" method provided by Arrays and Hashes
252 returned true if the attribute was not empty (no elements). Now it
253 returns true if the attribute is empty. It was also renamed to
254 "is_empty", to reflect this.
255 "find" was renamed to "first", and "first" and "last" were removed
257 List::Util refers to the functionality that we used to provide
258 under "find" as first, so that will likely be more familiar (and
259 will fit in better if we decide to add more List::Util functions).
260 "first" and "last" were removed, since their functionality is
261 easily duplicated with curries of "get".
262 Helpers that take a coderef of one argument now use $_
264 Subroutines passed as the first argument to "first", "map", and
265 "grep" now receive their argument in $_ rather than as a parameter
266 to the subroutine. Helpers that take a coderef of two or more
267 arguments remain using the argument list (there are technical
268 limitations to using $a and $b like "sort" does).
269 See Moose::Meta::Attribute::Native for the new documentation.
271 The "alias" and "excludes" role parameters have been renamed to
273 "-alias" and "-excludes". The old names still work, but new code should
274 use the new names, and eventually the old ones will be deprecated and
275 removed.
276
278 "use Moose -metaclass => 'Foo'" now does alias resolution, just like
279 "-traits" (and the "metaclass" and "traits" options to "has").
280 Added two functions "meta_class_alias" and "meta_attribute_alias" to
282 Moose::Util, to simplify aliasing metaclasses and metatraits. This is a
283 wrapper around the old
284 package Moose::Meta::Class::Custom::Trait::FooTrait;
286 sub register_implementation { 'My::Meta::Trait' }
287 way of doing this.
289
291 When an attribute generates no accessors, we now warn. This is to help
292 users who forget the "is" option. If you really do not want any
293 accessors, you can use "is => 'bare'". You can maintain back compat
294 with older versions of Moose by using something like:
295 ($Moose::VERSION >= 0.84 ? is => 'bare' : ())
297 When an accessor overwrites an existing method, we now warn. To work
299 around this warning (if you really must have this behavior), you can
300 explicitly remove the method before creating it as an accessor:
301 sub foo {}
303 __PACKAGE__->meta->remove_method('foo');
305 has foo => (
307 is => 'ro',
308 );
309 When an unknown option is passed to "has", we now warn. You can silence
311 the warning by fixing your code. :)
312 The "Role" type has been deprecated. On its own, it was useless, since
314 it just checked "$object->can('does')". If you were using it as a
315 parent type, just call "role_type('Role::Name')" to create an
316 appropriate type instead.
317
319 "use Moose::Exporter;" now imports "strict" and "warnings" into
320 packages that use it.
321
323 "DEMOLISHALL" and "DEMOLISH" now receive an argument indicating whether
324 or not we are in global destruction.
325
327 Type constraints no longer run coercions for a value that already
328 matches the constraint. This may affect some (arguably buggy) edge
329 case coercions that rely on side effects in the "via" clause.
330
332 Moose::Exporter now accepts the "-metaclass" option for easily
333 overriding the metaclass (without metaclass). This works for classes
334 and roles.
335
337 Added a "duck_type" sugar function to Moose::Util::TypeConstraints to
338 make integration with non-Moose classes easier. It simply checks if
339 "$obj->can()" a list of methods.
340 A number of methods (mostly inherited from Class::MOP) have been
342 renamed with a leading underscore to indicate their internal-ness. The
343 old method names will still work for a while, but will warn that the
344 method has been renamed. In a few cases, the method will be removed
345 entirely in the future. This may affect MooseX authors who were using
346 these methods.
347
349 Calling "subtype" with a name as the only argument now throws an
350 exception. If you want an anonymous subtype do:
351 my $subtype = subtype as 'Foo';
353 This is related to the changes in version 0.71_01.
355 The "is_needed" method in Moose::Meta::Method::Destructor is now only
357 usable as a class method. Previously, it worked as a class or object
358 method, with a different internal implementation for each version.
359 The internals of making a class immutable changed a lot in Class::MOP
361 0.78_02, and Moose's internals have changed along with it. The external
362 "$metaclass->make_immutable" method still works the same way.
363
365 A mutable class accepted "Foo->new(undef)" without complaint, while an
366 immutable class would blow up with an unhelpful error. Now, in both
367 cases we throw a helpful error instead.
368 This "feature" was originally added to allow for cases such as this:
370 my $args;
372 if ( something() ) {
374 $args = {...};
375 }
376 return My::Class->new($args);
378 But we decided this is a bad idea and a little too magical, because it
380 can easily mask real errors.
381
383 Calling "type" or "subtype" without the sugar helpers ("as", "where",
384 "message") is now deprecated.
385 As a side effect, this meant we ended up using Perl prototypes on "as",
387 and code like this will no longer work:
388 use Moose::Util::TypeConstraints;
390 use Declare::Constraints::Simple -All;
391 subtype 'ArrayOfInts'
393 => as 'ArrayRef'
394 => IsArrayRef(IsInt);
395 Instead it must be changed to this:
397 subtype(
399 'ArrayOfInts' => {
400 as => 'ArrayRef',
401 where => IsArrayRef(IsInt)
402 }
403 );
404 If you want to maintain backwards compat with older versions of Moose,
406 you must explicitly test Moose's "VERSION":
407 if ( Moose->VERSION < 0.71_01 ) {
409 subtype 'ArrayOfInts'
410 => as 'ArrayRef'
411 => IsArrayRef(IsInt);
412 }
413 else {
414 subtype(
415 'ArrayOfInts' => {
416 as => 'ArrayRef',
417 where => IsArrayRef(IsInt)
418 }
419 );
420 }
421
423 We no longer pass the meta-attribute object as a final argument to
424 triggers. This actually changed for inlined code a while back, but the
425 non-inlined version and the docs were still out of date.
426 If by some chance you actually used this feature, the workaround is
428 simple. You fetch the attribute object from out of the $self that is
429 passed as the first argument to trigger, like so:
430 has 'foo' => (
432 is => 'ro',
433 isa => 'Any',
434 trigger => sub {
435 my ( $self, $value ) = @_;
436 my $attr = $self->meta->find_attribute_by_name('foo');
437 # ...
439 }
440 );
441
443 If you created a subtype and passed a parent that Moose didn't know
444 about, it simply ignored the parent. Now it automatically creates the
445 parent as a class type. This may not be what you want, but is less
446 broken than before.
447 You could declare a name with subtype such as "Foo!Bar". Moose would
449 accept this allowed, but if you used it in a parameterized type such as
450 "ArrayRef[Foo!Bar]" it wouldn't work. We now do some vetting on names
451 created via the sugar functions, so that they can only contain
452 alphanumerics, ":", and ".".
453
455 Methods created via an attribute can now fulfill a "requires"
456 declaration for a role. Honestly we don't know why Stevan didn't make
457 this work originally, he was just insane or something.
458 Stack traces from inlined code will now report the line and file as
460 being in your class, as opposed to in Moose guts.
461
463 When a class does not provide all of a role's required methods, the
464 error thrown now mentions all of the missing methods, as opposed to
465 just the first missing method.
466 Moose will no longer inline a constructor for your class unless it
468 inherits its constructor from Moose::Object, and will warn when it
469 doesn't inline. If you want to force inlining anyway, pass
470 "replace_constructor => 1" to "make_immutable".
471 If you want to get rid of the warning, pass "inline_constructor => 0".
473
475 Removed the (deprecated) "make_immutable" keyword.
476 Removing an attribute from a class now also removes delegation
478 ("handles") methods installed for that attribute. This is correct
479 behavior, but if you were wrongly relying on it you might get bit.
480
482 Roles now add methods by calling "add_method", not "alias_method". They
483 make sure to always provide a method object, which will be cloned
484 internally. This means that it is now possible to track the source of a
485 method provided by a role, and even follow its history through
486 intermediate roles. This means that methods added by a role now show
487 up when looking at a class's method list/map.
488 Parameter and Union args are now sorted, this makes Int|Str the same
490 constraint as Str|Int. Also, incoming type constraint strings are
491 normalized to remove all whitespace differences. This is mostly for
492 internals and should not affect outside code.
493 Moose::Exporter will no longer remove a subroutine that the exporting
495 package re-exports. Moose re-exports the Carp::confess function, among
496 others. The reasoning is that we cannot know whether you have also
497 explicitly imported those functions for your own use, so we err on the
498 safe side and always keep them.
499
501 "Moose::init_meta" should now be called as a method.
502 New modules for extension writers, Moose::Exporter and
504 Moose::Util::MetaRole.
505
507 Implemented metaclass traits (and wrote a recipe for it):
508 use Moose -traits => 'Foo'
510 This should make writing small Moose extensions a little easier.
512
514 Fixed "coerce" to accept anon types just like "subtype" can. So that
515 you can do:
516 coerce $some_anon_type => from 'Str' => via { ... };
518
520 Added "BUILDARGS", a new step in "Moose::Object->new()".
521
523 Fixed how the "is => (ro|rw)" works with custom defined "reader",
524 "writer" and "accessor" options. See the below table for details:
525 is => ro, writer => _foo # turns into (reader => foo, writer => _foo)
527 is => rw, writer => _foo # turns into (reader => foo, writer => _foo)
528 is => rw, accessor => _foo # turns into (accessor => _foo)
529 is => ro, accessor => _foo # error, accesor is rw
530
532 The "before/around/after" method modifiers now support regexp matching
533 of method names. NOTE: this only works for classes, it is currently not
534 supported in roles, but, ... patches welcome.
535 The "has" keyword for roles now accepts the same array ref form that
537 Moose.pm does for classes.
538 A trigger on a read-only attribute is no longer an error, as it's
540 useful to trigger off of the constructor.
541 Subtypes of parameterizable types now are parameterizable types
543 themselves.
544
546 Fixed issue where "DEMOLISHALL" was eating the value in $@, and so not
547 working correctly. It still kind of eats them, but so does vanilla
548 perl.
549
551 Inherited attributes may now be extended without restriction on the
552 type ('isa', 'does').
553 The entire set of Moose::Meta::TypeConstraint::* classes were
555 refactored in this release. If you were relying on their internals you
556 should test your code carefully.
557
559 Documenting the use of '+name' with attributes that come from recently
560 composed roles. It makes sense, people are using it, and so why not
561 just officially support it.
562 The "Moose::Meta::Class->create" method now supports roles.
564 It is now possible to make anonymous enum types by passing "enum" an
566 array reference instead of the "enum $name => @values".
567
569 Added the "make_immutable" keyword as a shortcut to calling
570 "make_immutable" on the meta object. This eventually got removed!
571 Made "init_arg => undef" work in Moose. This means "do not accept a
573 constructor parameter for this attribute".
574 Type errors now use the provided message. Prior to this release they
576 didn't.
577
579 Moose is now a postmodern object system :)
580 The Role system was completely refactored. It is 100% backwards compat,
582 but the internals were totally changed. If you relied on the internals
583 then you are advised to test carefully.
584 Added method exclusion and aliasing for Roles in this release.
586 Added the Moose::Util::TypeConstraints::OptimizedConstraints module.
588 Passing a list of values to an accessor (which is only expecting one
590 value) used to be silently ignored, now it throws an error.
591
593 Added parameterized types and did a pretty heavy refactoring of the
594 type constraint system.
595 Better framework extendability and better support for "making your own
597 Moose".
598
600 Honestly, you shouldn't be using versions of Moose that are this old,
601 so many bug fixes and speed improvements have been made you would be
602 crazy to not upgrade.
603 Also, I am tired of going through the Changelog so I am stopping here,
605 if anyone would like to continue this please feel free.
606
608 Stevan Little <stevan@iinteractive.com>
609
611 Copyright 2009 by Infinity Interactive, Inc.
612 <http://www.iinteractive.com>
614 This library is free software; you can redistribute it and/or modify it
616 under the same terms as Perl itself.
617perl v5.12.2 2010-08-28 Moose::Manual::Delta(3)