3 Catalyst::Upgrading - Instructions for upgrading to the latest Catalyst
5 =head1 Upgrading to Catalyst 5.90090
7 L<Catalyst::Utils> has a new method 'inject_component' which works the same as the method of
8 the same name in L<CatalystX::InjectComponent>. You should start converting any
9 use of the non core method in your code as future changes to Catalyst will be
10 sychronized to the core method first. We reserve the right to cease support
11 of the non core version should we reach a point in time where it cannot be
12 properly supported as an external module. Luckily this should be a trivial
13 search and replace. Change all occurances of:
15 CatalystX::InjectComponent->inject(...)
19 Catalyst::Utils::inject_component(...)
21 and we expect everything to work the same (we'd consider it not working the same
22 to be a bug, and please report it.)
24 We also cored features from L<CatalystX::RoleApplicator> to compose a role into the
25 request, response and stats classes. The main difference is that with L<CatalystX::RoleApplicator>
31 use CatalystX::RoleApplicator;
33 __PACKAGE__->apply_request_class_roles(
34 qw/My::Request::Role Other::Request::Role/);
36 Whereas now we have three class attributes, 'request_class_traits', 'response_class_traits'
37 and 'stats_class_traits', so you use like this (note this value is an ArrayRef)
44 __PACKAGE__->request_class_traits([qw/
46 Other::Request::Role/]);
48 (And the same for response_class_traits and stats_class_traits. We left off the
49 traits for Engine, since that class does a lot less nowadays, and dispatcher. If you
50 used those and can share a use case, we'd be likely to support them.
52 Lastly, we have some of the feature from L<CatalystX::ComponentsFromConfig> in
53 core. This should mostly work the same way in core, except for now the
54 core version does not create an automatic base wrapper class for your configured
55 components (it requires these to be catalyst components and injects them directly.
56 So if you make heavy use of custom base classes in L<CatalystX::ComponentsFromConfig>
57 you might need a bit of work to use the core version (although there is no reason
58 to stop using L<CatalystX::ComponentsFromConfig> since it should continue to work
59 fine and we'd consider issues with it to be bugs). Here's one way to map from
60 L<CatalystX::ComponentsFromConfig> to core:
62 In L<CatalystX::ComponentsFromConfig>:
77 Also we added a new develop console mode only warning when you call a component
78 with arguments that don't expect or do anything meaningful with those args. Its
79 possible if you are logging debug mode in production (please don't...) this
80 could add verbosity to those logs if you also happen to be calling for components
81 and passing pointless arguments. We added this warning to help people not make this
82 error and to better understand the component resolution flow.
84 =head1 Upgrading to Catalyst 5.90085
86 In this version of Catalyst we made a small change to Chained Dispatching so
87 that when two or more actions all have the same path specification AND they
88 all have Args(0), we break the tie by choosing the last action defined, and
89 not the first one defined. This was done to normalize Chaining to following
90 the 'longest Path wins, and when several actions match the same Path specification
91 we choose the last defined.' rule. Previously Args(0) was hard coded to be a special
92 case such that the first action defined would match (which is not the case when
95 Its possible that this could be a breaking change for you, if you had used
96 action roles (custom or otherwise) to add additional matching rules to differentiate
97 between several Args(0) actions that share the same root action chain. For
98 example if you have code now like this:
100 sub check_default :Chained(/) CaptureArgs(0) { ... }
102 sub default_get :Chained('check_default') PathPart('') Args(0) GET {
103 pop->res->body('get3');
106 sub default_post :Chained('check_default') PathPart('') Args(0) POST {
107 pop->res->body('post3');
110 sub chain_default :Chained('check_default') PathPart('') Args(0) {
111 pop->res->body('chain_default');
114 The way that chaining will work previous is that when two or more equal actions can
115 match, the 'top' one wins. So if the request is "GET .../check_default" BOTH
116 actions 'default_get' AND 'chain_default' would match. To break the tie in
117 the case when Args is 0, we'd previous take the 'top' (or first defined) action.
118 Unfortunately this treatment of Args(0) is special case. In all other cases
119 we choose the 'last defined' action to break a tie. So this version of
120 Catalyst changed the dispatcher to make Args(0) no longer a special case for
121 breaking ties. This means that the above code must now become:
123 sub check_default :Chained(/) CaptureArgs(0) { ... }
125 sub chain_default :Chained('check_default') PathPart('') Args(0) {
126 pop->res->body('chain_default');
129 sub default_get :Chained('check_default') PathPart('') Args(0) GET {
130 pop->res->body('get3');
133 sub default_post :Chained('check_default') PathPart('') Args(0) POST {
134 pop->res->body('post3');
137 If we want it to work as expected (for example we we GET to match 'default_get' and
138 POST to match 'default_post' and any other http Method to match 'chain_default').
140 In other words Arg(0) and chained actions must now follow the normal rule where
141 in a tie the last defined action wins and you should place all your less defined
142 or 'catch all' actions first.
144 If this causes you trouble and you can't fix your code to conform, you may set the
145 application configuration setting "use_chained_args_0_special_case" to true and
146 that will revert you code to the previous behavior.
148 =head2 More backwards compatibility options with UTF-8 changes
150 In order to give better backwards compatiblity with the 5.90080+ UTF-8 changes
151 we've added several configuration options around control of how we try to decode
152 your URL keywords / query parameters.
154 C<do_not_decode_query>
156 If true, then do not try to character decode any wide characters in your
157 request URL query or keywords. Most readings of the relevent specifications
158 suggest these should be UTF-* encoded, which is the default that L<Catalyst>
159 will use, hwoever if you are creating a lot of URLs manually or have external
160 evil clients, this might cause you trouble. If you find the changes introduced
161 in Catalyst version 5.90080+ break some of your query code, you may disable
162 the UTF-8 decoding globally using this configuration.
164 This setting takes precedence over C<default_query_encoding> and
165 C<decode_query_using_global_encoding>
167 C<default_query_encoding>
169 By default we decode query and keywords in your request URL using UTF-8, which
170 is our reading of the relevent specifications. This setting allows one to
171 specify a fixed value for how to decode your query. You might need this if
172 you are doing a lot of custom encoding of your URLs and not using UTF-8.
174 This setting take precedence over C<decode_query_using_global_encoding>.
176 C<decode_query_using_global_encoding>
178 Setting this to true will default your query decoding to whatever your
179 general global encoding is (the default is UTF-8).
182 =head1 Upgrading to Catalyst 5.90080
184 UTF8 encoding is now default. For temporary backwards compatibility, if this
185 change is causing you trouble, you can disable it by setting the application
186 configuration option to undef:
188 MyApp->config(encoding => undef);
190 But please consider this a temporary measure since it is the intention that
191 UTF8 is enabled going forwards and the expectation is that other ecosystem
192 projects will assume this as well. At some point you application will not
193 correctly function without this setting.
195 As of 5.90084 we've added two additional configuration flags for more selective
196 control over some encoding changes: 'skip_body_param_unicode_decoding' and
197 'skip_complex_post_part_handling'. You may use these to more selectively
198 disable new features while you are seeking a long term fix. Please review
199 CONFIGURATION in L<Catalyst>.
201 For further information, please see L<Catalyst::UTF8>
203 A number of projects in the wider ecosystem required minor updates to be able
204 to work correctly. Here's the known list:
206 L<Catalyst::View::TT>, L<Catalyst::View::Mason>, L<Catalyst::View::HTML::Mason>,
207 L<Catalyst::View::Xslate>, L<Test::WWW::Mechanize::Catalyst>
209 You will need to update to modern versions in most cases, although quite a few
210 of these only needed minor test case and documentation changes so you will need
211 to review the changelog of each one that is relevant to you to determine your
214 =head1 Upgrading to Catalyst 5.90060
216 Starting in the v5.90059_001 development release, the regexp dispatch type is
217 no longer automatically included as a dependency. If you are still using this
218 dispatch type, you need to add L<Catalyst::DispatchType::Regex> into your build
221 The standalone distribution of Regexp will be supported for the time being, but
222 should we find that supporting it prevents us from moving L<Catalyst> forward
223 in necessary ways, we reserve the right to drop that support. It is highly
224 recommended that you use this last stage of deprecation to change your code.
226 =head1 Upgrading to Catalyst 5.90040
228 =head2 Catalyst::Plugin::Unicode::Encoding is now core
230 The previously stand alone Unicode support module L<Catalyst::Plugin::Unicode::Encoding>
231 has been brought into core as a default plugin. Going forward, all you need is
232 to add a configuration setting for the encoding type. For example:
238 __PACKAGE__->config( encoding => 'UTF-8' );
240 Please note that this is different from the old stand alone plugin which applied
241 C<UTF-8> encoding by default (that is, if you did not set an explicit
242 C<encoding> configuration value, it assumed you wanted UTF-8). In order to
243 preserve backwards compatibility you will need to explicitly turn it on via the
244 configuration setting. THIS MIGHT CHANGE IN THE FUTURE, so please consider
245 starting to test your application with proper UTF-8 support and remove all those
246 crappy hacks you munged into the code because you didn't know the Plugin
249 For people that are using the Plugin, you will note a startup warning suggesting
250 that you can remove it from the plugin list. When you do so, please remember to
251 add the configuration setting, since you can no longer rely on the default being
252 UTF-8. We'll add it for you if you continue to use the stand alone plugin and
253 we detect this, but this backwards compatibility shim will likely be removed in
254 a few releases (trying to clean up the codebase after all).
256 If you have trouble with any of this, please bring it to the attention of the
257 Catalyst maintainer group.
259 =head2 basic async and event loop support
261 This version of L<Catalyst> offers some support for using L<AnyEvent> and
262 L<IO::Async> event loops in your application. These changes should work
263 fine for most applications however if you are already trying to perform
264 some streaming, minor changes in this area of the code might affect your
265 functionality. Please see L<Catalyst::Response\write_fh> for more and for a
268 We consider this feature experimental. We will try not to break it, but we
269 reserve the right to make necessary changes to fix major issues that people
270 run into when the use this functionality in the wild.
272 =head1 Upgrading to Catalyst 5.90030
274 =head2 Regex dispatch type is deprecated.
276 The Regex dispatchtype (L<Catalyst::DispatchType::Regex>) has been deprecated.
278 You are encouraged to move your application to Chained dispatch (L<Catalyst::DispatchType::Chained>).
280 If you cannot do so, please add a dependency to Catalyst::DispatchType::Regex to your application's
283 =head1 Upgrading to Catalyst 5.9
285 The major change is that L<Plack>, a toolkit for using the L<PSGI>
286 specification, now replaces most of the subclasses of L<Catalyst::Engine>. If
287 you are using one of the standard subclasses of L<Catalyst::Engine> this
288 should be a straightforward upgrade for you. It was a design goal for
289 this release to preserve as much backwards compatibility as possible.
290 However, since L<Plack> is different from L<Catalyst::Engine>, it is
291 possible that differences exist for edge cases. Therefore, we recommend
292 that care be taken with this upgrade and that testing should be greater
293 than would be the case with a minor point update. Please inform the
294 Catalyst developers of any problems so that we can fix them and
297 It is highly recommended that you become familiar with the L<Plack> ecosystem
298 and documentation. Being able to take advantage of L<Plack> development and
299 middleware is a major bonus to this upgrade. Documentation about how to
300 take advantage of L<Plack::Middleware> by writing your own C<< .psgi >> file
301 is contained in L<Catalyst::PSGI>.
303 If you have created a custom subclass of L<Catalyst:Engine>, you will
304 need to convert it to be a subclass of L<Plack::Handler>.
306 If you are using the L<Plack> engine, L<Catalyst::Engine::PSGI>, this new
307 release supersedes that code.
309 If you are using a subclass of L<Catalyst::Engine> that is aimed at
310 nonstandard or internal/testing uses, such as
311 L<Catalyst::Engine::Embeddable>, you should still be able to continue
314 Advice for specific subclasses of L<Catalyst::Engine> follows:
316 =head2 Upgrading the FastCGI Engine
318 No upgrade is needed if your myapp_fastcgi.pl script is already upgraded
319 to use L<Catalyst::Script::FastCGI>.
321 =head2 Upgrading the mod_perl / Apache Engines
323 The engines that are built upon the various iterations of mod_perl,
324 L<Catalyst::Engine::Apache::MP13> (for mod_perl 1, and Apache 1.x) and
325 L<Catalyst::Engine::Apache2::MP20> (for mod_perl 2, and Apache 2.x),
326 should be seamless upgrades and will work using L<Plack::Handler::Apache1>
327 or L<Plack::Handler::Apache2> as required.
329 L<Catalyst::Engine::Apache2::MP19>, however, is no longer supported, as
330 Plack does not support mod_perl version 1.99. This is unlikely to be a
331 problem for anyone, as 1.99 was a brief beta-test release for mod_perl
332 2, and all users of mod_perl 1.99 are encouraged to upgrade to a
333 supported release of Apache 2 and mod_perl 2.
335 =head2 Upgrading the HTTP Engine
337 The default development server that comes with the L<Catalyst> distribution
338 should continue to work as expected with no changes as long as your C<myapp_server>
339 script is upgraded to use L<Catalyst::Script::HTTP>.
341 =head2 Upgrading the CGI Engine
343 If you were using L<Catalyst::Engine::CGI> there is no upgrade needed if your
344 myapp_cgi.pl script is already upgraded to use L<Catalyst::Script::CGI>.
346 =head2 Upgrading Catalyst::Engine::HTTP::Prefork
348 If you were using L<Catalyst::Engine::HTTP::Prefork> then L<Starman>
349 is automatically loaded. You should (at least) change your C<Makefile.PL>
350 to depend on Starman.
352 You can regenerate your C<myapp_server.pl> script with C<catalyst.pl>
353 and implement a C<MyApp::Script::Server> class that looks like this:
355 package MyApp::Script::Server;
357 use namespace::autoclean;
359 extends 'CatalystX::Script::Server::Starman';
363 This takes advantage of the new script system, and will add a number of
364 options to the standard server script as extra options are added by
367 More information about these options can be seen at
368 L<CatalystX::Script::Server::Starman/SYNOPSIS>.
370 An alternate route to implement this functionality is to write a simple .psgi
371 file for your application, and then use the L<plackup> utility to start the
374 =head2 Upgrading the PSGI Engine
376 If you were using L<Catalyst::Engine::PSGI>, this new release supersedes
377 this engine in supporting L<Plack>. By default the Engine is now always
378 L<Plack>. As a result, you can remove the dependency on
379 L<Catalyst::Engine::PSGI> in your C<Makefile.PL>.
381 Applications that were using L<Catalyst::Engine::PSGI>
382 previously should entirely continue to work in this release with no changes.
384 However, if you have an C<app.psgi> script, then you no longer need to
385 specify the PSGI engine. Instead, the L<Catalyst> application class now
386 has a new method C<psgi_app> which returns a L<PSGI> compatible coderef
387 which you can wrap in the middleware of your choice.
389 Catalyst will use the .psgi for your application if it is located in the C<home>
390 directory of the application.
392 For example, if you were using L<Catalyst::Engine::PSGI> in the past, you will
393 have written (or generated) a C<script/myapp.psgi> file similar to this one:
398 MyCatalystApp->setup_engine('PSGI');
401 enable ... # enable your desired middleware
402 sub { MyCatalystApp->run(@_) };
405 Instead, you now say:
411 enable ... #enable your desired middleware
412 MyCatalystApp->psgi_app;
415 In the simplest case:
417 MyCatalystApp->setup_engine('PSGI');
418 my $app = sub { MyCatalystApp->run(@_) }
422 my $app = MyCatalystApp->psgi_app(@_);
426 my $app = sub { MyCatalystApp->psgi_app(@_) };
427 # If you make ^^ this mistake, your app won't work, and will confuse the hell out of you!
429 You can now move C<< script/myapp.psgi >> to C<< myapp.psgi >>, and the built-in
430 Catalyst scripts and your test suite will start using your .psgi file.
432 B<NOTE:> If you rename your .psgi file without these modifications, then
433 any tests run via L<Catalyst::Test> will not be compatible with the new
434 release, and will result in the development server starting, rather than
435 the expected test running.
437 B<NOTE:> If you are directly accessing C<< $c->req->env >> to get the PSGI
438 environment then this accessor is moved to C<< $c->engine->env >>,
439 you will need to update your code.
441 =head2 Engines which are known to be broken
443 The following engines B<DO NOT> work as of Catalyst version 5.9. The
444 core team will be happy to work with the developers and/or users of
445 these engines to help them port to the new Plack/Engine system, but for
446 now, applications which are currently using these engines B<WILL NOT>
447 run without modification to the engine code.
451 =item Catalyst::Engine::Wx
453 =item Catalyst::Engine::Zeus
455 =item Catalyst::Engine::JobQueue::POE
457 =item Catalyst::Engine::XMPP2
459 =item Catalyst::Engine::SCGI
463 =head2 Engines with unknown status
465 The following engines are untested or have unknown compatibility.
466 Reports are highly encouraged:
470 =item Catalyst::Engine::Mojo
472 =item Catalyst::Engine::Server (marked as Deprecated)
474 =item Catalyst::Engine::HTTP::POE (marked as Deprecated)
478 =head2 Plack functionality
480 See L<Catalyst::PSGI>.
484 Tests should generally work the same in Catalyst 5.9, but there are
487 Previously, if using L<Catalyst::Test> and doing local requests (against
488 a local server), if the application threw an exception then this
489 exception propagated into the test.
491 This behavior has been removed, and now a 500 response will be returned
492 to the test. This change standardizes behavior, so that local test
493 requests behave similarly to remote requests.
495 =head1 Upgrading to Catalyst 5.80
497 Most applications and plugins should run unaltered on Catalyst 5.80.
499 However, a lot of refactoring work has taken place, and several changes have
500 been made which could cause incompatibilities. If your application or plugin
501 is using deprecated code, or relying on side effects, then you could have
502 issues upgrading to this release.
504 Most issues found with existing components have been easy to
505 solve. This document provides a complete description of behavior changes
506 which may cause compatibility issues, and of new Catalyst warnings which
509 If you think you have found an upgrade-related issue which is not covered in
510 this document, please email the Catalyst list to discuss the problem.
512 =head1 Moose features
514 =head2 Application class roles
516 You can only apply method modifiers after the application's C<< ->setup >>
517 method has been called. This means that modifiers will not work with methods
518 run during the call to C<< ->setup >>.
520 See L<Catalyst::Manual::ExtendingCatalyst> for more information about using
521 L<Moose> in your applications.
523 =head2 Controller actions in Moose roles
525 You can use L<MooseX::MethodAttributes::Role> if you want to declare actions
528 =head2 Using Moose in Components
530 The correct way to use Moose in a component in a both forward and backwards
533 package TestApp::Controller::Root;
535 BEGIN { extends 'Catalyst::Component' }; # Or ::Controller, or whatever
537 See L<Components which inherit from Moose::Object before Catalyst::Component>.
539 =head1 Known backwards compatibility breakages
541 =head2 Applications in a single file
543 Applications must be in their own file, and loaded at compile time. This
544 issue generally only affects the tests of CPAN distributions. Your
545 application will fail if you try to define an application inline in a
546 block, and use plugins which supply a C< new > method, then use that
547 application latter in tests within the same file.
549 This is due to the fact that Catalyst is inlining a new method on your
550 application class allowing it to be compatible with Moose. The method
551 used to do this changed in 5.80004 to avoid the possibility of reporting
552 an 'Unknown Error' if your application failed to compile.
554 =head2 Issues with Class::C3
556 Catalyst 5.80 uses the L<Algorithm::C3> method dispatch order. This is
557 built into Perl 5.10, and comes via L<Class::C3> for Perl 5.8. This
558 replaces L<NEXT> with L<Class::C3::Adopt::NEXT>, forcing all components
559 to resolve methods using C3, rather than the unpredictable dispatch
562 This issue manifests itself by your application failing to start due to an
563 error message about having a non-linear @ISA.
565 The Catalyst plugin most often causing this is
566 L<Catalyst::Plugin::Session::Store::FastMmap> - if you are using this
567 plugin and see issues, then please upgrade your plugins, as it has been
568 fixed. Note that Makefile.PL in the distribution will warn about known
569 incompatible components.
571 This issue can, however, be found in your own application - the only solution is
572 to go through each base class of the class the error was reported against, until
573 you identify the ones in conflict, and resolve them.
575 To be able to generate a linear @ISA, the list of superclasses for each
576 class must be resolvable using the C3 algorithm. Unfortunately, when
577 superclasses are being used as mixins (to add functionality used in your class),
578 and with multiple inheritance, it is easy to get this wrong.
580 Most common is the case of:
582 package Component1; # Note, this is the common case
583 use base qw/Class::Accessor::Fast Class::Data::Inheritable/;
585 package Component2; # Accidentally saying it this way causes a failure
586 use base qw/Class::Data::Inheritable Class::Accessor::Fast/;
589 use base qw/Component1 Component2/;
591 Any situation like this will cause your application to fail to start.
593 For additional documentation about this issue, and how to resolve it, see
594 L<Class::C3::Adopt::NEXT>.
596 =head2 Components which inherit from Moose::Object before Catalyst::Component
598 Moose components which say:
600 package TestApp::Controller::Example;
602 extends qw/Moose::Object Catalyst::Component/;
604 to use the constructor provided by Moose, while working (if you do some hacks
605 with the C< BUILDARGS > method), will not work with Catalyst 5.80 as
606 C<Catalyst::Component> inherits from C<Moose::Object>, and so C< @ISA > fails
609 The correct way to use Moose in a component in a both forward and backwards
612 package TestApp::Controller::Root;
614 BEGIN { extends 'Catalyst::Component' }; # Or ::Controller, or whatever
616 Note that the C< extends > declaration needs to occur in a begin block for
617 L<attributes> to operate correctly.
619 This way you do not inherit directly from C<Moose::Object>
620 yourself. Having components which do not inherit their constructor from
621 C<Catalyst::Component> is B<unsupported>, and has never been recommended,
622 therefore you're on your own if you're using this technique. You'll need
623 to detect the version of Catalyst your application is running, and deal
624 with it appropriately.
626 You also don't get the L<Moose::Object> constructor, and therefore attribute
627 initialization will not work as normally expected. If you want to use Moose
628 attributes, then they need to be made lazy to correctly initialize.
630 Note that this only applies if your component needs to maintain component
631 backwards compatibility for Catalyst versions before 5.71001 - in 5.71001
632 attributes work as expected, and the BUILD method is called normally
633 (although BUILDARGS is not).
635 If you depend on Catalyst 5.8, then B<all> Moose features work as expected.
637 You will also see this issue if you do the following:
639 package TestApp::Controller::Example;
641 use base 'Catalyst::Controller';
643 as C< use base > appends to @ISA.
645 =head3 use Moose in MyApp
647 Similar to the above, this will also fail:
656 If you need to use Moose in your application class (e.g. for method modifiers
657 etc.) then the correct technique is:
665 __PACKAGE__->config( name => 'MyApp' );
666 __PACKAGE__->setup(qw/
670 =head2 Anonymous closures installed directly into the symbol table
672 If you have any code which installs anonymous subroutine references directly
673 into the symbol table, you may encounter breakages. The simplest solution is
674 to use L<Sub::Name> to name the subroutine. Example:
676 # Original code, likely to break:
677 my $full_method_name = join('::', $package_name, $method_name);
678 *$full_method_name = sub { ... };
681 use Sub::Name 'subname';
682 my $full_method_name = join('::',$package_name, $method_name);
683 *$full_method_name = subname $full_method_name, sub { ... };
685 Additionally, you can take advantage of Catalyst's use of L<Class::MOP> and
686 install the closure using the appropriate metaclass. Example:
689 my $metaclass = Moose::Meta::Class->initialize($package_name);
690 $metaclass->add_method($method_name => sub { ... });
692 =head2 Hooking into application setup
694 To execute code during application start-up, the following snippet in MyApp.pm
698 my ($class, @args) = @_;
699 $class->NEXT::setup(@args);
700 ... # things to do after the actual setup
703 With Catalyst 5.80 this won't work anymore, because Catalyst no longer
704 uses NEXT.pm for method resolution. The functionality was only ever
705 originally operational as L<NEXT> remembers what methods have already
706 been called, and will not call them again.
708 Using this now causes infinite recursion between MyApp::setup and
709 Catalyst::setup, due to other backwards compatibility issues related to how
710 plugin setup works. Moose method modifiers like C<< before|after|around setup
711 => sub { ... }; >> also will not operate correctly on the setup method.
713 The right way to do it is this:
715 after setup_finalize => sub {
716 ... # things to do after the actual setup
719 The setup_finalize hook was introduced as a way to avoid this issue.
721 =head2 Components with a new method which returns false
723 Previously, if you had a component which inherited from Catalyst::COMPONENT,
724 but overrode the new method to return false, then your class's configuration
725 would be blessed into a hash on your behalf, and this would be returned from
726 the COMPONENT method.
728 This behavior makes no sense, and so has been removed. Implementing your own
729 C< new > method in components is B<highly> discouraged. Instead, you should
730 inherit the new method from Catalyst::Component, and use Moose's BUILD
731 functionality and/or Moose attributes to perform any construction work
732 necessary for your class.
734 =head2 __PACKAGE__->mk_accessor('meta');
736 Won't work due to a limitation of L<Moose>. This is currently being fixed
739 =head2 Class::Data::Inheritable side effects
741 Previously, writing to a class data accessor would copy the accessor method
742 down into your package.
744 This behavior has been removed. While the class data is still stored
745 per-class, it is stored on the metaclass of the class defining the accessor.
747 Therefore anything relying on the side effect of the accessor being copied down
750 The following test demonstrates the problem:
754 use base qw/Class::Data::Inheritable/;
755 __PACKAGE__->mk_classdata('foo');
760 use base qw/BaseClass/;
763 BaseClass->foo('base class');
764 Child->foo('sub class');
767 isnt(BaseClass->can('foo'), Child->can('foo'));
769 =head2 Extending Catalyst::Request or other classes in an ad hoc manner using mk_accessors
771 Previously, it was possible to add additional accessors to Catalyst::Request
772 (or other classes) by calling the mk_accessors class method.
774 This is no longer supported - users should make a subclass of the class whose
775 behavior they would like to change, rather than globally polluting the
778 =head2 Confused multiple inheritance with Catalyst::Component::COMPONENT
780 Previously, Catalyst's COMPONENT method would delegate to the method on
781 the right hand side, which could then delegate back again with
782 NEXT. This is poor practice, and in addition, makes no sense with C3
783 method dispatch order, and is therefore no longer supported.
785 If a COMPONENT method is detected in the inheritance hierarchy to the right
786 hand side of Catalyst::Component::COMPONENT, then the following warning
787 message will be emitted:
789 There is a COMPONENT method resolving after Catalyst::Component
792 The correct fix is to re-arrange your class's inheritance hierarchy so that the
793 COMPONENT method you would like to inherit is the first (left-hand most)
794 COMPONENT method in your @ISA.
796 =head2 Development server relying on environment variables
798 Previously, the development server would allow propagation of system
799 environment variables into the request environment, this has changed with the
800 adoption of Plack. You can use L<Plack::Middleware::ForceEnv> to achieve the
805 =head2 Actions in your application class
807 Having actions in your application class will now emit a warning at application
808 startup as this is deprecated. It is highly recommended that these actions are moved
809 into a MyApp::Controller::Root (as demonstrated by the scaffold application
810 generated by catalyst.pl).
812 This warning, also affects tests. You should move actions in your test,
813 creating a myTest::Controller::Root, like the following example:
815 package MyTest::Controller::Root;
820 use parent 'Catalyst::Controller';
822 __PACKAGE__->config(namespace => '');
825 my ( $self, $c ) = @_;
831 =head2 ::[MVC]:: naming scheme
833 Having packages called MyApp::[MVC]::XX is deprecated and can no longer be generated
836 This is still supported, but it is recommended that you rename your application
837 components to Model/View/Controller.
839 A warning will be issued at application startup if the ::[MVC]:: naming scheme is
842 =head2 Catalyst::Base
844 Any code using L<Catalyst::Base> will now emit a warning; this
845 module will be removed in a future release.
847 =head2 Methods in Catalyst::Dispatcher
849 The following methods in Catalyst::Dispatcher are implementation
850 details, which may change in the 5.8X release series, and therefore their use
851 is highly deprecated.
859 =item registered_dispatch_types
861 =item method_action_class
869 The first time one of these methods is called, a warning will be emitted:
871 Class $class is calling the deprecated method Catalyst::Dispatcher::$public_method_name,
872 this will be removed in Catalyst 5.9
874 You should B<NEVER> be calling any of these methods from application code.
876 Plugin authors and maintainers whose plugins currently call these methods
877 should change to using the public API, or, if you do not feel the public API
878 adequately supports your use case, please email the development list to
879 discuss what API features you need so that you can be appropriately supported.
881 =head2 Class files with names that don't correspond to the packages they define
883 In this version of Catalyst, if a component is loaded from disk, but no
884 symbols are defined in that component's name space after it is loaded, this
885 warning will be issued:
887 require $class was successful but the package is not defined.
889 This is to protect against confusing bugs caused by mistyping package names,
890 and will become a fatal error in a future version.
892 Please note that 'inner packages' (via L<Devel::InnerPackage>) are still fully
893 supported; this warning is only issued when component file naming does not map
894 to B<any> of the packages defined within that component.
896 =head2 $c->plugin method
898 Calling the plugin method is deprecated, and calling it at run time is B<highly
901 Instead you are recommended to use L<Catalyst::Model::Adaptor> or similar to
902 compose the functionality you need outside of the main application name space.
904 Calling the plugin method will not be supported past Catalyst 5.81.