3 Catalyst::Upgrading - Instructions for upgrading to the latest Catalyst
5 =head1 Upgrading to Catalyst 5.90100
7 We changed the way the middleware stash works so that it no longer localizes
8 the PSGI env hashref. This was done to fix bugs where people set PSGI ENV hash
9 keys and found them to disappear in certain cases. It also means that now if
10 a sub applications sets stash variables, that stash will now bubble up to the
11 parent application. This may be a breaking change for you since previous
12 versions of this code did not allow that. A workaround is to explicitly delete
13 stash keys in your sub application before returning control to the parent
16 =head1 Upgrading to Catalyst 5.90097
18 In older versions of Catalyst one could construct a L<URI> with a fragment (such as
19 https://localhost/foo/bar#fragment) by using a '#' in the path or final argument, for
22 $c->uri_for($action, 'foo#fragment');
24 This behavior was never documented and would break if using the Unicode plugin, or when
25 adding a query to the arguments:
27 $c->uri_for($action, 'foo#fragment', +{ a=>1, b=>2});
29 would define a fragment like "#fragment?a=1&b=2".
31 When we introduced UTF-8 encoding by default in Catalyst 5.9008x this side effect behavior
32 was broken since we started encoding the '#' when it was part of the URI path.
34 In version 5.90095 and 5.90096 we attempted to fix this, but all we managed to do was break
35 people with URIs that included '#' as part of the path data, when it was not expected to
36 be a fragment delimiter.
38 In general L<Catalyst> prefers an explicit specification rather than relying on side effects
39 or domain specific mini languages. As a result we are now defining how to set a fragment
40 for a URI via ->uri_for:
42 $c->uri_for($action_or_path, \@captures_or_args, @args, \$query, \$fragment);
44 If you are relying on the previous side effect behavior your URLs will now encode the '#'
45 delimiter, which is going to be a breaking change for you. You need to alter your code
46 to match the new specification or modify uri_for for your local case. Patches to solve
47 this are very welcomed, as long as they don't break existing test cases.
49 B<NOTE> If you are using the string form of the first argument:
51 $c->uri_for('/foo/bar#baz')
53 construction, we do not attempt to encode this and it will make a URL with a
57 =head1 Upgrading to Catalyst 5.90095
59 The method C<last_error> in L</Catalyst> was actually returning the first error. This has
60 been fixed but there is a small chance it could be a breaking issue for you. If this gives
61 you trouble changing to C<shift_errors> is the easiest workaround (although that does
62 modify the error stack so if you are relying on that not being changed you should try something
63 like @{$c->errors}[-1] instead. Since this method is relatively new and the cases when the
64 error stack actually has more than one error in it, we feel the exposure is very low, but bug
65 reports are very welcomed.
67 =head1 Upgrading to Catalyst 5.90090
69 L<Catalyst::Utils> has a new method 'inject_component' which works the same as the method of
70 the same name in L<CatalystX::InjectComponent>. You should start converting any
71 use of the non core method in your code as future changes to Catalyst will be
72 synchronized to the core method first. We reserve the right to cease support
73 of the non core version should we reach a point in time where it cannot be
74 properly supported as an external module. Luckily this should be a trivial
75 search and replace. Change all occurences of:
77 CatalystX::InjectComponent->inject(...)
81 Catalyst::Utils::inject_component(...)
83 and we expect everything to work the same (we'd consider it not working the same
84 to be a bug, and please report it.)
86 We also cored features from L<CatalystX::RoleApplicator> to compose a role into the
87 request, response and stats classes. The main difference is that with L<CatalystX::RoleApplicator>
93 use CatalystX::RoleApplicator;
95 __PACKAGE__->apply_request_class_roles(
96 qw/My::Request::Role Other::Request::Role/);
98 Whereas now we have three class attributes, 'request_class_traits', 'response_class_traits'
99 and 'stats_class_traits', so you use like this (note this value is an ArrayRef)
106 __PACKAGE__->request_class_traits([qw/
108 Other::Request::Role/]);
110 (And the same for response_class_traits and stats_class_traits. We left off the
111 traits for Engine, since that class does a lot less nowadays, and dispatcher. If you
112 used those and can share a use case, we'd be likely to support them.
114 Lastly, we have some of the feature from L<CatalystX::ComponentsFromConfig> in
115 core. This should mostly work the same way in core, except for now the
116 core version does not create an automatic base wrapper class for your configured
117 components (it requires these to be catalyst components and injects them directly.
118 So if you make heavy use of custom base classes in L<CatalystX::ComponentsFromConfig>
119 you might need a bit of work to use the core version (although there is no reason
120 to stop using L<CatalystX::ComponentsFromConfig> since it should continue to work
121 fine and we'd consider issues with it to be bugs). Here's one way to map from
122 L<CatalystX::ComponentsFromConfig> to core:
124 In L<CatalystX::ComponentsFromConfig>:
127 'Model::MyClass' => {
136 inject_components => {
137 'Model::MyClass' => { from_component => 'My::Class' },
139 'Model::MyClass' => {
144 Although the core behavior requires more code, it better separates concerns
145 as well as plays more into core Catalyst expectations of how configuration should
148 Also we added a new develop console mode only warning when you call a component
149 with arguments that don't expect or do anything meaningful with those args. Its
150 possible if you are logging debug mode in production (please don't...) this
151 could add verbosity to those logs if you also happen to be calling for components
152 and passing pointless arguments. We added this warning to help people not make this
153 error and to better understand the component resolution flow.
155 =head1 Upgrading to Catalyst 5.90085
157 In this version of Catalyst we made a small change to Chained Dispatching so
158 that when two or more actions all have the same path specification AND they
159 all have Args(0), we break the tie by choosing the last action defined, and
160 not the first one defined. This was done to normalize Chaining to following
161 the 'longest Path wins, and when several actions match the same Path specification
162 we choose the last defined.' rule. Previously Args(0) was hard coded to be a special
163 case such that the first action defined would match (which is not the case when
166 Its possible that this could be a breaking change for you, if you had used
167 action roles (custom or otherwise) to add additional matching rules to differentiate
168 between several Args(0) actions that share the same root action chain. For
169 example if you have code now like this:
171 sub check_default :Chained(/) CaptureArgs(0) { ... }
173 sub default_get :Chained('check_default') PathPart('') Args(0) GET {
174 pop->res->body('get3');
177 sub default_post :Chained('check_default') PathPart('') Args(0) POST {
178 pop->res->body('post3');
181 sub chain_default :Chained('check_default') PathPart('') Args(0) {
182 pop->res->body('chain_default');
185 The way that chaining will work previous is that when two or more equal actions can
186 match, the 'top' one wins. So if the request is "GET .../check_default" BOTH
187 actions 'default_get' AND 'chain_default' would match. To break the tie in
188 the case when Args is 0, we'd previous take the 'top' (or first defined) action.
189 Unfortunately this treatment of Args(0) is special case. In all other cases
190 we choose the 'last defined' action to break a tie. So this version of
191 Catalyst changed the dispatcher to make Args(0) no longer a special case for
192 breaking ties. This means that the above code must now become:
194 sub check_default :Chained(/) CaptureArgs(0) { ... }
196 sub chain_default :Chained('check_default') PathPart('') Args(0) {
197 pop->res->body('chain_default');
200 sub default_get :Chained('check_default') PathPart('') Args(0) GET {
201 pop->res->body('get3');
204 sub default_post :Chained('check_default') PathPart('') Args(0) POST {
205 pop->res->body('post3');
208 If we want it to work as expected (for example we we GET to match 'default_get' and
209 POST to match 'default_post' and any other http Method to match 'chain_default').
211 In other words Arg(0) and chained actions must now follow the normal rule where
212 in a tie the last defined action wins and you should place all your less defined
213 or 'catch all' actions first.
215 If this causes you trouble and you can't fix your code to conform, you may set the
216 application configuration setting "use_chained_args_0_special_case" to true and
217 that will revert you code to the previous behavior.
219 =head2 More backwards compatibility options with UTF-8 changes
221 In order to give better backwards compatibility with the 5.90080+ UTF-8 changes
222 we've added several configuration options around control of how we try to decode
223 your URL keywords / query parameters.
225 C<do_not_decode_query>
227 If true, then do not try to character decode any wide characters in your
228 request URL query or keywords. Most readings of the relevant specifications
229 suggest these should be UTF-* encoded, which is the default that L<Catalyst>
230 will use, however if you are creating a lot of URLs manually or have external
231 evil clients, this might cause you trouble. If you find the changes introduced
232 in Catalyst version 5.90080+ break some of your query code, you may disable
233 the UTF-8 decoding globally using this configuration.
235 This setting takes precedence over C<default_query_encoding> and
236 C<decode_query_using_global_encoding>
238 C<default_query_encoding>
240 By default we decode query and keywords in your request URL using UTF-8, which
241 is our reading of the relevant specifications. This setting allows one to
242 specify a fixed value for how to decode your query. You might need this if
243 you are doing a lot of custom encoding of your URLs and not using UTF-8.
245 This setting take precedence over C<decode_query_using_global_encoding>.
247 C<decode_query_using_global_encoding>
249 Setting this to true will default your query decoding to whatever your
250 general global encoding is (the default is UTF-8).
253 =head1 Upgrading to Catalyst 5.90080
255 UTF8 encoding is now default. For temporary backwards compatibility, if this
256 change is causing you trouble, you can disable it by setting the application
257 configuration option to undef:
259 MyApp->config(encoding => undef);
261 But please consider this a temporary measure since it is the intention that
262 UTF8 is enabled going forwards and the expectation is that other ecosystem
263 projects will assume this as well. At some point you application will not
264 correctly function without this setting.
266 As of 5.90084 we've added two additional configuration flags for more selective
267 control over some encoding changes: 'skip_body_param_unicode_decoding' and
268 'skip_complex_post_part_handling'. You may use these to more selectively
269 disable new features while you are seeking a long term fix. Please review
270 CONFIGURATION in L<Catalyst>.
272 For further information, please see L<Catalyst::UTF8>
274 A number of projects in the wider ecosystem required minor updates to be able
275 to work correctly. Here's the known list:
277 L<Catalyst::View::TT>, L<Catalyst::View::Mason>, L<Catalyst::View::HTML::Mason>,
278 L<Catalyst::View::Xslate>, L<Test::WWW::Mechanize::Catalyst>
280 You will need to update to modern versions in most cases, although quite a few
281 of these only needed minor test case and documentation changes so you will need
282 to review the changelog of each one that is relevant to you to determine your
285 =head1 Upgrading to Catalyst 5.90060
287 Starting in the v5.90059_001 development release, the regexp dispatch type is
288 no longer automatically included as a dependency. If you are still using this
289 dispatch type, you need to add L<Catalyst::DispatchType::Regex> into your build
292 The standalone distribution of Regexp will be supported for the time being, but
293 should we find that supporting it prevents us from moving L<Catalyst> forward
294 in necessary ways, we reserve the right to drop that support. It is highly
295 recommended that you use this last stage of deprecation to change your code.
297 =head1 Upgrading to Catalyst 5.90040
299 =head2 Catalyst::Plugin::Unicode::Encoding is now core
301 The previously stand alone Unicode support module L<Catalyst::Plugin::Unicode::Encoding>
302 has been brought into core as a default plugin. Going forward, all you need is
303 to add a configuration setting for the encoding type. For example:
309 __PACKAGE__->config( encoding => 'UTF-8' );
311 Please note that this is different from the old stand alone plugin which applied
312 C<UTF-8> encoding by default (that is, if you did not set an explicit
313 C<encoding> configuration value, it assumed you wanted UTF-8). In order to
314 preserve backwards compatibility you will need to explicitly turn it on via the
315 configuration setting. THIS MIGHT CHANGE IN THE FUTURE, so please consider
316 starting to test your application with proper UTF-8 support and remove all those
317 crappy hacks you munged into the code because you didn't know the Plugin
320 For people that are using the Plugin, you will note a startup warning suggesting
321 that you can remove it from the plugin list. When you do so, please remember to
322 add the configuration setting, since you can no longer rely on the default being
323 UTF-8. We'll add it for you if you continue to use the stand alone plugin and
324 we detect this, but this backwards compatibility shim will likely be removed in
325 a few releases (trying to clean up the codebase after all).
327 If you have trouble with any of this, please bring it to the attention of the
328 Catalyst maintainer group.
330 =head2 basic async and event loop support
332 This version of L<Catalyst> offers some support for using L<AnyEvent> and
333 L<IO::Async> event loops in your application. These changes should work
334 fine for most applications however if you are already trying to perform
335 some streaming, minor changes in this area of the code might affect your
336 functionality. Please see L<Catalyst::Response\write_fh> for more and for a
339 We consider this feature experimental. We will try not to break it, but we
340 reserve the right to make necessary changes to fix major issues that people
341 run into when the use this functionality in the wild.
343 =head1 Upgrading to Catalyst 5.90030
345 =head2 Regex dispatch type is deprecated.
347 The Regex dispatchtype (L<Catalyst::DispatchType::Regex>) has been deprecated.
349 You are encouraged to move your application to Chained dispatch (L<Catalyst::DispatchType::Chained>).
351 If you cannot do so, please add a dependency to Catalyst::DispatchType::Regex to your application's
354 =head1 Upgrading to Catalyst 5.9
356 The major change is that L<Plack>, a toolkit for using the L<PSGI>
357 specification, now replaces most of the subclasses of L<Catalyst::Engine>. If
358 you are using one of the standard subclasses of L<Catalyst::Engine> this
359 should be a straightforward upgrade for you. It was a design goal for
360 this release to preserve as much backwards compatibility as possible.
361 However, since L<Plack> is different from L<Catalyst::Engine>, it is
362 possible that differences exist for edge cases. Therefore, we recommend
363 that care be taken with this upgrade and that testing should be greater
364 than would be the case with a minor point update. Please inform the
365 Catalyst developers of any problems so that we can fix them and
368 It is highly recommended that you become familiar with the L<Plack> ecosystem
369 and documentation. Being able to take advantage of L<Plack> development and
370 middleware is a major bonus to this upgrade. Documentation about how to
371 take advantage of L<Plack::Middleware> by writing your own C<< .psgi >> file
372 is contained in L<Catalyst::PSGI>.
374 If you have created a custom subclass of L<Catalyst:Engine>, you will
375 need to convert it to be a subclass of L<Plack::Handler>.
377 If you are using the L<Plack> engine, L<Catalyst::Engine::PSGI>, this new
378 release supersedes that code.
380 If you are using a subclass of L<Catalyst::Engine> that is aimed at
381 nonstandard or internal/testing uses, such as
382 L<Catalyst::Engine::Embeddable>, you should still be able to continue
385 Advice for specific subclasses of L<Catalyst::Engine> follows:
387 =head2 Upgrading the FastCGI Engine
389 No upgrade is needed if your myapp_fastcgi.pl script is already upgraded
390 to use L<Catalyst::Script::FastCGI>.
392 =head2 Upgrading the mod_perl / Apache Engines
394 The engines that are built upon the various iterations of mod_perl,
395 L<Catalyst::Engine::Apache::MP13> (for mod_perl 1, and Apache 1.x) and
396 L<Catalyst::Engine::Apache2::MP20> (for mod_perl 2, and Apache 2.x),
397 should be seamless upgrades and will work using L<Plack::Handler::Apache1>
398 or L<Plack::Handler::Apache2> as required.
400 L<Catalyst::Engine::Apache2::MP19>, however, is no longer supported, as
401 Plack does not support mod_perl version 1.99. This is unlikely to be a
402 problem for anyone, as 1.99 was a brief beta-test release for mod_perl
403 2, and all users of mod_perl 1.99 are encouraged to upgrade to a
404 supported release of Apache 2 and mod_perl 2.
406 =head2 Upgrading the HTTP Engine
408 The default development server that comes with the L<Catalyst> distribution
409 should continue to work as expected with no changes as long as your C<myapp_server>
410 script is upgraded to use L<Catalyst::Script::HTTP>.
412 =head2 Upgrading the CGI Engine
414 If you were using L<Catalyst::Engine::CGI> there is no upgrade needed if your
415 myapp_cgi.pl script is already upgraded to use L<Catalyst::Script::CGI>.
417 =head2 Upgrading Catalyst::Engine::HTTP::Prefork
419 If you were using L<Catalyst::Engine::HTTP::Prefork> then L<Starman>
420 is automatically loaded. You should (at least) change your C<Makefile.PL>
421 to depend on Starman.
423 You can regenerate your C<myapp_server.pl> script with C<catalyst.pl>
424 and implement a C<MyApp::Script::Server> class that looks like this:
426 package MyApp::Script::Server;
428 use namespace::autoclean;
430 extends 'CatalystX::Script::Server::Starman';
434 This takes advantage of the new script system, and will add a number of
435 options to the standard server script as extra options are added by
438 More information about these options can be seen at
439 L<CatalystX::Script::Server::Starman/SYNOPSIS>.
441 An alternate route to implement this functionality is to write a simple .psgi
442 file for your application, and then use the L<plackup> utility to start the
445 =head2 Upgrading the PSGI Engine
447 If you were using L<Catalyst::Engine::PSGI>, this new release supersedes
448 this engine in supporting L<Plack>. By default the Engine is now always
449 L<Plack>. As a result, you can remove the dependency on
450 L<Catalyst::Engine::PSGI> in your C<Makefile.PL>.
452 Applications that were using L<Catalyst::Engine::PSGI>
453 previously should entirely continue to work in this release with no changes.
455 However, if you have an C<app.psgi> script, then you no longer need to
456 specify the PSGI engine. Instead, the L<Catalyst> application class now
457 has a new method C<psgi_app> which returns a L<PSGI> compatible coderef
458 which you can wrap in the middleware of your choice.
460 Catalyst will use the .psgi for your application if it is located in the C<home>
461 directory of the application.
463 For example, if you were using L<Catalyst::Engine::PSGI> in the past, you will
464 have written (or generated) a C<script/myapp.psgi> file similar to this one:
469 MyCatalystApp->setup_engine('PSGI');
472 enable ... # enable your desired middleware
473 sub { MyCatalystApp->run(@_) };
476 Instead, you now say:
482 enable ... #enable your desired middleware
483 MyCatalystApp->psgi_app;
486 In the simplest case:
488 MyCatalystApp->setup_engine('PSGI');
489 my $app = sub { MyCatalystApp->run(@_) }
493 my $app = MyCatalystApp->psgi_app(@_);
497 my $app = sub { MyCatalystApp->psgi_app(@_) };
498 # If you make ^^ this mistake, your app won't work, and will confuse the hell out of you!
500 You can now move C<< script/myapp.psgi >> to C<< myapp.psgi >>, and the built-in
501 Catalyst scripts and your test suite will start using your .psgi file.
503 B<NOTE:> If you rename your .psgi file without these modifications, then
504 any tests run via L<Catalyst::Test> will not be compatible with the new
505 release, and will result in the development server starting, rather than
506 the expected test running.
508 B<NOTE:> If you are directly accessing C<< $c->req->env >> to get the PSGI
509 environment then this accessor is moved to C<< $c->engine->env >>,
510 you will need to update your code.
512 =head2 Engines which are known to be broken
514 The following engines B<DO NOT> work as of Catalyst version 5.9. The
515 core team will be happy to work with the developers and/or users of
516 these engines to help them port to the new Plack/Engine system, but for
517 now, applications which are currently using these engines B<WILL NOT>
518 run without modification to the engine code.
522 =item Catalyst::Engine::Wx
524 =item Catalyst::Engine::Zeus
526 =item Catalyst::Engine::JobQueue::POE
528 =item Catalyst::Engine::XMPP2
530 =item Catalyst::Engine::SCGI
534 =head2 Engines with unknown status
536 The following engines are untested or have unknown compatibility.
537 Reports are highly encouraged:
541 =item Catalyst::Engine::Mojo
543 =item Catalyst::Engine::Server (marked as Deprecated)
545 =item Catalyst::Engine::HTTP::POE (marked as Deprecated)
549 =head2 Plack functionality
551 See L<Catalyst::PSGI>.
555 Tests should generally work the same in Catalyst 5.9, but there are
558 Previously, if using L<Catalyst::Test> and doing local requests (against
559 a local server), if the application threw an exception then this
560 exception propagated into the test.
562 This behavior has been removed, and now a 500 response will be returned
563 to the test. This change standardizes behavior, so that local test
564 requests behave similarly to remote requests.
566 =head1 Upgrading to Catalyst 5.80
568 Most applications and plugins should run unaltered on Catalyst 5.80.
570 However, a lot of refactoring work has taken place, and several changes have
571 been made which could cause incompatibilities. If your application or plugin
572 is using deprecated code, or relying on side effects, then you could have
573 issues upgrading to this release.
575 Most issues found with existing components have been easy to
576 solve. This document provides a complete description of behavior changes
577 which may cause compatibility issues, and of new Catalyst warnings which
580 If you think you have found an upgrade-related issue which is not covered in
581 this document, please email the Catalyst list to discuss the problem.
583 =head1 Moose features
585 =head2 Application class roles
587 You can only apply method modifiers after the application's C<< ->setup >>
588 method has been called. This means that modifiers will not work with methods
589 run during the call to C<< ->setup >>.
591 See L<Catalyst::Manual::ExtendingCatalyst> for more information about using
592 L<Moose> in your applications.
594 =head2 Controller actions in Moose roles
596 You can use L<MooseX::MethodAttributes::Role> if you want to declare actions
599 =head2 Using Moose in Components
601 The correct way to use Moose in a component in a both forward and backwards
604 package TestApp::Controller::Root;
606 BEGIN { extends 'Catalyst::Component' }; # Or ::Controller, or whatever
608 See L<Components which inherit from Moose::Object before Catalyst::Component>.
610 =head1 Known backwards compatibility breakages
612 =head2 Applications in a single file
614 Applications must be in their own file, and loaded at compile time. This
615 issue generally only affects the tests of CPAN distributions. Your
616 application will fail if you try to define an application inline in a
617 block, and use plugins which supply a C< new > method, then use that
618 application latter in tests within the same file.
620 This is due to the fact that Catalyst is inlining a new method on your
621 application class allowing it to be compatible with Moose. The method
622 used to do this changed in 5.80004 to avoid the possibility of reporting
623 an 'Unknown Error' if your application failed to compile.
625 =head2 Issues with Class::C3
627 Catalyst 5.80 uses the L<Algorithm::C3> method dispatch order. This is
628 built into Perl 5.10, and comes via L<Class::C3> for Perl 5.8. This
629 replaces L<NEXT> with L<Class::C3::Adopt::NEXT>, forcing all components
630 to resolve methods using C3, rather than the unpredictable dispatch
633 This issue manifests itself by your application failing to start due to an
634 error message about having a non-linear @ISA.
636 The Catalyst plugin most often causing this is
637 L<Catalyst::Plugin::Session::Store::FastMmap> - if you are using this
638 plugin and see issues, then please upgrade your plugins, as it has been
639 fixed. Note that Makefile.PL in the distribution will warn about known
640 incompatible components.
642 This issue can, however, be found in your own application - the only solution is
643 to go through each base class of the class the error was reported against, until
644 you identify the ones in conflict, and resolve them.
646 To be able to generate a linear @ISA, the list of superclasses for each
647 class must be resolvable using the C3 algorithm. Unfortunately, when
648 superclasses are being used as mixins (to add functionality used in your class),
649 and with multiple inheritance, it is easy to get this wrong.
651 Most common is the case of:
653 package Component1; # Note, this is the common case
654 use base qw/Class::Accessor::Fast Class::Data::Inheritable/;
656 package Component2; # Accidentally saying it this way causes a failure
657 use base qw/Class::Data::Inheritable Class::Accessor::Fast/;
660 use base qw/Component1 Component2/;
662 Any situation like this will cause your application to fail to start.
664 For additional documentation about this issue, and how to resolve it, see
665 L<Class::C3::Adopt::NEXT>.
667 =head2 Components which inherit from Moose::Object before Catalyst::Component
669 Moose components which say:
671 package TestApp::Controller::Example;
673 extends qw/Moose::Object Catalyst::Component/;
675 to use the constructor provided by Moose, while working (if you do some hacks
676 with the C< BUILDARGS > method), will not work with Catalyst 5.80 as
677 C<Catalyst::Component> inherits from C<Moose::Object>, and so C< @ISA > fails
680 The correct way to use Moose in a component in a both forward and backwards
683 package TestApp::Controller::Root;
685 BEGIN { extends 'Catalyst::Component' }; # Or ::Controller, or whatever
687 Note that the C< extends > declaration needs to occur in a begin block for
688 L<attributes> to operate correctly.
690 This way you do not inherit directly from C<Moose::Object>
691 yourself. Having components which do not inherit their constructor from
692 C<Catalyst::Component> is B<unsupported>, and has never been recommended,
693 therefore you're on your own if you're using this technique. You'll need
694 to detect the version of Catalyst your application is running, and deal
695 with it appropriately.
697 You also don't get the L<Moose::Object> constructor, and therefore attribute
698 initialization will not work as normally expected. If you want to use Moose
699 attributes, then they need to be made lazy to correctly initialize.
701 Note that this only applies if your component needs to maintain component
702 backwards compatibility for Catalyst versions before 5.71001 - in 5.71001
703 attributes work as expected, and the BUILD method is called normally
704 (although BUILDARGS is not).
706 If you depend on Catalyst 5.8, then B<all> Moose features work as expected.
708 You will also see this issue if you do the following:
710 package TestApp::Controller::Example;
712 use base 'Catalyst::Controller';
714 as C< use base > appends to @ISA.
716 =head3 use Moose in MyApp
718 Similar to the above, this will also fail:
727 If you need to use Moose in your application class (e.g. for method modifiers
728 etc.) then the correct technique is:
736 __PACKAGE__->config( name => 'MyApp' );
737 __PACKAGE__->setup(qw/
741 =head2 Anonymous closures installed directly into the symbol table
743 If you have any code which installs anonymous subroutine references directly
744 into the symbol table, you may encounter breakages. The simplest solution is
745 to use L<Sub::Name> to name the subroutine. Example:
747 # Original code, likely to break:
748 my $full_method_name = join('::', $package_name, $method_name);
749 *$full_method_name = sub { ... };
752 use Sub::Name 'subname';
753 my $full_method_name = join('::',$package_name, $method_name);
754 *$full_method_name = subname $full_method_name, sub { ... };
756 Additionally, you can take advantage of Catalyst's use of L<Class::MOP> and
757 install the closure using the appropriate metaclass. Example:
760 my $metaclass = Moose::Meta::Class->initialize($package_name);
761 $metaclass->add_method($method_name => sub { ... });
763 =head2 Hooking into application setup
765 To execute code during application start-up, the following snippet in MyApp.pm
769 my ($class, @args) = @_;
770 $class->NEXT::setup(@args);
771 ... # things to do after the actual setup
774 With Catalyst 5.80 this won't work anymore, because Catalyst no longer
775 uses NEXT.pm for method resolution. The functionality was only ever
776 originally operational as L<NEXT> remembers what methods have already
777 been called, and will not call them again.
779 Using this now causes infinite recursion between MyApp::setup and
780 Catalyst::setup, due to other backwards compatibility issues related to how
781 plugin setup works. Moose method modifiers like C<< before|after|around setup
782 => sub { ... }; >> also will not operate correctly on the setup method.
784 The right way to do it is this:
786 after setup_finalize => sub {
787 ... # things to do after the actual setup
790 The setup_finalize hook was introduced as a way to avoid this issue.
792 =head2 Components with a new method which returns false
794 Previously, if you had a component which inherited from Catalyst::COMPONENT,
795 but overrode the new method to return false, then your class's configuration
796 would be blessed into a hash on your behalf, and this would be returned from
797 the COMPONENT method.
799 This behavior makes no sense, and so has been removed. Implementing your own
800 C< new > method in components is B<highly> discouraged. Instead, you should
801 inherit the new method from Catalyst::Component, and use Moose's BUILD
802 functionality and/or Moose attributes to perform any construction work
803 necessary for your class.
805 =head2 __PACKAGE__->mk_accessor('meta');
807 Won't work due to a limitation of L<Moose>. This is currently being fixed
810 =head2 Class::Data::Inheritable side effects
812 Previously, writing to a class data accessor would copy the accessor method
813 down into your package.
815 This behavior has been removed. While the class data is still stored
816 per-class, it is stored on the metaclass of the class defining the accessor.
818 Therefore anything relying on the side effect of the accessor being copied down
821 The following test demonstrates the problem:
825 use base qw/Class::Data::Inheritable/;
826 __PACKAGE__->mk_classdata('foo');
831 use base qw/BaseClass/;
834 BaseClass->foo('base class');
835 Child->foo('sub class');
838 isnt(BaseClass->can('foo'), Child->can('foo'));
840 =head2 Extending Catalyst::Request or other classes in an ad hoc manner using mk_accessors
842 Previously, it was possible to add additional accessors to Catalyst::Request
843 (or other classes) by calling the mk_accessors class method.
845 This is no longer supported - users should make a subclass of the class whose
846 behavior they would like to change, rather than globally polluting the
849 =head2 Confused multiple inheritance with Catalyst::Component::COMPONENT
851 Previously, Catalyst's COMPONENT method would delegate to the method on
852 the right hand side, which could then delegate back again with
853 NEXT. This is poor practice, and in addition, makes no sense with C3
854 method dispatch order, and is therefore no longer supported.
856 If a COMPONENT method is detected in the inheritance hierarchy to the right
857 hand side of Catalyst::Component::COMPONENT, then the following warning
858 message will be emitted:
860 There is a COMPONENT method resolving after Catalyst::Component
863 The correct fix is to re-arrange your class's inheritance hierarchy so that the
864 COMPONENT method you would like to inherit is the first (left-hand most)
865 COMPONENT method in your @ISA.
867 =head2 Development server relying on environment variables
869 Previously, the development server would allow propagation of system
870 environment variables into the request environment, this has changed with the
871 adoption of Plack. You can use L<Plack::Middleware::ForceEnv> to achieve the
876 =head2 Actions in your application class
878 Having actions in your application class will now emit a warning at application
879 startup as this is deprecated. It is highly recommended that these actions are moved
880 into a MyApp::Controller::Root (as demonstrated by the scaffold application
881 generated by catalyst.pl).
883 This warning, also affects tests. You should move actions in your test,
884 creating a myTest::Controller::Root, like the following example:
886 package MyTest::Controller::Root;
891 use parent 'Catalyst::Controller';
893 __PACKAGE__->config(namespace => '');
896 my ( $self, $c ) = @_;
902 =head2 ::[MVC]:: naming scheme
904 Having packages called MyApp::[MVC]::XX is deprecated and can no longer be generated
907 This is still supported, but it is recommended that you rename your application
908 components to Model/View/Controller.
910 A warning will be issued at application startup if the ::[MVC]:: naming scheme is
913 =head2 Catalyst::Base
915 Any code using L<Catalyst::Base> will now emit a warning; this
916 module will be removed in a future release.
918 =head2 Methods in Catalyst::Dispatcher
920 The following methods in Catalyst::Dispatcher are implementation
921 details, which may change in the 5.8X release series, and therefore their use
922 is highly deprecated.
930 =item registered_dispatch_types
932 =item method_action_class
940 The first time one of these methods is called, a warning will be emitted:
942 Class $class is calling the deprecated method Catalyst::Dispatcher::$public_method_name,
943 this will be removed in Catalyst 5.9
945 You should B<NEVER> be calling any of these methods from application code.
947 Plugin authors and maintainers whose plugins currently call these methods
948 should change to using the public API, or, if you do not feel the public API
949 adequately supports your use case, please email the development list to
950 discuss what API features you need so that you can be appropriately supported.
952 =head2 Class files with names that don't correspond to the packages they define
954 In this version of Catalyst, if a component is loaded from disk, but no
955 symbols are defined in that component's name space after it is loaded, this
956 warning will be issued:
958 require $class was successful but the package is not defined.
960 This is to protect against confusing bugs caused by mistyping package names,
961 and will become a fatal error in a future version.
963 Please note that 'inner packages' (via L<Devel::InnerPackage>) are still fully
964 supported; this warning is only issued when component file naming does not map
965 to B<any> of the packages defined within that component.
967 =head2 $c->plugin method
969 Calling the plugin method is deprecated, and calling it at run time is B<highly
972 Instead you are recommended to use L<Catalyst::Model::Adaptor> or similar to
973 compose the functionality you need outside of the main application name space.
975 Calling the plugin method will not be supported past Catalyst 5.81.