3 Catalyst::Upgrading - Instructions for upgrading to the latest Catalyst
5 =head1 Upgrading to Catalyst 5.90097
7 In older versions of Catalyst one could construct a L<URI> with a fragment (such as
8 https://localhost/foo/bar#fragment) by using a '#' in the path or final argument, for
11 $c->uri_for($action, 'foo#fragment');
13 This behavior was never documented and would break if using the Unicode plugin, or when
14 adding a query to the arguments:
16 $c->uri_for($action, 'foo#fragment', +{ a=>1, b=>2});
18 would define a fragment like "#fragment?a=1&b=2".
20 When we introduced UTF-8 encoding by default in Catalyst 5.9008x this side effect behavior
21 was broken since we started encoding the '#' when it was part of the URI path.
23 In version 5.90095 and 5.90096 we attempted to fix this, but all we managed to do was break
24 people with URIs that included '#' as part of the path data, when it was not expected to
25 be a fragment delimiter.
27 In general L<Catalyst> prefers an explicit specification rather than relying on side effects
28 or domain specific mini languages. As a result we are now defining how to set a fragment
29 for a URI via ->uri_for:
31 $c->uri_for($action_or_path, \@captures_or_args, @args, \$query, \$fragment);
33 If you are relying on the previous side effect behavior your URLs will now encode the '#'
34 delimiter, which is going to be a breaking change for you. You need to alter your code
35 to match the new specification or modify uri_for for your local case. Patches to solve
36 this are very welcomed, as long as they don't break existing test cases.
38 B<NOTE> If you are using the string form of the first argument:
40 $c->uri_for('/foo/bar#baz')
42 construction, we do not attempt to encode this and it will make a URL with a
46 =head1 Upgrading to Catalyst 5.90095
48 The method C<last_error> in L</Catalyst> was actually returning the first error. This has
49 been fixed but there is a small chance it could be a breaking issue for you. If this gives
50 you trouble changing to C<shift_errors> is the easiest workaround (although that does
51 modify the error stack so if you are relying on that not being changed you should try something
52 like @{$c->errors}[-1] instead. Since this method is relatively new and the cases when the
53 error stack actually has more than one error in it, we feel the exposure is very low, but bug
54 reports are very welcomed.
56 =head1 Upgrading to Catalyst 5.90090
58 L<Catalyst::Utils> has a new method 'inject_component' which works the same as the method of
59 the same name in L<CatalystX::InjectComponent>. You should start converting any
60 use of the non core method in your code as future changes to Catalyst will be
61 sychronized to the core method first. We reserve the right to cease support
62 of the non core version should we reach a point in time where it cannot be
63 properly supported as an external module. Luckily this should be a trivial
64 search and replace. Change all occurances of:
66 CatalystX::InjectComponent->inject(...)
70 Catalyst::Utils::inject_component(...)
72 and we expect everything to work the same (we'd consider it not working the same
73 to be a bug, and please report it.)
75 We also cored features from L<CatalystX::RoleApplicator> to compose a role into the
76 request, response and stats classes. The main difference is that with L<CatalystX::RoleApplicator>
82 use CatalystX::RoleApplicator;
84 __PACKAGE__->apply_request_class_roles(
85 qw/My::Request::Role Other::Request::Role/);
87 Whereas now we have three class attributes, 'request_class_traits', 'response_class_traits'
88 and 'stats_class_traits', so you use like this (note this value is an ArrayRef)
95 __PACKAGE__->request_class_traits([qw/
97 Other::Request::Role/]);
99 (And the same for response_class_traits and stats_class_traits. We left off the
100 traits for Engine, since that class does a lot less nowadays, and dispatcher. If you
101 used those and can share a use case, we'd be likely to support them.
103 Lastly, we have some of the feature from L<CatalystX::ComponentsFromConfig> in
104 core. This should mostly work the same way in core, except for now the
105 core version does not create an automatic base wrapper class for your configured
106 components (it requires these to be catalyst components and injects them directly.
107 So if you make heavy use of custom base classes in L<CatalystX::ComponentsFromConfig>
108 you might need a bit of work to use the core version (although there is no reason
109 to stop using L<CatalystX::ComponentsFromConfig> since it should continue to work
110 fine and we'd consider issues with it to be bugs). Here's one way to map from
111 L<CatalystX::ComponentsFromConfig> to core:
113 In L<CatalystX::ComponentsFromConfig>:
116 'Model::MyClass' => {
125 inject_components => {
126 'Model::MyClass' => { from_component => 'My::Class' },
128 'Model::MyClass' => {
133 Although the cored behavior requires more code, its better separates concerns
134 as well as plays more into core Catalyst expections of how configuration shoul
137 Also we added a new develop console mode only warning when you call a component
138 with arguments that don't expect or do anything meaningful with those args. Its
139 possible if you are logging debug mode in production (please don't...) this
140 could add verbosity to those logs if you also happen to be calling for components
141 and passing pointless arguments. We added this warning to help people not make this
142 error and to better understand the component resolution flow.
144 =head1 Upgrading to Catalyst 5.90085
146 In this version of Catalyst we made a small change to Chained Dispatching so
147 that when two or more actions all have the same path specification AND they
148 all have Args(0), we break the tie by choosing the last action defined, and
149 not the first one defined. This was done to normalize Chaining to following
150 the 'longest Path wins, and when several actions match the same Path specification
151 we choose the last defined.' rule. Previously Args(0) was hard coded to be a special
152 case such that the first action defined would match (which is not the case when
155 Its possible that this could be a breaking change for you, if you had used
156 action roles (custom or otherwise) to add additional matching rules to differentiate
157 between several Args(0) actions that share the same root action chain. For
158 example if you have code now like this:
160 sub check_default :Chained(/) CaptureArgs(0) { ... }
162 sub default_get :Chained('check_default') PathPart('') Args(0) GET {
163 pop->res->body('get3');
166 sub default_post :Chained('check_default') PathPart('') Args(0) POST {
167 pop->res->body('post3');
170 sub chain_default :Chained('check_default') PathPart('') Args(0) {
171 pop->res->body('chain_default');
174 The way that chaining will work previous is that when two or more equal actions can
175 match, the 'top' one wins. So if the request is "GET .../check_default" BOTH
176 actions 'default_get' AND 'chain_default' would match. To break the tie in
177 the case when Args is 0, we'd previous take the 'top' (or first defined) action.
178 Unfortunately this treatment of Args(0) is special case. In all other cases
179 we choose the 'last defined' action to break a tie. So this version of
180 Catalyst changed the dispatcher to make Args(0) no longer a special case for
181 breaking ties. This means that the above code must now become:
183 sub check_default :Chained(/) CaptureArgs(0) { ... }
185 sub chain_default :Chained('check_default') PathPart('') Args(0) {
186 pop->res->body('chain_default');
189 sub default_get :Chained('check_default') PathPart('') Args(0) GET {
190 pop->res->body('get3');
193 sub default_post :Chained('check_default') PathPart('') Args(0) POST {
194 pop->res->body('post3');
197 If we want it to work as expected (for example we we GET to match 'default_get' and
198 POST to match 'default_post' and any other http Method to match 'chain_default').
200 In other words Arg(0) and chained actions must now follow the normal rule where
201 in a tie the last defined action wins and you should place all your less defined
202 or 'catch all' actions first.
204 If this causes you trouble and you can't fix your code to conform, you may set the
205 application configuration setting "use_chained_args_0_special_case" to true and
206 that will revert you code to the previous behavior.
208 =head2 More backwards compatibility options with UTF-8 changes
210 In order to give better backwards compatiblity with the 5.90080+ UTF-8 changes
211 we've added several configuration options around control of how we try to decode
212 your URL keywords / query parameters.
214 C<do_not_decode_query>
216 If true, then do not try to character decode any wide characters in your
217 request URL query or keywords. Most readings of the relevent specifications
218 suggest these should be UTF-* encoded, which is the default that L<Catalyst>
219 will use, hwoever if you are creating a lot of URLs manually or have external
220 evil clients, this might cause you trouble. If you find the changes introduced
221 in Catalyst version 5.90080+ break some of your query code, you may disable
222 the UTF-8 decoding globally using this configuration.
224 This setting takes precedence over C<default_query_encoding> and
225 C<decode_query_using_global_encoding>
227 C<default_query_encoding>
229 By default we decode query and keywords in your request URL using UTF-8, which
230 is our reading of the relevent specifications. This setting allows one to
231 specify a fixed value for how to decode your query. You might need this if
232 you are doing a lot of custom encoding of your URLs and not using UTF-8.
234 This setting take precedence over C<decode_query_using_global_encoding>.
236 C<decode_query_using_global_encoding>
238 Setting this to true will default your query decoding to whatever your
239 general global encoding is (the default is UTF-8).
242 =head1 Upgrading to Catalyst 5.90080
244 UTF8 encoding is now default. For temporary backwards compatibility, if this
245 change is causing you trouble, you can disable it by setting the application
246 configuration option to undef:
248 MyApp->config(encoding => undef);
250 But please consider this a temporary measure since it is the intention that
251 UTF8 is enabled going forwards and the expectation is that other ecosystem
252 projects will assume this as well. At some point you application will not
253 correctly function without this setting.
255 As of 5.90084 we've added two additional configuration flags for more selective
256 control over some encoding changes: 'skip_body_param_unicode_decoding' and
257 'skip_complex_post_part_handling'. You may use these to more selectively
258 disable new features while you are seeking a long term fix. Please review
259 CONFIGURATION in L<Catalyst>.
261 For further information, please see L<Catalyst::UTF8>
263 A number of projects in the wider ecosystem required minor updates to be able
264 to work correctly. Here's the known list:
266 L<Catalyst::View::TT>, L<Catalyst::View::Mason>, L<Catalyst::View::HTML::Mason>,
267 L<Catalyst::View::Xslate>, L<Test::WWW::Mechanize::Catalyst>
269 You will need to update to modern versions in most cases, although quite a few
270 of these only needed minor test case and documentation changes so you will need
271 to review the changelog of each one that is relevant to you to determine your
274 =head1 Upgrading to Catalyst 5.90060
276 Starting in the v5.90059_001 development release, the regexp dispatch type is
277 no longer automatically included as a dependency. If you are still using this
278 dispatch type, you need to add L<Catalyst::DispatchType::Regex> into your build
281 The standalone distribution of Regexp will be supported for the time being, but
282 should we find that supporting it prevents us from moving L<Catalyst> forward
283 in necessary ways, we reserve the right to drop that support. It is highly
284 recommended that you use this last stage of deprecation to change your code.
286 =head1 Upgrading to Catalyst 5.90040
288 =head2 Catalyst::Plugin::Unicode::Encoding is now core
290 The previously stand alone Unicode support module L<Catalyst::Plugin::Unicode::Encoding>
291 has been brought into core as a default plugin. Going forward, all you need is
292 to add a configuration setting for the encoding type. For example:
298 __PACKAGE__->config( encoding => 'UTF-8' );
300 Please note that this is different from the old stand alone plugin which applied
301 C<UTF-8> encoding by default (that is, if you did not set an explicit
302 C<encoding> configuration value, it assumed you wanted UTF-8). In order to
303 preserve backwards compatibility you will need to explicitly turn it on via the
304 configuration setting. THIS MIGHT CHANGE IN THE FUTURE, so please consider
305 starting to test your application with proper UTF-8 support and remove all those
306 crappy hacks you munged into the code because you didn't know the Plugin
309 For people that are using the Plugin, you will note a startup warning suggesting
310 that you can remove it from the plugin list. When you do so, please remember to
311 add the configuration setting, since you can no longer rely on the default being
312 UTF-8. We'll add it for you if you continue to use the stand alone plugin and
313 we detect this, but this backwards compatibility shim will likely be removed in
314 a few releases (trying to clean up the codebase after all).
316 If you have trouble with any of this, please bring it to the attention of the
317 Catalyst maintainer group.
319 =head2 basic async and event loop support
321 This version of L<Catalyst> offers some support for using L<AnyEvent> and
322 L<IO::Async> event loops in your application. These changes should work
323 fine for most applications however if you are already trying to perform
324 some streaming, minor changes in this area of the code might affect your
325 functionality. Please see L<Catalyst::Response\write_fh> for more and for a
328 We consider this feature experimental. We will try not to break it, but we
329 reserve the right to make necessary changes to fix major issues that people
330 run into when the use this functionality in the wild.
332 =head1 Upgrading to Catalyst 5.90030
334 =head2 Regex dispatch type is deprecated.
336 The Regex dispatchtype (L<Catalyst::DispatchType::Regex>) has been deprecated.
338 You are encouraged to move your application to Chained dispatch (L<Catalyst::DispatchType::Chained>).
340 If you cannot do so, please add a dependency to Catalyst::DispatchType::Regex to your application's
343 =head1 Upgrading to Catalyst 5.9
345 The major change is that L<Plack>, a toolkit for using the L<PSGI>
346 specification, now replaces most of the subclasses of L<Catalyst::Engine>. If
347 you are using one of the standard subclasses of L<Catalyst::Engine> this
348 should be a straightforward upgrade for you. It was a design goal for
349 this release to preserve as much backwards compatibility as possible.
350 However, since L<Plack> is different from L<Catalyst::Engine>, it is
351 possible that differences exist for edge cases. Therefore, we recommend
352 that care be taken with this upgrade and that testing should be greater
353 than would be the case with a minor point update. Please inform the
354 Catalyst developers of any problems so that we can fix them and
357 It is highly recommended that you become familiar with the L<Plack> ecosystem
358 and documentation. Being able to take advantage of L<Plack> development and
359 middleware is a major bonus to this upgrade. Documentation about how to
360 take advantage of L<Plack::Middleware> by writing your own C<< .psgi >> file
361 is contained in L<Catalyst::PSGI>.
363 If you have created a custom subclass of L<Catalyst:Engine>, you will
364 need to convert it to be a subclass of L<Plack::Handler>.
366 If you are using the L<Plack> engine, L<Catalyst::Engine::PSGI>, this new
367 release supersedes that code.
369 If you are using a subclass of L<Catalyst::Engine> that is aimed at
370 nonstandard or internal/testing uses, such as
371 L<Catalyst::Engine::Embeddable>, you should still be able to continue
374 Advice for specific subclasses of L<Catalyst::Engine> follows:
376 =head2 Upgrading the FastCGI Engine
378 No upgrade is needed if your myapp_fastcgi.pl script is already upgraded
379 to use L<Catalyst::Script::FastCGI>.
381 =head2 Upgrading the mod_perl / Apache Engines
383 The engines that are built upon the various iterations of mod_perl,
384 L<Catalyst::Engine::Apache::MP13> (for mod_perl 1, and Apache 1.x) and
385 L<Catalyst::Engine::Apache2::MP20> (for mod_perl 2, and Apache 2.x),
386 should be seamless upgrades and will work using L<Plack::Handler::Apache1>
387 or L<Plack::Handler::Apache2> as required.
389 L<Catalyst::Engine::Apache2::MP19>, however, is no longer supported, as
390 Plack does not support mod_perl version 1.99. This is unlikely to be a
391 problem for anyone, as 1.99 was a brief beta-test release for mod_perl
392 2, and all users of mod_perl 1.99 are encouraged to upgrade to a
393 supported release of Apache 2 and mod_perl 2.
395 =head2 Upgrading the HTTP Engine
397 The default development server that comes with the L<Catalyst> distribution
398 should continue to work as expected with no changes as long as your C<myapp_server>
399 script is upgraded to use L<Catalyst::Script::HTTP>.
401 =head2 Upgrading the CGI Engine
403 If you were using L<Catalyst::Engine::CGI> there is no upgrade needed if your
404 myapp_cgi.pl script is already upgraded to use L<Catalyst::Script::CGI>.
406 =head2 Upgrading Catalyst::Engine::HTTP::Prefork
408 If you were using L<Catalyst::Engine::HTTP::Prefork> then L<Starman>
409 is automatically loaded. You should (at least) change your C<Makefile.PL>
410 to depend on Starman.
412 You can regenerate your C<myapp_server.pl> script with C<catalyst.pl>
413 and implement a C<MyApp::Script::Server> class that looks like this:
415 package MyApp::Script::Server;
417 use namespace::autoclean;
419 extends 'CatalystX::Script::Server::Starman';
423 This takes advantage of the new script system, and will add a number of
424 options to the standard server script as extra options are added by
427 More information about these options can be seen at
428 L<CatalystX::Script::Server::Starman/SYNOPSIS>.
430 An alternate route to implement this functionality is to write a simple .psgi
431 file for your application, and then use the L<plackup> utility to start the
434 =head2 Upgrading the PSGI Engine
436 If you were using L<Catalyst::Engine::PSGI>, this new release supersedes
437 this engine in supporting L<Plack>. By default the Engine is now always
438 L<Plack>. As a result, you can remove the dependency on
439 L<Catalyst::Engine::PSGI> in your C<Makefile.PL>.
441 Applications that were using L<Catalyst::Engine::PSGI>
442 previously should entirely continue to work in this release with no changes.
444 However, if you have an C<app.psgi> script, then you no longer need to
445 specify the PSGI engine. Instead, the L<Catalyst> application class now
446 has a new method C<psgi_app> which returns a L<PSGI> compatible coderef
447 which you can wrap in the middleware of your choice.
449 Catalyst will use the .psgi for your application if it is located in the C<home>
450 directory of the application.
452 For example, if you were using L<Catalyst::Engine::PSGI> in the past, you will
453 have written (or generated) a C<script/myapp.psgi> file similar to this one:
458 MyCatalystApp->setup_engine('PSGI');
461 enable ... # enable your desired middleware
462 sub { MyCatalystApp->run(@_) };
465 Instead, you now say:
471 enable ... #enable your desired middleware
472 MyCatalystApp->psgi_app;
475 In the simplest case:
477 MyCatalystApp->setup_engine('PSGI');
478 my $app = sub { MyCatalystApp->run(@_) }
482 my $app = MyCatalystApp->psgi_app(@_);
486 my $app = sub { MyCatalystApp->psgi_app(@_) };
487 # If you make ^^ this mistake, your app won't work, and will confuse the hell out of you!
489 You can now move C<< script/myapp.psgi >> to C<< myapp.psgi >>, and the built-in
490 Catalyst scripts and your test suite will start using your .psgi file.
492 B<NOTE:> If you rename your .psgi file without these modifications, then
493 any tests run via L<Catalyst::Test> will not be compatible with the new
494 release, and will result in the development server starting, rather than
495 the expected test running.
497 B<NOTE:> If you are directly accessing C<< $c->req->env >> to get the PSGI
498 environment then this accessor is moved to C<< $c->engine->env >>,
499 you will need to update your code.
501 =head2 Engines which are known to be broken
503 The following engines B<DO NOT> work as of Catalyst version 5.9. The
504 core team will be happy to work with the developers and/or users of
505 these engines to help them port to the new Plack/Engine system, but for
506 now, applications which are currently using these engines B<WILL NOT>
507 run without modification to the engine code.
511 =item Catalyst::Engine::Wx
513 =item Catalyst::Engine::Zeus
515 =item Catalyst::Engine::JobQueue::POE
517 =item Catalyst::Engine::XMPP2
519 =item Catalyst::Engine::SCGI
523 =head2 Engines with unknown status
525 The following engines are untested or have unknown compatibility.
526 Reports are highly encouraged:
530 =item Catalyst::Engine::Mojo
532 =item Catalyst::Engine::Server (marked as Deprecated)
534 =item Catalyst::Engine::HTTP::POE (marked as Deprecated)
538 =head2 Plack functionality
540 See L<Catalyst::PSGI>.
544 Tests should generally work the same in Catalyst 5.9, but there are
547 Previously, if using L<Catalyst::Test> and doing local requests (against
548 a local server), if the application threw an exception then this
549 exception propagated into the test.
551 This behavior has been removed, and now a 500 response will be returned
552 to the test. This change standardizes behavior, so that local test
553 requests behave similarly to remote requests.
555 =head1 Upgrading to Catalyst 5.80
557 Most applications and plugins should run unaltered on Catalyst 5.80.
559 However, a lot of refactoring work has taken place, and several changes have
560 been made which could cause incompatibilities. If your application or plugin
561 is using deprecated code, or relying on side effects, then you could have
562 issues upgrading to this release.
564 Most issues found with existing components have been easy to
565 solve. This document provides a complete description of behavior changes
566 which may cause compatibility issues, and of new Catalyst warnings which
569 If you think you have found an upgrade-related issue which is not covered in
570 this document, please email the Catalyst list to discuss the problem.
572 =head1 Moose features
574 =head2 Application class roles
576 You can only apply method modifiers after the application's C<< ->setup >>
577 method has been called. This means that modifiers will not work with methods
578 run during the call to C<< ->setup >>.
580 See L<Catalyst::Manual::ExtendingCatalyst> for more information about using
581 L<Moose> in your applications.
583 =head2 Controller actions in Moose roles
585 You can use L<MooseX::MethodAttributes::Role> if you want to declare actions
588 =head2 Using Moose in Components
590 The correct way to use Moose in a component in a both forward and backwards
593 package TestApp::Controller::Root;
595 BEGIN { extends 'Catalyst::Component' }; # Or ::Controller, or whatever
597 See L<Components which inherit from Moose::Object before Catalyst::Component>.
599 =head1 Known backwards compatibility breakages
601 =head2 Applications in a single file
603 Applications must be in their own file, and loaded at compile time. This
604 issue generally only affects the tests of CPAN distributions. Your
605 application will fail if you try to define an application inline in a
606 block, and use plugins which supply a C< new > method, then use that
607 application latter in tests within the same file.
609 This is due to the fact that Catalyst is inlining a new method on your
610 application class allowing it to be compatible with Moose. The method
611 used to do this changed in 5.80004 to avoid the possibility of reporting
612 an 'Unknown Error' if your application failed to compile.
614 =head2 Issues with Class::C3
616 Catalyst 5.80 uses the L<Algorithm::C3> method dispatch order. This is
617 built into Perl 5.10, and comes via L<Class::C3> for Perl 5.8. This
618 replaces L<NEXT> with L<Class::C3::Adopt::NEXT>, forcing all components
619 to resolve methods using C3, rather than the unpredictable dispatch
622 This issue manifests itself by your application failing to start due to an
623 error message about having a non-linear @ISA.
625 The Catalyst plugin most often causing this is
626 L<Catalyst::Plugin::Session::Store::FastMmap> - if you are using this
627 plugin and see issues, then please upgrade your plugins, as it has been
628 fixed. Note that Makefile.PL in the distribution will warn about known
629 incompatible components.
631 This issue can, however, be found in your own application - the only solution is
632 to go through each base class of the class the error was reported against, until
633 you identify the ones in conflict, and resolve them.
635 To be able to generate a linear @ISA, the list of superclasses for each
636 class must be resolvable using the C3 algorithm. Unfortunately, when
637 superclasses are being used as mixins (to add functionality used in your class),
638 and with multiple inheritance, it is easy to get this wrong.
640 Most common is the case of:
642 package Component1; # Note, this is the common case
643 use base qw/Class::Accessor::Fast Class::Data::Inheritable/;
645 package Component2; # Accidentally saying it this way causes a failure
646 use base qw/Class::Data::Inheritable Class::Accessor::Fast/;
649 use base qw/Component1 Component2/;
651 Any situation like this will cause your application to fail to start.
653 For additional documentation about this issue, and how to resolve it, see
654 L<Class::C3::Adopt::NEXT>.
656 =head2 Components which inherit from Moose::Object before Catalyst::Component
658 Moose components which say:
660 package TestApp::Controller::Example;
662 extends qw/Moose::Object Catalyst::Component/;
664 to use the constructor provided by Moose, while working (if you do some hacks
665 with the C< BUILDARGS > method), will not work with Catalyst 5.80 as
666 C<Catalyst::Component> inherits from C<Moose::Object>, and so C< @ISA > fails
669 The correct way to use Moose in a component in a both forward and backwards
672 package TestApp::Controller::Root;
674 BEGIN { extends 'Catalyst::Component' }; # Or ::Controller, or whatever
676 Note that the C< extends > declaration needs to occur in a begin block for
677 L<attributes> to operate correctly.
679 This way you do not inherit directly from C<Moose::Object>
680 yourself. Having components which do not inherit their constructor from
681 C<Catalyst::Component> is B<unsupported>, and has never been recommended,
682 therefore you're on your own if you're using this technique. You'll need
683 to detect the version of Catalyst your application is running, and deal
684 with it appropriately.
686 You also don't get the L<Moose::Object> constructor, and therefore attribute
687 initialization will not work as normally expected. If you want to use Moose
688 attributes, then they need to be made lazy to correctly initialize.
690 Note that this only applies if your component needs to maintain component
691 backwards compatibility for Catalyst versions before 5.71001 - in 5.71001
692 attributes work as expected, and the BUILD method is called normally
693 (although BUILDARGS is not).
695 If you depend on Catalyst 5.8, then B<all> Moose features work as expected.
697 You will also see this issue if you do the following:
699 package TestApp::Controller::Example;
701 use base 'Catalyst::Controller';
703 as C< use base > appends to @ISA.
705 =head3 use Moose in MyApp
707 Similar to the above, this will also fail:
716 If you need to use Moose in your application class (e.g. for method modifiers
717 etc.) then the correct technique is:
725 __PACKAGE__->config( name => 'MyApp' );
726 __PACKAGE__->setup(qw/
730 =head2 Anonymous closures installed directly into the symbol table
732 If you have any code which installs anonymous subroutine references directly
733 into the symbol table, you may encounter breakages. The simplest solution is
734 to use L<Sub::Name> to name the subroutine. Example:
736 # Original code, likely to break:
737 my $full_method_name = join('::', $package_name, $method_name);
738 *$full_method_name = sub { ... };
741 use Sub::Name 'subname';
742 my $full_method_name = join('::',$package_name, $method_name);
743 *$full_method_name = subname $full_method_name, sub { ... };
745 Additionally, you can take advantage of Catalyst's use of L<Class::MOP> and
746 install the closure using the appropriate metaclass. Example:
749 my $metaclass = Moose::Meta::Class->initialize($package_name);
750 $metaclass->add_method($method_name => sub { ... });
752 =head2 Hooking into application setup
754 To execute code during application start-up, the following snippet in MyApp.pm
758 my ($class, @args) = @_;
759 $class->NEXT::setup(@args);
760 ... # things to do after the actual setup
763 With Catalyst 5.80 this won't work anymore, because Catalyst no longer
764 uses NEXT.pm for method resolution. The functionality was only ever
765 originally operational as L<NEXT> remembers what methods have already
766 been called, and will not call them again.
768 Using this now causes infinite recursion between MyApp::setup and
769 Catalyst::setup, due to other backwards compatibility issues related to how
770 plugin setup works. Moose method modifiers like C<< before|after|around setup
771 => sub { ... }; >> also will not operate correctly on the setup method.
773 The right way to do it is this:
775 after setup_finalize => sub {
776 ... # things to do after the actual setup
779 The setup_finalize hook was introduced as a way to avoid this issue.
781 =head2 Components with a new method which returns false
783 Previously, if you had a component which inherited from Catalyst::COMPONENT,
784 but overrode the new method to return false, then your class's configuration
785 would be blessed into a hash on your behalf, and this would be returned from
786 the COMPONENT method.
788 This behavior makes no sense, and so has been removed. Implementing your own
789 C< new > method in components is B<highly> discouraged. Instead, you should
790 inherit the new method from Catalyst::Component, and use Moose's BUILD
791 functionality and/or Moose attributes to perform any construction work
792 necessary for your class.
794 =head2 __PACKAGE__->mk_accessor('meta');
796 Won't work due to a limitation of L<Moose>. This is currently being fixed
799 =head2 Class::Data::Inheritable side effects
801 Previously, writing to a class data accessor would copy the accessor method
802 down into your package.
804 This behavior has been removed. While the class data is still stored
805 per-class, it is stored on the metaclass of the class defining the accessor.
807 Therefore anything relying on the side effect of the accessor being copied down
810 The following test demonstrates the problem:
814 use base qw/Class::Data::Inheritable/;
815 __PACKAGE__->mk_classdata('foo');
820 use base qw/BaseClass/;
823 BaseClass->foo('base class');
824 Child->foo('sub class');
827 isnt(BaseClass->can('foo'), Child->can('foo'));
829 =head2 Extending Catalyst::Request or other classes in an ad hoc manner using mk_accessors
831 Previously, it was possible to add additional accessors to Catalyst::Request
832 (or other classes) by calling the mk_accessors class method.
834 This is no longer supported - users should make a subclass of the class whose
835 behavior they would like to change, rather than globally polluting the
838 =head2 Confused multiple inheritance with Catalyst::Component::COMPONENT
840 Previously, Catalyst's COMPONENT method would delegate to the method on
841 the right hand side, which could then delegate back again with
842 NEXT. This is poor practice, and in addition, makes no sense with C3
843 method dispatch order, and is therefore no longer supported.
845 If a COMPONENT method is detected in the inheritance hierarchy to the right
846 hand side of Catalyst::Component::COMPONENT, then the following warning
847 message will be emitted:
849 There is a COMPONENT method resolving after Catalyst::Component
852 The correct fix is to re-arrange your class's inheritance hierarchy so that the
853 COMPONENT method you would like to inherit is the first (left-hand most)
854 COMPONENT method in your @ISA.
856 =head2 Development server relying on environment variables
858 Previously, the development server would allow propagation of system
859 environment variables into the request environment, this has changed with the
860 adoption of Plack. You can use L<Plack::Middleware::ForceEnv> to achieve the
865 =head2 Actions in your application class
867 Having actions in your application class will now emit a warning at application
868 startup as this is deprecated. It is highly recommended that these actions are moved
869 into a MyApp::Controller::Root (as demonstrated by the scaffold application
870 generated by catalyst.pl).
872 This warning, also affects tests. You should move actions in your test,
873 creating a myTest::Controller::Root, like the following example:
875 package MyTest::Controller::Root;
880 use parent 'Catalyst::Controller';
882 __PACKAGE__->config(namespace => '');
885 my ( $self, $c ) = @_;
891 =head2 ::[MVC]:: naming scheme
893 Having packages called MyApp::[MVC]::XX is deprecated and can no longer be generated
896 This is still supported, but it is recommended that you rename your application
897 components to Model/View/Controller.
899 A warning will be issued at application startup if the ::[MVC]:: naming scheme is
902 =head2 Catalyst::Base
904 Any code using L<Catalyst::Base> will now emit a warning; this
905 module will be removed in a future release.
907 =head2 Methods in Catalyst::Dispatcher
909 The following methods in Catalyst::Dispatcher are implementation
910 details, which may change in the 5.8X release series, and therefore their use
911 is highly deprecated.
919 =item registered_dispatch_types
921 =item method_action_class
929 The first time one of these methods is called, a warning will be emitted:
931 Class $class is calling the deprecated method Catalyst::Dispatcher::$public_method_name,
932 this will be removed in Catalyst 5.9
934 You should B<NEVER> be calling any of these methods from application code.
936 Plugin authors and maintainers whose plugins currently call these methods
937 should change to using the public API, or, if you do not feel the public API
938 adequately supports your use case, please email the development list to
939 discuss what API features you need so that you can be appropriately supported.
941 =head2 Class files with names that don't correspond to the packages they define
943 In this version of Catalyst, if a component is loaded from disk, but no
944 symbols are defined in that component's name space after it is loaded, this
945 warning will be issued:
947 require $class was successful but the package is not defined.
949 This is to protect against confusing bugs caused by mistyping package names,
950 and will become a fatal error in a future version.
952 Please note that 'inner packages' (via L<Devel::InnerPackage>) are still fully
953 supported; this warning is only issued when component file naming does not map
954 to B<any> of the packages defined within that component.
956 =head2 $c->plugin method
958 Calling the plugin method is deprecated, and calling it at run time is B<highly
961 Instead you are recommended to use L<Catalyst::Model::Adaptor> or similar to
962 compose the functionality you need outside of the main application name space.
964 Calling the plugin method will not be supported past Catalyst 5.81.