3 Catalyst::Upgrading - Instructions for upgrading to the latest Catalyst
5 =head1 Upgrading to Catalyst 5.90060
7 Starting in the v5.90059_001 development release, the regexp dispatch type is
8 no longer automatically included as a dependency. If you are still using this
9 dispatch type, you need to add L<Catalyst::DispatchType::Regex> into your build
12 The standalone distribution of Regexp will be supported for the time being, but
13 should we find that supporting it prevents us from moving L<Catalyst> forward
14 in necessary ways, we reserve the right to drop that support. It is highly
15 recommended that you use this last stage of deprecation to change your code.
17 =head1 Upgrading to Catalyst 5.90040
19 =head2 Catalyst::Plugin::Unicode::Encoding is now core
21 The previously stand alone Unicode support module L<Catalyst::Plugin::Unicode::Encoding>
22 has been brought into core as a default plugin. Going forward, all you need is
23 to add a configuration setting for the encoding type. For example:
29 __PACKAGE__->config( encoding => 'UTF-8' );
31 Please note that this is different from the old stand alone plugin which applied
32 C<UTF-8> encoding by default (that is, if you did not set an explicit
33 C<encoding> configuration value, it assumed you wanted UTF-8). In order to
34 preserve backwards compatibility you will need to explicitly turn it on via the
35 configuration setting. THIS MIGHT CHANGE IN THE FUTURE, so please consider
36 starting to test your application with proper UTF-8 support and remove all those
37 crappy hacks you munged into the code because you didn't know the Plugin
40 For people that are using the Plugin, you will note a startup warning suggesting
41 that you can remove it from the plugin list. When you do so, please remember to
42 add the configuration setting, since you can no longer rely on the default being
43 UTF-8. We'll add it for you if you continue to use the stand alone plugin and
44 we detect this, but this backwards compatibility shim will likely be removed in
45 a few releases (trying to clean up the codebase after all).
47 If you have trouble with any of this, please bring it to the attention of the
48 Catalyst maintainer group.
50 =head2 basic async and event loop support
52 This version of L<Catalyst> offers some support for using L<AnyEvent> and
53 L<IO::Async> event loops in your application. These changes should work
54 fine for most applications however if you are already trying to perform
55 some streaming, minor changes in this area of the code might affect your
56 functionality. Please see L<Catalyst::Response\write_fh> for more and for a
59 We consider this feature experimental. We will try not to break it, but we
60 reserve the right to make necessary changes to fix major issues that people
61 run into when the use this functionality in the wild.
63 =head1 Upgrading to Catalyst 5.90030
65 =head2 Regex dispatch type is deprecated.
67 The Regex dispatchtype (L<Catalyst::DispatchType::Regex>) has been deprecated.
69 You are encouraged to move your application to Chained dispatch (L<Catalyst::DispatchType::Chained>).
71 If you cannot do so, please add a dependency to Catalyst::DispatchType::Regex to your application's
74 =head1 Upgrading to Catalyst 5.9
76 The major change is that L<Plack>, a toolkit for using the L<PSGI>
77 specification, now replaces most of the subclasses of L<Catalyst::Engine>. If
78 you are using one of the standard subclasses of L<Catalyst::Engine> this
79 should be a straightforward upgrade for you. It was a design goal for
80 this release to preserve as much backwards compatibility as possible.
81 However, since L<Plack> is different from L<Catalyst::Engine>, it is
82 possible that differences exist for edge cases. Therefore, we recommend
83 that care be taken with this upgrade and that testing should be greater
84 than would be the case with a minor point update. Please inform the
85 Catalyst developers of any problems so that we can fix them and
88 It is highly recommended that you become familiar with the L<Plack> ecosystem
89 and documentation. Being able to take advantage of L<Plack> development and
90 middleware is a major bonus to this upgrade. Documentation about how to
91 take advantage of L<Plack::Middleware> by writing your own C<< .psgi >> file
92 is contained in L<Catalyst::PSGI>.
94 If you have created a custom subclass of L<Catalyst:Engine>, you will
95 need to convert it to be a subclass of L<Plack::Handler>.
97 If you are using the L<Plack> engine, L<Catalyst::Engine::PSGI>, this new
98 release supersedes that code.
100 If you are using a subclass of L<Catalyst::Engine> that is aimed at
101 nonstandard or internal/testing uses, such as
102 L<Catalyst::Engine::Embeddable>, you should still be able to continue
105 Advice for specific subclasses of L<Catalyst::Engine> follows:
107 =head2 Upgrading the FastCGI Engine
109 No upgrade is needed if your myapp_fastcgi.pl script is already upgraded
110 to use L<Catalyst::Script::FastCGI>.
112 =head2 Upgrading the mod_perl / Apache Engines
114 The engines that are built upon the various iterations of mod_perl,
115 L<Catalyst::Engine::Apache::MP13> (for mod_perl 1, and Apache 1.x) and
116 L<Catalyst::Engine::Apache2::MP20> (for mod_perl 2, and Apache 2.x),
117 should be seamless upgrades and will work using L<Plack::Handler::Apache1>
118 or L<Plack::Handler::Apache2> as required.
120 L<Catalyst::Engine::Apache2::MP19>, however, is no longer supported, as
121 Plack does not support mod_perl version 1.99. This is unlikely to be a
122 problem for anyone, as 1.99 was a brief beta-test release for mod_perl
123 2, and all users of mod_perl 1.99 are encouraged to upgrade to a
124 supported release of Apache 2 and mod_perl 2.
126 =head2 Upgrading the HTTP Engine
128 The default development server that comes with the L<Catalyst> distribution
129 should continue to work as expected with no changes as long as your C<myapp_server>
130 script is upgraded to use L<Catalyst::Script::HTTP>.
132 =head2 Upgrading the CGI Engine
134 If you were using L<Catalyst::Engine::CGI> there is no upgrade needed if your
135 myapp_cgi.pl script is already upgraded to use L<Catalyst::Script::CGI>.
137 =head2 Upgrading Catalyst::Engine::HTTP::Prefork
139 If you were using L<Catalyst::Engine::HTTP::Prefork> then L<Starman>
140 is automatically loaded. You should (at least) change your C<Makefile.PL>
141 to depend on Starman.
143 You can regenerate your C<myapp_server.pl> script with C<catalyst.pl>
144 and implement a C<MyApp::Script::Server> class that looks like this:
146 package MyApp::Script::Server;
148 use namespace::autoclean;
150 extends 'CatalystX::Script::Server::Starman';
154 This takes advantage of the new script system, and will add a number of
155 options to the standard server script as extra options are added by
158 More information about these options can be seen at
159 L<CatalystX::Script::Server::Starman/SYNOPSIS>.
161 An alternate route to implement this functionality is to write a simple .psgi
162 file for your application, and then use the L<plackup> utility to start the
165 =head2 Upgrading the PSGI Engine
167 If you were using L<Catalyst::Engine::PSGI>, this new release supersedes
168 this engine in supporting L<Plack>. By default the Engine is now always
169 L<Plack>. As a result, you can remove the dependency on
170 L<Catalyst::Engine::PSGI> in your C<Makefile.PL>.
172 Applications that were using L<Catalyst::Engine::PSGI>
173 previously should entirely continue to work in this release with no changes.
175 However, if you have an C<app.psgi> script, then you no longer need to
176 specify the PSGI engine. Instead, the L<Catalyst> application class now
177 has a new method C<psgi_app> which returns a L<PSGI> compatible coderef
178 which you can wrap in the middleware of your choice.
180 Catalyst will use the .psgi for your application if it is located in the C<home>
181 directory of the application.
183 For example, if you were using L<Catalyst::Engine::PSGI> in the past, you will
184 have written (or generated) a C<script/myapp.psgi> file similar to this one:
189 MyCatalystApp->setup_engine('PSGI');
192 enable ... # enable your desired middleware
193 sub { MyCatalystApp->run(@_) };
196 Instead, you now say:
202 enable ... #enable your desired middleware
203 MyCatalystApp->psgi_app;
206 In the simplest case:
208 MyCatalystApp->setup_engine('PSGI');
209 my $app = sub { MyCatalystApp->run(@_) }
213 my $app = MyCatalystApp->psgi_app(@_);
217 my $app = sub { MyCatalystApp->psgi_app(@_) };
218 # If you make ^^ this mistake, your app won't work, and will confuse the hell out of you!
220 You can now move C<< script/myapp.psgi >> to C<< myapp.psgi >>, and the built-in
221 Catalyst scripts and your test suite will start using your .psgi file.
223 B<NOTE:> If you rename your .psgi file without these modifications, then
224 any tests run via L<Catalyst::Test> will not be compatible with the new
225 release, and will result in the development server starting, rather than
226 the expected test running.
228 B<NOTE:> If you are directly accessing C<< $c->req->env >> to get the PSGI
229 environment then this accessor is moved to C<< $c->engine->env >>,
230 you will need to update your code.
232 =head2 Engines which are known to be broken
234 The following engines B<DO NOT> work as of Catalyst version 5.9. The
235 core team will be happy to work with the developers and/or users of
236 these engines to help them port to the new Plack/Engine system, but for
237 now, applications which are currently using these engines B<WILL NOT>
238 run without modification to the engine code.
242 =item Catalyst::Engine::Wx
244 =item Catalyst::Engine::Zeus
246 =item Catalyst::Engine::JobQueue::POE
248 =item Catalyst::Engine::XMPP2
250 =item Catalyst::Engine::SCGI
254 =head2 Engines with unknown status
256 The following engines are untested or have unknown compatibility.
257 Reports are highly encouraged:
261 =item Catalyst::Engine::Mojo
263 =item Catalyst::Engine::Server (marked as Deprecated)
265 =item Catalyst::Engine::HTTP::POE (marked as Deprecated)
269 =head2 Plack functionality
271 See L<Catalyst::PSGI>.
275 Tests should generally work the same in Catalyst 5.9, but there are
278 Previously, if using L<Catalyst::Test> and doing local requests (against
279 a local server), if the application threw an exception then this
280 exception propagated into the test.
282 This behavior has been removed, and now a 500 response will be returned
283 to the test. This change standardizes behavior, so that local test
284 requests behave similarly to remote requests.
286 =head1 Upgrading to Catalyst 5.80
288 Most applications and plugins should run unaltered on Catalyst 5.80.
290 However, a lot of refactoring work has taken place, and several changes have
291 been made which could cause incompatibilities. If your application or plugin
292 is using deprecated code, or relying on side effects, then you could have
293 issues upgrading to this release.
295 Most issues found with existing components have been easy to
296 solve. This document provides a complete description of behavior changes
297 which may cause compatibility issues, and of new Catalyst warnings which
300 If you think you have found an upgrade-related issue which is not covered in
301 this document, please email the Catalyst list to discuss the problem.
303 =head1 Moose features
305 =head2 Application class roles
307 You can only apply method modifiers after the application's C<< ->setup >>
308 method has been called. This means that modifiers will not work with methods
309 run during the call to C<< ->setup >>.
311 See L<Catalyst::Manual::ExtendingCatalyst> for more information about using
312 L<Moose> in your applications.
314 =head2 Controller actions in Moose roles
316 You can use L<MooseX::MethodAttributes::Role> if you want to declare actions
319 =head2 Using Moose in Components
321 The correct way to use Moose in a component in a both forward and backwards
324 package TestApp::Controller::Root;
326 BEGIN { extends 'Catalyst::Component' }; # Or ::Controller, or whatever
328 See L<Components which inherit from Moose::Object before Catalyst::Component>.
330 =head1 Known backwards compatibility breakages
332 =head2 Applications in a single file
334 Applications must be in their own file, and loaded at compile time. This
335 issue generally only affects the tests of CPAN distributions. Your
336 application will fail if you try to define an application inline in a
337 block, and use plugins which supply a C< new > method, then use that
338 application latter in tests within the same file.
340 This is due to the fact that Catalyst is inlining a new method on your
341 application class allowing it to be compatible with Moose. The method
342 used to do this changed in 5.80004 to avoid the possibility of reporting
343 an 'Unknown Error' if your application failed to compile.
345 =head2 Issues with Class::C3
347 Catalyst 5.80 uses the L<Algorithm::C3> method dispatch order. This is
348 built into Perl 5.10, and comes via L<Class::C3> for Perl 5.8. This
349 replaces L<NEXT> with L<Class::C3::Adopt::NEXT>, forcing all components
350 to resolve methods using C3, rather than the unpredictable dispatch
353 This issue manifests itself by your application failing to start due to an
354 error message about having a non-linear @ISA.
356 The Catalyst plugin most often causing this is
357 L<Catalyst::Plugin::Session::Store::FastMmap> - if you are using this
358 plugin and see issues, then please upgrade your plugins, as it has been
359 fixed. Note that Makefile.PL in the distribution will warn about known
360 incompatible components.
362 This issue can, however, be found in your own application - the only solution is
363 to go through each base class of the class the error was reported against, until
364 you identify the ones in conflict, and resolve them.
366 To be able to generate a linear @ISA, the list of superclasses for each
367 class must be resolvable using the C3 algorithm. Unfortunately, when
368 superclasses are being used as mixins (to add functionality used in your class),
369 and with multiple inheritance, it is easy to get this wrong.
371 Most common is the case of:
373 package Component1; # Note, this is the common case
374 use base qw/Class::Accessor::Fast Class::Data::Inheritable/;
376 package Component2; # Accidentally saying it this way causes a failure
377 use base qw/Class::Data::Inheritable Class::Accessor::Fast/;
380 use base qw/Component1 Component2/;
382 Any situation like this will cause your application to fail to start.
384 For additional documentation about this issue, and how to resolve it, see
385 L<Class::C3::Adopt::NEXT>.
387 =head2 Components which inherit from Moose::Object before Catalyst::Component
389 Moose components which say:
391 package TestApp::Controller::Example;
393 extends qw/Moose::Object Catalyst::Component/;
395 to use the constructor provided by Moose, while working (if you do some hacks
396 with the C< BUILDARGS > method), will not work with Catalyst 5.80 as
397 C<Catalyst::Component> inherits from C<Moose::Object>, and so C< @ISA > fails
400 The correct way to use Moose in a component in a both forward and backwards
403 package TestApp::Controller::Root;
405 BEGIN { extends 'Catalyst::Component' }; # Or ::Controller, or whatever
407 Note that the C< extends > declaration needs to occur in a begin block for
408 L<attributes> to operate correctly.
410 This way you do not inherit directly from C<Moose::Object>
411 yourself. Having components which do not inherit their constructor from
412 C<Catalyst::Component> is B<unsupported>, and has never been recommended,
413 therefore you're on your own if you're using this technique. You'll need
414 to detect the version of Catalyst your application is running, and deal
415 with it appropriately.
417 You also don't get the L<Moose::Object> constructor, and therefore attribute
418 initialization will not work as normally expected. If you want to use Moose
419 attributes, then they need to be made lazy to correctly initialize.
421 Note that this only applies if your component needs to maintain component
422 backwards compatibility for Catalyst versions before 5.71001 - in 5.71001
423 attributes work as expected, and the BUILD method is called normally
424 (although BUILDARGS is not).
426 If you depend on Catalyst 5.8, then B<all> Moose features work as expected.
428 You will also see this issue if you do the following:
430 package TestApp::Controller::Example;
432 use base 'Catalyst::Controller';
434 as C< use base > appends to @ISA.
436 =head3 use Moose in MyApp
438 Similar to the above, this will also fail:
447 If you need to use Moose in your application class (e.g. for method modifiers
448 etc.) then the correct technique is:
456 __PACKAGE__->config( name => 'MyApp' );
457 __PACKAGE__->setup(qw/
461 =head2 Anonymous closures installed directly into the symbol table
463 If you have any code which installs anonymous subroutine references directly
464 into the symbol table, you may encounter breakages. The simplest solution is
465 to use L<Sub::Name> to name the subroutine. Example:
467 # Original code, likely to break:
468 my $full_method_name = join('::', $package_name, $method_name);
469 *$full_method_name = sub { ... };
472 use Sub::Name 'subname';
473 my $full_method_name = join('::',$package_name, $method_name);
474 *$full_method_name = subname $full_method_name, sub { ... };
476 Additionally, you can take advantage of Catalyst's use of L<Class::MOP> and
477 install the closure using the appropriate metaclass. Example:
480 my $metaclass = Moose::Meta::Class->initialize($package_name);
481 $metaclass->add_method($method_name => sub { ... });
483 =head2 Hooking into application setup
485 To execute code during application start-up, the following snippet in MyApp.pm
489 my ($class, @args) = @_;
490 $class->NEXT::setup(@args);
491 ... # things to do after the actual setup
494 With Catalyst 5.80 this won't work anymore, because Catalyst no longer
495 uses NEXT.pm for method resolution. The functionality was only ever
496 originally operational as L<NEXT> remembers what methods have already
497 been called, and will not call them again.
499 Using this now causes infinite recursion between MyApp::setup and
500 Catalyst::setup, due to other backwards compatibility issues related to how
501 plugin setup works. Moose method modifiers like C<< before|after|around setup
502 => sub { ... }; >> also will not operate correctly on the setup method.
504 The right way to do it is this:
506 after setup_finalize => sub {
507 ... # things to do after the actual setup
510 The setup_finalize hook was introduced as a way to avoid this issue.
512 =head2 Components with a new method which returns false
514 Previously, if you had a component which inherited from Catalyst::COMPONENT,
515 but overrode the new method to return false, then your class's configuration
516 would be blessed into a hash on your behalf, and this would be returned from
517 the COMPONENT method.
519 This behavior makes no sense, and so has been removed. Implementing your own
520 C< new > method in components is B<highly> discouraged. Instead, you should
521 inherit the new method from Catalyst::Component, and use Moose's BUILD
522 functionality and/or Moose attributes to perform any construction work
523 necessary for your class.
525 =head2 __PACKAGE__->mk_accessor('meta');
527 Won't work due to a limitation of L<Moose>. This is currently being fixed
530 =head2 Class::Data::Inheritable side effects
532 Previously, writing to a class data accessor would copy the accessor method
533 down into your package.
535 This behavior has been removed. While the class data is still stored
536 per-class, it is stored on the metaclass of the class defining the accessor.
538 Therefore anything relying on the side effect of the accessor being copied down
541 The following test demonstrates the problem:
545 use base qw/Class::Data::Inheritable/;
546 __PACKAGE__->mk_classdata('foo');
551 use base qw/BaseClass/;
554 BaseClass->foo('base class');
555 Child->foo('sub class');
558 isnt(BaseClass->can('foo'), Child->can('foo'));
560 =head2 Extending Catalyst::Request or other classes in an ad hoc manner using mk_accessors
562 Previously, it was possible to add additional accessors to Catalyst::Request
563 (or other classes) by calling the mk_accessors class method.
565 This is no longer supported - users should make a subclass of the class whose
566 behavior they would like to change, rather than globally polluting the
569 =head2 Confused multiple inheritance with Catalyst::Component::COMPONENT
571 Previously, Catalyst's COMPONENT method would delegate to the method on
572 the right hand side, which could then delegate back again with
573 NEXT. This is poor practice, and in addition, makes no sense with C3
574 method dispatch order, and is therefore no longer supported.
576 If a COMPONENT method is detected in the inheritance hierarchy to the right
577 hand side of Catalyst::Component::COMPONENT, then the following warning
578 message will be emitted:
580 There is a COMPONENT method resolving after Catalyst::Component
583 The correct fix is to re-arrange your class's inheritance hierarchy so that the
584 COMPONENT method you would like to inherit is the first (left-hand most)
585 COMPONENT method in your @ISA.
587 =head2 Development server relying on environment variables
589 Previously, the development server would allow propagation of system
590 environment variables into the request environment, this has changed with the
591 adoption of Plack. You can use L<Plack::Middleware::ForceEnv> to achieve the
596 =head2 Actions in your application class
598 Having actions in your application class will now emit a warning at application
599 startup as this is deprecated. It is highly recommended that these actions are moved
600 into a MyApp::Controller::Root (as demonstrated by the scaffold application
601 generated by catalyst.pl).
603 This warning, also affects tests. You should move actions in your test,
604 creating a myTest::Controller::Root, like the following example:
606 package MyTest::Controller::Root;
611 use parent 'Catalyst::Controller';
613 __PACKAGE__->config(namespace => '');
616 my ( $self, $c ) = @_;
622 =head2 ::[MVC]:: naming scheme
624 Having packages called MyApp::[MVC]::XX is deprecated and can no longer be generated
627 This is still supported, but it is recommended that you rename your application
628 components to Model/View/Controller.
630 A warning will be issued at application startup if the ::[MVC]:: naming scheme is
633 =head2 Catalyst::Base
635 Any code using L<Catalyst::Base> will now emit a warning; this
636 module will be removed in a future release.
638 =head2 Methods in Catalyst::Dispatcher
640 The following methods in Catalyst::Dispatcher are implementation
641 details, which may change in the 5.8X release series, and therefore their use
642 is highly deprecated.
650 =item registered_dispatch_types
652 =item method_action_class
660 The first time one of these methods is called, a warning will be emitted:
662 Class $class is calling the deprecated method Catalyst::Dispatcher::$public_method_name,
663 this will be removed in Catalyst 5.9
665 You should B<NEVER> be calling any of these methods from application code.
667 Plugin authors and maintainers whose plugins currently call these methods
668 should change to using the public API, or, if you do not feel the public API
669 adequately supports your use case, please email the development list to
670 discuss what API features you need so that you can be appropriately supported.
672 =head2 Class files with names that don't correspond to the packages they define
674 In this version of Catalyst, if a component is loaded from disk, but no
675 symbols are defined in that component's name space after it is loaded, this
676 warning will be issued:
678 require $class was successful but the package is not defined.
680 This is to protect against confusing bugs caused by mistyping package names,
681 and will become a fatal error in a future version.
683 Please note that 'inner packages' (via L<Devel::InnerPackage>) are still fully
684 supported; this warning is only issued when component file naming does not map
685 to B<any> of the packages defined within that component.
687 =head2 $c->plugin method
689 Calling the plugin method is deprecated, and calling it at run time is B<highly
692 Instead you are recommended to use L<Catalyst::Model::Adaptor> or similar to
693 compose the functionality you need outside of the main application name space.
695 Calling the plugin method will not be supported past Catalyst 5.81.