3 Catalyst::Upgrading - Instructions for upgrading to the latest Catalyst
5 =head1 Upgrading to Catalyst 5.90040
7 =head2 Catalyst::Plugin::Unicode::Encoding is now core
9 The previously stand alone Unicode support module L<Catalyst::Plugin::Unicode::Encoding>
10 has been brought into core as a default plugin. Going forward, all you need is
11 to add a configuration setting for the encoding type. For example:
17 __PACKAGE__->config( encoding => 'UTF-8' );
19 Please note that this is different from the old stand alone plugin which applied
20 C<UTF-8> encoding by default (that is, if you did not set an explicit
21 C<encoding> configuration value, it assumed you wanted UTF-8). In order to
22 preserve backwards compatibility you will need to explicitly turn it on via the
23 configuration setting. THIS MIGHT CHANGE IN THE FUTURE, so please consider
24 starting to test your application with proper UTF-8 support and remove all those
25 crappy hacks you munged into the code because you didn't know the Plugin
28 For people that are using the Plugin, you will note a startup warning suggesting
29 that you can remove it from the plugin list. When you do so, please remember to
30 add the configuration setting, since you can no longer rely on the default being
31 UTF-8. We'll add it for you if you continue to use the stand alone plugin and
32 we detect this, but this backwards compatibility shim will likely be removed in
33 a few releases (trying to clean up the codebase after all).
35 If you have trouble with any of this, please bring it to the attention of the
36 Catalyst maintainer group.
38 =head2 basic async and event loop support
40 This version of L<Catalyst> offers some support for using L<AnyEvent> and
41 L<IO::Async> event loops in your application. These changes should work
42 fine for most applications however if you are already trying to perform
43 some streaming, minor changes in this area of the code might affect your
44 functionality. Please see L<Catalyst::Response\write_fh> for more and for a
47 We consider this feature experimental. We will try not to break it, but we
48 reserve the right to make necessary changes to fix major issues that people
49 run into when the use this functionality in the wild.
51 =head1 Upgrading to Catalyst 5.90030
53 =head2 Regex dispatch type is deprecated.
55 The Regex dispatchtype (L<Catalyst::DispatchType::Regex>) has been deprecated.
57 You are encouraged to move your application to Chained dispatch (L<Catalyst::DispatchType::Chained>).
59 If you cannot do so, please add a dependency to Catalyst::DispatchType::Regex to your application's
62 =head1 Upgrading to Catalyst 5.9
64 The major change is that L<Plack>, a toolkit for using the L<PSGI>
65 specification, now replaces most of the subclasses of L<Catalyst::Engine>. If
66 you are using one of the standard subclasses of L<Catalyst::Engine> this
67 should be a straightforward upgrade for you. It was a design goal for
68 this release to preserve as much backwards compatibility as possible.
69 However, since L<Plack> is different from L<Catalyst::Engine>, it is
70 possible that differences exist for edge cases. Therefore, we recommend
71 that care be taken with this upgrade and that testing should be greater
72 than would be the case with a minor point update. Please inform the
73 Catalyst developers of any problems so that we can fix them and
76 It is highly recommended that you become familiar with the L<Plack> ecosystem
77 and documentation. Being able to take advantage of L<Plack> development and
78 middleware is a major bonus to this upgrade. Documentation about how to
79 take advantage of L<Plack::Middleware> by writing your own C<< .psgi >> file
80 is contained in L<Catalyst::PSGI>.
82 If you have created a custom subclass of L<Catalyst:Engine>, you will
83 need to convert it to be a subclass of L<Plack::Handler>.
85 If you are using the L<Plack> engine, L<Catalyst::Engine::PSGI>, this new
86 release supersedes that code.
88 If you are using a subclass of L<Catalyst::Engine> that is aimed at
89 nonstandard or internal/testing uses, such as
90 L<Catalyst::Engine::Embeddable>, you should still be able to continue
93 Advice for specific subclasses of L<Catalyst::Engine> follows:
95 =head2 Upgrading the FastCGI Engine
97 No upgrade is needed if your myapp_fastcgi.pl script is already upgraded
98 to use L<Catalyst::Script::FastCGI>.
100 =head2 Upgrading the mod_perl / Apache Engines
102 The engines that are built upon the various iterations of mod_perl,
103 L<Catalyst::Engine::Apache::MP13> (for mod_perl 1, and Apache 1.x) and
104 L<Catalyst::Engine::Apache2::MP20> (for mod_perl 2, and Apache 2.x),
105 should be seamless upgrades and will work using using L<Plack::Handler::Apache1>
106 or L<Plack::Handler::Apache2> as required.
108 L<Catalyst::Engine::Apache2::MP19>, however, is no longer supported, as
109 Plack does not support mod_perl version 1.99. This is unlikely to be a
110 problem for anyone, as 1.99 was a brief beta-test release for mod_perl
111 2, and all users of mod_perl 1.99 are encouraged to upgrade to a
112 supported release of Apache 2 and mod_perl 2.
114 =head2 Upgrading the HTTP Engine
116 The default development server that comes with the L<Catalyst> distribution
117 should continue to work as expected with no changes as long as your C<myapp_server>
118 script is upgraded to use L<Catalyst::Script::HTTP>.
120 =head2 Upgrading the CGI Engine
122 If you were using L<Catalyst::Engine::CGI> there is no upgrade needed if your
123 myapp_cgi.pl script is already upgraded to use L<Catalyst::Script::CGI>.
125 =head2 Upgrading Catalyst::Engine::HTTP::Prefork
127 If you were using L<Catalyst::Engine::HTTP::Prefork> then L<Starman>
128 is automatically loaded. You should (at least) change your C<Makefile.PL>
129 to depend on Starman.
131 You can regenerate your C<myapp_server.pl> script with C<catalyst.pl>
132 and implement a C<MyApp::Script::Server> class that looks like this:
134 package MyApp::Script::Server;
136 use namespace::autoclean;
138 extends 'CatalystX::Script::Server::Starman';
142 This takes advantage of the new script system, and will add a number of
143 options to the standard server script as extra options are added by
146 More information about these options can be seen at
147 L<CatalystX::Script::Server::Starman/SYNOPSIS>.
149 An alternate route to implement this functionality is to write a simple .psgi
150 file for your application, and then use the L<plackup> utility to start the
153 =head2 Upgrading the PSGI Engine
155 If you were using L<Catalyst::Engine::PSGI>, this new release supersedes
156 this engine in supporting L<Plack>. By default the Engine is now always
157 L<Plack>. As a result, you can remove the dependency on
158 L<Catalyst::Engine::PSGI> in your C<Makefile.PL>.
160 Applications that were using L<Catalyst::Engine::PSGI>
161 previously should entirely continue to work in this release with no changes.
163 However, if you have an C<app.psgi> script, then you no longer need to
164 specify the PSGI engine. Instead, the L<Catalyst> application class now
165 has a new method C<psgi_app> which returns a L<PSGI> compatible coderef
166 which you can wrap in the middleware of your choice.
168 Catalyst will use the .psgi for your application if it is located in the C<home>
169 directory of the application.
171 For example, if you were using L<Catalyst::Engine::PSGI> in the past, you will
172 have written (or generated) a C<script/myapp.psgi> file similar to this one:
177 MyCatalystApp->setup_engine('PSGI');
180 enable ... # enable your desired middleware
181 sub { MyCatalystApp->run(@_) };
184 Instead, you now say:
190 enable ... #enable your desired middleware
191 MyCatalystApp->psgi_app;
194 In the simplest case:
196 MyCatalystApp->setup_engine('PSGI');
197 my $app = sub { MyCatalystApp->run(@_) }
201 my $app = MyCatalystApp->psgi_app(@_);
205 my $app = sub { MyCatalystApp->psgi_app(@_) };
206 # If you make ^^ this mistake, your app won't work, and will confuse the hell out of you!
208 You can now move C<< script/myapp.psgi >> to C<< myapp.psgi >>, and the built-in
209 Catalyst scripts and your test suite will start using your .psgi file.
211 B<NOTE:> If you rename your .psgi file without these modifications, then
212 any tests run via L<Catalyst::Test> will not be compatible with the new
213 release, and will result in the development server starting, rather than
214 the expected test running.
216 B<NOTE:> If you are directly accessing C<< $c->req->env >> to get the PSGI
217 environment then this accessor is moved to C<< $c->engine->env >>,
218 you will need to update your code.
220 =head2 Engines which are known to be broken
222 The following engines B<DO NOT> work as of Catalyst version 5.9. The
223 core team will be happy to work with the developers and/or users of
224 these engines to help them port to the new Plack/Engine system, but for
225 now, applications which are currently using these engines B<WILL NOT>
226 run without modification to the engine code.
230 =item Catalyst::Engine::Wx
232 =item Catalyst::Engine::Zeus
234 =item Catalyst::Engine::JobQueue::POE
236 =item Catalyst::Engine::XMPP2
238 =item Catalyst::Engine::SCGI
242 =head2 Engines with unknown status
244 The following engines are untested or have unknown compatibility.
245 Reports are highly encouraged:
249 =item Catalyst::Engine::Mojo
251 =item Catalyst::Engine::Server (marked as Deprecated)
253 =item Catalyst::Engine::HTTP::POE (marked as Deprecated)
257 =head2 Plack functionality
259 See L<Catalyst::PSGI>.
263 Tests should generally work the same in Catalyst 5.9, but there are
266 Previously, if using L<Catalyst::Test> and doing local requests (against
267 a local server), if the application threw an exception then this
268 exception propagated into the test.
270 This behavior has been removed, and now a 500 response will be returned
271 to the test. This change standardizes behavior, so that local test
272 requests behave similarly to remote requests.
274 =head1 Upgrading to Catalyst 5.80
276 Most applications and plugins should run unaltered on Catalyst 5.80.
278 However, a lot of refactoring work has taken place, and several changes have
279 been made which could cause incompatibilities. If your application or plugin
280 is using deprecated code, or relying on side effects, then you could have
281 issues upgrading to this release.
283 Most issues found with existing components have been easy to
284 solve. This document provides a complete description of behavior changes
285 which may cause compatibility issues, and of new Catalyst warnings which
288 If you think you have found an upgrade-related issue which is not covered in
289 this document, please email the Catalyst list to discuss the problem.
291 =head1 Moose features
293 =head2 Application class roles
295 You can only apply method modifiers after the application's C<< ->setup >>
296 method has been called. This means that modifiers will not work with methods
297 run during the call to C<< ->setup >>.
299 See L<Catalyst::Manual::ExtendingCatalyst> for more information about using
300 L<Moose> in your applications.
302 =head2 Controller actions in Moose roles
304 You can use L<MooseX::MethodAttributes::Role> if you want to declare actions
307 =head2 Using Moose in Components
309 The correct way to use Moose in a component in a both forward and backwards
312 package TestApp::Controller::Root;
314 BEGIN { extends 'Catalyst::Component' }; # Or ::Controller, or whatever
316 See L<Components which inherit from Moose::Object before Catalyst::Component>.
318 =head1 Known backwards compatibility breakages
320 =head2 Applications in a single file
322 Applications must be in their own file, and loaded at compile time. This
323 issue generally only affects the tests of CPAN distributions. Your
324 application will fail if you try to define an application inline in a
325 block, and use plugins which supply a C< new > method, then use that
326 application latter in tests within the same file.
328 This is due to the fact that Catalyst is inlining a new method on your
329 application class allowing it to be compatible with Moose. The method
330 used to do this changed in 5.80004 to avoid the possibility of reporting
331 an 'Unknown Error' if your application failed to compile.
333 =head2 Issues with Class::C3
335 Catalyst 5.80 uses the L<Algorithm::C3> method dispatch order. This is
336 built into Perl 5.10, and comes via L<Class::C3> for Perl 5.8. This
337 replaces L<NEXT> with L<Class::C3::Adopt::NEXT>, forcing all components
338 to resolve methods using C3, rather than the unpredictable dispatch
341 This issue manifests itself by your application failing to start due to an
342 error message about having a non-linear @ISA.
344 The Catalyst plugin most often causing this is
345 L<Catalyst::Plugin::Session::Store::FastMmap> - if you are using this
346 plugin and see issues, then please upgrade your plugins, as it has been
347 fixed. Note that Makefile.PL in the distribution will warn about known
348 incompatible components.
350 This issue can, however, be found in your own application - the only solution is
351 to go through each base class of the class the error was reported against, until
352 you identify the ones in conflict, and resolve them.
354 To be able to generate a linear @ISA, the list of superclasses for each
355 class must be resolvable using the C3 algorithm. Unfortunately, when
356 superclasses are being used as mixins (to add functionality used in your class),
357 and with multiple inheritance, it is easy to get this wrong.
359 Most common is the case of:
361 package Component1; # Note, this is the common case
362 use base qw/Class::Accessor::Fast Class::Data::Inheritable/;
364 package Component2; # Accidentally saying it this way causes a failure
365 use base qw/Class::Data::Inheritable Class::Accessor::Fast/;
368 use base qw/Component1 Component2/;
370 Any situation like this will cause your application to fail to start.
372 For additional documentation about this issue, and how to resolve it, see
373 L<Class::C3::Adopt::NEXT>.
375 =head2 Components which inherit from Moose::Object before Catalyst::Component
377 Moose components which say:
379 package TestApp::Controller::Example;
381 extends qw/Moose::Object Catalyst::Component/;
383 to use the constructor provided by Moose, while working (if you do some hacks
384 with the C< BUILDARGS > method), will not work with Catalyst 5.80 as
385 C<Catalyst::Component> inherits from C<Moose::Object>, and so C< @ISA > fails
388 The correct way to use Moose in a component in a both forward and backwards
391 package TestApp::Controller::Root;
393 BEGIN { extends 'Catalyst::Component' }; # Or ::Controller, or whatever
395 Note that the C< extends > declaration needs to occur in a begin block for
396 L<attributes> to operate correctly.
398 This way you do not inherit directly from C<Moose::Object>
399 yourself. Having components which do not inherit their constructor from
400 C<Catalyst::Component> is B<unsupported>, and has never been recommended,
401 therefore you're on your own if you're using this technique. You'll need
402 to detect the version of Catalyst your application is running, and deal
403 with it appropriately.
405 You also don't get the L<Moose::Object> constructor, and therefore attribute
406 initialization will not work as normally expected. If you want to use Moose
407 attributes, then they need to be made lazy to correctly initialize.
409 Note that this only applies if your component needs to maintain component
410 backwards compatibility for Catalyst versions before 5.71001 - in 5.71001
411 attributes work as expected, and the BUILD method is called normally
412 (although BUILDARGS is not).
414 If you depend on Catalyst 5.8, then B<all> Moose features work as expected.
416 You will also see this issue if you do the following:
418 package TestApp::Controller::Example;
420 use base 'Catalyst::Controller';
422 as C< use base > appends to @ISA.
424 =head3 use Moose in MyApp
426 Similar to the above, this will also fail:
435 If you need to use Moose in your application class (e.g. for method modifiers
436 etc.) then the correct technique is:
444 __PACKAGE__->config( name => 'MyApp' );
445 __PACKAGE__->setup(qw/
449 =head2 Anonymous closures installed directly into the symbol table
451 If you have any code which installs anonymous subroutine references directly
452 into the symbol table, you may encounter breakages. The simplest solution is
453 to use L<Sub::Name> to name the subroutine. Example:
455 # Original code, likely to break:
456 my $full_method_name = join('::', $package_name, $method_name);
457 *$full_method_name = sub { ... };
460 use Sub::Name 'subname';
461 my $full_method_name = join('::',$package_name, $method_name);
462 *$full_method_name = subname $full_method_name, sub { ... };
464 Additionally, you can take advantage of Catalyst's use of L<Class::MOP> and
465 install the closure using the appropriate metaclass. Example:
468 my $metaclass = Moose::Meta::Class->initialize($package_name);
469 $metaclass->add_method($method_name => sub { ... });
471 =head2 Hooking into application setup
473 To execute code during application start-up, the following snippet in MyApp.pm
477 my ($class, @args) = @_;
478 $class->NEXT::setup(@args);
479 ... # things to do after the actual setup
482 With Catalyst 5.80 this won't work anymore, because Catalyst no longer
483 uses NEXT.pm for method resolution. The functionality was only ever
484 originally operational as L<NEXT> remembers what methods have already
485 been called, and will not call them again.
487 Using this now causes infinite recursion between MyApp::setup and
488 Catalyst::setup, due to other backwards compatibility issues related to how
489 plugin setup works. Moose method modifiers like C<< before|after|around setup
490 => sub { ... }; >> also will not operate correctly on the setup method.
492 The right way to do it is this:
494 after setup_finalize => sub {
495 ... # things to do after the actual setup
498 The setup_finalize hook was introduced as a way to avoid this issue.
500 =head2 Components with a new method which returns false
502 Previously, if you had a component which inherited from Catalyst::COMPONENT,
503 but overrode the new method to return false, then your class's configuration
504 would be blessed into a hash on your behalf, and this would be returned from
505 the COMPONENT method.
507 This behavior makes no sense, and so has been removed. Implementing your own
508 C< new > method in components is B<highly> discouraged. Instead, you should
509 inherit the new method from Catalyst::Component, and use Moose's BUILD
510 functionality and/or Moose attributes to perform any construction work
511 necessary for your class.
513 =head2 __PACKAGE__->mk_accessor('meta');
515 Won't work due to a limitation of L<Moose>. This is currently being fixed
518 =head2 Class::Data::Inheritable side effects
520 Previously, writing to a class data accessor would copy the accessor method
521 down into your package.
523 This behavior has been removed. While the class data is still stored
524 per-class, it is stored on the metaclass of the class defining the accessor.
526 Therefore anything relying on the side effect of the accessor being copied down
529 The following test demonstrates the problem:
533 use base qw/Class::Data::Inheritable/;
534 __PACKAGE__->mk_classdata('foo');
539 use base qw/BaseClass/;
542 BaseClass->foo('base class');
543 Child->foo('sub class');
546 isnt(BaseClass->can('foo'), Child->can('foo'));
548 =head2 Extending Catalyst::Request or other classes in an ad hoc manner using mk_accessors
550 Previously, it was possible to add additional accessors to Catalyst::Request
551 (or other classes) by calling the mk_accessors class method.
553 This is no longer supported - users should make a subclass of the class whose
554 behavior they would like to change, rather than globally polluting the
557 =head2 Confused multiple inheritance with Catalyst::Component::COMPONENT
559 Previously, Catalyst's COMPONENT method would delegate to the method on
560 the right hand side, which could then delegate back again with
561 NEXT. This is poor practice, and in addition, makes no sense with C3
562 method dispatch order, and is therefore no longer supported.
564 If a COMPONENT method is detected in the inheritance hierarchy to the right
565 hand side of Catalyst::Component::COMPONENT, then the following warning
566 message will be emitted:
568 There is a COMPONENT method resolving after Catalyst::Component
571 The correct fix is to re-arrange your class's inheritance hierarchy so that the
572 COMPONENT method you would like to inherit is the first (left-hand most)
573 COMPONENT method in your @ISA.
575 =head2 Development server relying on environment variables
577 Previously, the development server would allow propagation of system
578 environment variables into the request environment, this has changed with the
579 adoption of Plack. You can use L<Plack::Middleware::ForceEnv> to achieve the
584 =head2 Actions in your application class
586 Having actions in your application class will now emit a warning at application
587 startup as this is deprecated. It is highly recommended that these actions are moved
588 into a MyApp::Controller::Root (as demonstrated by the scaffold application
589 generated by catalyst.pl).
591 This warning, also affects tests. You should move actions in your test,
592 creating a myTest::Controller::Root, like the following example:
594 package MyTest::Controller::Root;
599 use parent 'Catalyst::Controller';
601 __PACKAGE__->config(namespace => '');
604 my ( $self, $c ) = @_;
610 =head2 ::[MVC]:: naming scheme
612 Having packages called MyApp::[MVC]::XX is deprecated and can no longer be generated
615 This is still supported, but it is recommended that you rename your application
616 components to Model/View/Controller.
618 A warning will be issued at application startup if the ::[MVC]:: naming scheme is
621 =head2 Catalyst::Base
623 Any code using L<Catalyst::Base> will now emit a warning; this
624 module will be removed in a future release.
626 =head2 Methods in Catalyst::Dispatcher
628 The following methods in Catalyst::Dispatcher are implementation
629 details, which may change in the 5.8X release series, and therefore their use
630 is highly deprecated.
638 =item registered_dispatch_types
640 =item method_action_class
648 The first time one of these methods is called, a warning will be emitted:
650 Class $class is calling the deprecated method Catalyst::Dispatcher::$public_method_name,
651 this will be removed in Catalyst 5.9
653 You should B<NEVER> be calling any of these methods from application code.
655 Plugin authors and maintainers whose plugins currently call these methods
656 should change to using the public API, or, if you do not feel the public API
657 adequately supports your use case, please email the development list to
658 discuss what API features you need so that you can be appropriately supported.
660 =head2 Class files with names that don't correspond to the packages they define
662 In this version of Catalyst, if a component is loaded from disk, but no
663 symbols are defined in that component's name space after it is loaded, this
664 warning will be issued:
666 require $class was successful but the package is not defined.
668 This is to protect against confusing bugs caused by mistyping package names,
669 and will become a fatal error in a future version.
671 Please note that 'inner packages' (via L<Devel::InnerPackage>) are still fully
672 supported; this warning is only issued when component file naming does not map
673 to B<any> of the packages defined within that component.
675 =head2 $c->plugin method
677 Calling the plugin method is deprecated, and calling it at run time is B<highly
680 Instead you are recommended to use L<Catalyst::Model::Adaptor> or similar to
681 compose the functionality you need outside of the main application name space.
683 Calling the plugin method will not be supported past Catalyst 5.81.