3 Catalyst::Upgrading - Instructions for upgrading to the latest Catalyst
5 =head1 Upgrading to Catalyst 5.90080
7 UTF8 encoding is now default. For temporary backwards compatibility, if this
8 change is causing you trouble, you can disable it by setting the application
9 configuration option to undef:
11 MyApp->config(encoding => undef);
13 But please consider this a temporary measure since it is the intention that
14 UTF8 is enabled going forwards and the expectation is that other ecosystem
15 projects will assume this as well. At some point you application will not
16 correctly function without this setting.
18 A number of projects in the wider ecosystem required minor updates to be able
19 to work correctly. Here's the known list:
21 L<Catalyst::View::TT>, L<Catalyst::View::Mason>, L<Catalyst::View::HTML::Mason>,
22 L<Catalyst::View::Xslate>, L<Test::WWW::Mechanize::Catalyst>
24 You will need to update to modern versions in most cases, although quite a few
25 of these only needed minor test case and documentation changes so you will need
26 to review the changelog of each one that is relevant to you to determine your
29 =head1 Upgrading to Catalyst 5.90060
31 Starting in the v5.90059_001 development release, the regexp dispatch type is
32 no longer automatically included as a dependency. If you are still using this
33 dispatch type, you need to add L<Catalyst::DispatchType::Regex> into your build
36 The standalone distribution of Regexp will be supported for the time being, but
37 should we find that supporting it prevents us from moving L<Catalyst> forward
38 in necessary ways, we reserve the right to drop that support. It is highly
39 recommended that you use this last stage of deprecation to change your code.
41 =head1 Upgrading to Catalyst 5.90040
43 =head2 Catalyst::Plugin::Unicode::Encoding is now core
45 The previously stand alone Unicode support module L<Catalyst::Plugin::Unicode::Encoding>
46 has been brought into core as a default plugin. Going forward, all you need is
47 to add a configuration setting for the encoding type. For example:
53 __PACKAGE__->config( encoding => 'UTF-8' );
55 Please note that this is different from the old stand alone plugin which applied
56 C<UTF-8> encoding by default (that is, if you did not set an explicit
57 C<encoding> configuration value, it assumed you wanted UTF-8). In order to
58 preserve backwards compatibility you will need to explicitly turn it on via the
59 configuration setting. THIS MIGHT CHANGE IN THE FUTURE, so please consider
60 starting to test your application with proper UTF-8 support and remove all those
61 crappy hacks you munged into the code because you didn't know the Plugin
64 For people that are using the Plugin, you will note a startup warning suggesting
65 that you can remove it from the plugin list. When you do so, please remember to
66 add the configuration setting, since you can no longer rely on the default being
67 UTF-8. We'll add it for you if you continue to use the stand alone plugin and
68 we detect this, but this backwards compatibility shim will likely be removed in
69 a few releases (trying to clean up the codebase after all).
71 If you have trouble with any of this, please bring it to the attention of the
72 Catalyst maintainer group.
74 =head2 basic async and event loop support
76 This version of L<Catalyst> offers some support for using L<AnyEvent> and
77 L<IO::Async> event loops in your application. These changes should work
78 fine for most applications however if you are already trying to perform
79 some streaming, minor changes in this area of the code might affect your
80 functionality. Please see L<Catalyst::Response\write_fh> for more and for a
83 We consider this feature experimental. We will try not to break it, but we
84 reserve the right to make necessary changes to fix major issues that people
85 run into when the use this functionality in the wild.
87 =head1 Upgrading to Catalyst 5.90030
89 =head2 Regex dispatch type is deprecated.
91 The Regex dispatchtype (L<Catalyst::DispatchType::Regex>) has been deprecated.
93 You are encouraged to move your application to Chained dispatch (L<Catalyst::DispatchType::Chained>).
95 If you cannot do so, please add a dependency to Catalyst::DispatchType::Regex to your application's
98 =head1 Upgrading to Catalyst 5.9
100 The major change is that L<Plack>, a toolkit for using the L<PSGI>
101 specification, now replaces most of the subclasses of L<Catalyst::Engine>. If
102 you are using one of the standard subclasses of L<Catalyst::Engine> this
103 should be a straightforward upgrade for you. It was a design goal for
104 this release to preserve as much backwards compatibility as possible.
105 However, since L<Plack> is different from L<Catalyst::Engine>, it is
106 possible that differences exist for edge cases. Therefore, we recommend
107 that care be taken with this upgrade and that testing should be greater
108 than would be the case with a minor point update. Please inform the
109 Catalyst developers of any problems so that we can fix them and
112 It is highly recommended that you become familiar with the L<Plack> ecosystem
113 and documentation. Being able to take advantage of L<Plack> development and
114 middleware is a major bonus to this upgrade. Documentation about how to
115 take advantage of L<Plack::Middleware> by writing your own C<< .psgi >> file
116 is contained in L<Catalyst::PSGI>.
118 If you have created a custom subclass of L<Catalyst:Engine>, you will
119 need to convert it to be a subclass of L<Plack::Handler>.
121 If you are using the L<Plack> engine, L<Catalyst::Engine::PSGI>, this new
122 release supersedes that code.
124 If you are using a subclass of L<Catalyst::Engine> that is aimed at
125 nonstandard or internal/testing uses, such as
126 L<Catalyst::Engine::Embeddable>, you should still be able to continue
129 Advice for specific subclasses of L<Catalyst::Engine> follows:
131 =head2 Upgrading the FastCGI Engine
133 No upgrade is needed if your myapp_fastcgi.pl script is already upgraded
134 to use L<Catalyst::Script::FastCGI>.
136 =head2 Upgrading the mod_perl / Apache Engines
138 The engines that are built upon the various iterations of mod_perl,
139 L<Catalyst::Engine::Apache::MP13> (for mod_perl 1, and Apache 1.x) and
140 L<Catalyst::Engine::Apache2::MP20> (for mod_perl 2, and Apache 2.x),
141 should be seamless upgrades and will work using L<Plack::Handler::Apache1>
142 or L<Plack::Handler::Apache2> as required.
144 L<Catalyst::Engine::Apache2::MP19>, however, is no longer supported, as
145 Plack does not support mod_perl version 1.99. This is unlikely to be a
146 problem for anyone, as 1.99 was a brief beta-test release for mod_perl
147 2, and all users of mod_perl 1.99 are encouraged to upgrade to a
148 supported release of Apache 2 and mod_perl 2.
150 =head2 Upgrading the HTTP Engine
152 The default development server that comes with the L<Catalyst> distribution
153 should continue to work as expected with no changes as long as your C<myapp_server>
154 script is upgraded to use L<Catalyst::Script::HTTP>.
156 =head2 Upgrading the CGI Engine
158 If you were using L<Catalyst::Engine::CGI> there is no upgrade needed if your
159 myapp_cgi.pl script is already upgraded to use L<Catalyst::Script::CGI>.
161 =head2 Upgrading Catalyst::Engine::HTTP::Prefork
163 If you were using L<Catalyst::Engine::HTTP::Prefork> then L<Starman>
164 is automatically loaded. You should (at least) change your C<Makefile.PL>
165 to depend on Starman.
167 You can regenerate your C<myapp_server.pl> script with C<catalyst.pl>
168 and implement a C<MyApp::Script::Server> class that looks like this:
170 package MyApp::Script::Server;
172 use namespace::autoclean;
174 extends 'CatalystX::Script::Server::Starman';
178 This takes advantage of the new script system, and will add a number of
179 options to the standard server script as extra options are added by
182 More information about these options can be seen at
183 L<CatalystX::Script::Server::Starman/SYNOPSIS>.
185 An alternate route to implement this functionality is to write a simple .psgi
186 file for your application, and then use the L<plackup> utility to start the
189 =head2 Upgrading the PSGI Engine
191 If you were using L<Catalyst::Engine::PSGI>, this new release supersedes
192 this engine in supporting L<Plack>. By default the Engine is now always
193 L<Plack>. As a result, you can remove the dependency on
194 L<Catalyst::Engine::PSGI> in your C<Makefile.PL>.
196 Applications that were using L<Catalyst::Engine::PSGI>
197 previously should entirely continue to work in this release with no changes.
199 However, if you have an C<app.psgi> script, then you no longer need to
200 specify the PSGI engine. Instead, the L<Catalyst> application class now
201 has a new method C<psgi_app> which returns a L<PSGI> compatible coderef
202 which you can wrap in the middleware of your choice.
204 Catalyst will use the .psgi for your application if it is located in the C<home>
205 directory of the application.
207 For example, if you were using L<Catalyst::Engine::PSGI> in the past, you will
208 have written (or generated) a C<script/myapp.psgi> file similar to this one:
213 MyCatalystApp->setup_engine('PSGI');
216 enable ... # enable your desired middleware
217 sub { MyCatalystApp->run(@_) };
220 Instead, you now say:
226 enable ... #enable your desired middleware
227 MyCatalystApp->psgi_app;
230 In the simplest case:
232 MyCatalystApp->setup_engine('PSGI');
233 my $app = sub { MyCatalystApp->run(@_) }
237 my $app = MyCatalystApp->psgi_app(@_);
241 my $app = sub { MyCatalystApp->psgi_app(@_) };
242 # If you make ^^ this mistake, your app won't work, and will confuse the hell out of you!
244 You can now move C<< script/myapp.psgi >> to C<< myapp.psgi >>, and the built-in
245 Catalyst scripts and your test suite will start using your .psgi file.
247 B<NOTE:> If you rename your .psgi file without these modifications, then
248 any tests run via L<Catalyst::Test> will not be compatible with the new
249 release, and will result in the development server starting, rather than
250 the expected test running.
252 B<NOTE:> If you are directly accessing C<< $c->req->env >> to get the PSGI
253 environment then this accessor is moved to C<< $c->engine->env >>,
254 you will need to update your code.
256 =head2 Engines which are known to be broken
258 The following engines B<DO NOT> work as of Catalyst version 5.9. The
259 core team will be happy to work with the developers and/or users of
260 these engines to help them port to the new Plack/Engine system, but for
261 now, applications which are currently using these engines B<WILL NOT>
262 run without modification to the engine code.
266 =item Catalyst::Engine::Wx
268 =item Catalyst::Engine::Zeus
270 =item Catalyst::Engine::JobQueue::POE
272 =item Catalyst::Engine::XMPP2
274 =item Catalyst::Engine::SCGI
278 =head2 Engines with unknown status
280 The following engines are untested or have unknown compatibility.
281 Reports are highly encouraged:
285 =item Catalyst::Engine::Mojo
287 =item Catalyst::Engine::Server (marked as Deprecated)
289 =item Catalyst::Engine::HTTP::POE (marked as Deprecated)
293 =head2 Plack functionality
295 See L<Catalyst::PSGI>.
299 Tests should generally work the same in Catalyst 5.9, but there are
302 Previously, if using L<Catalyst::Test> and doing local requests (against
303 a local server), if the application threw an exception then this
304 exception propagated into the test.
306 This behavior has been removed, and now a 500 response will be returned
307 to the test. This change standardizes behavior, so that local test
308 requests behave similarly to remote requests.
310 =head1 Upgrading to Catalyst 5.80
312 Most applications and plugins should run unaltered on Catalyst 5.80.
314 However, a lot of refactoring work has taken place, and several changes have
315 been made which could cause incompatibilities. If your application or plugin
316 is using deprecated code, or relying on side effects, then you could have
317 issues upgrading to this release.
319 Most issues found with existing components have been easy to
320 solve. This document provides a complete description of behavior changes
321 which may cause compatibility issues, and of new Catalyst warnings which
324 If you think you have found an upgrade-related issue which is not covered in
325 this document, please email the Catalyst list to discuss the problem.
327 =head1 Moose features
329 =head2 Application class roles
331 You can only apply method modifiers after the application's C<< ->setup >>
332 method has been called. This means that modifiers will not work with methods
333 run during the call to C<< ->setup >>.
335 See L<Catalyst::Manual::ExtendingCatalyst> for more information about using
336 L<Moose> in your applications.
338 =head2 Controller actions in Moose roles
340 You can use L<MooseX::MethodAttributes::Role> if you want to declare actions
343 =head2 Using Moose in Components
345 The correct way to use Moose in a component in a both forward and backwards
348 package TestApp::Controller::Root;
350 BEGIN { extends 'Catalyst::Component' }; # Or ::Controller, or whatever
352 See L<Components which inherit from Moose::Object before Catalyst::Component>.
354 =head1 Known backwards compatibility breakages
356 =head2 Applications in a single file
358 Applications must be in their own file, and loaded at compile time. This
359 issue generally only affects the tests of CPAN distributions. Your
360 application will fail if you try to define an application inline in a
361 block, and use plugins which supply a C< new > method, then use that
362 application latter in tests within the same file.
364 This is due to the fact that Catalyst is inlining a new method on your
365 application class allowing it to be compatible with Moose. The method
366 used to do this changed in 5.80004 to avoid the possibility of reporting
367 an 'Unknown Error' if your application failed to compile.
369 =head2 Issues with Class::C3
371 Catalyst 5.80 uses the L<Algorithm::C3> method dispatch order. This is
372 built into Perl 5.10, and comes via L<Class::C3> for Perl 5.8. This
373 replaces L<NEXT> with L<Class::C3::Adopt::NEXT>, forcing all components
374 to resolve methods using C3, rather than the unpredictable dispatch
377 This issue manifests itself by your application failing to start due to an
378 error message about having a non-linear @ISA.
380 The Catalyst plugin most often causing this is
381 L<Catalyst::Plugin::Session::Store::FastMmap> - if you are using this
382 plugin and see issues, then please upgrade your plugins, as it has been
383 fixed. Note that Makefile.PL in the distribution will warn about known
384 incompatible components.
386 This issue can, however, be found in your own application - the only solution is
387 to go through each base class of the class the error was reported against, until
388 you identify the ones in conflict, and resolve them.
390 To be able to generate a linear @ISA, the list of superclasses for each
391 class must be resolvable using the C3 algorithm. Unfortunately, when
392 superclasses are being used as mixins (to add functionality used in your class),
393 and with multiple inheritance, it is easy to get this wrong.
395 Most common is the case of:
397 package Component1; # Note, this is the common case
398 use base qw/Class::Accessor::Fast Class::Data::Inheritable/;
400 package Component2; # Accidentally saying it this way causes a failure
401 use base qw/Class::Data::Inheritable Class::Accessor::Fast/;
404 use base qw/Component1 Component2/;
406 Any situation like this will cause your application to fail to start.
408 For additional documentation about this issue, and how to resolve it, see
409 L<Class::C3::Adopt::NEXT>.
411 =head2 Components which inherit from Moose::Object before Catalyst::Component
413 Moose components which say:
415 package TestApp::Controller::Example;
417 extends qw/Moose::Object Catalyst::Component/;
419 to use the constructor provided by Moose, while working (if you do some hacks
420 with the C< BUILDARGS > method), will not work with Catalyst 5.80 as
421 C<Catalyst::Component> inherits from C<Moose::Object>, and so C< @ISA > fails
424 The correct way to use Moose in a component in a both forward and backwards
427 package TestApp::Controller::Root;
429 BEGIN { extends 'Catalyst::Component' }; # Or ::Controller, or whatever
431 Note that the C< extends > declaration needs to occur in a begin block for
432 L<attributes> to operate correctly.
434 This way you do not inherit directly from C<Moose::Object>
435 yourself. Having components which do not inherit their constructor from
436 C<Catalyst::Component> is B<unsupported>, and has never been recommended,
437 therefore you're on your own if you're using this technique. You'll need
438 to detect the version of Catalyst your application is running, and deal
439 with it appropriately.
441 You also don't get the L<Moose::Object> constructor, and therefore attribute
442 initialization will not work as normally expected. If you want to use Moose
443 attributes, then they need to be made lazy to correctly initialize.
445 Note that this only applies if your component needs to maintain component
446 backwards compatibility for Catalyst versions before 5.71001 - in 5.71001
447 attributes work as expected, and the BUILD method is called normally
448 (although BUILDARGS is not).
450 If you depend on Catalyst 5.8, then B<all> Moose features work as expected.
452 You will also see this issue if you do the following:
454 package TestApp::Controller::Example;
456 use base 'Catalyst::Controller';
458 as C< use base > appends to @ISA.
460 =head3 use Moose in MyApp
462 Similar to the above, this will also fail:
471 If you need to use Moose in your application class (e.g. for method modifiers
472 etc.) then the correct technique is:
480 __PACKAGE__->config( name => 'MyApp' );
481 __PACKAGE__->setup(qw/
485 =head2 Anonymous closures installed directly into the symbol table
487 If you have any code which installs anonymous subroutine references directly
488 into the symbol table, you may encounter breakages. The simplest solution is
489 to use L<Sub::Name> to name the subroutine. Example:
491 # Original code, likely to break:
492 my $full_method_name = join('::', $package_name, $method_name);
493 *$full_method_name = sub { ... };
496 use Sub::Name 'subname';
497 my $full_method_name = join('::',$package_name, $method_name);
498 *$full_method_name = subname $full_method_name, sub { ... };
500 Additionally, you can take advantage of Catalyst's use of L<Class::MOP> and
501 install the closure using the appropriate metaclass. Example:
504 my $metaclass = Moose::Meta::Class->initialize($package_name);
505 $metaclass->add_method($method_name => sub { ... });
507 =head2 Hooking into application setup
509 To execute code during application start-up, the following snippet in MyApp.pm
513 my ($class, @args) = @_;
514 $class->NEXT::setup(@args);
515 ... # things to do after the actual setup
518 With Catalyst 5.80 this won't work anymore, because Catalyst no longer
519 uses NEXT.pm for method resolution. The functionality was only ever
520 originally operational as L<NEXT> remembers what methods have already
521 been called, and will not call them again.
523 Using this now causes infinite recursion between MyApp::setup and
524 Catalyst::setup, due to other backwards compatibility issues related to how
525 plugin setup works. Moose method modifiers like C<< before|after|around setup
526 => sub { ... }; >> also will not operate correctly on the setup method.
528 The right way to do it is this:
530 after setup_finalize => sub {
531 ... # things to do after the actual setup
534 The setup_finalize hook was introduced as a way to avoid this issue.
536 =head2 Components with a new method which returns false
538 Previously, if you had a component which inherited from Catalyst::COMPONENT,
539 but overrode the new method to return false, then your class's configuration
540 would be blessed into a hash on your behalf, and this would be returned from
541 the COMPONENT method.
543 This behavior makes no sense, and so has been removed. Implementing your own
544 C< new > method in components is B<highly> discouraged. Instead, you should
545 inherit the new method from Catalyst::Component, and use Moose's BUILD
546 functionality and/or Moose attributes to perform any construction work
547 necessary for your class.
549 =head2 __PACKAGE__->mk_accessor('meta');
551 Won't work due to a limitation of L<Moose>. This is currently being fixed
554 =head2 Class::Data::Inheritable side effects
556 Previously, writing to a class data accessor would copy the accessor method
557 down into your package.
559 This behavior has been removed. While the class data is still stored
560 per-class, it is stored on the metaclass of the class defining the accessor.
562 Therefore anything relying on the side effect of the accessor being copied down
565 The following test demonstrates the problem:
569 use base qw/Class::Data::Inheritable/;
570 __PACKAGE__->mk_classdata('foo');
575 use base qw/BaseClass/;
578 BaseClass->foo('base class');
579 Child->foo('sub class');
582 isnt(BaseClass->can('foo'), Child->can('foo'));
584 =head2 Extending Catalyst::Request or other classes in an ad hoc manner using mk_accessors
586 Previously, it was possible to add additional accessors to Catalyst::Request
587 (or other classes) by calling the mk_accessors class method.
589 This is no longer supported - users should make a subclass of the class whose
590 behavior they would like to change, rather than globally polluting the
593 =head2 Confused multiple inheritance with Catalyst::Component::COMPONENT
595 Previously, Catalyst's COMPONENT method would delegate to the method on
596 the right hand side, which could then delegate back again with
597 NEXT. This is poor practice, and in addition, makes no sense with C3
598 method dispatch order, and is therefore no longer supported.
600 If a COMPONENT method is detected in the inheritance hierarchy to the right
601 hand side of Catalyst::Component::COMPONENT, then the following warning
602 message will be emitted:
604 There is a COMPONENT method resolving after Catalyst::Component
607 The correct fix is to re-arrange your class's inheritance hierarchy so that the
608 COMPONENT method you would like to inherit is the first (left-hand most)
609 COMPONENT method in your @ISA.
611 =head2 Development server relying on environment variables
613 Previously, the development server would allow propagation of system
614 environment variables into the request environment, this has changed with the
615 adoption of Plack. You can use L<Plack::Middleware::ForceEnv> to achieve the
620 =head2 Actions in your application class
622 Having actions in your application class will now emit a warning at application
623 startup as this is deprecated. It is highly recommended that these actions are moved
624 into a MyApp::Controller::Root (as demonstrated by the scaffold application
625 generated by catalyst.pl).
627 This warning, also affects tests. You should move actions in your test,
628 creating a myTest::Controller::Root, like the following example:
630 package MyTest::Controller::Root;
635 use parent 'Catalyst::Controller';
637 __PACKAGE__->config(namespace => '');
640 my ( $self, $c ) = @_;
646 =head2 ::[MVC]:: naming scheme
648 Having packages called MyApp::[MVC]::XX is deprecated and can no longer be generated
651 This is still supported, but it is recommended that you rename your application
652 components to Model/View/Controller.
654 A warning will be issued at application startup if the ::[MVC]:: naming scheme is
657 =head2 Catalyst::Base
659 Any code using L<Catalyst::Base> will now emit a warning; this
660 module will be removed in a future release.
662 =head2 Methods in Catalyst::Dispatcher
664 The following methods in Catalyst::Dispatcher are implementation
665 details, which may change in the 5.8X release series, and therefore their use
666 is highly deprecated.
674 =item registered_dispatch_types
676 =item method_action_class
684 The first time one of these methods is called, a warning will be emitted:
686 Class $class is calling the deprecated method Catalyst::Dispatcher::$public_method_name,
687 this will be removed in Catalyst 5.9
689 You should B<NEVER> be calling any of these methods from application code.
691 Plugin authors and maintainers whose plugins currently call these methods
692 should change to using the public API, or, if you do not feel the public API
693 adequately supports your use case, please email the development list to
694 discuss what API features you need so that you can be appropriately supported.
696 =head2 Class files with names that don't correspond to the packages they define
698 In this version of Catalyst, if a component is loaded from disk, but no
699 symbols are defined in that component's name space after it is loaded, this
700 warning will be issued:
702 require $class was successful but the package is not defined.
704 This is to protect against confusing bugs caused by mistyping package names,
705 and will become a fatal error in a future version.
707 Please note that 'inner packages' (via L<Devel::InnerPackage>) are still fully
708 supported; this warning is only issued when component file naming does not map
709 to B<any> of the packages defined within that component.
711 =head2 $c->plugin method
713 Calling the plugin method is deprecated, and calling it at run time is B<highly
716 Instead you are recommended to use L<Catalyst::Model::Adaptor> or similar to
717 compose the functionality you need outside of the main application name space.
719 Calling the plugin method will not be supported past Catalyst 5.81.