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 As of 5.90084 we've added two additional configuration flags for more selective
19 control over some encoding changes: 'skip_body_param_unicode_decoding' and
20 'skip_complex_post_part_handling'. You may use these to more selectively
21 disable new features while you are seeking a long term fix. Please review
22 CONFIGURATION in L<Catalyst>.
24 For further information, please see L<Catalyst::UTF8>
26 A number of projects in the wider ecosystem required minor updates to be able
27 to work correctly. Here's the known list:
29 L<Catalyst::View::TT>, L<Catalyst::View::Mason>, L<Catalyst::View::HTML::Mason>,
30 L<Catalyst::View::Xslate>, L<Test::WWW::Mechanize::Catalyst>
32 You will need to update to modern versions in most cases, although quite a few
33 of these only needed minor test case and documentation changes so you will need
34 to review the changelog of each one that is relevant to you to determine your
37 =head1 Upgrading to Catalyst 5.90060
39 Starting in the v5.90059_001 development release, the regexp dispatch type is
40 no longer automatically included as a dependency. If you are still using this
41 dispatch type, you need to add L<Catalyst::DispatchType::Regex> into your build
44 The standalone distribution of Regexp will be supported for the time being, but
45 should we find that supporting it prevents us from moving L<Catalyst> forward
46 in necessary ways, we reserve the right to drop that support. It is highly
47 recommended that you use this last stage of deprecation to change your code.
49 =head1 Upgrading to Catalyst 5.90040
51 =head2 Catalyst::Plugin::Unicode::Encoding is now core
53 The previously stand alone Unicode support module L<Catalyst::Plugin::Unicode::Encoding>
54 has been brought into core as a default plugin. Going forward, all you need is
55 to add a configuration setting for the encoding type. For example:
61 __PACKAGE__->config( encoding => 'UTF-8' );
63 Please note that this is different from the old stand alone plugin which applied
64 C<UTF-8> encoding by default (that is, if you did not set an explicit
65 C<encoding> configuration value, it assumed you wanted UTF-8). In order to
66 preserve backwards compatibility you will need to explicitly turn it on via the
67 configuration setting. THIS MIGHT CHANGE IN THE FUTURE, so please consider
68 starting to test your application with proper UTF-8 support and remove all those
69 crappy hacks you munged into the code because you didn't know the Plugin
72 For people that are using the Plugin, you will note a startup warning suggesting
73 that you can remove it from the plugin list. When you do so, please remember to
74 add the configuration setting, since you can no longer rely on the default being
75 UTF-8. We'll add it for you if you continue to use the stand alone plugin and
76 we detect this, but this backwards compatibility shim will likely be removed in
77 a few releases (trying to clean up the codebase after all).
79 If you have trouble with any of this, please bring it to the attention of the
80 Catalyst maintainer group.
82 =head2 basic async and event loop support
84 This version of L<Catalyst> offers some support for using L<AnyEvent> and
85 L<IO::Async> event loops in your application. These changes should work
86 fine for most applications however if you are already trying to perform
87 some streaming, minor changes in this area of the code might affect your
88 functionality. Please see L<Catalyst::Response\write_fh> for more and for a
91 We consider this feature experimental. We will try not to break it, but we
92 reserve the right to make necessary changes to fix major issues that people
93 run into when the use this functionality in the wild.
95 =head1 Upgrading to Catalyst 5.90030
97 =head2 Regex dispatch type is deprecated.
99 The Regex dispatchtype (L<Catalyst::DispatchType::Regex>) has been deprecated.
101 You are encouraged to move your application to Chained dispatch (L<Catalyst::DispatchType::Chained>).
103 If you cannot do so, please add a dependency to Catalyst::DispatchType::Regex to your application's
106 =head1 Upgrading to Catalyst 5.9
108 The major change is that L<Plack>, a toolkit for using the L<PSGI>
109 specification, now replaces most of the subclasses of L<Catalyst::Engine>. If
110 you are using one of the standard subclasses of L<Catalyst::Engine> this
111 should be a straightforward upgrade for you. It was a design goal for
112 this release to preserve as much backwards compatibility as possible.
113 However, since L<Plack> is different from L<Catalyst::Engine>, it is
114 possible that differences exist for edge cases. Therefore, we recommend
115 that care be taken with this upgrade and that testing should be greater
116 than would be the case with a minor point update. Please inform the
117 Catalyst developers of any problems so that we can fix them and
120 It is highly recommended that you become familiar with the L<Plack> ecosystem
121 and documentation. Being able to take advantage of L<Plack> development and
122 middleware is a major bonus to this upgrade. Documentation about how to
123 take advantage of L<Plack::Middleware> by writing your own C<< .psgi >> file
124 is contained in L<Catalyst::PSGI>.
126 If you have created a custom subclass of L<Catalyst:Engine>, you will
127 need to convert it to be a subclass of L<Plack::Handler>.
129 If you are using the L<Plack> engine, L<Catalyst::Engine::PSGI>, this new
130 release supersedes that code.
132 If you are using a subclass of L<Catalyst::Engine> that is aimed at
133 nonstandard or internal/testing uses, such as
134 L<Catalyst::Engine::Embeddable>, you should still be able to continue
137 Advice for specific subclasses of L<Catalyst::Engine> follows:
139 =head2 Upgrading the FastCGI Engine
141 No upgrade is needed if your myapp_fastcgi.pl script is already upgraded
142 to use L<Catalyst::Script::FastCGI>.
144 =head2 Upgrading the mod_perl / Apache Engines
146 The engines that are built upon the various iterations of mod_perl,
147 L<Catalyst::Engine::Apache::MP13> (for mod_perl 1, and Apache 1.x) and
148 L<Catalyst::Engine::Apache2::MP20> (for mod_perl 2, and Apache 2.x),
149 should be seamless upgrades and will work using L<Plack::Handler::Apache1>
150 or L<Plack::Handler::Apache2> as required.
152 L<Catalyst::Engine::Apache2::MP19>, however, is no longer supported, as
153 Plack does not support mod_perl version 1.99. This is unlikely to be a
154 problem for anyone, as 1.99 was a brief beta-test release for mod_perl
155 2, and all users of mod_perl 1.99 are encouraged to upgrade to a
156 supported release of Apache 2 and mod_perl 2.
158 =head2 Upgrading the HTTP Engine
160 The default development server that comes with the L<Catalyst> distribution
161 should continue to work as expected with no changes as long as your C<myapp_server>
162 script is upgraded to use L<Catalyst::Script::HTTP>.
164 =head2 Upgrading the CGI Engine
166 If you were using L<Catalyst::Engine::CGI> there is no upgrade needed if your
167 myapp_cgi.pl script is already upgraded to use L<Catalyst::Script::CGI>.
169 =head2 Upgrading Catalyst::Engine::HTTP::Prefork
171 If you were using L<Catalyst::Engine::HTTP::Prefork> then L<Starman>
172 is automatically loaded. You should (at least) change your C<Makefile.PL>
173 to depend on Starman.
175 You can regenerate your C<myapp_server.pl> script with C<catalyst.pl>
176 and implement a C<MyApp::Script::Server> class that looks like this:
178 package MyApp::Script::Server;
180 use namespace::autoclean;
182 extends 'CatalystX::Script::Server::Starman';
186 This takes advantage of the new script system, and will add a number of
187 options to the standard server script as extra options are added by
190 More information about these options can be seen at
191 L<CatalystX::Script::Server::Starman/SYNOPSIS>.
193 An alternate route to implement this functionality is to write a simple .psgi
194 file for your application, and then use the L<plackup> utility to start the
197 =head2 Upgrading the PSGI Engine
199 If you were using L<Catalyst::Engine::PSGI>, this new release supersedes
200 this engine in supporting L<Plack>. By default the Engine is now always
201 L<Plack>. As a result, you can remove the dependency on
202 L<Catalyst::Engine::PSGI> in your C<Makefile.PL>.
204 Applications that were using L<Catalyst::Engine::PSGI>
205 previously should entirely continue to work in this release with no changes.
207 However, if you have an C<app.psgi> script, then you no longer need to
208 specify the PSGI engine. Instead, the L<Catalyst> application class now
209 has a new method C<psgi_app> which returns a L<PSGI> compatible coderef
210 which you can wrap in the middleware of your choice.
212 Catalyst will use the .psgi for your application if it is located in the C<home>
213 directory of the application.
215 For example, if you were using L<Catalyst::Engine::PSGI> in the past, you will
216 have written (or generated) a C<script/myapp.psgi> file similar to this one:
221 MyCatalystApp->setup_engine('PSGI');
224 enable ... # enable your desired middleware
225 sub { MyCatalystApp->run(@_) };
228 Instead, you now say:
234 enable ... #enable your desired middleware
235 MyCatalystApp->psgi_app;
238 In the simplest case:
240 MyCatalystApp->setup_engine('PSGI');
241 my $app = sub { MyCatalystApp->run(@_) }
245 my $app = MyCatalystApp->psgi_app(@_);
249 my $app = sub { MyCatalystApp->psgi_app(@_) };
250 # If you make ^^ this mistake, your app won't work, and will confuse the hell out of you!
252 You can now move C<< script/myapp.psgi >> to C<< myapp.psgi >>, and the built-in
253 Catalyst scripts and your test suite will start using your .psgi file.
255 B<NOTE:> If you rename your .psgi file without these modifications, then
256 any tests run via L<Catalyst::Test> will not be compatible with the new
257 release, and will result in the development server starting, rather than
258 the expected test running.
260 B<NOTE:> If you are directly accessing C<< $c->req->env >> to get the PSGI
261 environment then this accessor is moved to C<< $c->engine->env >>,
262 you will need to update your code.
264 =head2 Engines which are known to be broken
266 The following engines B<DO NOT> work as of Catalyst version 5.9. The
267 core team will be happy to work with the developers and/or users of
268 these engines to help them port to the new Plack/Engine system, but for
269 now, applications which are currently using these engines B<WILL NOT>
270 run without modification to the engine code.
274 =item Catalyst::Engine::Wx
276 =item Catalyst::Engine::Zeus
278 =item Catalyst::Engine::JobQueue::POE
280 =item Catalyst::Engine::XMPP2
282 =item Catalyst::Engine::SCGI
286 =head2 Engines with unknown status
288 The following engines are untested or have unknown compatibility.
289 Reports are highly encouraged:
293 =item Catalyst::Engine::Mojo
295 =item Catalyst::Engine::Server (marked as Deprecated)
297 =item Catalyst::Engine::HTTP::POE (marked as Deprecated)
301 =head2 Plack functionality
303 See L<Catalyst::PSGI>.
307 Tests should generally work the same in Catalyst 5.9, but there are
310 Previously, if using L<Catalyst::Test> and doing local requests (against
311 a local server), if the application threw an exception then this
312 exception propagated into the test.
314 This behavior has been removed, and now a 500 response will be returned
315 to the test. This change standardizes behavior, so that local test
316 requests behave similarly to remote requests.
318 =head1 Upgrading to Catalyst 5.80
320 Most applications and plugins should run unaltered on Catalyst 5.80.
322 However, a lot of refactoring work has taken place, and several changes have
323 been made which could cause incompatibilities. If your application or plugin
324 is using deprecated code, or relying on side effects, then you could have
325 issues upgrading to this release.
327 Most issues found with existing components have been easy to
328 solve. This document provides a complete description of behavior changes
329 which may cause compatibility issues, and of new Catalyst warnings which
332 If you think you have found an upgrade-related issue which is not covered in
333 this document, please email the Catalyst list to discuss the problem.
335 =head1 Moose features
337 =head2 Application class roles
339 You can only apply method modifiers after the application's C<< ->setup >>
340 method has been called. This means that modifiers will not work with methods
341 run during the call to C<< ->setup >>.
343 See L<Catalyst::Manual::ExtendingCatalyst> for more information about using
344 L<Moose> in your applications.
346 =head2 Controller actions in Moose roles
348 You can use L<MooseX::MethodAttributes::Role> if you want to declare actions
351 =head2 Using Moose in Components
353 The correct way to use Moose in a component in a both forward and backwards
356 package TestApp::Controller::Root;
358 BEGIN { extends 'Catalyst::Component' }; # Or ::Controller, or whatever
360 See L<Components which inherit from Moose::Object before Catalyst::Component>.
362 =head1 Known backwards compatibility breakages
364 =head2 Applications in a single file
366 Applications must be in their own file, and loaded at compile time. This
367 issue generally only affects the tests of CPAN distributions. Your
368 application will fail if you try to define an application inline in a
369 block, and use plugins which supply a C< new > method, then use that
370 application latter in tests within the same file.
372 This is due to the fact that Catalyst is inlining a new method on your
373 application class allowing it to be compatible with Moose. The method
374 used to do this changed in 5.80004 to avoid the possibility of reporting
375 an 'Unknown Error' if your application failed to compile.
377 =head2 Issues with Class::C3
379 Catalyst 5.80 uses the L<Algorithm::C3> method dispatch order. This is
380 built into Perl 5.10, and comes via L<Class::C3> for Perl 5.8. This
381 replaces L<NEXT> with L<Class::C3::Adopt::NEXT>, forcing all components
382 to resolve methods using C3, rather than the unpredictable dispatch
385 This issue manifests itself by your application failing to start due to an
386 error message about having a non-linear @ISA.
388 The Catalyst plugin most often causing this is
389 L<Catalyst::Plugin::Session::Store::FastMmap> - if you are using this
390 plugin and see issues, then please upgrade your plugins, as it has been
391 fixed. Note that Makefile.PL in the distribution will warn about known
392 incompatible components.
394 This issue can, however, be found in your own application - the only solution is
395 to go through each base class of the class the error was reported against, until
396 you identify the ones in conflict, and resolve them.
398 To be able to generate a linear @ISA, the list of superclasses for each
399 class must be resolvable using the C3 algorithm. Unfortunately, when
400 superclasses are being used as mixins (to add functionality used in your class),
401 and with multiple inheritance, it is easy to get this wrong.
403 Most common is the case of:
405 package Component1; # Note, this is the common case
406 use base qw/Class::Accessor::Fast Class::Data::Inheritable/;
408 package Component2; # Accidentally saying it this way causes a failure
409 use base qw/Class::Data::Inheritable Class::Accessor::Fast/;
412 use base qw/Component1 Component2/;
414 Any situation like this will cause your application to fail to start.
416 For additional documentation about this issue, and how to resolve it, see
417 L<Class::C3::Adopt::NEXT>.
419 =head2 Components which inherit from Moose::Object before Catalyst::Component
421 Moose components which say:
423 package TestApp::Controller::Example;
425 extends qw/Moose::Object Catalyst::Component/;
427 to use the constructor provided by Moose, while working (if you do some hacks
428 with the C< BUILDARGS > method), will not work with Catalyst 5.80 as
429 C<Catalyst::Component> inherits from C<Moose::Object>, and so C< @ISA > fails
432 The correct way to use Moose in a component in a both forward and backwards
435 package TestApp::Controller::Root;
437 BEGIN { extends 'Catalyst::Component' }; # Or ::Controller, or whatever
439 Note that the C< extends > declaration needs to occur in a begin block for
440 L<attributes> to operate correctly.
442 This way you do not inherit directly from C<Moose::Object>
443 yourself. Having components which do not inherit their constructor from
444 C<Catalyst::Component> is B<unsupported>, and has never been recommended,
445 therefore you're on your own if you're using this technique. You'll need
446 to detect the version of Catalyst your application is running, and deal
447 with it appropriately.
449 You also don't get the L<Moose::Object> constructor, and therefore attribute
450 initialization will not work as normally expected. If you want to use Moose
451 attributes, then they need to be made lazy to correctly initialize.
453 Note that this only applies if your component needs to maintain component
454 backwards compatibility for Catalyst versions before 5.71001 - in 5.71001
455 attributes work as expected, and the BUILD method is called normally
456 (although BUILDARGS is not).
458 If you depend on Catalyst 5.8, then B<all> Moose features work as expected.
460 You will also see this issue if you do the following:
462 package TestApp::Controller::Example;
464 use base 'Catalyst::Controller';
466 as C< use base > appends to @ISA.
468 =head3 use Moose in MyApp
470 Similar to the above, this will also fail:
479 If you need to use Moose in your application class (e.g. for method modifiers
480 etc.) then the correct technique is:
488 __PACKAGE__->config( name => 'MyApp' );
489 __PACKAGE__->setup(qw/
493 =head2 Anonymous closures installed directly into the symbol table
495 If you have any code which installs anonymous subroutine references directly
496 into the symbol table, you may encounter breakages. The simplest solution is
497 to use L<Sub::Name> to name the subroutine. Example:
499 # Original code, likely to break:
500 my $full_method_name = join('::', $package_name, $method_name);
501 *$full_method_name = sub { ... };
504 use Sub::Name 'subname';
505 my $full_method_name = join('::',$package_name, $method_name);
506 *$full_method_name = subname $full_method_name, sub { ... };
508 Additionally, you can take advantage of Catalyst's use of L<Class::MOP> and
509 install the closure using the appropriate metaclass. Example:
512 my $metaclass = Moose::Meta::Class->initialize($package_name);
513 $metaclass->add_method($method_name => sub { ... });
515 =head2 Hooking into application setup
517 To execute code during application start-up, the following snippet in MyApp.pm
521 my ($class, @args) = @_;
522 $class->NEXT::setup(@args);
523 ... # things to do after the actual setup
526 With Catalyst 5.80 this won't work anymore, because Catalyst no longer
527 uses NEXT.pm for method resolution. The functionality was only ever
528 originally operational as L<NEXT> remembers what methods have already
529 been called, and will not call them again.
531 Using this now causes infinite recursion between MyApp::setup and
532 Catalyst::setup, due to other backwards compatibility issues related to how
533 plugin setup works. Moose method modifiers like C<< before|after|around setup
534 => sub { ... }; >> also will not operate correctly on the setup method.
536 The right way to do it is this:
538 after setup_finalize => sub {
539 ... # things to do after the actual setup
542 The setup_finalize hook was introduced as a way to avoid this issue.
544 =head2 Components with a new method which returns false
546 Previously, if you had a component which inherited from Catalyst::COMPONENT,
547 but overrode the new method to return false, then your class's configuration
548 would be blessed into a hash on your behalf, and this would be returned from
549 the COMPONENT method.
551 This behavior makes no sense, and so has been removed. Implementing your own
552 C< new > method in components is B<highly> discouraged. Instead, you should
553 inherit the new method from Catalyst::Component, and use Moose's BUILD
554 functionality and/or Moose attributes to perform any construction work
555 necessary for your class.
557 =head2 __PACKAGE__->mk_accessor('meta');
559 Won't work due to a limitation of L<Moose>. This is currently being fixed
562 =head2 Class::Data::Inheritable side effects
564 Previously, writing to a class data accessor would copy the accessor method
565 down into your package.
567 This behavior has been removed. While the class data is still stored
568 per-class, it is stored on the metaclass of the class defining the accessor.
570 Therefore anything relying on the side effect of the accessor being copied down
573 The following test demonstrates the problem:
577 use base qw/Class::Data::Inheritable/;
578 __PACKAGE__->mk_classdata('foo');
583 use base qw/BaseClass/;
586 BaseClass->foo('base class');
587 Child->foo('sub class');
590 isnt(BaseClass->can('foo'), Child->can('foo'));
592 =head2 Extending Catalyst::Request or other classes in an ad hoc manner using mk_accessors
594 Previously, it was possible to add additional accessors to Catalyst::Request
595 (or other classes) by calling the mk_accessors class method.
597 This is no longer supported - users should make a subclass of the class whose
598 behavior they would like to change, rather than globally polluting the
601 =head2 Confused multiple inheritance with Catalyst::Component::COMPONENT
603 Previously, Catalyst's COMPONENT method would delegate to the method on
604 the right hand side, which could then delegate back again with
605 NEXT. This is poor practice, and in addition, makes no sense with C3
606 method dispatch order, and is therefore no longer supported.
608 If a COMPONENT method is detected in the inheritance hierarchy to the right
609 hand side of Catalyst::Component::COMPONENT, then the following warning
610 message will be emitted:
612 There is a COMPONENT method resolving after Catalyst::Component
615 The correct fix is to re-arrange your class's inheritance hierarchy so that the
616 COMPONENT method you would like to inherit is the first (left-hand most)
617 COMPONENT method in your @ISA.
619 =head2 Development server relying on environment variables
621 Previously, the development server would allow propagation of system
622 environment variables into the request environment, this has changed with the
623 adoption of Plack. You can use L<Plack::Middleware::ForceEnv> to achieve the
628 =head2 Actions in your application class
630 Having actions in your application class will now emit a warning at application
631 startup as this is deprecated. It is highly recommended that these actions are moved
632 into a MyApp::Controller::Root (as demonstrated by the scaffold application
633 generated by catalyst.pl).
635 This warning, also affects tests. You should move actions in your test,
636 creating a myTest::Controller::Root, like the following example:
638 package MyTest::Controller::Root;
643 use parent 'Catalyst::Controller';
645 __PACKAGE__->config(namespace => '');
648 my ( $self, $c ) = @_;
654 =head2 ::[MVC]:: naming scheme
656 Having packages called MyApp::[MVC]::XX is deprecated and can no longer be generated
659 This is still supported, but it is recommended that you rename your application
660 components to Model/View/Controller.
662 A warning will be issued at application startup if the ::[MVC]:: naming scheme is
665 =head2 Catalyst::Base
667 Any code using L<Catalyst::Base> will now emit a warning; this
668 module will be removed in a future release.
670 =head2 Methods in Catalyst::Dispatcher
672 The following methods in Catalyst::Dispatcher are implementation
673 details, which may change in the 5.8X release series, and therefore their use
674 is highly deprecated.
682 =item registered_dispatch_types
684 =item method_action_class
692 The first time one of these methods is called, a warning will be emitted:
694 Class $class is calling the deprecated method Catalyst::Dispatcher::$public_method_name,
695 this will be removed in Catalyst 5.9
697 You should B<NEVER> be calling any of these methods from application code.
699 Plugin authors and maintainers whose plugins currently call these methods
700 should change to using the public API, or, if you do not feel the public API
701 adequately supports your use case, please email the development list to
702 discuss what API features you need so that you can be appropriately supported.
704 =head2 Class files with names that don't correspond to the packages they define
706 In this version of Catalyst, if a component is loaded from disk, but no
707 symbols are defined in that component's name space after it is loaded, this
708 warning will be issued:
710 require $class was successful but the package is not defined.
712 This is to protect against confusing bugs caused by mistyping package names,
713 and will become a fatal error in a future version.
715 Please note that 'inner packages' (via L<Devel::InnerPackage>) are still fully
716 supported; this warning is only issued when component file naming does not map
717 to B<any> of the packages defined within that component.
719 =head2 $c->plugin method
721 Calling the plugin method is deprecated, and calling it at run time is B<highly
724 Instead you are recommended to use L<Catalyst::Model::Adaptor> or similar to
725 compose the functionality you need outside of the main application name space.
727 Calling the plugin method will not be supported past Catalyst 5.81.