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 B<NOTE>: One other difference between the cored plugin and the stand alone one
36 is that in core we no longer throw an exception when there's a decode failure
37 but instead log a warning. If you rely on exceptions for control flow, you
38 will need to override method C<handle_unicode_encoding_exception> to die instead
39 of warning. Please let the dev team know if this is a problem for you.
41 If you have trouble with any of this, please bring it to the attention of the
42 Catalyst maintainer group.
44 =head2 basic async and event loop support
46 This version of L<Catalyst> offers some support for using L<AnyEvent> and
47 L<IO::Async> event loops in your application. These changes should work
48 fine for most applications however if you are already trying to perform
49 some streaming, minor changes in this area of the code might affect your
50 functionality. Please see L<Catalyst::Response\write_fh> for more and for a
53 We consider this feature experimental. We will try not to break it, but we
54 reserve the right to make necessary changes to fix major issues that people
55 run into when the use this functionality in the wild.
57 =head1 Upgrading to Catalyst 5.90030
59 =head2 Regex dispatch type is deprecated.
61 The Regex dispatchtype (L<Catalyst::DispatchType::Regex>) has been deprecated.
63 You are encouraged to move your application to Chained dispatch (L<Catalyst::DispatchType::Chained>).
65 If you cannot do so, please add a dependency to Catalyst::DispatchType::Regex to your application's
68 =head1 Upgrading to Catalyst 5.9
70 The major change is that L<Plack>, a toolkit for using the L<PSGI>
71 specification, now replaces most of the subclasses of L<Catalyst::Engine>. If
72 you are using one of the standard subclasses of L<Catalyst::Engine> this
73 should be a straightforward upgrade for you. It was a design goal for
74 this release to preserve as much backwards compatibility as possible.
75 However, since L<Plack> is different from L<Catalyst::Engine>, it is
76 possible that differences exist for edge cases. Therefore, we recommend
77 that care be taken with this upgrade and that testing should be greater
78 than would be the case with a minor point update. Please inform the
79 Catalyst developers of any problems so that we can fix them and
82 It is highly recommended that you become familiar with the L<Plack> ecosystem
83 and documentation. Being able to take advantage of L<Plack> development and
84 middleware is a major bonus to this upgrade. Documentation about how to
85 take advantage of L<Plack::Middleware> by writing your own C<< .psgi >> file
86 is contained in L<Catalyst::PSGI>.
88 If you have created a custom subclass of L<Catalyst:Engine>, you will
89 need to convert it to be a subclass of L<Plack::Handler>.
91 If you are using the L<Plack> engine, L<Catalyst::Engine::PSGI>, this new
92 release supersedes that code.
94 If you are using a subclass of L<Catalyst::Engine> that is aimed at
95 nonstandard or internal/testing uses, such as
96 L<Catalyst::Engine::Embeddable>, you should still be able to continue
99 Advice for specific subclasses of L<Catalyst::Engine> follows:
101 =head2 Upgrading the FastCGI Engine
103 No upgrade is needed if your myapp_fastcgi.pl script is already upgraded
104 to use L<Catalyst::Script::FastCGI>.
106 =head2 Upgrading the mod_perl / Apache Engines
108 The engines that are built upon the various iterations of mod_perl,
109 L<Catalyst::Engine::Apache::MP13> (for mod_perl 1, and Apache 1.x) and
110 L<Catalyst::Engine::Apache2::MP20> (for mod_perl 2, and Apache 2.x),
111 should be seamless upgrades and will work using using L<Plack::Handler::Apache1>
112 or L<Plack::Handler::Apache2> as required.
114 L<Catalyst::Engine::Apache2::MP19>, however, is no longer supported, as
115 Plack does not support mod_perl version 1.99. This is unlikely to be a
116 problem for anyone, as 1.99 was a brief beta-test release for mod_perl
117 2, and all users of mod_perl 1.99 are encouraged to upgrade to a
118 supported release of Apache 2 and mod_perl 2.
120 =head2 Upgrading the HTTP Engine
122 The default development server that comes with the L<Catalyst> distribution
123 should continue to work as expected with no changes as long as your C<myapp_server>
124 script is upgraded to use L<Catalyst::Script::HTTP>.
126 =head2 Upgrading the CGI Engine
128 If you were using L<Catalyst::Engine::CGI> there is no upgrade needed if your
129 myapp_cgi.pl script is already upgraded to use L<Catalyst::Script::CGI>.
131 =head2 Upgrading Catalyst::Engine::HTTP::Prefork
133 If you were using L<Catalyst::Engine::HTTP::Prefork> then L<Starman>
134 is automatically loaded. You should (at least) change your C<Makefile.PL>
135 to depend on Starman.
137 You can regenerate your C<myapp_server.pl> script with C<catalyst.pl>
138 and implement a C<MyApp::Script::Server> class that looks like this:
140 package MyApp::Script::Server;
142 use namespace::autoclean;
144 extends 'CatalystX::Script::Server::Starman';
148 This takes advantage of the new script system, and will add a number of
149 options to the standard server script as extra options are added by
152 More information about these options can be seen at
153 L<CatalystX::Script::Server::Starman/SYNOPSIS>.
155 An alternate route to implement this functionality is to write a simple .psgi
156 file for your application, and then use the L<plackup> utility to start the
159 =head2 Upgrading the PSGI Engine
161 If you were using L<Catalyst::Engine::PSGI>, this new release supersedes
162 this engine in supporting L<Plack>. By default the Engine is now always
163 L<Plack>. As a result, you can remove the dependency on
164 L<Catalyst::Engine::PSGI> in your C<Makefile.PL>.
166 Applications that were using L<Catalyst::Engine::PSGI>
167 previously should entirely continue to work in this release with no changes.
169 However, if you have an C<app.psgi> script, then you no longer need to
170 specify the PSGI engine. Instead, the L<Catalyst> application class now
171 has a new method C<psgi_app> which returns a L<PSGI> compatible coderef
172 which you can wrap in the middleware of your choice.
174 Catalyst will use the .psgi for your application if it is located in the C<home>
175 directory of the application.
177 For example, if you were using L<Catalyst::Engine::PSGI> in the past, you will
178 have written (or generated) a C<script/myapp.psgi> file similar to this one:
183 MyCatalystApp->setup_engine('PSGI');
186 enable ... # enable your desired middleware
187 sub { MyCatalystApp->run(@_) };
190 Instead, you now say:
196 enable ... #enable your desired middleware
197 MyCatalystApp->psgi_app;
200 In the simplest case:
202 MyCatalystApp->setup_engine('PSGI');
203 my $app = sub { MyCatalystApp->run(@_) }
207 my $app = MyCatalystApp->psgi_app(@_);
211 my $app = sub { MyCatalystApp->psgi_app(@_) };
212 # If you make ^^ this mistake, your app won't work, and will confuse the hell out of you!
214 You can now move C<< script/myapp.psgi >> to C<< myapp.psgi >>, and the built-in
215 Catalyst scripts and your test suite will start using your .psgi file.
217 B<NOTE:> If you rename your .psgi file without these modifications, then
218 any tests run via L<Catalyst::Test> will not be compatible with the new
219 release, and will result in the development server starting, rather than
220 the expected test running.
222 B<NOTE:> If you are directly accessing C<< $c->req->env >> to get the PSGI
223 environment then this accessor is moved to C<< $c->engine->env >>,
224 you will need to update your code.
226 =head2 Engines which are known to be broken
228 The following engines B<DO NOT> work as of Catalyst version 5.9. The
229 core team will be happy to work with the developers and/or users of
230 these engines to help them port to the new Plack/Engine system, but for
231 now, applications which are currently using these engines B<WILL NOT>
232 run without modification to the engine code.
236 =item Catalyst::Engine::Wx
238 =item Catalyst::Engine::Zeus
240 =item Catalyst::Engine::JobQueue::POE
242 =item Catalyst::Engine::XMPP2
244 =item Catalyst::Engine::SCGI
248 =head2 Engines with unknown status
250 The following engines are untested or have unknown compatibility.
251 Reports are highly encouraged:
255 =item Catalyst::Engine::Mojo
257 =item Catalyst::Engine::Server (marked as Deprecated)
259 =item Catalyst::Engine::HTTP::POE (marked as Deprecated)
263 =head2 Plack functionality
265 See L<Catalyst::PSGI>.
269 Tests should generally work the same in Catalyst 5.9, but there are
272 Previously, if using L<Catalyst::Test> and doing local requests (against
273 a local server), if the application threw an exception then this
274 exception propagated into the test.
276 This behavior has been removed, and now a 500 response will be returned
277 to the test. This change standardizes behavior, so that local test
278 requests behave similarly to remote requests.
280 =head1 Upgrading to Catalyst 5.80
282 Most applications and plugins should run unaltered on Catalyst 5.80.
284 However, a lot of refactoring work has taken place, and several changes have
285 been made which could cause incompatibilities. If your application or plugin
286 is using deprecated code, or relying on side effects, then you could have
287 issues upgrading to this release.
289 Most issues found with existing components have been easy to
290 solve. This document provides a complete description of behavior changes
291 which may cause compatibility issues, and of new Catalyst warnings which
294 If you think you have found an upgrade-related issue which is not covered in
295 this document, please email the Catalyst list to discuss the problem.
297 =head1 Moose features
299 =head2 Application class roles
301 You can only apply method modifiers after the application's C<< ->setup >>
302 method has been called. This means that modifiers will not work with methods
303 run during the call to C<< ->setup >>.
305 See L<Catalyst::Manual::ExtendingCatalyst> for more information about using
306 L<Moose> in your applications.
308 =head2 Controller actions in Moose roles
310 You can use L<MooseX::MethodAttributes::Role> if you want to declare actions
313 =head2 Using Moose in Components
315 The correct way to use Moose in a component in a both forward and backwards
318 package TestApp::Controller::Root;
320 BEGIN { extends 'Catalyst::Component' }; # Or ::Controller, or whatever
322 See L<Components which inherit from Moose::Object before Catalyst::Component>.
324 =head1 Known backwards compatibility breakages
326 =head2 Applications in a single file
328 Applications must be in their own file, and loaded at compile time. This
329 issue generally only affects the tests of CPAN distributions. Your
330 application will fail if you try to define an application inline in a
331 block, and use plugins which supply a C< new > method, then use that
332 application latter in tests within the same file.
334 This is due to the fact that Catalyst is inlining a new method on your
335 application class allowing it to be compatible with Moose. The method
336 used to do this changed in 5.80004 to avoid the possibility of reporting
337 an 'Unknown Error' if your application failed to compile.
339 =head2 Issues with Class::C3
341 Catalyst 5.80 uses the L<Algorithm::C3> method dispatch order. This is
342 built into Perl 5.10, and comes via L<Class::C3> for Perl 5.8. This
343 replaces L<NEXT> with L<Class::C3::Adopt::NEXT>, forcing all components
344 to resolve methods using C3, rather than the unpredictable dispatch
347 This issue manifests itself by your application failing to start due to an
348 error message about having a non-linear @ISA.
350 The Catalyst plugin most often causing this is
351 L<Catalyst::Plugin::Session::Store::FastMmap> - if you are using this
352 plugin and see issues, then please upgrade your plugins, as it has been
353 fixed. Note that Makefile.PL in the distribution will warn about known
354 incompatible components.
356 This issue can, however, be found in your own application - the only solution is
357 to go through each base class of the class the error was reported against, until
358 you identify the ones in conflict, and resolve them.
360 To be able to generate a linear @ISA, the list of superclasses for each
361 class must be resolvable using the C3 algorithm. Unfortunately, when
362 superclasses are being used as mixins (to add functionality used in your class),
363 and with multiple inheritance, it is easy to get this wrong.
365 Most common is the case of:
367 package Component1; # Note, this is the common case
368 use base qw/Class::Accessor::Fast Class::Data::Inheritable/;
370 package Component2; # Accidentally saying it this way causes a failure
371 use base qw/Class::Data::Inheritable Class::Accessor::Fast/;
374 use base qw/Component1 Component2/;
376 Any situation like this will cause your application to fail to start.
378 For additional documentation about this issue, and how to resolve it, see
379 L<Class::C3::Adopt::NEXT>.
381 =head2 Components which inherit from Moose::Object before Catalyst::Component
383 Moose components which say:
385 package TestApp::Controller::Example;
387 extends qw/Moose::Object Catalyst::Component/;
389 to use the constructor provided by Moose, while working (if you do some hacks
390 with the C< BUILDARGS > method), will not work with Catalyst 5.80 as
391 C<Catalyst::Component> inherits from C<Moose::Object>, and so C< @ISA > fails
394 The correct way to use Moose in a component in a both forward and backwards
397 package TestApp::Controller::Root;
399 BEGIN { extends 'Catalyst::Component' }; # Or ::Controller, or whatever
401 Note that the C< extends > declaration needs to occur in a begin block for
402 L<attributes> to operate correctly.
404 This way you do not inherit directly from C<Moose::Object>
405 yourself. Having components which do not inherit their constructor from
406 C<Catalyst::Component> is B<unsupported>, and has never been recommended,
407 therefore you're on your own if you're using this technique. You'll need
408 to detect the version of Catalyst your application is running, and deal
409 with it appropriately.
411 You also don't get the L<Moose::Object> constructor, and therefore attribute
412 initialization will not work as normally expected. If you want to use Moose
413 attributes, then they need to be made lazy to correctly initialize.
415 Note that this only applies if your component needs to maintain component
416 backwards compatibility for Catalyst versions before 5.71001 - in 5.71001
417 attributes work as expected, and the BUILD method is called normally
418 (although BUILDARGS is not).
420 If you depend on Catalyst 5.8, then B<all> Moose features work as expected.
422 You will also see this issue if you do the following:
424 package TestApp::Controller::Example;
426 use base 'Catalyst::Controller';
428 as C< use base > appends to @ISA.
430 =head3 use Moose in MyApp
432 Similar to the above, this will also fail:
441 If you need to use Moose in your application class (e.g. for method modifiers
442 etc.) then the correct technique is:
450 __PACKAGE__->config( name => 'MyApp' );
451 __PACKAGE__->setup(qw/
455 =head2 Anonymous closures installed directly into the symbol table
457 If you have any code which installs anonymous subroutine references directly
458 into the symbol table, you may encounter breakages. The simplest solution is
459 to use L<Sub::Name> to name the subroutine. Example:
461 # Original code, likely to break:
462 my $full_method_name = join('::', $package_name, $method_name);
463 *$full_method_name = sub { ... };
466 use Sub::Name 'subname';
467 my $full_method_name = join('::',$package_name, $method_name);
468 *$full_method_name = subname $full_method_name, sub { ... };
470 Additionally, you can take advantage of Catalyst's use of L<Class::MOP> and
471 install the closure using the appropriate metaclass. Example:
474 my $metaclass = Moose::Meta::Class->initialize($package_name);
475 $metaclass->add_method($method_name => sub { ... });
477 =head2 Hooking into application setup
479 To execute code during application start-up, the following snippet in MyApp.pm
483 my ($class, @args) = @_;
484 $class->NEXT::setup(@args);
485 ... # things to do after the actual setup
488 With Catalyst 5.80 this won't work anymore, because Catalyst no longer
489 uses NEXT.pm for method resolution. The functionality was only ever
490 originally operational as L<NEXT> remembers what methods have already
491 been called, and will not call them again.
493 Using this now causes infinite recursion between MyApp::setup and
494 Catalyst::setup, due to other backwards compatibility issues related to how
495 plugin setup works. Moose method modifiers like C<< before|after|around setup
496 => sub { ... }; >> also will not operate correctly on the setup method.
498 The right way to do it is this:
500 after setup_finalize => sub {
501 ... # things to do after the actual setup
504 The setup_finalize hook was introduced as a way to avoid this issue.
506 =head2 Components with a new method which returns false
508 Previously, if you had a component which inherited from Catalyst::COMPONENT,
509 but overrode the new method to return false, then your class's configuration
510 would be blessed into a hash on your behalf, and this would be returned from
511 the COMPONENT method.
513 This behavior makes no sense, and so has been removed. Implementing your own
514 C< new > method in components is B<highly> discouraged. Instead, you should
515 inherit the new method from Catalyst::Component, and use Moose's BUILD
516 functionality and/or Moose attributes to perform any construction work
517 necessary for your class.
519 =head2 __PACKAGE__->mk_accessor('meta');
521 Won't work due to a limitation of L<Moose>. This is currently being fixed
524 =head2 Class::Data::Inheritable side effects
526 Previously, writing to a class data accessor would copy the accessor method
527 down into your package.
529 This behavior has been removed. While the class data is still stored
530 per-class, it is stored on the metaclass of the class defining the accessor.
532 Therefore anything relying on the side effect of the accessor being copied down
535 The following test demonstrates the problem:
539 use base qw/Class::Data::Inheritable/;
540 __PACKAGE__->mk_classdata('foo');
545 use base qw/BaseClass/;
548 BaseClass->foo('base class');
549 Child->foo('sub class');
552 isnt(BaseClass->can('foo'), Child->can('foo'));
554 =head2 Extending Catalyst::Request or other classes in an ad hoc manner using mk_accessors
556 Previously, it was possible to add additional accessors to Catalyst::Request
557 (or other classes) by calling the mk_accessors class method.
559 This is no longer supported - users should make a subclass of the class whose
560 behavior they would like to change, rather than globally polluting the
563 =head2 Confused multiple inheritance with Catalyst::Component::COMPONENT
565 Previously, Catalyst's COMPONENT method would delegate to the method on
566 the right hand side, which could then delegate back again with
567 NEXT. This is poor practice, and in addition, makes no sense with C3
568 method dispatch order, and is therefore no longer supported.
570 If a COMPONENT method is detected in the inheritance hierarchy to the right
571 hand side of Catalyst::Component::COMPONENT, then the following warning
572 message will be emitted:
574 There is a COMPONENT method resolving after Catalyst::Component
577 The correct fix is to re-arrange your class's inheritance hierarchy so that the
578 COMPONENT method you would like to inherit is the first (left-hand most)
579 COMPONENT method in your @ISA.
581 =head2 Development server relying on environment variables
583 Previously, the development server would allow propagation of system
584 environment variables into the request environment, this has changed with the
585 adoption of Plack. You can use L<Plack::Middleware::ForceEnv> to achieve the
590 =head2 Actions in your application class
592 Having actions in your application class will now emit a warning at application
593 startup as this is deprecated. It is highly recommended that these actions are moved
594 into a MyApp::Controller::Root (as demonstrated by the scaffold application
595 generated by catalyst.pl).
597 This warning, also affects tests. You should move actions in your test,
598 creating a myTest::Controller::Root, like the following example:
600 package MyTest::Controller::Root;
605 use parent 'Catalyst::Controller';
607 __PACKAGE__->config(namespace => '');
610 my ( $self, $c ) = @_;
616 =head2 ::[MVC]:: naming scheme
618 Having packages called MyApp::[MVC]::XX is deprecated and can no longer be generated
621 This is still supported, but it is recommended that you rename your application
622 components to Model/View/Controller.
624 A warning will be issued at application startup if the ::[MVC]:: naming scheme is
627 =head2 Catalyst::Base
629 Any code using L<Catalyst::Base> will now emit a warning; this
630 module will be removed in a future release.
632 =head2 Methods in Catalyst::Dispatcher
634 The following methods in Catalyst::Dispatcher are implementation
635 details, which may change in the 5.8X release series, and therefore their use
636 is highly deprecated.
644 =item registered_dispatch_types
646 =item method_action_class
654 The first time one of these methods is called, a warning will be emitted:
656 Class $class is calling the deprecated method Catalyst::Dispatcher::$public_method_name,
657 this will be removed in Catalyst 5.9
659 You should B<NEVER> be calling any of these methods from application code.
661 Plugin authors and maintainers whose plugins currently call these methods
662 should change to using the public API, or, if you do not feel the public API
663 adequately supports your use case, please email the development list to
664 discuss what API features you need so that you can be appropriately supported.
666 =head2 Class files with names that don't correspond to the packages they define
668 In this version of Catalyst, if a component is loaded from disk, but no
669 symbols are defined in that component's name space after it is loaded, this
670 warning will be issued:
672 require $class was successful but the package is not defined.
674 This is to protect against confusing bugs caused by mistyping package names,
675 and will become a fatal error in a future version.
677 Please note that 'inner packages' (via L<Devel::InnerPackage>) are still fully
678 supported; this warning is only issued when component file naming does not map
679 to B<any> of the packages defined within that component.
681 =head2 $c->plugin method
683 Calling the plugin method is deprecated, and calling it at run time is B<highly
686 Instead you are recommended to use L<Catalyst::Model::Adaptor> or similar to
687 compose the functionality you need outside of the main application name space.
689 Calling the plugin method will not be supported past Catalyst 5.81.