3 Catalyst::Upgrading - Instructions for upgrading to the latest Catalyst
5 =head1 Upgrading to Catalyst 5.90
7 The major change is that L<Plack> now replaces most of the subclasses of
8 L<Catalyst::Engine>. If you are using one of the standard subclasses of
9 L<Catalyst::Engine> this should be a straightforward upgrade for you. It was
10 a design goal for this release to be as backwardly compatible as possible.
11 However since L<Plack> is different from L<Catalyst::Engine> it would be
12 possible that edge case differences would exist. Therefore we recommend care
13 be taken with this upgrade and that testing should be greater than would be
14 the case with a minor point update.
16 It is highly recommended that you become familar with the L<Plack> ecosystem
17 and documentation. Being able to take advantage of L<Plack> development and
18 middleware is a major bonus to this upgrade.
20 If you have created a custom subclass of L<Catalyst:Engine> you will need to
21 convert it to be a subclass of L<Plack::Handler>.
23 If you are using the L<Plack> engine, L<Catalyst::Engine::PSGI>, this new
24 release supercedes that code.
26 If you are using a subclass of L<Catalyst::Engine> that is aimed at nonstandard
27 or internal / testing uses, such as L<Catalyst::Engine::Embeddable> you should
28 still be able to continue using that engine.
30 Advice for specific subclasses of L<Catalyst::Engine> follows:
32 =head2 Upgrading the FastCGI Engine
34 No upgrade needed if your myapp_fastcgi.pl script is already upgraded
35 enough to use L<Catalyst::Script::FastCGI>.
37 =head2 Upgrading the mod_perl / Apache Engines
39 The engines that are build upon the various iterations of mod_perl,
40 L<Catalyst::Engine::Apache::MP13> and
41 L<Catalyst::Engine::Apache2::MP20> should be seemless upgrades and will
42 work using using L<Plack::Handler::Apache1> or L<Plack::Handler::Apache2>
45 L<Catalyst::Engine::Apache2::MP19>, is however no longer supported, as Plack
46 does not support mod_perl version 1.99??? FIXME - is this true?
48 =head2 Upgrading the HTTP Engine
50 The default development server that comes with the L<Catalyst> distribution
51 should continue to work as expected with no changes as long as your C<myapp_server>
52 script is upgraded to use L<Catalyst::Script::HTTP>.
54 =head2 Upgrading the CGI Engine
56 If you were using L<Catalyst::Engine::CGI> there is no upgrade needed if your
57 myapp_cgi.pl script is already upgraded enough to use L<Catalyst::Script::CGI>.
59 =head2 Upgrading the Preforking Engine
61 If you were using L<Catalyst::Engine::HTTP::Prefork> then L<Starman>
62 is automatically loaded.
64 XXX FIXME - note how to run Starman with different options.
66 =head2 Upgrading the PSGI Engine
68 If you were using L<Catalyst::Engine::PSGI> this new release supercedes this
69 engine in supporting L<Plack>. By default the Engine is now always L<Plack>.
70 As a result, you can stop depending on L<Catalyst::Engine::PSGI> in your
73 Applications that were using L<Catalyst::Engine::PSGI>
74 previously should entirely continue to work in this release with no changes.
76 However, if you have an C<app.psgi> script, then you no longer
77 need to specify the PSGI engine. Instead, the L<Catalyst> application class
78 now has a new method C<psgi_app> which returns a L<PSGI> compatible coderef
79 which you can wrap in middleware of your choice.
81 Catalyst will use the .psgi for your application if it is located in the C<home>
82 directory of the application
84 For example, if you were using L<Catalyst::Engine::PSGI> in the past, you will
85 have written (or generated) a C<script/myapp.psgi> file similar to this one:
90 MyCatalystApp->setup_engine('PSGI');
93 enable ... # enable your desired middleware
94 sub { MyCatalystApp->run(@_) };
103 enable ... #enable your desired middleware
104 MyCatalystApp->psgi_app;
107 And also rename C<< script/myapp.psgi >> to C<< myapp.psgi >>.
109 XXX - FIXME - t/psgi_file_testapp_engine_psgi_compat.t
111 If you rename your .psgi file without these modifications, then any tests run via
112 L<Catalyst::Test> will not be compatible with the new release, and will result in
113 the development server starting, rather than the expected test running.
115 =head2 Engines which are known broken
117 The following engines B<DO NOT> work as of Catalyst version 5.90. The core
118 team is extremely happy to work with the developers and/or users of these
119 engines to help them port to the new Plack/Engine system, however applications
120 which are currently using these engines B<WILL NOT> run without modification
125 =item Catalyst::Engine::Wx
127 =item Catalyst::Engine::Zeus
129 =item Catalyst::Engine::JobQueue::POE
131 =item Catalyst::Engine::XMPP2
133 =item Catalyst::Engine::SCGI
137 =head2 Engines with unknown status
139 The following engines have untested or unknown compatibility. Reports are
144 =item Catalyst::Engine::Mojo
146 =item Catalyst::Engine::Server (Marked as Deprecated)
148 =item Catalyst::Engine::HTTP::POE (Marked as Deprecated)
152 =head2 Using middleware
154 XXX Should this be here or elsewhere?
156 =head2 Making an app.psgi file
158 =head2 Running with plackup?
160 =head1 Upgrading to Catalyst 5.80
162 Most applications and plugins should run unaltered on Catalyst 5.80.
164 However, a lot of refactoring work has taken place, and several changes have
165 been made which could cause incompatibilities. If your application or plugin
166 is using deprecated code, or relying on side effects, then you could have
167 issues upgrading to this release.
169 Most issues found with pre-existing components have been easy to
170 solve. This document provides a complete description of behavior changes
171 which may cause compatibility issues, and of new Catalyst warnings which
174 If you think you have found an upgrade-related issue which is not covered in
175 this document, please email the Catalyst list to discuss the problem.
177 =head1 Moose features
179 =head2 Application class roles
181 You can only apply method modifiers after the application's C<< ->setup >>
182 method has been called. This means that modifiers will not work with methods
183 which run during the call to C<< ->setup >>.
185 See L<Catalyst::Manual::ExtendingCatalyst> for more information about using
186 L<Moose> in your applications.
188 =head2 Controller actions in Moose roles
190 You can use L<MooseX::MethodAttributes::Role> if you want to declare actions
193 =head2 Using Moose in Components
195 The correct way to use Moose in a component in a both forward and backwards
198 package TestApp::Controller::Root;
200 BEGIN { extends 'Catalyst::Component' }; # Or ::Controller, or whatever
202 See L<Components which inherit from Moose::Object before Catalyst::Component>.
204 =head1 Known backwards compatibility breakages
206 =head2 Applications in a single file
208 Applications must be in their own file, and loaded at compile time. This
209 issue generally only affects the tests of CPAN distributions. Your
210 application will fail if you try to define an application inline in a
211 block, and use plugins which supply a C< new > method, then use that
212 application latter in tests within the same file.
214 This is due to the fact that Catalyst is inlining a new method on your
215 application class allowing it to be compatible with Moose. The method
216 used to do this changed in 5.80004 to avoid the possibility of reporting
217 an 'Unknown Error' if your application failed to compile.
219 =head2 Issues with Class::C3
221 Catalyst 5.80 uses the L<Algorithm::C3> method dispatch order. This is
222 built into Perl 5.10, and comes via L<Class::C3> for Perl 5.8. This
223 replaces L<NEXT> with L<Class::C3::Adopt::NEXT>, forcing all components
224 to resolve methods using C3, rather than the unpredictable dispatch
227 This issue is characterised by your application failing to start due to an
228 error message about having a non-linear @ISA.
230 The Catalyst plugin most often causing this is
231 L<Catalyst::Plugin::Session::Store::FastMmap> - if you are using this
232 plugin and see issues, then please upgrade your plugins, as it has been
233 fixed. Note that Makefile.PL in the distribution will warn about known
234 incompatible components.
236 This issue can, however, be found in your own application - the only solution is
237 to go through each base class of the class the error was reported against, until
238 you identify the ones in conflict, and resolve them.
240 To be able to generate a linear @ISA, the list of superclasses for each
241 class must be resolvable using the C3 algorithm. Unfortunately, when
242 superclasses are being used as mixins (to add functionality used in your class),
243 and with multiple inheritence, it is easy to get this wrong.
245 Most common is the case of:
247 package Component1; # Note, this is the common case
248 use base qw/Class::Accessor::Fast Class::Data::Inheritable/;
250 package Component2; # Accidentally saying it this way causes a failure
251 use base qw/Class::Data::Inheritable Class::Accessor::Fast/;
254 use base qw/Component1 Component2/;
256 Any situation like this will cause your application to fail to start.
258 For additional documentation about this issue, and how to resolve it, see
259 L<Class::C3::Adopt::NEXT>.
261 =head2 Components which inherit from Moose::Object before Catalyst::Component
263 Moose components which say:
265 package TestApp::Controller::Example;
267 extends qw/Moose::Object Catalyst::Component/;
269 to use the constructor provided by Moose, while working (if you do some hacks
270 with the C< BUILDARGS > method), will not work with Catalyst 5.80 as
271 C<Catalyst::Component> inherits from C<Moose::Object>, and so C< @ISA > fails
274 The correct way to use Moose in a component in a both forward and backwards
277 package TestApp::Controller::Root;
279 BEGIN { extends 'Catalyst::Component' }; # Or ::Controller, or whatever
281 Note that the C< extends > declaration needs to occur in a begin block for
282 L<attributes> to operate correctly.
284 This way you do not inherit directly from C<Moose::Object>
285 yourself. Having components which do not inherit their constructor from
286 C<Catalyst::Component> is B<unsupported>, and has never been recommended,
287 therefore you're on your own if you're using this technique. You'll need
288 to detect the version of Catalyst your application is running, and deal
289 with it appropriately.
291 You also don't get the L<Moose::Object> constructor, and therefore attribute
292 initialization will not work as normally expected. If you want to use Moose
293 attributes, then they need to be made lazy to correctly initialize.
295 Note that this only applies if your component needs to maintain component
296 backwards compatibility for Catalyst versions before 5.71001 - in 5.71001
297 attributes work as expected, and the BUILD method is called normally
298 (although BUILDARGS is not).
300 If you depend on Catalyst 5.8, then B<all> Moose features work as expected.
302 You will also see this issue if you do the following:
304 package TestApp::Controller::Example;
306 use base 'Catalyst::Controller';
308 as C< use base > appends to @ISA.
310 =head3 use Moose in MyApp
312 Similar to the above, this will also fail:
321 If you need to use Moose in your application class (e.g. for method modifiers
322 etc.) then the correct technique is:
330 __PACKAGE__->config( name => 'MyApp' );
331 __PACKAGE__->setup(qw/
335 =head2 Anonymous closures installed directly into the symbol table
337 If you have any code which installs anonymous subroutine references directly
338 into the symbol table, you may encounter breakages. The simplest solution is
339 to use L<Sub::Name> to name the subroutine. Example:
341 # Original code, likely to break:
342 my $full_method_name = join('::', $package_name, $method_name);
343 *$full_method_name = sub { ... };
346 use Sub::Name 'subname';
347 my $full_method_name = join('::',$package_name, $method_name);
348 *$full_method_name = subname $full_method_name, sub { ... };
350 Additionally, you can take advantage of Catalyst's use of L<Class::MOP> and
351 install the closure using the appropriate metaclass. Example:
354 my $metaclass = Moose::Meta::Class->initialize($package_name);
355 $metaclass->add_method($method_name => sub { ... });
357 =head2 Hooking into application setup
359 To execute code during application start-up, the following snippet in MyApp.pm
363 my ($class, @args) = @_;
364 $class->NEXT::setup(@args);
365 ... # things to do after the actual setup
368 With Catalyst 5.80 this won't work anymore, because Catalyst no longer
369 uses NEXT.pm for method resolution. The functionality was only ever
370 originally operational as L<NEXT> remembers what methods have already
371 been called, and will not call them again.
373 Using this now causes infinite recursion between MyApp::setup and
374 Catalyst::setup, due to other backwards compatibility issues related to how
375 plugin setup works. Moose method modifiers like C<< before|after|around setup
376 => sub { ... }; >> also will not operate correctly on the setup method.
378 The right way to do it is this:
380 after setup_finalize => sub {
381 ... # things to do after the actual setup
384 The setup_finalize hook was introduced as a way to avoid this issue.
386 =head2 Components with a new method which returns false
388 Previously, if you had a component which inherited from Catalyst::COMPONENT,
389 but overrode the new method to return false, then your class's configuration
390 would be blessed into a hash on your behalf, and this would be returned from
391 the COMPONENT method.
393 This behavior makes no sense, and so has been removed. Implementing your own
394 C< new > method in components is B<highly> discouraged. Instead, you should
395 inherit the new method from Catalyst::Component, and use Moose's BUILD
396 functionality and/or Moose attributes to perform any construction work
397 necessary for your class.
399 =head2 __PACKAGE__->mk_accessor('meta');
401 Won't work due to a limitation of L<Moose>. This is currently being fixed
404 =head2 Class::Data::Inheritable side effects
406 Previously, writing to a class data accessor would copy the accessor method
407 down into your package.
409 This behavior has been removed. While the class data is still stored
410 per-class, it is stored on the metaclass of the class defining the accessor.
412 Therefore anything relying on the side effect of the accessor being copied down
415 The following test demonstrates the problem:
419 use base qw/Class::Data::Inheritable/;
420 __PACKAGE__->mk_classdata('foo');
425 use base qw/BaseClass/;
428 BaseClass->foo('base class');
429 Child->foo('sub class');
432 isnt(BaseClass->can('foo'), Child->can('foo'));
434 =head2 Extending Catalyst::Request or other classes in an ad-hoc manner using mk_accessors
436 Previously, it was possible to add additional accessors to Catalyst::Request
437 (or other classes) by calling the mk_accessors class method.
439 This is no longer supported - users should make a subclass of the class whose
440 behavior they would like to change, rather than globally polluting the
443 =head2 Confused multiple inheritance with Catalyst::Component::COMPONENT
445 Previously, Catalyst's COMPONENT method would delegate to the method on
446 the right hand side, which could then delegate back again with
447 NEXT. This is poor practice, and in addition, makes no sense with C3
448 method dispatch order, and is therefore no longer supported.
450 If a COMPONENT method is detected in the inheritance hierarchy to the right
451 hand side of Catalyst::Component::COMPONENT, then the following warning
452 message will be emitted:
454 There is a COMPONENT method resolving after Catalyst::Component
457 The correct fix is to re-arrange your class's inheritance hierarchy so that the
458 COMPONENT method you would like to inherit is the first (left-hand most)
459 COMPONENT method in your @ISA.
463 =head2 Actions in your application class
465 Having actions in your application class will now emit a warning at application
466 startup as this is deprecated. It is highly recommended that these actions are moved
467 into a MyApp::Controller::Root (as demonstrated by the scaffold application
468 generated by catalyst.pl).
470 This warning, also affects tests. You should move actions in your test,
471 creating a myTest::Controller::Root, like the following example:
473 package MyTest::Controller::Root;
478 use parent 'Catalyst::Controller';
480 __PACKAGE__->config(namespace => '');
483 my ( $self, $c ) = @_;
489 =head2 ::[MVC]:: naming scheme
491 Having packages called MyApp::[MVC]::XX is deprecated and can no longer be generated
494 This is still supported, but it is recommended that you rename your application
495 components to Model/View/Controller.
497 A warning will be issued at application startup if the ::[MVC]:: naming scheme is
500 =head2 Catalyst::Base
502 Any code using L<Catalyst::Base> will now emit a warning; this
503 module will be removed in a future release.
505 =head2 Methods in Catalyst::Dispatcher
507 The following methods in Catalyst::Dispatcher are implementation
508 details, which may change in the 5.8X release series, and therefore their use
509 is highly deprecated.
517 =item registered_dispatch_types
519 =item method_action_class
527 The first time one of these methods is called, a warning will be emitted:
529 Class $class is calling the deprecated method Catalyst::Dispatcher::$public_method_name,
530 this will be removed in Catalyst 5.9X
532 You should B<NEVER> be calling any of these methods from application code.
534 Plugin authors and maintainers whose plugins currently call these methods
535 should change to using the public API, or, if you do not feel the public API
536 adequately supports your use case, please email the development list to
537 discuss what API features you need so that you can be appropriately supported.
539 =head2 Class files with names that don't correspond to the packages they define
541 In this version of Catalyst, if a component is loaded from disk, but no
542 symbols are defined in that component's name space after it is loaded, this
543 warning will be issued:
545 require $class was successful but the package is not defined.
547 This is to protect against confusing bugs caused by mistyping package names,
548 and will become a fatal error in a future version.
550 Please note that 'inner packages' (via L<Devel::InnerPackage>) are still fully
551 supported; this warning is only issued when component file naming does not map
552 to B<any> of the packages defined within that component.
554 =head2 $c->plugin method
556 Calling the plugin method is deprecated, and calling it at run time is B<highly
559 Instead you are recommended to use L<Catalyst::Model::Adaptor> or similar to
560 compose the functionality you need outside of the main application name space.
562 Calling the plugin method will not be supported past Catalyst 5.81.