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. Documentation about how to
19 take advantage of L<Plack::Middleware> by writing your own C<< .psgi >> file
20 is contained in L<Catalyst::PSGI>.
22 If you have created a custom subclass of L<Catalyst:Engine> you will need to
23 convert it to be a subclass of L<Plack::Handler>.
25 If you are using the L<Plack> engine, L<Catalyst::Engine::PSGI>, this new
26 release supercedes that code.
28 If you are using a subclass of L<Catalyst::Engine> that is aimed at nonstandard
29 or internal / testing uses, such as L<Catalyst::Engine::Embeddable> you should
30 still be able to continue using that engine.
32 Advice for specific subclasses of L<Catalyst::Engine> follows:
34 =head2 Upgrading the FastCGI Engine
36 No upgrade needed if your myapp_fastcgi.pl script is already upgraded
37 enough to use L<Catalyst::Script::FastCGI>.
39 =head2 Upgrading the mod_perl / Apache Engines
41 The engines that are build upon the various iterations of mod_perl,
42 L<Catalyst::Engine::Apache::MP13> and
43 L<Catalyst::Engine::Apache2::MP20> should be seemless upgrades and will
44 work using using L<Plack::Handler::Apache1> or L<Plack::Handler::Apache2>
47 L<Catalyst::Engine::Apache2::MP19>, is however no longer supported, as Plack
48 does not support mod_perl version 1.99??? FIXME - is this true?
50 =head2 Upgrading the HTTP Engine
52 The default development server that comes with the L<Catalyst> distribution
53 should continue to work as expected with no changes as long as your C<myapp_server>
54 script is upgraded to use L<Catalyst::Script::HTTP>.
56 =head2 Upgrading the CGI Engine
58 If you were using L<Catalyst::Engine::CGI> there is no upgrade needed if your
59 myapp_cgi.pl script is already upgraded enough to use L<Catalyst::Script::CGI>.
61 =head2 Upgrading the Preforking Engine
63 If you were using L<Catalyst::Engine::HTTP::Prefork> then L<Starman>
64 is automatically loaded.
66 XXX FIXME - note how to run Starman with different options.
68 =head2 Upgrading the PSGI Engine
70 If you were using L<Catalyst::Engine::PSGI> this new release supercedes this
71 engine in supporting L<Plack>. By default the Engine is now always L<Plack>.
72 As a result, you can stop depending on L<Catalyst::Engine::PSGI> in your
75 Applications that were using L<Catalyst::Engine::PSGI>
76 previously should entirely continue to work in this release with no changes.
78 However, if you have an C<app.psgi> script, then you no longer
79 need to specify the PSGI engine. Instead, the L<Catalyst> application class
80 now has a new method C<psgi_app> which returns a L<PSGI> compatible coderef
81 which you can wrap in middleware of your choice.
83 Catalyst will use the .psgi for your application if it is located in the C<home>
84 directory of the application
86 For example, if you were using L<Catalyst::Engine::PSGI> in the past, you will
87 have written (or generated) a C<script/myapp.psgi> file similar to this one:
92 MyCatalystApp->setup_engine('PSGI');
95 enable ... # enable your desired middleware
96 sub { MyCatalystApp->run(@_) };
105 enable ... #enable your desired middleware
106 MyCatalystApp->psgi_app;
109 In the simplest case:
111 MyCatalystApp->setup_engine('PSGI');
112 my $app = sub { MyCatalystApp->run(@_) }
116 MyCatalystApp->setup_engine('PSGI');
117 my $app = MyCatalystApp->psgi_app(@_);
121 my $app = sub { MyCatalystApp->psgi_app(@_) };
122 # If you make ^^ this mistake, your app won't work, and will confuse the hell out of you!
124 You can now rename C<< script/myapp.psgi >> to C<< myapp.psgi >>, and the built-in
125 Catalyst scripts, and your test suite will start using your .psgi file.
127 B<NOTE:> If you rename your .psgi file without these modifications, then any tests run via
128 L<Catalyst::Test> will not be compatible with the new release, and will result in
129 the development server starting, rather than the expected test running.
131 =head2 Engines which are known broken
133 The following engines B<DO NOT> work as of Catalyst version 5.90. The core
134 team is extremely happy to work with the developers and/or users of these
135 engines to help them port to the new Plack/Engine system, however applications
136 which are currently using these engines B<WILL NOT> run without modification
141 =item Catalyst::Engine::Wx
143 =item Catalyst::Engine::Zeus
145 =item Catalyst::Engine::JobQueue::POE
147 =item Catalyst::Engine::XMPP2
149 =item Catalyst::Engine::SCGI
153 =head2 Engines with unknown status
155 The following engines have untested or unknown compatibility. Reports are
160 =item Catalyst::Engine::Mojo
162 =item Catalyst::Engine::Server (Marked as Deprecated)
164 =item Catalyst::Engine::HTTP::POE (Marked as Deprecated)
168 =head2 Using middleware
170 XXX Should this be here or elsewhere?
172 =head2 Making an app.psgi file
174 =head2 Running with plackup?
176 =head1 Upgrading to Catalyst 5.80
178 Most applications and plugins should run unaltered on Catalyst 5.80.
180 However, a lot of refactoring work has taken place, and several changes have
181 been made which could cause incompatibilities. If your application or plugin
182 is using deprecated code, or relying on side effects, then you could have
183 issues upgrading to this release.
185 Most issues found with pre-existing components have been easy to
186 solve. This document provides a complete description of behavior changes
187 which may cause compatibility issues, and of new Catalyst warnings which
190 If you think you have found an upgrade-related issue which is not covered in
191 this document, please email the Catalyst list to discuss the problem.
193 =head1 Moose features
195 =head2 Application class roles
197 You can only apply method modifiers after the application's C<< ->setup >>
198 method has been called. This means that modifiers will not work with methods
199 which run during the call to C<< ->setup >>.
201 See L<Catalyst::Manual::ExtendingCatalyst> for more information about using
202 L<Moose> in your applications.
204 =head2 Controller actions in Moose roles
206 You can use L<MooseX::MethodAttributes::Role> if you want to declare actions
209 =head2 Using Moose in Components
211 The correct way to use Moose in a component in a both forward and backwards
214 package TestApp::Controller::Root;
216 BEGIN { extends 'Catalyst::Component' }; # Or ::Controller, or whatever
218 See L<Components which inherit from Moose::Object before Catalyst::Component>.
220 =head1 Known backwards compatibility breakages
222 =head2 Applications in a single file
224 Applications must be in their own file, and loaded at compile time. This
225 issue generally only affects the tests of CPAN distributions. Your
226 application will fail if you try to define an application inline in a
227 block, and use plugins which supply a C< new > method, then use that
228 application latter in tests within the same file.
230 This is due to the fact that Catalyst is inlining a new method on your
231 application class allowing it to be compatible with Moose. The method
232 used to do this changed in 5.80004 to avoid the possibility of reporting
233 an 'Unknown Error' if your application failed to compile.
235 =head2 Issues with Class::C3
237 Catalyst 5.80 uses the L<Algorithm::C3> method dispatch order. This is
238 built into Perl 5.10, and comes via L<Class::C3> for Perl 5.8. This
239 replaces L<NEXT> with L<Class::C3::Adopt::NEXT>, forcing all components
240 to resolve methods using C3, rather than the unpredictable dispatch
243 This issue is characterised by your application failing to start due to an
244 error message about having a non-linear @ISA.
246 The Catalyst plugin most often causing this is
247 L<Catalyst::Plugin::Session::Store::FastMmap> - if you are using this
248 plugin and see issues, then please upgrade your plugins, as it has been
249 fixed. Note that Makefile.PL in the distribution will warn about known
250 incompatible components.
252 This issue can, however, be found in your own application - the only solution is
253 to go through each base class of the class the error was reported against, until
254 you identify the ones in conflict, and resolve them.
256 To be able to generate a linear @ISA, the list of superclasses for each
257 class must be resolvable using the C3 algorithm. Unfortunately, when
258 superclasses are being used as mixins (to add functionality used in your class),
259 and with multiple inheritence, it is easy to get this wrong.
261 Most common is the case of:
263 package Component1; # Note, this is the common case
264 use base qw/Class::Accessor::Fast Class::Data::Inheritable/;
266 package Component2; # Accidentally saying it this way causes a failure
267 use base qw/Class::Data::Inheritable Class::Accessor::Fast/;
270 use base qw/Component1 Component2/;
272 Any situation like this will cause your application to fail to start.
274 For additional documentation about this issue, and how to resolve it, see
275 L<Class::C3::Adopt::NEXT>.
277 =head2 Components which inherit from Moose::Object before Catalyst::Component
279 Moose components which say:
281 package TestApp::Controller::Example;
283 extends qw/Moose::Object Catalyst::Component/;
285 to use the constructor provided by Moose, while working (if you do some hacks
286 with the C< BUILDARGS > method), will not work with Catalyst 5.80 as
287 C<Catalyst::Component> inherits from C<Moose::Object>, and so C< @ISA > fails
290 The correct way to use Moose in a component in a both forward and backwards
293 package TestApp::Controller::Root;
295 BEGIN { extends 'Catalyst::Component' }; # Or ::Controller, or whatever
297 Note that the C< extends > declaration needs to occur in a begin block for
298 L<attributes> to operate correctly.
300 This way you do not inherit directly from C<Moose::Object>
301 yourself. Having components which do not inherit their constructor from
302 C<Catalyst::Component> is B<unsupported>, and has never been recommended,
303 therefore you're on your own if you're using this technique. You'll need
304 to detect the version of Catalyst your application is running, and deal
305 with it appropriately.
307 You also don't get the L<Moose::Object> constructor, and therefore attribute
308 initialization will not work as normally expected. If you want to use Moose
309 attributes, then they need to be made lazy to correctly initialize.
311 Note that this only applies if your component needs to maintain component
312 backwards compatibility for Catalyst versions before 5.71001 - in 5.71001
313 attributes work as expected, and the BUILD method is called normally
314 (although BUILDARGS is not).
316 If you depend on Catalyst 5.8, then B<all> Moose features work as expected.
318 You will also see this issue if you do the following:
320 package TestApp::Controller::Example;
322 use base 'Catalyst::Controller';
324 as C< use base > appends to @ISA.
326 =head3 use Moose in MyApp
328 Similar to the above, this will also fail:
337 If you need to use Moose in your application class (e.g. for method modifiers
338 etc.) then the correct technique is:
346 __PACKAGE__->config( name => 'MyApp' );
347 __PACKAGE__->setup(qw/
351 =head2 Anonymous closures installed directly into the symbol table
353 If you have any code which installs anonymous subroutine references directly
354 into the symbol table, you may encounter breakages. The simplest solution is
355 to use L<Sub::Name> to name the subroutine. Example:
357 # Original code, likely to break:
358 my $full_method_name = join('::', $package_name, $method_name);
359 *$full_method_name = sub { ... };
362 use Sub::Name 'subname';
363 my $full_method_name = join('::',$package_name, $method_name);
364 *$full_method_name = subname $full_method_name, sub { ... };
366 Additionally, you can take advantage of Catalyst's use of L<Class::MOP> and
367 install the closure using the appropriate metaclass. Example:
370 my $metaclass = Moose::Meta::Class->initialize($package_name);
371 $metaclass->add_method($method_name => sub { ... });
373 =head2 Hooking into application setup
375 To execute code during application start-up, the following snippet in MyApp.pm
379 my ($class, @args) = @_;
380 $class->NEXT::setup(@args);
381 ... # things to do after the actual setup
384 With Catalyst 5.80 this won't work anymore, because Catalyst no longer
385 uses NEXT.pm for method resolution. The functionality was only ever
386 originally operational as L<NEXT> remembers what methods have already
387 been called, and will not call them again.
389 Using this now causes infinite recursion between MyApp::setup and
390 Catalyst::setup, due to other backwards compatibility issues related to how
391 plugin setup works. Moose method modifiers like C<< before|after|around setup
392 => sub { ... }; >> also will not operate correctly on the setup method.
394 The right way to do it is this:
396 after setup_finalize => sub {
397 ... # things to do after the actual setup
400 The setup_finalize hook was introduced as a way to avoid this issue.
402 =head2 Components with a new method which returns false
404 Previously, if you had a component which inherited from Catalyst::COMPONENT,
405 but overrode the new method to return false, then your class's configuration
406 would be blessed into a hash on your behalf, and this would be returned from
407 the COMPONENT method.
409 This behavior makes no sense, and so has been removed. Implementing your own
410 C< new > method in components is B<highly> discouraged. Instead, you should
411 inherit the new method from Catalyst::Component, and use Moose's BUILD
412 functionality and/or Moose attributes to perform any construction work
413 necessary for your class.
415 =head2 __PACKAGE__->mk_accessor('meta');
417 Won't work due to a limitation of L<Moose>. This is currently being fixed
420 =head2 Class::Data::Inheritable side effects
422 Previously, writing to a class data accessor would copy the accessor method
423 down into your package.
425 This behavior has been removed. While the class data is still stored
426 per-class, it is stored on the metaclass of the class defining the accessor.
428 Therefore anything relying on the side effect of the accessor being copied down
431 The following test demonstrates the problem:
435 use base qw/Class::Data::Inheritable/;
436 __PACKAGE__->mk_classdata('foo');
441 use base qw/BaseClass/;
444 BaseClass->foo('base class');
445 Child->foo('sub class');
448 isnt(BaseClass->can('foo'), Child->can('foo'));
450 =head2 Extending Catalyst::Request or other classes in an ad-hoc manner using mk_accessors
452 Previously, it was possible to add additional accessors to Catalyst::Request
453 (or other classes) by calling the mk_accessors class method.
455 This is no longer supported - users should make a subclass of the class whose
456 behavior they would like to change, rather than globally polluting the
459 =head2 Confused multiple inheritance with Catalyst::Component::COMPONENT
461 Previously, Catalyst's COMPONENT method would delegate to the method on
462 the right hand side, which could then delegate back again with
463 NEXT. This is poor practice, and in addition, makes no sense with C3
464 method dispatch order, and is therefore no longer supported.
466 If a COMPONENT method is detected in the inheritance hierarchy to the right
467 hand side of Catalyst::Component::COMPONENT, then the following warning
468 message will be emitted:
470 There is a COMPONENT method resolving after Catalyst::Component
473 The correct fix is to re-arrange your class's inheritance hierarchy so that the
474 COMPONENT method you would like to inherit is the first (left-hand most)
475 COMPONENT method in your @ISA.
479 =head2 Actions in your application class
481 Having actions in your application class will now emit a warning at application
482 startup as this is deprecated. It is highly recommended that these actions are moved
483 into a MyApp::Controller::Root (as demonstrated by the scaffold application
484 generated by catalyst.pl).
486 This warning, also affects tests. You should move actions in your test,
487 creating a myTest::Controller::Root, like the following example:
489 package MyTest::Controller::Root;
494 use parent 'Catalyst::Controller';
496 __PACKAGE__->config(namespace => '');
499 my ( $self, $c ) = @_;
505 =head2 ::[MVC]:: naming scheme
507 Having packages called MyApp::[MVC]::XX is deprecated and can no longer be generated
510 This is still supported, but it is recommended that you rename your application
511 components to Model/View/Controller.
513 A warning will be issued at application startup if the ::[MVC]:: naming scheme is
516 =head2 Catalyst::Base
518 Any code using L<Catalyst::Base> will now emit a warning; this
519 module will be removed in a future release.
521 =head2 Methods in Catalyst::Dispatcher
523 The following methods in Catalyst::Dispatcher are implementation
524 details, which may change in the 5.8X release series, and therefore their use
525 is highly deprecated.
533 =item registered_dispatch_types
535 =item method_action_class
543 The first time one of these methods is called, a warning will be emitted:
545 Class $class is calling the deprecated method Catalyst::Dispatcher::$public_method_name,
546 this will be removed in Catalyst 5.9X
548 You should B<NEVER> be calling any of these methods from application code.
550 Plugin authors and maintainers whose plugins currently call these methods
551 should change to using the public API, or, if you do not feel the public API
552 adequately supports your use case, please email the development list to
553 discuss what API features you need so that you can be appropriately supported.
555 =head2 Class files with names that don't correspond to the packages they define
557 In this version of Catalyst, if a component is loaded from disk, but no
558 symbols are defined in that component's name space after it is loaded, this
559 warning will be issued:
561 require $class was successful but the package is not defined.
563 This is to protect against confusing bugs caused by mistyping package names,
564 and will become a fatal error in a future version.
566 Please note that 'inner packages' (via L<Devel::InnerPackage>) are still fully
567 supported; this warning is only issued when component file naming does not map
568 to B<any> of the packages defined within that component.
570 =head2 $c->plugin method
572 Calling the plugin method is deprecated, and calling it at run time is B<highly
575 Instead you are recommended to use L<Catalyst::Model::Adaptor> or similar to
576 compose the functionality you need outside of the main application name space.
578 Calling the plugin method will not be supported past Catalyst 5.81.