X-Git-Url: http://git.shadowcat.co.uk/gitweb/gitweb.cgi?a=blobdiff_plain;f=lib%2FCatalyst%2FUpgrading.pod;h=66201a589af4c2158aa443fba624c429fd0cf469;hb=fb495632d15d5aa112371bb5c3c39a6189ddb9a0;hp=69141d7c26b08d3fa32b6fb602c3eae068d173eb;hpb=38f90e4941605c36b800159739cc030ad44905b2;p=catagits%2FCatalyst-Runtime.git diff --git a/lib/Catalyst/Upgrading.pod b/lib/Catalyst/Upgrading.pod index 69141d7..66201a5 100644 --- a/lib/Catalyst/Upgrading.pod +++ b/lib/Catalyst/Upgrading.pod @@ -1,50 +1,107 @@ +=head1 NAME + +Catalyst::Upgrading - Instructions for upgrading to the latest Catalyst + =head1 Upgrading to Catalyst 5.80 Most applications and plugins should run unaltered on Catalyst 5.80. -However as a lot of refactoring work has taken place, and several changes have +However, a lot of refactoring work has taken place, and several changes have been made which could cause incompatibilities. If your application or plugin -is using deprecated code, or relying on side-effects, then you could have +is using deprecated code, or relying on side effects, then you could have issues upgrading to this release. -Most issues found with pre-existing components have been easy to solve, and a -complete description of behaviour changes which may cause compatibility issues, -or warnings which are now emitted is included below to help if you have problems. +Most issues found with pre-existing components have been easy to +solve. This document provides a complete description of behavior changes +which may cause compatibility issues, and of new Catalyst warnings which +be unclear. + +If you think you have found an upgrade-related issue which is not covered in +this document, please email the Catalyst list to discuss the problem. + +=head1 Moose features + +=head2 Application class roles + +You can only apply method modifiers after the application's C<< ->setup >> +method has been called. This means that modifiers will not work with methods +which run during the call to C<< ->setup >>. + +See L for more information about using +L in your applications. + +=head2 Controller actions in Moose roles + +You can use L if you want to declare actions +inside Moose roles. + +=head2 Using Moose in Components + +The correct way to use Moose in a component in a both forward and backwards +compatible way is: + + package TestApp::Controller::Root; + use Moose; + BEGIN { extends 'Catalyst::Component' }; # Or ::Controller, or whatever -If you think you have found an upgrade related issue which is not covered in -this document, then please email the Catalyst list to discuss the problem. +See L. -=head1 Known backwards compatibility breakages. +=head1 Known backwards compatibility breakages + +=head2 Applications in a single file + +Applications must be in their own file, and loaded at compile time. This +issue generally only affects the tests of CPAN distributions. Your +application will fail if you try to define an application inline in a +block, and use plugins which supply a C< new > method, then use that +application latter in tests within the same file. + +This is due to the fact that Catalyst is inlining a new method on your +application class allowing it to be compatible with Moose. The method +used to do this changed in 5.80004 to avoid the possibility of reporting +an 'Unknown Error' if your application failed to compile. =head2 Issues with Class::C3 -Catalyst 5.80 uses L method dispatch order. This is built into -perl 5.10, and comes via L for perl 5.8. This replaces L -with L, forcing all components to resolve methods using -C3, rather than the unpredictable dispatch order of L. +Catalyst 5.80 uses the L method dispatch order. This is +built into Perl 5.10, and comes via L for Perl 5.8. This +replaces L with L, forcing all components +to resolve methods using C3, rather than the unpredictable dispatch +order of L. + +This issue is characterised by your application failing to start due to an +error message about having a non-linear @ISA. -To be able to do this, however, entails that the graph of superclasses for each -class must be linearizable using the C3 algorithm. Unfortunately, when -superclasses are being used as mixins, it is easy to get this wrong. +The Catalyst plugin most often causing this is +L - if you are using this +plugin and see issues, then please upgrade your plugins, as it has been +fixed. Note that Makefile.PL in the distribution will warn about known +incompatible components. + +This issue can, however, be found in your own application - the only solution is +to go through each base class of the class the error was reported against, until +you identify the ones in conflict, and resolve them. + +To be able to generate a linear @ISA, the list of superclasses for each +class must be resolvable using the C3 algorithm. Unfortunately, when +superclasses are being used as mixins (to add functionality used in your class), +and with multiple inheritence, it is easy to get this wrong. Most common is the case of: package Component1; # Note, this is the common case use base qw/Class::Accessor::Fast Class::Data::Inheritable/; - package Component2; # Accidentally saying it this way round causes fail. + package Component2; # Accidentally saying it this way causes a failure use base qw/Class::Data::Inheritable Class::Accessor::Fast/; package GoesBang; use base qw/Component1 Component2/; -And the Catalyst plugin most often causing this, is -L - if you are using this plugin -and see issues, then please upgrade! +Any situation like this will cause your application to fail to start. -This can, however, be found in your own application - the only solution is to -go through each base class of the class the error was reported against, until -you identify the ones in conflict, and resolve them. +For additional documentation about this issue, and how to resolve it, see +L. =head2 Components which inherit from Moose::Object before Catalyst::Component @@ -54,18 +111,39 @@ Moose components which say: use Moose; extends qw/Moose::Object Catalyst::Component/; -to use the constructor provided by Moose, whilst working (if you do some hacks +to use the constructor provided by Moose, while working (if you do some hacks with the C< BUILDARGS > method), will not work with Catalyst 5.80 as C inherits from C, and so C< @ISA > fails -to linearise. +to linearize. -The fix for this is to not inherit directly from C +The correct way to use Moose in a component in a both forward and backwards +compatible way is: + + package TestApp::Controller::Root; + use Moose; + BEGIN { extends 'Catalyst::Component' }; # Or ::Controller, or whatever + +Note that the C< extends > declaration needs to occur in a begin block for +L to operate correctly. + +This way you do not inherit directly from C yourself. Having components which do not inherit their constructor from C is B, and has never been recommended, therefore you're on your own if you're using this technique. You'll need -to detect the version of Catalyst your application is running with and deal +to detect the version of Catalyst your application is running, and deal with it appropriately. +You also don't get the L constructor, and therefore attribute +initialization will not work as normally expected. If you want to use Moose +attributes, then they need to be made lazy to correctly initialize. + +Note that this only applies if your component needs to maintain component +backwards compatibility for Catalyst versions before 5.71001 - in 5.71001 +attributes work as expected, and the BUILD method is called normally +(although BUILDARGS is not). + +If you depend on Catalyst 5.8, then B Moose features work as expected. + You will also see this issue if you do the following: package TestApp::Controller::Example; @@ -74,19 +152,6 @@ You will also see this issue if you do the following: as C< use base > appends to @ISA. -The correct way to use Moose in a component in a both forward and backwards -compatible way is: - - package TestApp::Controller::Root; - use Moose; - BEGIN { extends 'Catalyst::Component' }; # Or ::Controller, or whatever - -Note that the C< extends > declaration needs to occur in a begin block for -L to operate correctly. You also don't get the L -constructor, and therefore attribute initialization will not work as normally -expected. If you want to use Moose attributes, then they need to be made lazy -to correctly initialize. - =head3 use Moose in MyApp Similar to the above, this will also fail: @@ -99,11 +164,15 @@ Similar to the above, this will also fail: __PACKAGE__->setup; If you need to use Moose in your application class (e.g. for method modifiers -etc) then the correct technique is: +etc.) then the correct technique is: package MyApp; use Moose; + use Catalyst; + extends 'Catalyst'; + + __PACKAGE__->config( name => 'MyApp' ); __PACKAGE__->setup(qw/ ConfigLoader /); @@ -123,7 +192,7 @@ to use L to name the subroutine. Example: my $full_method_name = join('::',$package_name, $method_name); *$full_method_name = subname $full_method_name, sub { ... }; -Additionally, you can take advantage of Catalysts use of L and +Additionally, you can take advantage of Catalyst's use of L and install the closure using the appropriate metaclass. Example: use Class::MOP; @@ -132,7 +201,7 @@ install the closure using the appropriate metaclass. Example: =head2 Hooking into application setup -To execute code during application startup the following snippet in MyApp.pm +To execute code during application start-up, the following snippet in MyApp.pm used to work: sub setup { @@ -141,14 +210,14 @@ used to work: ... # things to do after the actual setup } -With Catalyst 5.80 this won't work anymore. Due to the fact that Catalyst is -no longer using NEXT.pm for method resolution, this no longer works. The -functionality was only ever originally operational as L remembers what -methods have already been called, and will not call them again. +With Catalyst 5.80 this won't work anymore, because Catalyst no longer +uses NEXT.pm for method resolution. The functionality was only ever +originally operational as L remembers what methods have already +been called, and will not call them again. Using this now causes infinite recursion between MyApp::setup and Catalyst::setup, due to other backwards compatibility issues related to how -plugin setup works. Moose method modifiers like C<< before|after|around 'setup +plugin setup works. Moose method modifiers like C<< before|after|around setup => sub { ... }; >> also will not operate correctly on the setup method. The right way to do it is this: @@ -157,18 +226,18 @@ The right way to do it is this: ... # things to do after the actual setup }; -The setup_finalize hook was introduced as a way to void this issue. +The setup_finalize hook was introduced as a way to avoid this issue. =head2 Components with a new method which returns false Previously, if you had a component which inherited from Catalyst::COMPONENT, -but overrode the new method to return false, then your class' configuration +but overrode the new method to return false, then your class's configuration would be blessed into a hash on your behalf, and this would be returned from the COMPONENT method. -This behaviour makes no sense, and so has been removed. Implementing your own -C< new > method in components is B discouraged, instead, you should -inherit the new method from Catalyst::Component, and use Mooses BUILD +This behavior makes no sense, and so has been removed. Implementing your own +C< new > method in components is B discouraged. Instead, you should +inherit the new method from Catalyst::Component, and use Moose's BUILD functionality and/or Moose attributes to perform any construction work necessary for your class. @@ -182,10 +251,10 @@ inside Moose. Previously, writing to a class data accessor would copy the accessor method down into your package. -This behaviour has been removed. Whilst the class data is still stored +This behavior has been removed. While the class data is still stored per-class, it is stored on the metaclass of the class defining the accessor. -Therefore anything relying on the side-effect of the accessor being copied down +Therefore anything relying on the side effect of the accessor being copied down will be broken. The following test demonstrates the problem: @@ -203,25 +272,25 @@ The following test demonstrates the problem: BaseClass->foo('base class'); Child->foo('sub class'); - + use Test::More; isnt(BaseClass->can('foo'), Child->can('foo')); -=head2 Extending Catalyst::Request or other classes in an ad-hoc manor using mk_accessors +=head2 Extending Catalyst::Request or other classes in an ad-hoc manner using mk_accessors Previously, it was possible to add additional accessors to Catalyst::Request (or other classes) by calling the mk_accessors class method. -This is no longer supported - users should make a sub-class of the class whose -behaviour they would like to change, rather than globally polluting the +This is no longer supported - users should make a subclass of the class whose +behavior they would like to change, rather than globally polluting the Catalyst objects. =head2 Confused multiple inheritance with Catalyst::Component::COMPONENT -Previously, Catalyst's COMPONENT method would delegate to the method on the -right hand side, which could then delegate back again with NEXT. This (as it -is insane AND makes no sense with C3 method dispatch order), and is therefore -no longer supported. +Previously, Catalyst's COMPONENT method would delegate to the method on +the right hand side, which could then delegate back again with +NEXT. This is poor practice, and in addition, makes no sense with C3 +method dispatch order, and is therefore no longer supported. If a COMPONENT method is detected in the inheritance hierarchy to the right hand side of Catalyst::Component::COMPONENT, then the following warning @@ -230,16 +299,58 @@ message will be emitted: There is a COMPONENT method resolving after Catalyst::Component in ${next_package}. -The correct fix is to re-arrange your class' inheritance hierarchy so that the +The correct fix is to re-arrange your class's inheritance hierarchy so that the COMPONENT method you would like to inherit is the first (left-hand most) COMPONENT method in your @ISA. =head1 WARNINGS +=head2 Actions in your application class + +Having actions in your application class will now emit a warning at application +startup as this is deprecated. It is highly recommended that these actions are moved +into a MyApp::Controller::Root (as demonstrated by the scaffold application +generated by catalyst.pl). + +This warning, also affects tests. You should move actions in your test, +creating a myTest::Controller::Root, like the following example: + + package MyTest::Controller::Root; + + use strict; + use warnings; + + use parent 'Catalyst::Controller'; + + __PACKAGE__->config(namespace => ''); + + sub action : Local { + my ( $self, $c ) = @_; + $c->do_something; + } + + 1; + +=head2 ::[MVC]:: naming scheme + +Having packages called MyApp::[MVC]::XX is deprecated and can no longer be generated +by catalyst.pl + +This is still supported, but it is recommended that you rename your application +components to Model/View/Controller. + +A warning will be issued at application startup if the ::[MVC]:: naming scheme is +in use. + +=head2 Catalyst::Base + +Any code using L will now emit a warning; this +module will be removed in a future release. + =head2 Methods in Catalyst::Dispatcher -The following methods in Catalyst::Dispatcher are both an implementation -detail, which may change in the 5.8X release series, and therefore their use +The following methods in Catalyst::Dispatcher are implementation +details, which may change in the 5.8X release series, and therefore their use is highly deprecated. =over @@ -265,12 +376,12 @@ The first time one of these methods is called, a warning will be emitted: You should B be calling any of these methods from application code. -Plugins authors and maintainers whose plugins currently call these methods +Plugin authors and maintainers whose plugins currently call these methods should change to using the public API, or, if you do not feel the public API -adequately supports your use-case, please email the development list to +adequately supports your use case, please email the development list to discuss what API features you need so that you can be appropriately supported. -=head2 Class naming to packages defined does not correspond. +=head2 Class files with names that don't correspond to the packages they define In this version of Catalyst, if a component is loaded from disk, but no symbols are defined in that component's name space after it is loaded, this @@ -278,19 +389,19 @@ warning will be issued: require $class was successful but the package is not defined. -This is to protect against confusing bugs caused by mis-typing package names, +This is to protect against confusing bugs caused by mistyping package names, and will become a fatal error in a future version. Please note that 'inner packages' (via L) are still fully -supported, this warning is only issued when component file naming does not map +supported; this warning is only issued when component file naming does not map to B of the packages defined within that component. =head2 $c->plugin method -Calling the plugin method is deprecated, and calling it at runtime is B. -Instead you are recommended to use L< Catalyst::Model::Adaptor > or similar to +Instead you are recommended to use L or similar to compose the functionality you need outside of the main application name space. Calling the plugin method will not be supported past Catalyst 5.81.