X-Git-Url: http://git.shadowcat.co.uk/gitweb/gitweb.cgi?a=blobdiff_plain;f=lib%2FCatalyst%2FUpgrading.pod;h=c639b16ccbc75ae2824a900cea14764a40b0d7c3;hb=8f61d649008a9894aed05cb4aa418da44cf710c8;hp=5918872f17f8beeaa17fe83a365c439f724ee4a0;hpb=ae29b412955743885e80350085167b54b69672da;p=catagits%2FCatalyst-Runtime.git diff --git a/lib/Catalyst/Upgrading.pod b/lib/Catalyst/Upgrading.pod index 5918872..c639b16 100644 --- a/lib/Catalyst/Upgrading.pod +++ b/lib/Catalyst/Upgrading.pod @@ -1,20 +1,95 @@ +=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, several changes have -been made which could cause incompatibilities, if your application or plugin -is using deprecated code, or relying on side-effects then there could be -incompatibility. +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 +issues upgrading to this release. + +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 + +Declaring actions in Roles is currently unsupported. + +=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 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. + +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. -Most issues found with pre-existing components have been easy to solve, and a -complete description of behavior changes which may cause compatibility issues, -or warnings to be emitted is included below to help if you have problems. +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. -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. +Most common is the case of: -=head1 Known backwards compatibility breakages. + package Component1; # Note, this is the common case + use base qw/Class::Accessor::Fast Class::Data::Inheritable/; + + 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/; + +Any situation like this will cause your application to fail to start. + +For additional documentation about this issue, and how to resolve it, see +L. =head2 Components which inherit from Moose::Object before Catalyst::Component @@ -24,16 +99,16 @@ 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 -with the C< BUILDARGS > method, will not work with Catalyst 5.80 as +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 fix for this is to 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 will also see this issue if you do the following: @@ -51,9 +126,20 @@ compatible way is: use Moose; BEGIN { extends 'Catalyst::Component' }; # Or ::Controller, or whatever -Note that the C< extends > decleration needs to occur in a begin block for +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. + +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. + =head3 use Moose in MyApp Similar to the above, this will also fail: @@ -66,11 +152,15 @@ 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 /); @@ -82,7 +172,7 @@ into the symbol table, you may encounter breakages. The simplest solution is to use L to name the subroutine. Example: # Original code, likely to break: - my $full_method_name = join('::',$package_name, $method_name); + my $full_method_name = join('::', $package_name, $method_name); *$full_method_name = sub { ... }; # Fixed Code @@ -90,7 +180,7 @@ 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; @@ -99,7 +189,7 @@ 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 { @@ -108,15 +198,15 @@ used to work: ... # things to do after the actual setup } -With Catalyst 5.80 this won't work anymore. Because instead of using NEXT.pm it -relies on L, which uses plain C3 method resolution. +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. -As L hacks to remember what methods have already been called, this -causes infinite recursion between MyApp::setup and Catalyst::setup. - -Moose method modifiers like C<< before|after|around 'setup => sub { ... }; >> -also will not operate correctly due to backward compatibility issues with the -way plugin setup methods. +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 +=> sub { ... }; >> also will not operate correctly on the setup method. The right way to do it is this: @@ -124,17 +214,20 @@ 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 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 -new method in components is B discouraged, instead, you should inherit -the new method from Catalyst::Component, and use Moose's BUILD functionality -to perform any construction work necessary for your sub-class. +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. =head2 __PACKAGE__->mk_accessor('meta'); @@ -146,13 +239,13 @@ inside Moose. Previously, writing to a class data accessor would copy the accessor method down into your package. -This behavior 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 example demonstrates the problem: +The following test demonstrates the problem: { package BaseClass; @@ -167,46 +260,49 @@ The following example 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 whos +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 -Warning message: +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 +message will be emitted: There is a COMPONENT method resolving after Catalyst::Component in ${next_package}. -This means that one of the packages on the right hand side of -Catalyst::Component in your Class' inheritance hierarchy defines a COMPONENT -method. +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. -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), is no longer supported, as it makes no sense with C3 method -dispatch order. +=head1 WARNINGS -Therefore the correct fix is to re-arrange your class' inheritance hierarchy -so that the COMPONENT method you would like to inherit is the first COMPONENT -method in your @ISA. +=head2 Catalyst::Base -=head1 WARNINGS +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, -and also likely to change significantly in the 5.8X release series, and therefore -their use is highly deprecated. +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 @@ -226,32 +322,40 @@ their use is highly deprecated. The first time one of these methods is called, a warning will be emitted: - Class $class is calling the deprecated method Catalyst::Dispatcher::$public_method_name,\n" - . "this will be removed in Catalyst 5.9X" + Class $class is calling the deprecated method Catalyst::Dispatcher::$public_method_name, + this will be removed in Catalyst 5.9X You should B be calling any of these methods from application code. -Plugins authors and maintainers whos 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 -adaquately 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 require $class was successful but the package is not defined. +=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 namespace after it is loaded, this -warning will be issued. +symbols are defined in that component's name space after it is loaded, this +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. -This 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 +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 -compose the functionality you need outside of the main application namespace. +compose the functionality you need outside of the main application name space. + +Calling the plugin method will not be supported past Catalyst 5.81. =cut +