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 incompatibilties, if your application
+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.
-Most issues found with pre-existing components have been easy to solve,
+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.
=head1 Known backwards compatibility breakages.
-=head2 Moose applications
+=head2 Components which inherit from Moose::Object before Catalyst::Component
-Moose components for Catalyst 5.70 needed to do
+Moose components which say:
+ package TestApp::Controller::Example;
+ use Moose;
extends qw/Moose::Object Catalyst::Component/;
-to be able to use the constructor provided by Moose. In 5.80
-C<Catalyst::Component> already inherits from C<Moose::Object>. Therefor you
-shouldn't directly inherit from C<Moose::Object> yourself, otherwise your
-Class' @ISA will not linearise with C3.
+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
+C<Catalyst::Component> inherits from C<Moose::Object>, and so C< @ISA > fails
+to linearise.
+
+The fix for this, is to not inherit directly from C<Moose::Object>
+yourself. Having components which do not inherit their constructor from
+C<Catalyst::Component> is B<unsupported>, 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
+with it appropriately.
+
+You will also see this issue if you do the following:
+
+ package TestApp::Controller::Example;
+ use Moose;
+ use base 'Catalyst::Controller';
+
+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 > decleration needs to occur in a begin block for
+L<attributes> to operate correctly.
=head2 Anonymous closures installed directly into the symbol table
my $metaclass = Moose::Meta::Class->initialize($package_name);
$metaclass->add_method($method_name => sub { ... });
+=head2 Hooking into application setup
+
+To execute code during application startup the following snippet in MyApp.pm
+used to work:
+
+ sub setup {
+ my ($class, @args) = @_;
+ $class->NEXT::setup(@args);
+ ... # 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 Class::C3::Adopt::NEXT, which doesn't remember what methods it
+already called, like NEXT does and therefore goes into a deep recursion between
+MyApp::setup and Catalyst::setup.
+
+Moose method modifiers line C<< before|after|around 'setup => sub { ... }; >>
+won't work either because of backward compatibility issues related to plugin
+setup methods.
+
+The right way to do it is this:
+
+ after setup_finalize => sub {
+ ... # things to do after the actual setup
+ };
+
=head2 Components whos new method returns false
Previously if your new method returned a false value,
This is no longer supported - users should make a sub-class of the class who's behavior they would
like to change, rather than globally polluting the Catalyst objects.
-=head2 Confused multiple inheritence with Catalyst::Component::COMPONENT
+=head2 Confused multiple inheritance with Catalyst::Component::COMPONENT
Warning message:
=head2 Assigning lists to accessors
-FIXME
+Accessors generated by Class::Accessor::Fast will, when multiple values
+are assigned to them, store a reference to a list automatically for you.
+
+This is not currently supported by MooseX::Emulate::Class::Accessor::Fast,
+and only the first value in the list will be stored.
+
+If you are relying on this behavior, and inheriting mk_accessors from a
+Catalyst component, then your code will fail.
=head1 WARNINGS
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.
-This is to pretect against confusing bugs caused by mis-typing package names.
+This is to protect against confusing bugs caused by mis-typing package names.
This will become a fatal error in a future version.