[Catalyst] My experience porting to CataMoose

[Daisuke Maki]

Hi,

I've switched an application of mine to CataMoose. Thanks for the hard
work, it's seems surprisingly stable for such a massive overhaul.

I've observed a few glitches / gotchas, they seem like things that
probably should be documented, but I'd like to share with the list
before writing them up:

1. MyApp->config->{home} and Catalyst::Upgrading

Catalyst::Upgrading suggests that the following is possible:

  package MyApp;
  use Moose;

  extends 'Catalyst';

  __PACKAGE__->setup( ... );

This is fine, but things gets a bit hairy when you mix this with calls
MyApp->config->{home} BEFORE setup(), for example:

  package MyApp;
  use Moose;

  extends 'Catalyst';

  __PACKAGE__->config(
     'View::TT' => {
         INCLUDE_PATH => __PACKAGE__->path_to('whatever')
     }
  );

  __PACKAGE__->setup( .... );

path_to will return something like "/whatever" instead of
"/path/to/MyApp/whatever", because home isn't set. to get around it, you
 would need to force setup_home() to be called, or say

  package MyApp;
  use Moose;
  use Catalyst; # so import() gets called

  extends 'Catalyst';

  __PACKAGE__->config(...);
  __PACKAGE__->setup(...);

2. Hooking to methods that Plugins use via method modifiers breaks
method dispatch

I got bit by this while depending on Catalyst::Plugin::Unicode, and
trying to hook a custom error handling mechanism at finalize().

I was doing this in MyApp.pm:

  before finalize => sub {
      my $c = shift;
      $c->handle_exception if @{ $c->error };
  };

At that moment, Catalyst::Plugin::Unicode's finalize() stopped from
being called. I fully expected MyApp->finalize() to trigger all the
plugins' finalize(), then Catalyst::finalize(), but it only called
MyApp::finalize() and Catalyst::finalize().

I never got exactly why this happens, but it seems to me like Moose's
Method object interacts oddly with the method dispatch. My fix was to do

  override finalize => sub {
     my $c = shift;
     $c->handle_exception if @{ $c->error };
     $c->next::method(@_); # doing super() didn't work here.
  };



regards,
--d

P.S. MST: yes, this has been blogged:
http://mt.endeworks.jp/d-6/2009/05/moosification-catalyst-58.html