[Catalyst] Problem with Catalyst::Engine::component()

[Wade.Stuart at fallon.com]

Here is one of the same issues I remember seeing,  eventually this thread
decided not to pull out the regex search because it was used in default end
and other modules.



catalyst-bounces at lists.rawmode.org wrote on 08/26/2005 02:45:37 AM:

> Cheers,
>
> yesterday I spent some hours tracking an error in my CatApp.
> Finally I spotted Catalyst::Engine::component() as the point of failure.
> This method looks like this:
>
> sub component {
>     my $c = shift;
>
>     if (@_) {
>
>         my $name = shift;
>
>         if ( my $component = $c->components->{$name} ) {
>             return $component;
>         }
>
>         else {
>             for my $component ( keys %{ $c->components } ) {
>                 return $c->components->{$component} if $component
=~/$name/i;
>             }
>         }
>     }
>
>     return sort keys %{ $c->components };
> }
>
> What this does is:
> If $c->component('MyApp::M::Shop') can't find a component called
> "MyApp::M::Shop" it will either happily return the component
> "MyApp::M::ShopItem" provided we also have this among our components
> or else return an array of the component keys which probably will result
> in a numerical value since we typically call this method in a scalar
> context.
>
> Of course I see the doc saying
> <cite>
> Regex search for a component.
>
>     $c->comp('mymodel')->do_stuff;
> </cite>
>
> but is this really the intended behaviour?
>
>
> But wait ... now it gets really weired:
> Actually there /was/ a component called "MyApp::M::Shop", but the line
>    if ( my $component = $c->components->{$name} ) {
> evaluated to false!!!
> That's probably because MyApp::M::Shop->isa('Class::DBI') and
>    package Class::DBI;
>    [...]
>    use overload [...]
>    bool => sub { not shift->_undefined_primary }, [...]
> which seems to evaluate to false for all my CDBI based classes in
> boolean context (don't know why, but I don't feel like digging in the
> CDBI sources).
>
> And indeed $c->component('MyApp::M::Shop') gave me the component for
> "MyApp::M::ShopItem", because this came at first when looping through
> the component keys.
>
> So if the answer to my question above is "no" and to fix handling of
> CDBI based components I'd suggest (which abolishes regex search):
>
> sub component {
>     my $c = shift;
>
>     if (@_) {
>         my $comp = $c->components->{shift};
>         # using define() takes overload boolean => false into account
>         return defined($comp) ? $comp : ();
>     }
>
>     return sort keys %{ $c->components };
> }
>
> If regex component search is really needed by someone, it can be done in
> the application itself like:
>    my $name = 'mymodel';
>    my $comp;
>    foreach my $key ($c->component) {
>      $comp = $c->component($key), last
>        if $key =~ /$name/i;
>    }
>
> --
> Bernhard Graf
>
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