Plugins - helper function is an "undefined method", Objects "can't be referred"

I'm modifying a shopping cart plugin, MinimalCart, and for some reason
I can add one item to the cart multiple times, but as soon as I add a
second item, all kinds of strange things start happening.

An actionview::template error is thrown because a method defined in
application_helper is "undefined"

What could cause a defined application helper method to all the sudden
not be defined?

here is the trace : http://pastie.org/211114

Thanks,
Nik

I'm modifying a shopping cart plugin, MinimalCart, and for some reason
I can add one item to the cart multiple times, but as soon as I add a
second item, all kinds of strange things start happening.

An actionview::template error is thrown because a method defined in
application_helper is "undefined"

What could cause a defined application helper method to all the sudden
not be defined?

Does the problem go away if you turn on class caching in
development.rb ? (and then restart the server)

Fred

Does the problem go away if you turn on class caching in
development.rb ? (and then restart the server)

Yes it does! Mind explaining a little bit about how that might be
causing this issue?

Short version: when that setting is false your app is reloaded between
requests, but plugins aren't. If a plugin is holding onto a class,
reference etc... from before the app gets reloaded then post-reload
it's holding onto (essentially) junk. One way around is to make the
plugin be reloaded at the same time as the app
Long version: http://www.spacevatican.org/2008/5/28/reload-me-reload-me-not

Fred