read_fragment should cache itself for a request to avoid race conditions

Hi,
I'm reposting this bug from the old Rails trac site since I can't sign up to comment on it (http://dev.rubyonrails.org/ticket/8408) and the post seems to have been abandoned. The original bug post is as follows:

A good paradigm to support would be to allow in your controller:

unless read_fragment(blah)

#do something to set instance variables from the database here

end

Then you only do the tough database access from your controller if there is no cache for the relevant items (this would be less necessary if there were support for pagination in the models or at least in views, though there are still cases where it would apply). The problem is that the cache can be expired between the controller method and the view method.

So, let's say that @result is the result of a large database query.

MyController.rb:

unless read_fragment(blah)

@result = do_large_calc

end

myview.rhtml: cache(blah) do

#do something with @result

end

The problem is that if someone expires your cache fragment between the controller and the view (which I have happen a LOT), then you wind up using @result even though it is not set up.

What needs to happen is that read_fragment is cached in memory during a request, so that all future cache requests to that fragment within the same request returns the same result.

I would like to second this bug report and confirm the bug still exists in ActionPack 2.3.5 (the bug was originally reported in version 1.2.3). I think it would be great if the bug could be fixed in this way or if there were some other workaround.

Thanks a ton,
Mike