Default cache key produces clashes

[samstickland]

If there are two cells in the same namespace the same cache will be produced by default, which of course causes all sorts of problems in production.

In caching.rb we have:

def state_cache_key(state, key_parts={})
  expand_cache_key([controller_path, state, key_parts])
end

https://github.com/trailblazer/cells/blob/master/lib/cell/caching.rb#L30

And in cell.rb

def controller_path
  @controller_path ||= File.join(util.underscore(name.sub(/(::Cell.+)/, '')), views_dir)
end

https://github.com/trailblazer/trailblazer-cells/blob/master/lib/trailblazer/cell.rb#L36

This means that a cells called SomeNamespace::Cell::One and SomeNamespace::Cell::Two will produce the same controller_path and hence the same cache key.

I can't see why we simply wouldn't the class name for cache key?

Our workaround for this is currently:

cache :show do
  self.class.name
end

etc.

I think the first code should be:

def state_cache_key(state, key_parts={})
  expand_cache_key([self.class.name, state, key_parts])
end

[samstickland]

As example, this was the result of a cache key clash in production!

[yogeshjain999]

@samstickland Thanks for reporting this! Created #494 for same but with the difference of using snake case style for naming instead of direct class names.

[apotonick]

@yogeshjain999 also found https://github.com/trailblazer/trailblazer-cells/issues/13 which is a the same bug.

[apotonick]

@yogeshjain999 Can't we fix this in Trailblazer::Cell? I think it's a problem there and not in the cells gem?