rails/rails — pull request #4877 by bogdan (2012-02-04 11:45:07+00:00)
Title: AS::Callbacks: rip out per_key option.

This commit drops the support of `:per_key` option as it's "for perfomance" role is no longer makes sense.

All tests with `:per_key` option was converted into general `:if` and `:unless` to make sure we migrate smoothly.
If someone is using `:per_key` option outside of rails - he will receive this message:

``` ruby
raise NotImplementedError, ":per_key option is no longer supported. Use generic :if and :unless options instead."
```