When you use :dependent => true or :exclusively_dependent => true, the deprecation message printed to the console contains the deprecation reference URL twice:
DEPRECATION WARNING: The :dependent => true option is deprecated and will
be removed from Rails 2.0. Please use :dependent => :destroy instead. See
http://www.rubyonrails.org/deprecation for details. See
http://www.rubyonrails.org/deprecation for details. (called from has_many at
/Users/chrisk/railstest/vendor/rails/activerecord/lib/active_record/associations.rb:673)
It's because ActiveSupport::Deprecation.warn prints the URL message for every deprecation, but the URL is specified in the deprecation messages for these two methods as well.
Attached patch generated against trunk as of [7247].