* Passing method reference symbols to ActionController::Base#url_for. Use named routes instead.
* Calling ActionController::Base#render with string arguments. Ex: render(’weblog/show’)
* Using model, service, observer, depend_on and dependencies_on in your controller. Rails handles most dependency issues automatically now.
* Calling keep_flash instead of flash.keep
* Pagination will be extracted out into a plugin in Rails 2.0
* Auto complete will be extracted out into a plugin in Rails 2.0
* In place editing will be extracted out into a plugin in Rails 2.0
* start_form_tag and end_form_tag have been deprecated. form_tag still works the same, but there is no wrapper method for the . The preferred method is to use the new block form of form_tag. Ex: form_tag :action => :create do … end
* The number helper method human_size is deprecated in favor of number_to_human_size
* link_to_image and link_image_to helpers are deprecated in favor of wrapping an image_tag in a link_to. Ex: link_to(image_tag(…), :action => :new)
* Using @cookies, @flash, @headers, @params, @request, @response or @session has been deprecated. Use the method form without the @. Ex: response.content_type
* Calling content_for :layout || :symbol. Use yield || yield :symbol instead
* Calling image_tag without an extension is deprecated. Auto appending .png will be removed. Don’t be lazy.
* Passing :post as a link_to modifier to force a POST request via a link tag. Use :method => :post instead.
* push_with_attributes and concat_with_attributes on a HABTM association are deprecated. Use has_many :through with a join model instead.
* find_all and find_first on a has_many association. Use find(:all) and find(:first)
* :dependent => true on a has_many association. Use :dependent => :destroy
* :exclusively_dependent => true on a has_many association. Use :dependent => :delete_all
* When using :class_name on a belongs_to association, the foreign_key name will be inferred from the association rather than the :class_name. Therefor, use :foreign_key if using :class_name and they differ.
* A welcome deprecation, internally, the quote method of ActiveRecord has been renamed. After Rails 2.0 you will be able to use a column named quote again.
* Calling count on a model with string arguments for conditions and joins. Use an options hash instead. Ex: Model.count(:conditions => ‘…’)
* Validations helper method add_on_boundary_breaking in favor of validates_length_of
* Hash extension create_from_xml has been renamed to from_xml
* All the old rake tasks have been moved to namespaced task, old ones are deprected. Ex: rake db:migrate instead of rake migrate