Association named 'variations' was not found; perhaps you misspelled it?

I just was hunting down a strange error with this model:

class Model
  placeholder = 'variations'
  
  has_many placeholder
  
  nested_scope :verbose, :include => :variations
end

Everything, including Model.variations and Model.reflect_on_all_associations.map &:name did work (the latter returned [ :some_association, 'variations' ]).
Eventually, the quotes led me to the solution: I had to write has_many placeholder.to_sym.
...

The ActionMailer in Rails 2 depends on a buggy version of TMail, which sometimes inserts a blank line into the mail header when sending a mail to multiple recipients. This makes the header end prematurely.

The reason why this is not exploding in your face all the time is that when you are relaying your e-mail through an MTA like Exim, it will fix this for you.

Fix for Rails if you don't have an awesome MTA

TMail is no longer maintained. The bug is fixed...

Have you ever mistaken one Rails environment for another? The attached helper will help you to never do it again.

Save the attached file to app/helpers/ and use the widget in your layout like this:

%body
  = rails_env_widget unless Rails.env.production?

It'll render a small light gray box in the top left corner of your screen, containing the current Rails environment. On click, it'll disappear. Actually, it has the same UX as our Query Diet widget.

This will show you how to create a RSS feed that the Feed Validator considers valid.

Note that RSS is a poorly specified format. Consider using the Atom builder to make an Atom feed instead. Write a note here if you do.

1. Controller

Create a FeedsController to host the RSS feed. Such a controller is also useful to host other data feeds that tend to gather over the lifetime of an application, e.g. sitemap.xml.:

class...

It is common in Rails 3.0 applications that you want to provide default views for a group of controllers. Let’s say you have a bunch of controllers inside the Admin namespace and you would like each action to fallback to a default template. So if you are rendering the index action for Admin::PostsController and “app/views/admin/posts/index.html.*” is not available, it should then render “app/views/admin/defaults/index.html”.

Since Rails 3.0, we have a new abstraction called resolvers that holds the logic to find a template.

Using uncountable resources is not recommended as it breaks Rails' magic, e.g. when using form_for. You'll always be better off using simple pluralizable resources.

Rails automatically creates path names for routes defined via the resource method. When you put resource 'user' into config/routes.rb, you can call users_path and get the path to the index action in the UsersController: /users.

However, if you have an uncountable resource like Sheep, you cannot access the index action via sheep_path, because it will...

Note: ActiveRecord::Base#becomes has a lot of quirks and inconsistent behavior. You probably want to use ActiveType.cast instead.

This issue will be encountered when relying on attribute_was methods of ActiveModel::Dirty after casting a model which has defaults to a form model, for example.

In my case a record with an assignable_values legacy value beca...

When writing Rails migrations to convert a string column to an integer you'd usually say:

change_column :table_name, :column_name, :integer

However, PostgreSQL will complain:

PG::DatatypeMismatch: ERROR:  column "column_name" cannot be cast automatically to type integer
HINT:  Specify a USING expression to perform the conversion.

The "hint" basically tells you that you need to confirm you want this to happen, and how data shall be converted. Just say this in your migration:

change_column :table_name, :column_name, 'i...

So you're getting an error message like the following, although your Gemfile lists shoulda-matchers and it has always worked:

NoMethodError:
  undefined method `allow_value' for #<RSpec::ExampleGroups::Person::Age:0x007feb239fa6a8>

This is due to Rails 4.1 (specifically, Spring) revealing a weak point of shoulda-matchers -- jonleighton explains why.

Solution

The solution is to follow [the gem's installation guide](https://github.com/thoughtbot/sh...

There are a few ways to access view helpers from the Rails console. The easiest way is the helper shortcut:

helper.translate 'i18n.string'
helper.your_helper_method

If the desired helper renders a view template, you need this setup:

view_paths = Rails::Application::Configuration.new(Rails.root).paths["app/views"]
av_helper = ActionView::Base.new(view_paths).extend YourHelperModule

av_helper.your_helper_method

jQuery as new default Javascript library, streaming response support, attr_accessible with roles, prepared statements, easier migrations.

Leads to awesomeness and unicorns when used in production.

These two models can be used to access the posts and associated comments of a WordPress database.

Do that for noble reasons only.

This project is (or will be) a best effort semi-static verifier for your Ruby on Rails projects. Delivered as a Ruby gem it provides a shell command task "railscheck" that you can run against your Rails projects to test for a number of typical bugs, potential problems and inconsistencies.

Finish the remainder of the ActiveModel todo list (observers, callbacks, validations, scoping, and serialization) in addition to associations. Also wire up ActiveModel up to ActiveRecord and ActiveResource.

Asynchronous JavaScript and CSS, also known as CSSHttpRequest, is a method of URI-encoding data in 2KB chunks split over several CSS rules with a modified data URI scheme. Because CSS is not subject to the same-origin policy, no service proxy is required.

How to rescue a project without losing your mind.