Like in any language, a FLOAT will eventually corrupt data due to rounding errors. Please use DECIMAL, which has well...

Tests are about 100% control over UI interaction and your test scenario. Randomness makes writing tests hard. You will also...

Sometimes you have a test expectation but actually want a better error message in case of a failure. Here is...

What Rails version Within before_* Within after_* Cancel later callbacks Rails 1-4 return false return false Cancel later callbacks...

Say you have a User with a Carrierwave attribute #avatar: class User < ActiveRecord::Base mount_uploader :avatar, AvatarUploader end

Whenever you create a table from a database migration, remember to add updated_at and created_at timestamps to that...

When two classes implement the same behavior (methods, callbacks, etc.), you should extract that behavior into a trait or module...

Custom matchers are a useful RSpec feature which you can use to DRY up repetitive expectations in your specs. Unfortunately...

So you're hunting down a regression (or just a bug) and want to use git bisect to find out...

Remember why preloading associations "randomly" uses joined tables or multiple queries? If you don't like the cleverness of this...

1. Saving files to a directory that is not shared between deploys or servers If you save your uploads to...

Merge requests are often rejected for similar reasons. To avoid this, before you send a merge request, please confirm that...

Sometimes you want git to ignore certain files that appear on your machine. You can do this in 3 ways...

When HTTP clients make an request they can define which response formats they can process. They do it by adding...

In the following example the method update_offices_people_count won't be called when office_id changes, because it...

Rails gives you migrations to change your database schema with simple commands like add_column or update. Unfortunately these commands...

Caution when using .where to exclude records from a scope like this: # Fragile - avoid User.where("id NOT IN (?)", excluded_ids...

All Rubyists should be familiar with the common definitions for include and extend. You include a module to add instance...

All columns of a model's database table are automagically available through accessors on the Active Record object.

What you copy may not be what you see in the browser. Here is an online tool to determine the...

Rails has generic error messages you can define in your locale .yml files. You may override those application-wide error...

Do not pass times to date attributes. Always convert times to dates when your application uses time zones. Background

Guide how to make fixes in other people's GitHub repositories. It's basically "Open Source Development 101".

TL;DR: You should generally use #size to count associated records. size Counts already loaded elements If the association is...