Rails console improvements, assertionless tests reporting and more!

Hi, it’s Greg. Let’s explore this week’s changes in the Rails codebase.

Build Rails console on top of IRB’s latest official APIs
The Rails console is built on top of IRB, but due to the lack of an extension API, it was extending it with monkey patches. Since IRB received a lot of improvements and an extension API recently, this pull request changes the Rails console to be built on top of that. This will make the Rails helpers show up in the help message among others wins.

Turn app:update into a command to add –force
This pull request changes the app:update task to be a Rails command, and then adds the --force flag to it, to allow running bin/rails app:update while accepting all the changes it makes.

Fix count queries on includes+references for models with composite primary keys
Since SQLite and older MySQL do not support using COUNT DISTINCT with multiple columns, running a count query with composite primary keys caused an error. This pull request changes them to use a subquery.

Allow assertionless tests to be reported
It is very easy to write a “false positive” broken test that actually tests nothing (or can become such in the future). A simple example:

def test_active
  active_users = User.active.to_a
  active_users.each do |user|
    assert user.active?
  end
end

The assertion is only run if the scope returns at least one user. The change in this pull request allows to easily detect when such assertion is not run. With the following configuration, assertionless tests will be marked as failed and not silently pass.

config.active_support.assertionless_tests_behavior = :raise # also available :ignore and :log

Add support for recursive common table expressions in ActiveRecord
While Rails 7.1 has added support for writing Common Table Expressions(CTEs), this support does not extend to recursive CTEs. This pull request adds a QueryMethods#with_recursive construct to enable recursive CTEs.

Add a Date decoder to the PostgreSQL adapter
This pull request adds a Date decoder to the PostgreSQL adapter to type cast dates at the connection level, so when a raw query is run, the columns will be cast to a date instead of a string. Before:

ActiveRecord::Base.connection.select_value("select '2024-01-01'::date").class 
#=> String

After:

ActiveRecord::Base.connection.select_value("select '2024-01-01'::date").class 
#=>  Date

This change brings the PostgreSQL adapter to parity (for dates) with the Mysql2 adapter.

Remove all deprecated code
All code deprecated in 7.1 is removed from the codebase in this pull request.

You can view the whole list of changes here. We had 30 contributors to the Rails codebase this past week!

Until next time!