A gem that will print a message if a developer is trying to use a column that is from a legacy system but has to stay there.

Add this line to your application's Gemfile:

gem 'legacy_column'

And then execute:

bundle install

This gem supports:

• Ruby 2.7+
• Rails 5.2+, 6.0+, 6.1+, 7.0+, 7.1+, 7.2+, 8.0+

Just list the column names:

legacy_column :old_email, :old_phone_number

A custom message can be added:

legacy_column :old_email, :old_phone_number, message: 'Do not touch this!!!'

By default, the gem only detects write operations (when columns are modified). To also detect read access, use the detect_reads option:

legacy_column :old_email, :old_phone_number, detect_reads: true

This will warn whenever the legacy columns are accessed:

legacy_column :old_status, message: 'This field is deprecated!', detect_reads: true

user.old_status  # Will log a warning about read access
user.old_status = 'active'  # Will log a warning about write access

You can combine read detection with custom messages:

legacy_column :old_price, :old_name, 
              message: 'These fields will be removed in v2.0!', 
              detect_reads: true

USE of legacy column detected.
  User => old_email
  Do not touch this!!!

READ of legacy column detected.
  User => old_email
  Do not touch this!!!

The gem will:

• Log warnings to Rails.logger when Rails is available
• Fall back to puts for non-Rails environments or when Rails.logger is not available

Pull requests are welcome. For major changes, please open an issue first to discuss what you would like to change.

Please make sure to update tests as appropriate.

MIT