anonymize fails in Rails initializers: constantize runs before autoloading

[Spone]

Problem

config.anonymize("User") fails with NameError: uninitialized constant User when used in a Rails initializer (config/initializers/evil_seed.rb), because Anonymizer#initialize calls model_name.constantize immediately at config time — before Rails autoloading has loaded the model.

NameError: uninitialized constant User (NameError)
  evil-seed/lib/evil_seed/anonymizer.rb:20:in 'EvilSeed::Anonymizer#initialize'
  evil-seed/lib/evil_seed/configuration.rb:38:in 'EvilSeed::Configuration#anonymize'
  config/initializers/evil_seed.rb

Root cause

Anonymizer#initialize eagerly constantizes the model name:

# lib/evil_seed/anonymizer.rb
def initialize(model_name, &block)
  @model_class = model_name.constantize  # <-- runs at config time
  @changers = {}
  instance_eval(&block)
end

This is only needed for method_missing to validate column names. By contrast, customize works fine because it just stores a lambda without calling constantize.

Suggested fix

Lazily resolve the model class:

def initialize(model_name, &block)
  @model_name = model_name
  @changers = {}
  instance_eval(&block)
end

def model_class
  @model_class ||= @model_name.constantize
end

This defers the constantize call until the anonymizer is actually used (at dump time), when all models are loaded.

Workaround

Use customize instead of anonymize:

config.customize("User") do |u|
  u["email"] = Faker::Internet.email
  u["name"]  = Faker::Internet.username
end

Environment

• evil-seed 0.7.0
• Rails 8.1
• Ruby 4.0.1