NameError：尽管具有正确的 application_record 文件，但未初始化的常量 ApplicationRecord

Question

I am having trouble using my actual models, I am getting the following error when trying to create a user:

app/models/user.rb:1:in `<top (required)>': uninitialized constant ApplicationRecord (NameError)

I do have the following file in models/application_record.rb

which looks like:

class ApplicationRecord < ActiveRecord::Base
  self.abstract_class = true
end

When I change the User class to inherit from ActiveRecord::Base instead, I get the same error, except for ActiveRecord.

My application.rb:

class Application < Rails::Application

    config.load_defaults 6.1

    config.generators.system_tests = nil
  end

I am using Rails 6.1.

My Gemfile:

ruby '2.6.3'
gem 'activerecord'
# Bundle edge Rails instead: gem 'rails', github: 'rails/rails', branch: 'main'
gem 'rails', '~> 6.1.4'
# Use sqlite3 as the database for Active Record
gem 'sqlite3', '~> 1.4'
# Use Puma as the app server
gem 'puma', '~> 5.0'
# Use SCSS for stylesheets
gem 'sass-rails', '>= 6'
# Transpile app-like JavaScript. Read more: https://github.com/rails/webpacker
gem 'webpacker', '~> 5.0'
# Turbolinks makes navigating your web application faster. Read more: https://github.com/turbolinks/turbolinks
gem 'turbolinks', '~> 5'
# Build JSON APIs with ease. Read more: https://github.com/rails/jbuilder
gem 'jbuilder', '~> 2.7'
# Use Redis adapter to run Action Cable in production
# gem 'redis', '~> 4.0'
# Use Active Model has_secure_password
# gem 'bcrypt', '~> 3.1.7'

# Use Active Storage variant
# gem 'image_processing', '~> 1.2'

# Reduces boot times through caching; required in config/boot.rb
gem 'bootsnap', '>= 1.4.4', require: false

group :development, :test do
  # Call 'byebug' anywhere in the code to stop execution and get a debugger console
  gem 'byebug', platforms: [:mri, :mingw, :x64_mingw]
end

group :development do
  # Access an interactive console on exception pages or by calling 'console' anywhere in the code.
  gem 'web-console', '>= 4.1.0'
  # Display performance information such as SQL time and flame graphs for each request in your browser.
  # Can be configured to work on production as well see: https://github.com/MiniProfiler/rack-mini-profiler/blob/master/README.md
  gem 'rack-mini-profiler', '~> 2.0'
  gem 'listen', '~> 3.3'
  # Spring speeds up development by keeping your application running in the background. Read more: https://github.com/rails/spring
  gem 'spring'
end

# Windows does not include zoneinfo files, so bundle the tzinfo-data gem
gem 'tzinfo-data', platforms: [:mingw, :mswin, :x64_mingw, :jruby]

What is happening? I have no spelling mistakes, the model is user.rb, I can't figure out what's going on.

All of the advice I have found

Answer 1

So, if anyone is running into this problem, and you have the files you need, check to see if you're loading the rails environment. I added:

require "#{File.dirname(__FILE__)}/config/environment.rb"

to the top of the file I was running where I was calling the classes and that solved the problem.