"can't modify frozen Array" error during generation

[robwise]

This is a pretty stock rails 5.2 app with Ruby 2.4.4 and rails_admin 1.4.1.

Downgrading to rails_admin 1.3 resolves the issue.

9/5/2018: It seems that you only need to downgrade to 1.4.0.

Full error message:

rails g rails_admin:install
/Users/rob/.rbenv/versions/2.4.4/lib/ruby/gems/2.4.0/gems/actionpack-5.2.1/lib/action_dispatch/middleware/stack.rb:76:in `insert': can't modify frozen Array (RuntimeError)
	from /Users/rob/.rbenv/versions/2.4.4/lib/ruby/gems/2.4.0/gems/actionpack-5.2.1/lib/action_dispatch/middleware/stack.rb:76:in `insert'
	from /Users/rob/.rbenv/versions/2.4.4/lib/ruby/gems/2.4.0/gems/webpacker-3.5.5/lib/webpacker/railtie.rb:51:in `block in <class:Engine>'
	from /Users/rob/.rbenv/versions/2.4.4/lib/ruby/gems/2.4.0/gems/railties-5.2.1/lib/rails/initializable.rb:32:in `instance_exec'
	from /Users/rob/.rbenv/versions/2.4.4/lib/ruby/gems/2.4.0/gems/railties-5.2.1/lib/rails/initializable.rb:32:in `run'
	from /Users/rob/.rbenv/versions/2.4.4/lib/ruby/gems/2.4.0/gems/railties-5.2.1/lib/rails/initializable.rb:61:in `block in run_initializers'
	from /Users/rob/.rbenv/versions/2.4.4/lib/ruby/2.4.0/tsort.rb:228:in `block in tsort_each'
	from /Users/rob/.rbenv/versions/2.4.4/lib/ruby/2.4.0/tsort.rb:350:in `block (2 levels) in each_strongly_connected_component'
	from /Users/rob/.rbenv/versions/2.4.4/lib/ruby/2.4.0/tsort.rb:431:in `each_strongly_connected_component_from'
	from /Users/rob/.rbenv/versions/2.4.4/lib/ruby/2.4.0/tsort.rb:349:in `block in each_strongly_connected_component'
	from /Users/rob/.rbenv/versions/2.4.4/lib/ruby/2.4.0/tsort.rb:347:in `each'
	from /Users/rob/.rbenv/versions/2.4.4/lib/ruby/2.4.0/tsort.rb:347:in `call'
	from /Users/rob/.rbenv/versions/2.4.4/lib/ruby/2.4.0/tsort.rb:347:in `each_strongly_connected_component'
	from /Users/rob/.rbenv/versions/2.4.4/lib/ruby/2.4.0/tsort.rb:226:in `tsort_each'
	from /Users/rob/.rbenv/versions/2.4.4/lib/ruby/2.4.0/tsort.rb:205:in `tsort_each'
	from /Users/rob/.rbenv/versions/2.4.4/lib/ruby/gems/2.4.0/gems/railties-5.2.1/lib/rails/initializable.rb:60:in `run_initializers'
	from /Users/rob/.rbenv/versions/2.4.4/lib/ruby/gems/2.4.0/gems/railties-5.2.1/lib/rails/application.rb:361:in `initialize!'
	from /Users/rob/dev/link_legal/web_app/config/environment.rb:7:in `<main>'
	from /Users/rob/.rbenv/versions/2.4.4/lib/ruby/gems/2.4.0/gems/bootsnap-1.3.1/lib/bootsnap/load_path_cache/core_ext/kernel_require.rb:21:in `require'
	from /Users/rob/.rbenv/versions/2.4.4/lib/ruby/gems/2.4.0/gems/bootsnap-1.3.1/lib/bootsnap/load_path_cache/core_ext/kernel_require.rb:21:in `block in require_with_bootsnap_lfi'
	from /Users/rob/.rbenv/versions/2.4.4/lib/ruby/gems/2.4.0/gems/bootsnap-1.3.1/lib/bootsnap/load_path_cache/loaded_features_index.rb:65:in `register'
	from /Users/rob/.rbenv/versions/2.4.4/lib/ruby/gems/2.4.0/gems/bootsnap-1.3.1/lib/bootsnap/load_path_cache/core_ext/kernel_require.rb:20:in `require_with_bootsnap_lfi'
	from /Users/rob/.rbenv/versions/2.4.4/lib/ruby/gems/2.4.0/gems/bootsnap-1.3.1/lib/bootsnap/load_path_cache/core_ext/kernel_require.rb:29:in `require'
	from /Users/rob/.rbenv/versions/2.4.4/lib/ruby/gems/2.4.0/gems/activesupport-5.2.1/lib/active_support/dependencies.rb:287:in `block in require'
	from /Users/rob/.rbenv/versions/2.4.4/lib/ruby/gems/2.4.0/gems/activesupport-5.2.1/lib/active_support/dependencies.rb:253:in `load_dependency'
	from /Users/rob/.rbenv/versions/2.4.4/lib/ruby/gems/2.4.0/gems/activesupport-5.2.1/lib/active_support/dependencies.rb:287:in `require'
	from /Users/rob/.rbenv/versions/2.4.4/lib/ruby/gems/2.4.0/gems/spring-2.0.2/lib/spring/application.rb:102:in `preload'
	from /Users/rob/.rbenv/versions/2.4.4/lib/ruby/gems/2.4.0/gems/spring-2.0.2/lib/spring/application.rb:153:in `serve'
	from /Users/rob/.rbenv/versions/2.4.4/lib/ruby/gems/2.4.0/gems/spring-2.0.2/lib/spring/application.rb:141:in `block in run'
	from /Users/rob/.rbenv/versions/2.4.4/lib/ruby/gems/2.4.0/gems/spring-2.0.2/lib/spring/application.rb:135:in `loop'
	from /Users/rob/.rbenv/versions/2.4.4/lib/ruby/gems/2.4.0/gems/spring-2.0.2/lib/spring/application.rb:135:in `run'
	from /Users/rob/.rbenv/versions/2.4.4/lib/ruby/gems/2.4.0/gems/spring-2.0.2/lib/spring/application/boot.rb:19:in `<top (required)>'
	from /Users/rob/.rbenv/versions/2.4.4/lib/ruby/2.4.0/rubygems/core_ext/kernel_require.rb:55:in `require'%
	from /Users/rob/.rbenv/versions/2.4.4/lib/ruby/2.4.0/rubygems/core_ext/kernel_require.rb:55:in `require'
	from -e:1:in `<main>'

Gemfile:

# frozen_string_literal: true

source "https://rubygems.org"
git_source(:github) { |repo| "https://github.com/#{repo}.git" }

ruby "2.4.4"

# === Core Stack
gem "pg" # Use postgresql as the database for Active Record
gem "puma" # Use Puma as the app server
gem "rails"
gem "sass-rails" # Use SCSS for stylesheets
gem "tzinfo-data", platforms: %i[mingw mswin x64_mingw jruby] # Windows does not include zoneinfo files
# gem 'mini_racer', platforms: :ruby # See https://github.com/rails/execjs#readme for more supported runtimes
# gem 'redis', '~> 4.0' # Use Redis adapter to run Action Cable in production

# === Rails Addons
gem "bootsnap", require: false # Reduces boot times through caching; required in config/boot.rb
gem "turbolinks" # https://github.com/turbolinks/turbolinks
gem "enumerize"
gem "rails_admin", "1.3" # bug regarding frozen array with 1.4
# gem 'mini_magick', '~> 4.8' # Use ActiveStorage variant

# === Asset Packaging and Serving
gem "uglifier" # Use Uglifier as compressor for JavaScript assets
gem "webpacker" # Transpile app-like JavaScript. Read more: https://github.com/rails/webpacker

# === Utilities
gem "awesome_print"

group :development, :test do
  gem "annotate"
  gem "byebug", platforms: %i[mri mingw x64_mingw] # Call 'byebug' anywhere in the code
  gem "rspec-rails"
  gem "rspec_junit_formatter" # See https://circleci.com/docs/test-metadata/#rspec
  gem "rubocop", require: false
  gem "rubocop-rspec"
  gem "faker"
  gem "factory_bot_rails"
end

group :development do
  gem "listen" # https://github.com/rails/spring
  gem "spring"
  gem "spring-watcher-listen"
  gem "web-console" # Access an interactive console on exception pages or by calling 'console' anywhere in the code.
end

group :test do
  gem "capybara" # Adds support for Capybara system testing and selenium driver
  gem "chromedriver-helper"
  gem "selenium-webdriver" # Easy installation and use of chromedriver to run system tests with Chrome
  gem "shoulda-matchers"
end

[sandipsubedi]

Downgrading rails_admin to 1.4.0 worked for us.

[abepark01]

I am experiencing the same issue; rails_admin 1.4.0 works okay, but not 1.4.1 in rails 5.2.1

ruby 2.5.1
rails 5.2.1
rails_admin 1.4.1
webpacker 3.5.5

rails g rails_admin:install

Traceback

Traceback (most recent call last): 32: from bin/rails:4:in `' 31: from bin/rails:4:in `require' 30: from /Users/admin/.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/railties-5.2.1/lib/rails/commands.rb:18:in `' 29: from /Users/admin/.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/railties-5.2.1/lib/rails/command.rb:46:in `invoke' 28: from /Users/admin/.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/railties-5.2.1/lib/rails/command/base.rb:65:in `perform' 27: from /Users/admin/.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/thor-0.20.0/lib/thor.rb:387:in `dispatch' 26: from /Users/admin/.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/thor-0.20.0/lib/thor/invocation.rb:126:in `invoke_command' 25: from /Users/admin/.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/thor-0.20.0/lib/thor/command.rb:27:in `run' 24: from /Users/admin/.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/railties-5.2.1/lib/rails/commands/generate/generate_command.rb:21:in `perform' 23: from /Users/admin/.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/railties-5.2.1/lib/rails/command/actions.rb:18:in `require_application_and_environment!' 22: from /Users/admin/.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/railties-5.2.1/lib/rails/application.rb:337:in `require_environment!' 21: from /Users/admin/.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/activesupport-5.2.1/lib/active_support/dependencies.rb:287:in `require' 20: from /Users/admin/.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/activesupport-5.2.1/lib/active_support/dependencies.rb:253:in `load_dependency' 19: from /Users/admin/.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/activesupport-5.2.1/lib/active_support/dependencies.rb:287:in `block in require' 18: from /Users/admin/.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/activesupport-5.2.1/lib/active_support/dependencies.rb:287:in `require' 17: from /Users/admin/spark-io/config/environment.rb:3:in `' 16: from /Users/admin/.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/railties-5.2.1/lib/rails/application.rb:361:in `initialize!' 15: from /Users/admin/.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/railties-5.2.1/lib/rails/initializable.rb:60:in `run_initializers' 14: from /Users/admin/.rbenv/versions/2.5.1/lib/ruby/2.5.0/tsort.rb:205:in `tsort_each' 13: from /Users/admin/.rbenv/versions/2.5.1/lib/ruby/2.5.0/tsort.rb:226:in `tsort_each' 12: from /Users/admin/.rbenv/versions/2.5.1/lib/ruby/2.5.0/tsort.rb:347:in `each_strongly_connected_component' 11: from /Users/admin/.rbenv/versions/2.5.1/lib/ruby/2.5.0/tsort.rb:347:in `call' 10: from /Users/admin/.rbenv/versions/2.5.1/lib/ruby/2.5.0/tsort.rb:347:in `each' 9: from /Users/admin/.rbenv/versions/2.5.1/lib/ruby/2.5.0/tsort.rb:349:in `block in each_strongly_connected_component' 8: from /Users/admin/.rbenv/versions/2.5.1/lib/ruby/2.5.0/tsort.rb:431:in `each_strongly_connected_component_from' 7: from /Users/admin/.rbenv/versions/2.5.1/lib/ruby/2.5.0/tsort.rb:350:in `block (2 levels) in each_strongly_connected_component' 6: from /Users/admin/.rbenv/versions/2.5.1/lib/ruby/2.5.0/tsort.rb:228:in `block in tsort_each' 5: from /Users/admin/.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/railties-5.2.1/lib/rails/initializable.rb:61:in `block in run_initializers' 4: from /Users/admin/.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/railties-5.2.1/lib/rails/initializable.rb:32:in `run' 3: from /Users/admin/.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/railties-5.2.1/lib/rails/initializable.rb:32:in `instance_exec' 2: from /Users/admin/.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/webpacker-3.5.5/lib/webpacker/railtie.rb:51:in `block in ' 1: from /Users/admin/.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/actionpack-5.2.1/lib/action_dispatch/middleware/stack.rb:76:in `insert' /Users/admin/.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/actionpack-5.2.1/lib/action_dispatch/middleware/stack.rb:76:in `insert': can't modify frozen Array (FrozenError)

[gabrieletassoni]

Also on my side:

rails 5.2.1
rails_admin 1.4.1
serviceworker-rails 0.5.5

the problem was with serviceworker-rails, downgrading rails_admin to 1.4.0 solved the issue, but I now can't upgrade rails_admin until a solution is found.

[Jemisson]

That problem still happens in:

Ruby 3.0.3
Rails 6.1.7
Webpacker 5.0

To solve it I ran:
rails g rails_admin:install

and solve it! \o/