NoMethodError when using with Rails 6.0.0.beta2

[alea12]

Overview

• rails_admin version 1.4.2 seems to have an incompatibility issue with Rails 6.0.0.beta2.
• It seems like strip_heredoc used below is causing the problem, but I haven't had enough time to investigate this issue deeply. https://github.com/sferik/rails_admin/blob/f592d68f2c611cee3733ce3f1ef1085a89a1b898/lib/rails_admin/extensions/paper_trail/auditing_adapter.rb#L40

Environment

$ ruby -v
ruby 2.5.1p57 (2018-03-29 revision 63029) [x86_64-darwin16]
$ rails -v
Rails 6.0.0.beta2

How to reproduce

$ rails _6.0.0.beta2_ new testapp
$ cd testapp
$ echo "gem 'rails_admin', '~> 1.3'" >> Gemfile
$ bundle install
$ rails g rails_admin:install
/Users/alea12/.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/rails_admin-1.4.2/lib/rails_admin/extensions/paper_trail/auditing_adapter.rb:40:in `<class:AuditingAdapter>': undefined method `strip_heredoc' for #<String:0x00007fcb7325c718> (NoMethodError)
	from /Users/alea12/.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/rails_admin-1.4.2/lib/rails_admin/extensions/paper_trail/auditing_adapter.rb:32:in `<module:PaperTrail>'
	from /Users/alea12/.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/rails_admin-1.4.2/lib/rails_admin/extensions/paper_trail/auditing_adapter.rb:3:in `<module:Extensions>'
	from /Users/alea12/.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/rails_admin-1.4.2/lib/rails_admin/extensions/paper_trail/auditing_adapter.rb:2:in `<module:RailsAdmin>'
	from /Users/alea12/.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/rails_admin-1.4.2/lib/rails_admin/extensions/paper_trail/auditing_adapter.rb:1:in `<main>'
	from /Users/alea12/.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/bootsnap-1.4.1/lib/bootsnap/load_path_cache/core_ext/kernel_require.rb:21:in `require'
	from /Users/alea12/.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/bootsnap-1.4.1/lib/bootsnap/load_path_cache/core_ext/kernel_require.rb:21:in `block in require_with_bootsnap_lfi'
	from /Users/alea12/.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/bootsnap-1.4.1/lib/bootsnap/load_path_cache/loaded_features_index.rb:83:in `register'
	from /Users/alea12/.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/bootsnap-1.4.1/lib/bootsnap/load_path_cache/core_ext/kernel_require.rb:20:in `require_with_bootsnap_lfi'
	from /Users/alea12/.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/bootsnap-1.4.1/lib/bootsnap/load_path_cache/core_ext/kernel_require.rb:29:in `require'
	from /Users/alea12/.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/activesupport-6.0.0.beta2/lib/active_support/dependencies.rb:297:in `block in require'
	from /Users/alea12/.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/activesupport-6.0.0.beta2/lib/active_support/dependencies.rb:263:in `load_dependency'
	from /Users/alea12/.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/activesupport-6.0.0.beta2/lib/active_support/dependencies.rb:297:in `require'
	from /Users/alea12/.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/rails_admin-1.4.2/lib/rails_admin/extensions/paper_trail.rb:1:in `<main>'
	from /Users/alea12/.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/bootsnap-1.4.1/lib/bootsnap/load_path_cache/core_ext/kernel_require.rb:21:in `require'
	from /Users/alea12/.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/bootsnap-1.4.1/lib/bootsnap/load_path_cache/core_ext/kernel_require.rb:21:in `block in require_with_bootsnap_lfi'
	from /Users/alea12/.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/bootsnap-1.4.1/lib/bootsnap/load_path_cache/loaded_features_index.rb:83:in `register'
	from /Users/alea12/.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/bootsnap-1.4.1/lib/bootsnap/load_path_cache/core_ext/kernel_require.rb:20:in `require_with_bootsnap_lfi'
	from /Users/alea12/.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/bootsnap-1.4.1/lib/bootsnap/load_path_cache/core_ext/kernel_require.rb:29:in `require'
	from /Users/alea12/.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/activesupport-6.0.0.beta2/lib/active_support/dependencies.rb:297:in `block in require'
	from /Users/alea12/.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/activesupport-6.0.0.beta2/lib/active_support/dependencies.rb:263:in `load_dependency'
	from /Users/alea12/.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/activesupport-6.0.0.beta2/lib/active_support/dependencies.rb:297:in `require'
	from /Users/alea12/.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/rails_admin-1.4.2/lib/rails_admin.rb:8:in `<main>'
	from /Users/alea12/.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/bootsnap-1.4.1/lib/bootsnap/load_path_cache/core_ext/kernel_require.rb:21:in `require'
	from /Users/alea12/.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/bootsnap-1.4.1/lib/bootsnap/load_path_cache/core_ext/kernel_require.rb:21:in `block in require_with_bootsnap_lfi'
	from /Users/alea12/.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/bootsnap-1.4.1/lib/bootsnap/load_path_cache/loaded_features_index.rb:83:in `register'
	from /Users/alea12/.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/bootsnap-1.4.1/lib/bootsnap/load_path_cache/core_ext/kernel_require.rb:20:in `require_with_bootsnap_lfi'
	from /Users/alea12/.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/bootsnap-1.4.1/lib/bootsnap/load_path_cache/core_ext/kernel_require.rb:29:in `require'
	from /Users/alea12/.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/bundler-2.0.1/lib/bundler/runtime.rb:81:in `block (2 levels) in require'
	from /Users/alea12/.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/bundler-2.0.1/lib/bundler/runtime.rb:76:in `each'
	from /Users/alea12/.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/bundler-2.0.1/lib/bundler/runtime.rb:76:in `block in require'
	from /Users/alea12/.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/bundler-2.0.1/lib/bundler/runtime.rb:65:in `each'
	from /Users/alea12/.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/bundler-2.0.1/lib/bundler/runtime.rb:65:in `require'
	from /Users/alea12/.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/bundler-2.0.1/lib/bundler.rb:114:in `require'
	from /Users/alea12/projects/sandbox/testapp/config/application.rb:7:in `<top (required)>'
	from /Users/alea12/.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/spring-2.0.2/lib/spring/application.rb:92:in `require'
	from /Users/alea12/.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/spring-2.0.2/lib/spring/application.rb:92:in `preload'
	from /Users/alea12/.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/spring-2.0.2/lib/spring/application.rb:153:in `serve'
	from /Users/alea12/.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/spring-2.0.2/lib/spring/application.rb:141:in `block in run'
	from /Users/alea12/.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/spring-2.0.2/lib/spring/application.rb:135:in `loop'
	from /Users/alea12/.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/spring-2.0.2/lib/spring/application.rb:135:in `run'
	from /Users/alea12/.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/spring-2.0.2/lib/spring/application/boot.rb:19:in `<top (required)>'
	from /Users/alea12/.rbenv/versions/2.5.1/lib/ruby/site_ruby/2.5.0/rubygems/core_ext/kernel_require.rb:59:in `require'
	from /Users/alea12/.rbenv/versions/2.5.1/lib/ruby/site_ruby/2.5.0/rubygems/core_ext/kernel_require.rb:59:in `require'
	from -e:1:in `<main>'

Notes

• I've tested bundling my gems with bundle install --path=vendor/bundle, but it didn't solve this issue.

[seanwmitchell]

I am experiencing the same. Although I am using 2.6.1p33 (2019-01-30 revision 66950) [x86_64-darwin18]

I also agree that it is just isolated to the Rails Admin gem definitely. Without it the rails server with rails 6.0.0beta2 starts fine.

[alea12]

Update: Tested again with Ruby 2.6.0 + Rails 6.0.0.beta3, but the result was the same.

[Alexander-Senko]

I haven't got any approval yet, but it looks like String#strip_heredoc has been deprecated since Rails has moved to Ruby 2.3. Just replace it with <<~ heredoc syntax for Ruby 2.3+.

[Alexander-Senko]

I haven't got any approval yet, but it looks like String#strip_heredoc has been deprecated since Rails has moved to Ruby 2.3. Just replace it with <<~ heredoc syntax for Ruby 2.3+.

Sorry, it's still present in ActiveSupport 6.0.0.beta3. So, I wonder how we manage to get the exception this way.

Anyway, replacing it with <<~ should fix the problem.

[alea12]

@SoftPro Thanks for reaching out! As an alternative, requiring ActiveSupport explicitly in auditing_adapter.rb also solved the problem for me. This should also work for ruby < 2.3

require 'active_support/core_ext/string/strip'

module RailsAdmin
  module Extensions
    module PaperTrail
      class VersionProxy
        # ...
      end

      class AuditingAdapter
        # ...
        E_VERSION_MODEL_NOT_SET = <<-EOS.to_s.strip_heredoc.freeze
          # ...
        EOS
        # ...
      end
    end
  end
end