Rails 5.2.0 with Ruby 2.5.1 console - `warning:` `already` initialized constant FileUtils::VERSION

Question

I'm currently experiencing an issue with my new rails application, more specifically:

• Rails 5.2.0
• Ruby 2.5.1p57 (2018-03-29 revision 63029) [x86_64-darwin17]
• rvm 1.29.4 (latest) by Michal Papis, Piotr Kuczynski, Wayne E. Seguin [https://rvm.io]

When I run rails c, it produces a warning links to fileutils gem as the following:

`/usr/local/Cellar/ruby/2.5.1/lib/ruby/2.5.0/fileutils.rb:90:` `warning:` `already` initialized constant FileUtils::VERSION
/usr/local/lib/ruby/gems/2.5.0/gems/fileutils-1.1.0/lib/fileutils.rb:92: warning: previous definition of VERSION was here
/usr/local/Cellar/ruby/2.5.1/lib/ruby/2.5.0/fileutils.rb:1188: warning: already initialized constant FileUtils::Entry_::S_IF_DOOR
/usr/local/lib/ruby/gems/2.5.0/gems/fileutils-1.1.0/lib/fileutils.rb:1267: warning: previous definition of S_IF_DOOR was here
/usr/local/Cellar/ruby/2.5.1/lib/ruby/2.5.0/fileutils.rb:1446: warning: already initialized constant FileUtils::Entry_::DIRECTORY_TERM
/usr/local/lib/ruby/gems/2.5.0/gems/fileutils-1.1.0/lib/fileutils.rb:1541: warning: previous definition of DIRECTORY_TERM was here
/usr/local/Cellar/ruby/2.5.1/lib/ruby/2.5.0/fileutils.rb:1448: warning: already initialized constant FileUtils::Entry_::SYSCASE
/usr/local/lib/ruby/gems/2.5.0/gems/fileutils-1.1.0/lib/fileutils.rb:1543: warning: previous definition of SYSCASE was here
/usr/local/Cellar/ruby/2.5.1/lib/ruby/2.5.0/fileutils.rb:1501: warning: already initialized constant FileUtils::OPT_TABLE
/usr/local/lib/ruby/gems/2.5.0/gems/fileutils-1.1.0/lib/fileutils.rb:1596: warning: previous definition of OPT_TABLE was here
/usr/local/Cellar/ruby/2.5.1/lib/ruby/2.5.0/fileutils.rb:1555: warning: already initialized constant FileUtils::LOW_METHODS
/usr/local/lib/ruby/gems/2.5.0/gems/fileutils-1.1.0/lib/fileutils.rb:1650: warning: previous definition of LOW_METHODS was here
/usr/local/Cellar/ruby/2.5.1/lib/ruby/2.5.0/fileutils.rb:1562: warning: already initialized constant FileUtils::METHODS
/usr/local/lib/ruby/gems/2.5.0/gems/fileutils-1.1.0/lib/fileutils.rb:1657: warning: previous definition of METHODS was here

I follow all the step as outlined in this guideline http://railsapps.github.io/installrubyonrails-mac.html.

You can replicate the issue by just following the guideline or with the following steps:

1. rvm install ruby-2.5.1
2. rails new app
3. cd app
4. gem update
5. bundle update

After observing and working around, I've found that the default version of fileutils come with Ruby 2.5.* is 1.0.2 and the gem update command installs a another newer version 1.1.0. Therefore, there are two versions of fileutils are loaded when I run the rails c.

To deal with this issue, I append --default option to the gem update command.

gem update --default

As a result, I got two default versions which can be seen by running gem list | grep fileutils. This is the only way I can get rid the warning.

mac: gem list | grep fileutils
fileutils (default: 1.1.0, default: 1.0.2)

I write this question with, kind of, answer just to share with someone who may experience the same issue. I spent hours to sort it out as I couldn't find any helps on the internet.

Note: the same issue happens when I use rbenv instead of rvm on macOS Sierra.

Please let me know if anyone has a better approach to deal with such an issue.

Cheers,

Answer 1

I had the same issue. The one step missing from your post is to uninstall the fileutils gem first, then gem update with the default option.

gem uninstall fileutils
Successfully uninstalled fileutils-1.1.0
gem update --default
Updating installed gems
Updating fileutils
Fetching: fileutils-1.1.0.gem (100%)
Successfully installed fileutils-1.1.0

That got rid of the verbose fileutils messages for me.

Update: Instead of gem update --default, do gem update fileutils --default. This process should work for other gems too. Thanks to Matijs van Zuijlen for this.