When installing Ruby's default gems from rubygems, both gems load.

[y-yagi]

Hi.

I installed Ruby's Default gems separately from rubygems (version is different from default).
After that, when run a script using bundler/inline, a warning is generated that the constants of the installed gem are redefined.

Steps to reproduce

# main.rb

# frozen_string_literal: true

require "bundler/inline"

gemfile(true) do
  source "https://rubygems.org"

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

  gem "rack-test"
end

require "rack/test" 

$ gem install fileutils
Fetching: fileutils-1.1.0.gem (100%)
Successfully installed fileutils-1.1.0
1 gem installed 

$ ruby main.rb
Fetching gem metadata from https://rubygems.org/...............
Resolving dependencies...
Using bundler 1.16.2
Using rack 2.0.5
Using rack-test 1.0.0
/home/yaginuma/.rbenv/versions/2.5.1/lib/ruby/2.5.0/fileutils.rb:90: warning: already initialized constant FileUtils::VERSION
/home/yaginuma/.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/fileutils-1.1.0/lib/fileutils.rb:92: warning: previous definition of VERSION was here
/home/yaginuma/.rbenv/versions/2.5.1/lib/ruby/2.5.0/fileutils.rb:1188: warning: already initialized constant FileUtils::Entry_::S_IF_DOOR
/home/yaginuma/.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/fileutils-1.1.0/lib/fileutils.rb:1267: warning: previous definition of S_IF_DOOR was here
/home/yaginuma/.rbenv/versions/2.5.1/lib/ruby/2.5.0/fileutils.rb:1446: warning: already initialized constant FileUtils::Entry_::DIRECTORY_TERM
/home/yaginuma/.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/fileutils-1.1.0/lib/fileutils.rb:1541: warning: previous definition of DIRECTORY_TERM was here
/home/yaginuma/.rbenv/versions/2.5.1/lib/ruby/2.5.0/fileutils.rb:1448: warning: already initialized constant FileUtils::Entry_::SYSCASE
/home/yaginuma/.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/fileutils-1.1.0/lib/fileutils.rb:1543: warning: previous definition of SYSCASE was here
/home/yaginuma/.rbenv/versions/2.5.1/lib/ruby/2.5.0/fileutils.rb:1501: warning: already initialized constant FileUtils::OPT_TABLE
/home/yaginuma/.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/fileutils-1.1.0/lib/fileutils.rb:1596: warning: previous definition of OPT_TABLE was here
/home/yaginuma/.rbenv/versions/2.5.1/lib/ruby/2.5.0/fileutils.rb:1555: warning: already initialized constant FileUtils::LOW_METHODS
/home/yaginuma/.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/fileutils-1.1.0/lib/fileutils.rb:1650: warning: previous definition of LOW_METHODS was here
/home/yaginuma/.rbenv/versions/2.5.1/lib/ruby/2.5.0/fileutils.rb:1562: warning: already initialized constant FileUtils::METHODS
/home/yaginuma/.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/fileutils-1.1.0/lib/fileutils.rb:1657: warning: previous definition of METHODS was here

FYI: rack-test requires fileutils.
https://github.com/rack-test/rack-test/blob/03eb717b3e95faf1d64fc26fb9559868884333ce/lib/rack/test/uploaded_file.rb#L1

Expected behavior

Warnings are not displayed.

Actual behavior

Warnings are displayed.

System configuration

Ruby version:

$ ruby -v
ruby 2.5.1p57 (2018-03-29 revision 63029) [x86_64-linux]

Bundler version:

$ bundler -v
Bundler version 1.16.2

[segiddins]

Out of curiosity, does this happen if you use a normal gemfile instead of an inline one?

[y-yagi]

Hmm. It seems that this does not happen with normal gemfile.

$ cat Gemfile
source 'https://rubygems.org'

gem 'rack-test' 

$ bundle install
Using bundler 1.16.2
Using rack 2.0.5
Using rack-test 1.0.0
Bundle complete! 1 Gemfile dependency, 3 gems now installed.
Use `bundle info [gemname]` to see where a bundled gem is installed.
$ bundle exec ruby -w -e "p require 'rack/test'"
true

[segiddins]

I'm going to guess this is because inline goes through the installation code, which requires fileutils, so I'm not sure this is even fixable :/

[mturnaviotov]

I create rails 5.2 test app with ruby 2.5.1 some days ago and have a same errors when rails server starting too.
Seems like double loading fileutils ?

% rails db:migrate
/home/user/.rbenv/versions/2.5.1/lib/ruby/2.5.0/fileutils.rb:90: warning: already initialized constant Fi
leUtils::VERSION
/home/user/.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/fileutils-1.1.0/lib/fileutils.rb:92: warning: p
revious definition of VERSION was here
/home/user/.rbenv/versions/2.5.1/lib/ruby/2.5.0/fileutils.rb:1188: warning: already initialized constant
FileUtils::Entry_::S_IF_DOOR
/home/user/.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/fileutils-1.1.0/lib/fileutils.rb:1267: warning:
previous definition of S_IF_DOOR was here
/home/user/.rbenv/versions/2.5.1/lib/ruby/2.5.0/fileutils.rb:1446: warning: already initialized constant
FileUtils::Entry_::DIRECTORY_TERM
/home/user/.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/fileutils-1.1.0/lib/fileutils.rb:1541: warning:
previous definition of DIRECTORY_TERM was here
/home/user/.rbenv/versions/2.5.1/lib/ruby/2.5.0/fileutils.rb:1448: warning: already initialized constant
FileUtils::Entry_::SYSCASE
/home/user/.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/fileutils-1.1.0/lib/fileutils.rb:1543: warning:
previous definition of SYSCASE was here
/home/user/.rbenv/versions/2.5.1/lib/ruby/2.5.0/fileutils.rb:1501: warning: already initialized constant
FileUtils::OPT_TABLE
/home/user/.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/fileutils-1.1.0/lib/fileutils.rb:1596: warning:
previous definition of OPT_TABLE was here
/home/user/.rbenv/versions/2.5.1/lib/ruby/2.5.0/fileutils.rb:1555: warning: already initialized constant
FileUtils::LOW_METHODS
/home/user/.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/fileutils-1.1.0/lib/fileutils.rb:1650: warning:
previous definition of LOW_METHODS was here
/home/user/.rbenv/versions/2.5.1/lib/ruby/2.5.0/fileutils.rb:1562: warning: already initialized constant
FileUtils::METHODS
/home/user/.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/fileutils-1.1.0/lib/fileutils.rb:1657: warning:
previous definition of METHODS was here

[deivid-rodriguez]

Hi @y-yagi! Still pending a regression spec, but I think #3991 should fix this!

[deivid-rodriguez]

The PR should be ready now, I'll merge it in a couple of days!