Avoid -I rubylibdir with default-gem bundler

[k0kubun]

Since Ruby 2.6.0, bundler.gem has been a default gem. It means that $LOADED_FEATURES.grep(/bundler\/setup\.rb$/).first could be the same as RbConfig::CONFIG["rubylibdir"], which is the default gem directory and not dedicated for a specific bundler version, if no newer bundler were manually installed.

Passing default gem directory with -I is really problematic because it has other default gems like json.gem, and -I is prioritized more than $LOAD_PATHs added by Bundler.require. Using default-gem Bundler could cause a wrong default gem version on spring server process.

[k0kubun]

Reproductive steps

# Use clean Ruby 2.6.x, or uninstall any non-default bundler installation
$ rails new springapp --skip-active-record
$ cd springapp
$ echo 'gem "json", "1.8.6"' >> Gemfile
$ bundle install

$ DISABLE_SPRING=1 bin/rails r 'p JSON.load(nil)'
nil

$ DISABLE_SPRING=0 bin/rails r 'p JSON.load(nil)'
Running via Spring preloader in process 17934
Traceback (most recent call last):
# ...
/home/k0kubun/.rbenv/versions/2.6.3/lib/ruby/2.6.0/json/common.rb:156:in `parse': 784: unexpected token at 'null' (JSON::ParserError)

I believe this is not something we want.

Example

$ ruby -v
ruby 2.6.3p62 (2019-04-16 revision 67580) [x86_64-linux]

$ rails -v
Rails 5.2.3

$ gem list | grep bundler
bundler (default: 1.17.2)

$ rails new springapp --skip-active-record
# ...

$ cd springapp
$ echo 'gem "json", "1.8.6"' >> Gemfile
$ bundle install
# ...

$ bundle exec spring -v
Spring version 2.1.0

$ DISABLE_SPRING=1 bin/rails r 'p JSON.load(nil)'
nil

$ bin/spring stop
Spring is not running

$ DISABLE_SPRING=0 bin/rails r 'p JSON.load(nil)'
Running via Spring preloader in process 17934
Traceback (most recent call last):
        28: from -e:1:in `<main>'
        27: from /home/k0kubun/.rbenv/versions/2.6.3/lib/ruby/2.6.0/rubygems/core_ext/kernel_require.rb:54:in `require'
        26: from /home/k0kubun/.rbenv/versions/2.6.3/lib/ruby/2.6.0/rubygems/core_ext/kernel_require.rb:54:in `require'
        25: from /home/k0kubun/.rbenv/versions/2.6.3/lib/ruby/gems/2.6.0/gems/activesupport-5.2.3/lib/active_support/dependencies.rb:285:in `load'
        24: from /home/k0kubun/.rbenv/versions/2.6.3/lib/ruby/gems/2.6.0/gems/activesupport-5.2.3/lib/active_support/dependencies.rb:257:in `load_dependency'
        23: from /home/k0kubun/.rbenv/versions/2.6.3/lib/ruby/gems/2.6.0/gems/activesupport-5.2.3/lib/active_support/dependencies.rb:285:in `block in load'
        22: from /home/k0kubun/.rbenv/versions/2.6.3/lib/ruby/gems/2.6.0/gems/bootsnap-1.4.4/lib/bootsnap/load_path_cache/core_ext/kernel_require.rb:54:in `load'
        21: from /home/k0kubun/.rbenv/versions/2.6.3/lib/ruby/gems/2.6.0/gems/bootsnap-1.4.4/lib/bootsnap/load_path_cache/core_ext/kernel_require.rb:54:in `load'
        20: from /home/k0kubun/tmp/springapp/bin/rails:9:in `<main>'
        19: from /home/k0kubun/.rbenv/versions/2.6.3/lib/ruby/gems/2.6.0/gems/activesupport-5.2.3/lib/active_support/dependencies.rb:291:in `require'
        18: from /home/k0kubun/.rbenv/versions/2.6.3/lib/ruby/gems/2.6.0/gems/activesupport-5.2.3/lib/active_support/dependencies.rb:257:in `load_dependency'
        17: from /home/k0kubun/.rbenv/versions/2.6.3/lib/ruby/gems/2.6.0/gems/activesupport-5.2.3/lib/active_support/dependencies.rb:291:in `block in require'
        16: from /home/k0kubun/.rbenv/versions/2.6.3/lib/ruby/gems/2.6.0/gems/bootsnap-1.4.4/lib/bootsnap/load_path_cache/core_ext/kernel_require.rb:30:in `require'
        15: from /home/k0kubun/.rbenv/versions/2.6.3/lib/ruby/gems/2.6.0/gems/bootsnap-1.4.4/lib/bootsnap/load_path_cache/core_ext/kernel_require.rb:21:in `require_with_bootsnap_lfi'
        14: from /home/k0kubun/.rbenv/versions/2.6.3/lib/ruby/gems/2.6.0/gems/bootsnap-1.4.4/lib/bootsnap/load_path_cache/loaded_features_index.rb:92:in `register'
        13: from /home/k0kubun/.rbenv/versions/2.6.3/lib/ruby/gems/2.6.0/gems/bootsnap-1.4.4/lib/bootsnap/load_path_cache/core_ext/kernel_require.rb:22:in `block in require_with_bootsnap_lfi'
        12: from /home/k0kubun/.rbenv/versions/2.6.3/lib/ruby/gems/2.6.0/gems/bootsnap-1.4.4/lib/bootsnap/load_path_cache/core_ext/kernel_require.rb:22:in `require'
        11: from /home/k0kubun/.rbenv/versions/2.6.3/lib/ruby/gems/2.6.0/gems/railties-5.2.3/lib/rails/commands.rb:18:in `<main>'
        10: from /home/k0kubun/.rbenv/versions/2.6.3/lib/ruby/gems/2.6.0/gems/railties-5.2.3/lib/rails/command.rb:46:in `invoke'
         9: from /home/k0kubun/.rbenv/versions/2.6.3/lib/ruby/gems/2.6.0/gems/railties-5.2.3/lib/rails/command/base.rb:65:in `perform'
         8: from /home/k0kubun/.rbenv/versions/2.6.3/lib/ruby/gems/2.6.0/gems/thor-0.20.3/lib/thor.rb:387:in `dispatch'
         7: from /home/k0kubun/.rbenv/versions/2.6.3/lib/ruby/gems/2.6.0/gems/thor-0.20.3/lib/thor/invocation.rb:126:in `invoke_command'
         6: from /home/k0kubun/.rbenv/versions/2.6.3/lib/ruby/gems/2.6.0/gems/thor-0.20.3/lib/thor/command.rb:27:in `run'
         5: from /home/k0kubun/.rbenv/versions/2.6.3/lib/ruby/gems/2.6.0/gems/railties-5.2.3/lib/rails/commands/runner/runner_command.rb:41:in `perform'
         4: from /home/k0kubun/.rbenv/versions/2.6.3/lib/ruby/gems/2.6.0/gems/railties-5.2.3/lib/rails/commands/runner/runner_command.rb:41:in `eval'
         3: from /home/k0kubun/.rbenv/versions/2.6.3/lib/ruby/gems/2.6.0/gems/railties-5.2.3/lib/rails/commands/runner/runner_command.rb:41:in `<main>'
         2: from /home/k0kubun/.rbenv/versions/2.6.3/lib/ruby/2.6.0/json/common.rb:335:in `load'
         1: from /home/k0kubun/.rbenv/versions/2.6.3/lib/ruby/2.6.0/json/common.rb:156:in `parse'
/home/k0kubun/.rbenv/versions/2.6.3/lib/ruby/2.6.0/json/common.rb:156:in `parse': 784: unexpected token at 'null' (JSON::ParserError)

[kamipo]

👍 People who using Ruby 2.6 may be faced with this issue as we've faced.