Why "require 'rubygems'" In Your Library/App/Tests Is Wrong

Tests Is Wrong

In response to all the responses to:

http://twitter.com/rtomayko/status/1155906157

You should never do this in a source file included with your library,
app, or tests:

    require 'rubygems'

The system I use to manage my $LOAD_PATH is not your library/app/tests
concern. Whether rubygems is used or not is an environment issue. Your
library or app should have no say in the matter. Explicitly requiring
rubygems is either not necessary or misguided.

When you feel the urge to "require 'rubygems'" because some shit isn't
working, stop and consider whether one of these solutions is more
appropriate:

1. RubyGems installs special versions of executables included with
gems. Here's rake's as an example:

    $ cat /opt/local/bin/rake
    #!/opt/local/bin/ruby
    #
    # This file was generated by RubyGems.
    #
    # The application 'rake' is installed as part of a gem, and
    # this file is here to facilitate running it.
    #
    require 'rubygems'
    version = ">= 0"
    if ARGV.first =~ /^_(.*)_$/ and Gem::Version.correct? $1 then
      version = $1
      ARGV.shift
    end
    gem 'rake', version
    load 'rake'

In this case, rubygems is required when the executable is run. Explicitly
requiring rubygems in code loaded by these files doesn't make sense. The
whole point of these wrapper scripts is to push the rubygems loading
machinery into the environment and out of your app/library/tests.

2. When running "ruby FOO.rb" and a LoadError occurs because rubygems
is not available, DO NOT add "require 'rubygems'" to FOO.rb. Instead,
run the command as "ruby -rubygems FOO.rb". This will require rubygems
before evaluating FOO.rb.

3. When running "ruby FOO.rb" and a LoadError occurs because rubygems
is not available, DO NOT add "require 'rubygems'" to FOO.rb. Instead,
set the RUBYOPT environment variable:

    $ RUBYOPT="rubygems"
    $ export RUBYOPT
    $ ruby FOO.rb

You can even put that in your ~/.{bash,zsh,sh}rc if you prefer to always
have rubygems loaded and available.

Why You Shouldn't Force Rubygems On People
------------------------------------------

When I use your library, deploy your app, or run your tests I may not want
to use rubygems. When you "require 'rubygems'" in your code, you remove my
ability to make that decision. I cannot unrequire rubygems, but you can
not require it in the first place.

If you need to remove this from a bunch of source files, this library might help 😛