Ruby: require vs require_relative - best practice to workaround running in both Ruby <1.9.2 and >=1.9.2 Ask Question

What is the best practice if I want to require a relative file in Ruby and I want it to work in both 1.8.x and >=1.9.2?

I see a few options:

• just do $LOAD_PATH << '.' and forget everything
• do $LOAD_PATH << File.dirname(__FILE__)
• require './path/to/file'
• check if RUBY_VERSION < 1.9.2, then define require_relative as require, use require_relative everywhere where it's needed afterwards
• check if require_relative already exists, if it does, try to proceed as in previous case
• use weird constructions such as

  require File.join(File.dirname(__FILE__), 'path/to/file')

  - alas they don't seem to work in Ruby 1.9 throughly, because, for example:

  $ cat caller.rb
  require File.join(File.dirname(__FILE__), 'path/to/file')
  $ cat path/to/file.rb
  puts 'Some testing'
  $ ruby caller
  Some testing
  $ pwd
  /tmp
  $ ruby /tmp/caller
  Some testing
  $ ruby tmp/caller
  tmp/caller.rb:1:in 'require': no such file to load -- tmp/path/to/file (LoadError)
      from tmp/caller.rb:1:in '<main>'

• Even weirder construction:

  require File.join(File.expand_path(File.dirname(__FILE__)), 'path/to/file')

  seems to work, but it's weird and not quite good looking.
• Use backports gem - it's kind of heavy, it requires rubygems infrastructure and includes tons of other workarounds, while I just want require to work with relative files.

There's a closely related question at StackOverflow that gives some more examples, but it doesn't give a clear answer - which is a best practice.

Is there are any decent, accepted-by-everyone universal solution to make my application run on both Ruby <1.9.2 and >=1.9.2?

UPDATE

Clarification: I don't want just answers like "you can do X" - in fact, I've already mentioned most of choices in question. I want rationale, i.e. why it is a best practice, what are its pros and cons and why it should be chosen among the others.