Today I Learned

A Hashrocket project

Ready to join Hashrocket? Find Openings here and apply today.

Ensure Ruby returns the correct value

Ruby has implicit returns for any possible block that I can think of, except ensure. There might be more, but this is the only one that I can think of now.

So in order to return something from inside the ensure block we must use the return reserved word explicitly. Check this out:

def check_this_out
  yield if block_given?
  :ok
rescue
  :error
ensure
  :ensured
end

irb()> check_this_out { "should work" }
=> :ok

irb()> check_this_out { raise "should fail" }
=> :error

As we can see even though the ensure code runs on all calls it does not return :ensured.

Here’s the code with the explicit return:

def check_this_out_explicit_ensure_return
  yield if block_given?
  :ok
rescue
  :error
ensure
  return :ensured
end

irb()> check_this_out_explicit_ensure_return { "should work" }
=> :ensured

irb()> check_this_out_explicit_ensure_return { raise "should fail" }
=> :ensured
Looking for help? Each developer at Hashrocket has years of experience working with Ruby applications of all types and sizes. We're an active presence at Ruby conferences, have written some of the most popular gems, and have worked on many of the web's Ruby on Rails success stories. Contact us today to talk about your Ruby project.