Rails 2.3.11 -> 3.2.3 simple gsub with regex does not work

Question

I tried to upgrade my Rails 2.3.11 application to Rails 3.2.3, but this function in ApplicationHelper does not work properly anymore in the browser (in Rails console everything is fine):

def basic_markup(text)
  if text
    text.gsub!(/(\A|\s|\[|\()_(.+?)_/iu, '\1<em>\2</em>')
    text.gsub!(/(\A|\s|\[|\()#(.+?)([^&])#/iu, '\1<del>\2\3</del>')
    text.gsub!('->', '→')
    text.gsub!('<-', '←')
  end
  text
end

text = '#strikeout# normal _italic_'
puts basic_markup(text)
# Rails 2.3.11
# => "<del>strikeout</del> normal <em>italic</em>"
# Rails 3.2.3
# => "#strikeout# normal <em>italic</em>"

Sample on Rails 2.3.11: http://moly.hu/karcok/150362

The same on Rails 3.2.3: http://moly.hu:3000/karcok/150362

What's wrong?

Answer 1

Copying the answer from the comments in order to remove this question from the "Unanswered" filter:

Frost suggested an upgrade:

Update to my comment above: I just tried creating a new rails 3.2.3 project, put that method in the application_helper and calling it from a view with the same text, and works just fine. I think you're missing something somewhere else.

Nagy Bence confirmed:

Problem solved, maybe Rails' simple_format has changed between 2.3.11 and 3.2.3, but now it runs correctly. Thanks for the comments!