invalid byte sequence utf-8 error in rails 2.3 and ruby 1.9

Question

I've migrated my app from Rails 2.3.8 / Ruby 1.8.7 to 2.3.14 / Ruby 1.9.2 - it hasn't been easy, but basically works. An issue I keep having is that in the occasional Haml template I'll get the following error:

ActionView::TemplateError (invalid byte sequence in UTF-8) on line #....

This is an encoding issue, and I've seen some suggestions on how to deal with it (using Iconv.conv), but the things I tried didn't seem to work. How do I resolve this on the application level (not having to patch every template)? Thanks.

EDIT: Some stack trace

ActionView::TemplateError (invalid byte sequence in UTF-8) on line #28 of app/views/users/_user.haml:
27:     - if user.valid?
28:       - image_onclick = remote_function( :url => { :action => :toggle_image, :id => user.id } )

    vendor/rails/activesupport/lib/active_support/core_ext/object/blank.rb:68:in `=~'
    vendor/rails/activesupport/lib/active_support/core_ext/object/blank.rb:68:in `!~'
    vendor/rails/activesupport/lib/active_support/core_ext/object/blank.rb:68:in `blank?'
    vendor/rails/activerecord/lib/active_record/validations.rb:478:in `block (2 levels) in validates_each'
    vendor/rails/activerecord/lib/active_record/validations.rb:476:in `each'
    vendor/rails/activerecord/lib/active_record/validations.rb:476:in `block in validates_each'
    ... etc

The database tables' CHARSET is encoded in UTF-8. I didn't assign any specific encoding to my templates, although I set

Encoding.default_internal = 'utf-8'
Encoding.default_external = 'utf-8'

in environment.rb

Answer 1

This seems to be an issue with the MySQL adapter I've been using - the old ruby-mysql gem. I've upgraded to mysql2 and that seemed to have solved the issue.