Add `:enforce_utf8` option to form_for

Since 06388b0 `form_tag` accepts the option `enforce_utf8` which, when set to
false, prevents the hidden "UTF8 enforcer" field from appearing in the output.

This commit implements the same behavior for `form_for`.

Stems from https://github.com/rails/rails/pull/17685#issuecomment-63871395

1 files changed, 3 insertions, 0 deletions

diff --git a/actionview/lib/action_view/helpers/form_helper.rb b/actionview/lib/action_view/helpers/form_helper.rb
index 03f80ff360..2119ea938f 100644
--- a/actionview/lib/action_view/helpers/form_helper.rb
+++ b/actionview/lib/action_view/helpers/form_helper.rb
@@ -164,6 +164,8 @@ module ActionView
       # * <tt>:namespace</tt> - A namespace for your form to ensure uniqueness of
       #   id attributes on form elements. The namespace attribute will be prefixed
       #   with underscore on the generated HTML id.
+      # * <tt>:enforce_utf8</tt> - If set to false, a hidden input with name
+      #   utf8 is not output.
       # * <tt>:html</tt> - Optional HTML attributes for the form tag.
       #
       # Also note that +form_for+ doesn't create an exclusive scope. It's still
@@ -420,6 +422,7 @@ module ActionView
         html_options[:data]   = options.delete(:data)   if options.has_key?(:data)
         html_options[:remote] = options.delete(:remote) if options.has_key?(:remote)
         html_options[:method] = options.delete(:method) if options.has_key?(:method)
+        html_options[:enforce_utf8] = options.delete(:enforce_utf8) if options.has_key?(:enforce_utf8)
         html_options[:authenticity_token] = options.delete(:authenticity_token)
 
         builder = instantiate_builder(object_name, object, options)