add 'include_hidden' option to select tag, closes #5402

actionpack/CHANGELOG.md

@@ -1,5 +1,7 @@
 ## Rails 4.0.0 (unreleased) ##
 
+*   Add `include_hidden` option to select tag. With `:include_hidden => true` select with `multiple` attribute doesn't generate hidden input with blank value. *Vasiliy Ermolovich*
+
 *   Removed default `size` option from the `text_field`, `search_field`, `telephone_field`, `url_field`, `email_field` helpers. *Philip Arndt*
 
 *   Removed default `cols` and `rows` options from the `text_area` helper. *Philip Arndt*

actionpack/lib/action_view/helpers/form_options_helper.rb

@@ -153,6 +153,8 @@ module ActionView
       # form, and parameters extraction gets the last occurrence of any repeated
       # key in the query string, that works for ordinary forms.
       #
+      # In case if you don't want the helper to generate this hidden field you can specify <tt>:include_blank => false</tt> option.
+      #
       def select(object, method, choices, options = {}, html_options = {})
         Tags::Select.new(object, method, self, choices, options, html_options).render
       end

actionpack/lib/action_view/helpers/tags/base.rb

@@ -122,7 +122,8 @@ module ActionView
           html_options = html_options.stringify_keys
           add_default_name_and_id(html_options)
           select = content_tag("select", add_options(option_tags, options, value(object)), html_options)
-          if html_options["multiple"]
+
+          if html_options["multiple"] && options.fetch(:include_hidden) { true }
             tag("input", :disabled => html_options["disabled"], :name => html_options["name"], :type => "hidden", :value => "") + select
           else
             select

actionpack/test/template/form_options_helper_test.rb

@@ -529,6 +529,14 @@ class FormOptionsHelperTest < ActionView::TestCase
     )
   end
 
+  def test_select_with_multiple_and_without_hidden_input
+    output_buffer =  select(:post, :category, "", {:include_hidden => false}, :multiple => true)
+    assert_dom_equal(
+      "<select multiple=\"multiple\" id=\"post_category\" name=\"post[category][]\"></select>",
+      output_buffer
+    )
+  end
+
   def test_select_with_multiple_and_disabled_to_add_disabled_hidden_input
     output_buffer =  select(:post, :category, "", {}, :multiple => true, :disabled => true)
     assert_dom_equal(