Merge branch 'master' into adequaterecord

* master: (70 commits)
  [ci skip] Added link to ruby-lang.org installation.
  Use the index on hidden field
  `collection_check_boxes` respects `:index` option for the hidden filed name.
  docs, double meaning of `serialize` argument. Closes #14284.
  Just call read_attribute, no need to use `send`.
  - Fix lingering reference to `:text` instead of the newer `:plain` - Section references `form_tag` instead of the `form_for` used in the example
  again, read_attribute is public, so just call it
  read_attribute is public, so we should just call it
  Disable assest cache store in docs [ci skip]
  Make counter cache decrementation on destroy idempotent
  Write the failing test case for concurrent counter cache
  [ci skip] Use plain underscore instead of "\_".
  Update documentation to use Rails.application instead
  Add a changelog entry for #14546 [ci skip]
  Move tests for deep_dup and duplicable to object directory
  Missing 'are' in note - [ci skip]
  CollectionHelpers now accepts a readonly option
  Fix a few typos [ci skip]
  Bundle tzinfo-data on :x64_mingw (64-bit Ruby on Windows).
  don't bother with an offset if the offset is zero
  ...

2 files changed, 14 insertions, 5 deletions

diff --git a/actionview/lib/action_view/helpers/tags/collection_check_boxes.rb b/actionview/lib/action_view/helpers/tags/collection_check_boxes.rb
index 8b28e4fc33..6242a2a085 100644
--- a/actionview/lib/action_view/helpers/tags/collection_check_boxes.rb
+++ b/actionview/lib/action_view/helpers/tags/collection_check_boxes.rb
@@ -28,10 +28,7 @@ module ActionView
           # Append a hidden field to make sure something will be sent back to the
           # server if all check boxes are unchecked.
           if @options.fetch(:include_hidden, true)
-            hidden_name = @html_options[:name] || "#{tag_name}[]"
-            hidden = @template_object.hidden_field_tag(hidden_name, "", :id => nil)
-
-            rendered_collection + hidden
+            rendered_collection + hidden_field
           else
             rendered_collection
           end
@@ -42,6 +39,18 @@ module ActionView
         def render_component(builder)
           builder.check_box + builder.label
         end
+
+        def hidden_field
+          hidden_name = @html_options[:name]
+
+          hidden_name ||= if @options.has_key?(:index)
+            "#{tag_name_with_index(@options[:index])}[]"
+          else
+            "#{tag_name}[]"
+          end
+
+          @template_object.hidden_field_tag(hidden_name, "", id: nil)
+        end
       end
     end
   end
diff --git a/actionview/lib/action_view/helpers/tags/collection_helpers.rb b/actionview/lib/action_view/helpers/tags/collection_helpers.rb
index 991f32cea2..8050638363 100644
--- a/actionview/lib/action_view/helpers/tags/collection_helpers.rb
+++ b/actionview/lib/action_view/helpers/tags/collection_helpers.rb
@@ -44,7 +44,7 @@ module ActionView
         def default_html_options_for_collection(item, value) #:nodoc:
           html_options = @html_options.dup
 
-          [:checked, :selected, :disabled].each do |option|
+          [:checked, :selected, :disabled, :readonly].each do |option|
             current_value = @options[option]
             next if current_value.nil?