Merge pull request #9616 from exviva/multiple_select_name_double_square_brackets

Fix incorrectly appended square brackets to a multiple select box

Before:

    select(:category, [], {}, {:multiple => true, :name => "post[category][]"})
    # => <select name="post[category][][]" ...>

After:

    select(:category, [], {}, {:multiple => true, :name => "post[category][]"})
    # => <select name="post[category][]" ...>

1 files changed, 1 insertions, 1 deletions

diff --git a/actionpack/lib/action_view/helpers/tags/base.rb b/actionpack/lib/action_view/helpers/tags/base.rb
index 3d597079c4..aef1572290 100644
--- a/actionpack/lib/action_view/helpers/tags/base.rb
+++ b/actionpack/lib/action_view/helpers/tags/base.rb
@@ -84,7 +84,7 @@ module ActionView
             options["id"] = options.fetch("id"){ tag_id }
           end
 
-          options["name"] += "[]" if options["multiple"]
+          options["name"] += "[]" if options["multiple"] && !options["name"].ends_with?("[]")
           options["id"] = [options.delete('namespace'), options["id"]].compact.join("_").presence
         end