Change render to support any hash keys in locals

this lets you pass ruby keywords to templates:

    <%= render 'example', class: "cool" %>

    <%= render 'example', "spaces are" => "a-ok" %>

    <%= render 'example', Foo: "bar" %>

Previously you'd see confusing syntax errors like this:

    SyntaxError (.../_example.html.erb:1: syntax error, unexpected '='

Now you can reference invalid identifiers through local_assigns.

If you try to use an invalid keyword (e.g. class) in your template, you
get a syntax error on the line where you use it.

1 files changed, 7 insertions, 1 deletions

diff --git a/actionview/lib/action_view/template.rb b/actionview/lib/action_view/template.rb
index 513935cef0..c01dd1c028 100644
--- a/actionview/lib/action_view/template.rb
+++ b/actionview/lib/action_view/template.rb
@@ -1,5 +1,6 @@
 require "active_support/core_ext/object/try"
 require "active_support/core_ext/kernel/singleton_class"
+require "active_support/core_ext/module/delegation"
 require "thread"
 
 module ActionView
@@ -324,8 +325,13 @@ module ActionView
       end
 
       def locals_code #:nodoc:
+        # Only locals with valid variable names get set directly. Others will
+        # still be available in local_assigns.
+        locals = @locals.to_set - Module::DELEGATION_RESERVED_METHOD_NAMES
+        locals = locals.grep(/\A(?![A-Z0-9])(?:[[:alnum:]_]|[^\0-\177])+\z/)
+
         # Double assign to suppress the dreaded 'assigned but unused variable' warning
-        @locals.each_with_object("") { |key, code| code << "#{key} = #{key} = local_assigns[:#{key}];" }
+        locals.each_with_object("") { |key, code| code << "#{key} = #{key} = local_assigns[:#{key}];" }
       end
 
       def method_name #:nodoc: