Instead of marking raw text in templates as safe, and then putting them through String#<< which checks if the String is safe, use safe_concat, which uses the original (internal) String#<< and leaves the safe flag as is. Results in a significant performance improvement.

2 files changed, 3 insertions, 1 deletions

diff --git a/actionpack/lib/action_view/template/handlers/erb.rb b/actionpack/lib/action_view/template/handlers/erb.rb
index f8e6376589..93a4315108 100644
--- a/actionpack/lib/action_view/template/handlers/erb.rb
+++ b/actionpack/lib/action_view/template/handlers/erb.rb
@@ -10,7 +10,8 @@ module ActionView
       end
 
       def add_text(src, text)
-        src << "@output_buffer << ('" << escape_text(text) << "'.html_safe!);"
+        return if text.empty?
+        src << "@output_buffer.safe_concat('" << escape_text(text) << "');"
       end
 
       def add_expr_literal(src, code)
diff --git a/activesupport/lib/active_support/core_ext/string/output_safety.rb b/activesupport/lib/active_support/core_ext/string/output_safety.rb
index a2a88eb7df..9db563f78b 100644
--- a/activesupport/lib/active_support/core_ext/string/output_safety.rb
+++ b/activesupport/lib/active_support/core_ext/string/output_safety.rb
@@ -23,6 +23,7 @@ class String
   end
 
   alias original_concat <<
+  alias safe_concat <<
   def <<(other)
     result = original_concat(other)
     unless html_safe? && also_html_safe?(other)