rails/rails — pull request #5724 by anjshenoy (2012-04-03 18:28:20+00:00)
Title: symbolize_keys now works recursively in addition to being fully backward compatible.

1. Current behavior of symbolize_keys remains unaltered (recursive flag is set to false by default)
2. If the recursive flag is set to true and the value is a Hash, then the value's keys will also be symbolized recursively.