tenderlove/psych — pull request #191 by amarshall (2014-05-20 18:46:18+00:00)
Title: Fix loading objects with instance variables named "null"

Do so by always interpreting mapping keys in an object as symbols rather than strings. When interpreted as a string it becomes `nil` which is then coerced to a string (`""`) and then tries to set the ivar `"@"` rather than `"@null"` raising the following error:

> NameError: `@' is not allowed as an instance variable name