Modifying a class method's state

Hi guys. I'm experiencing some strange behaviour in my Rails app. I
have a constant, and two class methods:

Hi Nick,
This is because Ruby constants are not constants. They can change.
Ruby warns you when you reinitialize a constant, but not otherwise.
That is,
Constant << “anything”

won’t produce a warning.

You should use something like,
conditions_string = self.sql_for_non_null_coordinates.dup

Thanks for the tip, Kazim! That answers my question perfectly.