Ruby Hash Constants are Anything But Constant

constant_troll.rb

irb(main):001:0> I_AM_A_CONSTANT = "I never change"
=> "I never change"
irb(main):002:0> i_am_a_variable = I_AM_A_CONSTANT
=> "I never change"
irb(main):003:0> i_am_a_variable = "I can change"
=> "I can change"
irb(main):004:0> I_AM_A_CONSTANT
=> "I never change"
irb(main):005:0> I_AM_A_CONSTANT_HASH = {contents: "I never change"}
=> {:contents=>"I never change"}
irb(main):006:0> variable_hash = I_AM_A_CONSTANT_HASH
=> {:contents=>"I never change"}
irb(main):007:0> variable_hash[:contents] = "zomg!"
=> "zomg!"
irb(main):008:0> I_AM_A_CONSTANT_HASH
=> {:contents=>"zomg!"}
irb(main):009:0> 

Thanks @caius - I'm aware of the underpinnings and the way references work and my production code is already using #dup and #freeze.

What sucks is that these things are referred to as "constants" by all documentation and examples like this, contrived as they are, serve to show why people in functional languages care so much about immutability.

I love Ruby, but I imagine the thousands of bugs introduced to production codebases by this easily misinterpreted behaviour and my mind boggles. They shouldn't be called constants, they need a different name.