CODEWITHSUNDEEP
ruby
Niels Kristian
Niels Kristian

Reputation: 8825

Why is it possible to change a frozen constant?

Why is it possible to do the following? I would not expect it to be.

CAD={:hey => {a: [1], b: [2]}}.freeze
CAD.frozen?     #=> true 
p=CAD[:hey][:a] #=> [1] 
p << nil        #=> [1, nil] 
CAD             #=> {:hey=>{:a=>[1, nil], :b=>[2]}}

UPDATE

I found a solution, thanks to the answer: http://blog.flavorjon.es/2008/08/freezing-deep-ruby-data-structures.html

Upvotes: 1

Views: 78

Answers (1)

konsolebox
konsolebox

Reputation: 75458

Only the hash object represented by CAD is frozen, but not the other objects referenced on the hash like CAD[:hey][:a].

> CAD={:hey => {a: [1], b: [2]}}.freeze
=> {:hey=>{:a=>[1], :b=>[2]}}
> CAD.frozen?
=> true
> CAD[:hey].frozen?
=> false
> CAD[:hey][:a].frozen?
=> false

Upvotes: 5

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