Bug #17181
Updated by sawa (Tsuyoshi Sawada) over 3 years ago
I found a problem with Hashes that use uses a default proc. ```ruby x = Hash.new { |h, k| h[k] = [] } x[:a] << 1 x[:b] << 2 ``` I expected that transforming the values as follows: ```ruby y = x.transform_values { |arr| arr.map(&:next) } ``` should create a new array, and I should still be able to push a new element into it as follows: ```ruby y[:c] << 3 y # => {:a=>[2], :b=>[3], :c=>[3]} ``` But I expected that even after transforming the values I could add a new key, but the result is weird. ```ruby y[:c] # This returns the default_proc Proc object y[:c] << 3 # >> Since it is not the newly created array, it breaks with TypeError (callable object is expected) y[:c] Y[:c].call # => When tried to call the default_proc Proc object Y[:c].call # I found out that the 'h' is nil, meaning that it doesn't have the reference to the hash anymore ``` It should work by just creating the new array on that hey and pushing the new value ```ruby y[:c] << 3 # Now y should be {:a=>[2], :b=>[3], :c=>[3]} ```