WTF default value hash

hash_default.rb

2.0.0p247 :021 > h = Hash.new([])
# => {}
2.0.0p247 :022 > h[:test]
# => []
2.0.0p247 :023 > h[:test] << "h"
# => ["h"]
2.0.0p247 :024 > h
# => {}
2.0.0p247 :025 > h.values
# => []
2.0.0p247 :026 > h.keys
# => []
2.0.0p247 :027 > h[:test]
# => ["h"]
2.0.0p247 :028 > h[:something_else]
# => ["h"]

# So the shoveling of the "h" is modifying the default value (array on line 1) in place.