Bug #10997: String in Hash 'prepend', '<<' bug

• Status: Rejected
• Assignee: matz (Yukihiro Matsumoto)
• Target version: -
• ruby -v: ruby 2.2.1p85 (2015-02-26 revision 49769) [x86_64-darwin14]
• Backport: 2.0.0: UNKNOWN, 2.1: UNKNOWN, 2.2: UNKNOWN

[hiphapis (Johan Kim)]

i used with Rails console

Only String is great

original = "a" #=> "a"
clone = original.clone #=> "a"
clone.prepend("prepend_") #=> "prepend_a"
clone #=> "prepend_a"
original #=> "a"

but String in Hash then get some issue

original = { a: "a" } #=> {:a=>"a"}
clone = original.clone #=> {:a=>"a"}
clone[:a].prepend("prepend_") #=> "prepend_a"
clone #=> {:a=>"prepend_a"}
original #=> {:a=>"prepend_a"}

i expect original to {:a=>"a"}
and when you use literal then works

original = { a: "a" } #=> {:a=>"a"}
clone = original.clone #=> {:a=>"a"}
clone[:a] = "prepend_#{clone[:a]}" #=> "prepend_a"
clone #=> {:a=>"prepend_a"}
original #=> {:a=>"a"}

<< has same issue too.

[nobu (Nobuyoshi Nakada)]

• Description updated (diff)
• Status changed from Open to Rejected

Hash#clone does not clone the elements, so the value is shared.
In the last example, you assign different object.