Questions about Class#remove_class implementation

Ruby
1

I am reading Rails’s Class#remove_class:

def remove_class(*klasses)
klasses.flatten.each do |klass|
# Skip this class if there is nothing bound to this name
next unless defined?(klass.name)

   basename = klass.to_s.split("::").last
   parent = klass.parent

   # Skip this class if it does not match the current one bound

to this name
next unless parent.const_defined?(basename) && klass =
parent.const_get(basename)

   parent.send :remove_const, basename unless parent == klass
 end

end

and have a few questions:

  1. Do you think there’s a reason for using Module#name
    first and Module#to_s afterwards? Looks to me that
    they are only different for singleton classes, and
    for those ones split does not provide a meaningful
    chunk anyway:

    irb(main):002:0> klass = (class << ActiveRecord::Base; self; end)
    => #Class:ActiveRecord::Base
    irb(main):003:0> klass.name
    => “”
    irb(main):004:0> klass.to_s.split("::").last
    => “Base>”

  2. In which situation do you think parent.const_defined?(basename)
    && klass = parent.const_get(basename) could return false?

  3. Does parent.send :remove_const effectively unload the
    class definition from the interpreter? If yes, what
    would happen to some dangling instance afterwards if
    some method of that class was invoked? Would the object
    still hold some kind of relationship to the now non-
    existent class that could result in some fatal error?

  4. When could parent == klass hold at the end of the block?

– fxn

PS: Rails defines Module#parent as

def parent
parent_name = name.split(’::’)[0…-2] * ‘::’
parent_name.empty? ? Object : parent_name.constantize
end