deep copy of object

bundler/helpers/v2/lib/functions/lockfile_updater.rb

@@ -191,7 +191,7 @@ def build_definition(dependencies_to_unlock)
       # mutate the unlocked gems array.
       # @gems_to_unlock = {}
       @gems_to_unlock = @unlock.dup
-      unlocked = defn.instance_variable_get(:@unlock).fetch(:gems)
+      unlocked = defn.instance_variable_get(:@gems_to_unlock).fetch(:gems)
       must_not_unlock = defn.dependencies.map { |x| x.name.to_s } -
                         dependencies_to_unlock
       unlocked.reject! { |n| must_not_unlock.include?(n) }