[ruby-core:74369] [Ruby trunk Feature#12092][Feedback] Allow Object#clone to yield cloned object before freezing

Issue #12092 has been updated by Nobuyoshi Nakada.

Description updated
Status changed from Open to Feedback

Why does it need to be a singleton method but can't a method from an included module?


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Feature #12092: Allow Object#clone to yield cloned object before freezing
https://bugs.ruby-lang.org/issues/12092#change-57489

* Author: Jeremy Evans
* Status: Feedback
* Priority: Normal
* Assignee: ruby-core
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This allows creating modified clones of frozen objects that have
singleton classes:

~~~ruby
a = [1,2,3]
def a.fl; first + last; end
a.freeze
a.fl # => 4

clone = a.clone{|c| c << 10}
clone.last # => 10
clone.fl # => 11
clone.frozen? # => true
~~~

Previously, this was not possible at all.  If an object was
frozen, the clone was frozen before the cloned object could
be modified.  It was possible to modify the clone using
`initialize_clone` or `initialize_copy`, but you couldn't change how
to modify the clone on a per-call basis.  You couldn't use `dup`
to return an unfrozen copy, modify it, and then freeze it, because
`dup` doesn't copy singleton classes.

This allows ruby to be used in a functional style with immutable
data structures, while still keeping the advantages of singleton
classes.

---Files--------------------------------
0001-Allow-clone-to-yield-cloned-object-before-freezing.patch (2.51 KB)
0001-Allow-clone-to-take-a-second-argument-passed-to-init.patch (2.37 KB)


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