Issue #12979 has been updated by Kazuhiro NISHIYAMA. Does this feature mention in NEWS file? ---------------------------------------- Feature #12979: Avoid exception for #dup on Integer (and similar cases) https://bugs.ruby-lang.org/issues/12979#change-62099 * Author: Martin Drst * Status: Closed * Priority: Normal * Assignee: Nobuyoshi Nakada * Target version: ---------------------------------------- This is a proposal resulting from a discussion in Bug #11929. Because this is proposing a different solution from #11929, it has a new number. #11929 shows that people are confused that e.g. 3.dup throws an exception (but Integer#dup is actually implemented, so Integer.respond_to? :dup => true). Integer#dup should fail silently, returning the receiver, in the same way as Integer#freeze fails silently. Citing from #11929 (comment by Mike Vastola): "If the object can't be duped/cloned because it's an immediate, dup/clone should return the object itself. (There shouldn't be any harm in doing so since nothing about the object can be changed in the first place.)". Citing some more: > I literally can't imagine any scenario in which a dev, when, say, coding a class with the line: > > return val.dup.freeze > .. really wants an Exception thrown when val happens to be de-facto un-dup-able. What they really want is: > > return val.dup.freeze rescue val The proposal also has the advantage that it leads to a much more unified, streamlined protocol, avoiding needless exposition of internals. It would do exactly what dup (and clone) are described to do, namely (pretend to) return a shallow copy. -- https://bugs.ruby-lang.org/ Unsubscribe: <mailto:ruby-core-request / ruby-lang.org?subject=unsubscribe> <http://lists.ruby-lang.org/cgi-bin/mailman/options/ruby-core>