Issue #21780 has been updated by knu (Akinori MUSHA). The choice of the default is a design decision, with valid arguments for both options. That said, with limited time before release, I'll err on the safe side and prioritize compatibility by reverting to the original default of infinity. ---------------------------------------- Bug #21780: Change the default size of Enumerator.produce back to infinity https://bugs.ruby-lang.org/issues/21780#change-115779 * Author: zverok (Victor Shepelev) * Status: Open * Backport: 3.2: UNKNOWN, 3.3: UNKNOWN, 3.4: UNKNOWN ---------------------------------------- In #21701 a new argument `size:` was introduced, and its default value is `nil` (unknown). While I support the new argument, I'd argue that the default should be `Float::INFINITY`. **Reasoning:** By _design_, `Enumerator.produce` is infinite (there is no internal condition to stop iteration), and the simplest, most straightforward usages of the method would produce _definitely infinite_ iterators, which the user than can limit with `take`, or `take_while` or similar methods. To produce the enumerator that will stop by itself requires explicit raising of `StopIteration`, which I expect to be a (slightly) advanced technique, and those who use it might be more inclined to provide additional arguments to clarify the semantics. While `Enumerator#size` is hardly frequently used now (other than in `#to_set`, which started the discussion), it might be in the future, and I believe it is better to stick with more user-friendly defaults. Now: ```ruby # very trivial enumerator, but if you want it to have "proper" size, you need # to not forget to use an elaborate argument and type additional 21 characters Enumerator.produce(1, size: Float::INFINITY, &:succ) # already non-trivial enumerator, which is hardly frequently used, but the # current defaults correspond to its semantics: Enumerator.produce(Date.today) { raise StopIteration if it.tuesday? && it.day.odd? it + 1 } ``` With my proposal: ```ruby # trivial, most widespread case: Enumerator.produce(1, &:succ).size #=> Infinity # non-trivial case, with the enumerator designer clarifying their # intention that "we are sure it stops somewhere": Enumerator.produce(Date.today, size: nil) { raise StopIteration if it.tuesday? && it.day.odd? it + 1 } ``` -- https://bugs.ruby-lang.org/