Bug #21124: Enumerable#find called without a block returns Enumerator without size

• Status: Rejected
• Assignee: -
• Target version: -
• ruby -v: 3.4.1
• Backport: 3.1: UNKNOWN, 3.2: UNKNOWN, 3.3: UNKNOWN, 3.4: UNKNOWN

[andrykonchin (Andrew Konchin)]

When a collection's size is known then enumerator that iterates it usually has size (that's #size returns a collection size).

But an enumerator returned by Enumerable#find called without a block doesn't have size:

[1, 2, 3].find.size # => nil

Expected result here is 3.

Usually similar methods in the Enumerable module return enumerators with size (when these enumerators for instance iterate the collection itself):

[1, 2, 3].each_entry.size # => 3

[andrykonchin (Andrew Konchin)]

• Subject changed from Enumerable#find called without block returns Enumerator without size to Enumerable#find called without a block returns Enumerator without size

[mame (Yusuke Endoh)]

I really don't understand what the "size" of the Enumerator returned by find means, but I guess it returns nil, which means "unknown size", because the number of calls depends on the return value of the block.

i = 0; [1, 2, 3].find.each {|x| i += 1; true }; p i #=> 1
i = 0; [1, 2, 3].find.each {|x| i += 1; false }; p i #=> 3

Why did you expect 3?

[nobu (Nobuyoshi Nakada)]

• Status changed from Open to Feedback

[andrykonchin (Andrew Konchin)]

Yes, indeed. You are right. My bad.

I was confused by result of #to_a called on such Enumerator:

[1, 2, 3].find.to_a # => [1, 2, 3]

[mame (Yusuke Endoh)]

• Status changed from Feedback to Rejected

Thanks for your confirmation. Closing.