Bug #6473: Enumerable#count

• Status: Closed
• Assignee: drbrain (Eric Hodel)
• Target version: -
• ruby -v: ruby 2.0.0dev (2012-05-19 trunk 35705) [x86_64-linux]

[no6v (Nobuhiro IMAI)]

=begin
Enumerable#count には、

Returns the number of items in enum if it responds to a #size call,
otherwise the items are counted through enumeration. If an argument is

というコメントが書いてありますが、実際には

class E
include Enumerable

def each
end

def size
1
end
end

e = E.new
e.size # => 1
e.count # => 0

size は呼ばれていないようです。1.8 系や 1.9.1 の頃は 0 ではなく 1 が返っていたようです。
=end

[no6v (Nobuhiro IMAI)]

• File enum_count.patch enum_count.patch added

最終的に r25603 で size は呼ばなくなったようなので、コメントを修正したパッチを添付します。
改行位置の関係で行数が多いですが、内容は1文目しか変更してません。

[mame (Yusuke Endoh)]

• Status changed from Open to Assigned
• Assignee set to drbrain (Eric Hodel)

Hello, drbrain

This is a doc issue of Enumerable#count.
Could you check and import Nobuhiro's patch?

English translation:

The rdoc of Enumerable#count says:

Returns the number of items in enum if it responds to a #size call,
otherwise the items are counted through enumeration. If an argument is

but actually it behaves as below:

class E
include Enumerable

def each
end

def size
  1
end

end

e = E.new
e.size # => 1
e.count # => 0

As you see, it does not call #size. 1.8 series and 1.9.1 returns 1 instead of 0.

As r25603 seemed to finally decide to stop calling #size, I'm attaching a patch
that changes the rdoc.
The patch just changes the first line, though it looks bigger because of new line.

--
Yusuke Endoh [e-mail]

[drbrain (Eric Hodel)]

• Status changed from Assigned to Closed
• % Done changed from 0 to 100

This issue was solved with changeset r35780.
Nobuhiro, thank you for reporting this issue.
Your contribution to Ruby is greatly appreciated.
May Ruby be with you.

---

• enum.c (enum_count): Enumerable#count no longer uses #size when
  counting elements. Patch by Nobuhiro IMAI. [ruby-trunk - Bug #6473]