Bug #18983: Range#size for beginless Range is not nil.

• Status: Closed
• Assignee: -
• Target version: -
• ruby -v: ruby 3.1.2p20 (2022-04-12 revision 4491bb740a) [x86_64-darwin20]
• Backport: 2.7: UNKNOWN, 3.0: UNKNOWN, 3.1: UNKNOWN

[masasakano (Masa Sakano)]

Range#size should, according to Official docs,

Returns the count of elements in self if both begin and end values are numeric; otherwise, returns nil

but it doesn't with beginless non-Numeric Ranges (in Ruby-3.1.2 or earlier).

(..?a).size      # => Infinity
(nil..nil).size  # => Infinity

whereas it certainly does with endless Ranges

(?a..).size      # => nil

[thiagofm (Thiago Massa)]

• File 6378.patch 6378.patch added

[thiagofm (Thiago Massa)]

Nevermind. Build failed.

[jeremyevans0 (Jeremy Evans)]

Returning Infinity for numeric ranges bounded in either direction is expected (there are tests explicitly for it).

It does seem inconsistent that (..object).size returns Infinity and (object..).size returns nil for non-numeric objects. I think returning nil in both cases makes sense.

[mame (Yusuke Endoh)]

• Related to Bug #14699: Subtle behaviors with endless range added

[matz (Yukihiro Matsumoto)]

I agree with inconsistency; if edges were numeric, return the count (or Infinity), otherwise it should return nil.
nil .. nil can be considered as numeric-range both edge omitted, but at the moment I feel it should return nil as well.
Let us experiment how it works.

Matz.

[mame (Yusuke Endoh)]

https://github.com/ruby/ruby/pull/6604

[mame (Yusuke Endoh)]

Oops, I missed the attached patch. Sorry

[mame (Yusuke Endoh)]

• Status changed from Open to Closed

Applied in changeset git|e026368061c56bc925aff58910a4b02f18b78c70.

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Range#size returns nil for (.."a") and (nil..)

Fixes [Bug #18983]