Feature #19588
Updated by kyanagi (Kouhei Yanagita) about 2 years ago
`Comparable#clamp(min, max)` (with two arguments) accepts `nil`. This behaves the same as beginless/endless Range.
~~~ruby
5.clamp(nil, 0) # => 0
5.clamp(10, nil) # => 10
5.clamp(..0) # => 0
5.clamp(10..) # => 10
~~~
This behavior is not documented. Presumably, this was not introduced intentionally.
The old Rubies did not accept accept a `Range` argument.
In Ruby 2.7, accepting `Range` as an argument was introduced.
At that time, the approach of passing `nil` as a two-argument method was also discussed but not adopted,
and using Range was chosen instead. https://bugs.ruby-lang.org/issues/14784
However, in Ruby 3.0, the behavior of `clamp` has changed to accept `nil`.
This change is not documented in the NEWS or the documentation for `clamp`,
and I believe that it was not an intentional change.
~~~
% docker run -it --rm rubylang/all-ruby env ALL_RUBY_SINCE=ruby-2.4.0 ./all-ruby -e "p 5.clamp(0, nil)"
ruby-2.4.0 -e:1:in `clamp': comparison of Integer with nil failed (ArgumentError)
from -e:1:in `<main>'
exit 1
...
ruby-2.7.8 -e:1:in `clamp': comparison of Integer with nil failed (ArgumentError)
from -e:1:in `<main>'
exit 1
ruby-3.0.0-preview1 5
...
ruby-3.2.2 5
~~~
It seems that https://github.com/ruby/ruby/commit/a93da4970be44a473b7b42e7516eb2663dece2c3 brought about this change.
How about making the current behavior a specification?
It has been three years since the behavior changed, and I don't see much point in prohibiting `nil` now.
https://github.com/ruby/ruby/pull/7692 updates the documentation.